SIMPLE EPHEMERIS with Tables of Aspect for Astrology Phoenix 2015-2019

We are developing the Mark IV FS software extension modules, which will allow us to control the receiving complex of the radio telescope by special SNAP commands from both operator input and schedule files. We are also developing procedures of automatic measurements of SEFD, system noise temperature and other parameters, available both in VLBI and single-dish modes of operation.

It has proved to be working quite reliably and to show the perfonmance expected. Baseline Interferometry project at JPL. Now, through a magnificent international effort, we will be able to break this barrier and see fine details of celestial objects that are beyond the reach of a purely ground-based telescope array. In the first weeks after launch, scientists and engineers will "test the deployment of the reflecting mesh telescope in orbit, the wide-band data link from the satellite to the ground, the performance of the low noise amplifiers in orbit, and the high-precision orbit determination and attitude control necessary for VLBI observations with an orbiting telescope ," according to Dr.

Joel Smith, manager of the U. Scientific observations are expected to begin in May. The foot diameter orbiting radio telescope will observe celestial radio sources in concert with a number of the world's ground-based radio telescopes. The satellite will go into an elliptical orbit, varying between to 12, miles above the Earth's surface. This orbit provides a wide range of distances between the satellite and ground-based telescopes , which is important for producing a high-quality image of the radio source being observed.

One orbit of the Earth will take about six hours. The satellite's observations will concentrate on some of the most distant and intriguing objects in the. Marking an important new milestone in radio astronomy history, scientists at the National Radio Astronomy Observatory NRAO in Socorro, New Mexico, have made the first images using a radio telescope antenna in space. In Socorro, astronomers and computer scientists used a special-purpose computer to digitally combine the signals from the satellite and the ground telescopes to make them all work together as a single, giant radio telescope.

Ground level enhancements GLEs of cosmic-ray intensity occur, on average, once a year. Because they are rare, studying the solar sources of GLEs is especially important to approach understanding their origin. Deficient observations limited our understanding of it. Analysis of additional observations found for this event provided new results that shed light on the flare configuration and evolution. Taking advantage of its instrumental characteristics, we analyze the detailed SSRT observations of a major long-duration flare at 5. The analysis confirms that the source of GLE63 was associated with an event in active region that comprised two flares.

The first flare Two microwave sources were observed , whose brightness temperatures at 5. The main flare, up to an importance of M7. The observed microwave sources reached a brightness temperature of about MK. They were not static. After appearing on the weaker-field periphery of the active region, the microwave sources moved toward each other nearly along the magnetic neutral line, approaching the stronger-field core of the active region, and then moved away from the neutral line like expanding ribbons.

These motions rule out an association of the non-thermal microwave sources with a single flaring loop. Astronomy is inherently fascinating to students but dark skies and good weather are not often scheduled during the school day. Radio telescopes provide an all-weather, all-day opportunity for astronomical observations. These telescopes are relatively affordable and are designed to be remotely operated through a Windows, Linux, or Macintosh environment.

A comprehensive website of projects suitable for high-school students and undergraduates is maintained by a group at MIT. Radio telescopes also provide a slight engineering flavor drawing in students who might not otherwise be interested in astronomy. This poster will provide a summary of installation, calibration, and future plans, and will share some observations by undergraduates at CSU. Observing with Sibling and Twin Telescopes. With the transition to VGOS, co-located radio telescopes will be common at many sites.

This can be as a sibling telescope when a VGOS antenna is built next to a legacy one, or as the concept of a twin telescope with two identical VGOS antennas. The co-location of two antennas offers new possibilities in both operation and analysis. In this contribution we report about our efforts implementing new scheduling modes for sibling and twin telescopes in the Vienna VLBI Software. For the example of the sibling telescope in Hobart, several types of sessions will be discussed: Lazio, Joseph; Bowman, Judd D. Observations with radio telescopes address key problems in cosmology, astrobiology, heliophysics, and planetary science including the first light in the Universe Cosmic Dawn , magnetic fields of extrasolar planets, particle acceleration mechanisms, and the lunar ionosphere.

The Moon is a unique science platform because it allows access to radio frequencies that do not penetrate the Earth's ionosphere and because its far side is shielded from intense terrestrial emissions. The instrument packages and infrastructure needed for radio telescopes can be transported and deployed as part of Exploration activities, and the resulting science measurements may inform Exploration e. An illustrative roadmap for the staged deployment of lunar radio telescopes.

Detecting axion stars with radio telescopes. When axion stars fly through an astrophysical magnetic background, the axion-to-photon conversion may generate a large electromagnetic radiation power. After including the interference effects of the spacially-extended axion-star source and the macroscopic medium effects, we estimate the radiation power when an axion star meets a neutron star. For axion stars occupy a large fraction of dark matter energy density, this encounter event with a transient O 0. Phase-retrieval is a general term used in optics to describe the estimation of optical imperfections or "aberrations.

Earlier techniques do not approximate the incoherent subtraction process as a coherent propagation. This approximation reduces the noise in the data and allows a straightforward application of conventional phase retrieval techniques for radio telescope and antenna control. The application of iterative-transform phase retrieval to radio telescope and antenna control is made by approximating the incoherent subtraction process as a coherent propagation. Thus, for systems utilizing both positive and negative polarity feeds, this approximation allows both surface and alignment errors to be assessed without the use of additional hardware or laser metrology.

Knowledge of the antenna surface profile allows errors to be corrected at a given surface temperature and observing angle. In addition to imperfections of the antenna surface figure, the misalignment of multiple antennas operating in unison can reduce or degrade the signal-to-noise ratio of the received or broadcast signals.

This technique also has application to the alignment of antenna array configurations. Finally in , the whole communications station with a meters parabolic antenna was donated to the Geophysical Institute of Peru.

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Many things have happened since that, but finally we are almost ready to have a radio telescope. National Astronomical Observatory of Japan contributed enormously to set up the radio telescope. Initially as a single dish radio telescope , it will observe methanol maser at 6. In the near future, equipping for VLBI observations is in the scope. Sicaya is situated on the central part of Peru at 3, meters of altitude and the weather is benign for radio astronomical observations , also humidity is low and allows have radio telescopes free of rust.

This paper describes the techniques used to analyse and calibrate the data, and presents the data base of results along with a representative sample of the better-sampled light curves. April to June A re-analysis of previously published data from to is also presented. The combined catalogue, comprising flux density measurements, provides a unique and valuable resource for studies of extragalactic radio sources.

Next generation radio telescopes , transients and cognitive computing. Thus far, both targeted and wide-area surveys have yet to detect artificial signals from intelligent civilisations. In this paper, I argue that the incidence of co-existing intelligent and communicating civilisations is probably small in the Milky Way. While this makes successful SETI searches a very difficult pursuit indeed, the huge impact of even a single detection requires us to continue the search.

A substantial increase in the overall performance of radio telescopes and in particular future wide-field instruments such as the Square Kilometre Array - SKA , provide renewed optimism in the field. Evidence for this is already to be seen in the success of SETI researchers in acquiring observations on some of the world's most sensitive radio telescope facilities via open, peer-reviewed processes. The increasing interest in the dynamic radio sky, and our ability to detect new and rapid transient phenomena such as Fast Radio Bursts FRB is also greatly encouraging.

While the nature of FRBs is not yet fully understood, I argue they are unlikely to be the signature of distant extra-terrestrial civilisations. As astronomers face a data avalanche on all sides, advances made in related areas such as advanced Big Data analytics, and cognitive computing are crucial to enable serendipitous discoveries to be made. Byrd Green Bank Telescope GBT have detected remarkably faint radio signals from an year-old pulsar, making it the youngest radio -emitting pulsar known.

This discovery pushes the boundaries of radio telescope sensitivity for discovering pulsars, and will enable scientists to conduct observations that could lead to a better understanding of how these stars evolve. Byrd Green Bank Telescope "Important questions about pulsars may be answered by long-term monitoring of objects such as the one we just detected," said Fernando Camilo of Columbia University in New York City. Scientists have long suspected that a pulsar - a rapidly spinning, superdense neutron star - was born when a giant star ended its life in a cataclysmic supernova explosion observed in late summer of , as suggested by Japanese and Chinese historical records.

For the past 20 years, astronomers have searched this supernova remnant 3C58 , located 10, light-years away in the constellation Cassiopeia, for the telltale pulsations of a newly born pulsar. Late in , data from NASA's Chandra X-ray satellite confirmed its existence, but it remained an elusive quarry for radio telescopes.

Workshop on Mars Telescopic Observations. The first goal was to facilitate discussions among and between amateur and professional observers and to create a workshop environment fostering collaborations and comparisons within the Mars observing community. The second goal was to explore the role of continuing telescopic observations of Mars in the upcoming era of increased spacecraft exploration.

The 24 papers presented at the workshop described the current NASA plans for Mars exploration over the next decade, current and recent Mars research being performed by professional astronomers, and current and past Mars observations being performed by amateur observers and observing associations. The workshop was divided into short topical sessions concentrating on programmatic overviews, groundbased support of upcoming spacecraft experiments, atmospheric observations , surface observations , modeling and numerical studies, and contributions from amateur astronomers.

The study of the sun in the radio portion of the electromagnetic spectrum furthers our understanding of fundamental solar processes observed in the X-ray, UV, and visible regions of the spectrum. For example, the study of solar radio bursts, which have been shown to cause serious disruptions of technologies at Earth, are essential for advancing our knowledge and understanding of solar flares and their relationship to coronal mass ejections and solar energetic particles, as well as the underlying particle acceleration mechanisms associated with these processes.

In addition, radio coverage of the solar atmosphere could yield completely new insights into the variations of output solar energy, including Alfven wave propagation through the solar atmosphere and into the solar wind, which can potentially modulate and disturb the solar wind and Earth's geospace environment. In this presentation we discuss the development, construction, and testing of the South Pole, Antarctica, Solar Radio Telescope that is planned for installation at South Pole.

The system will allow for hour continuous, long-term observations of the sun across the GHz frequency band and allow for truly continuous solar observations. We show that this system will enable unique scientific investigations of the solar atmosphere. The improvement of the short-wavelength performance of the Jodrell Bank Mk II radio telescope is described. A final rms profile error of 0. Some further improvements to extend the short wavelength performance are suggested.

The primary reflector of the Tianma Radio Telescope TMRT distorts due to gravity, which dramatically reduces the aperture efficiency of high-frequency observations. A technique known as outof-focus holography OOF has been developed to measure gravitational deformation. A new calculation method is developed to calculate the extra phase and illumination. A new measurement strategy is proposed that uses only one feed, reduces the length of the scan pattern, and allows the telescope to scan smoothly at low speed.

We have acquired a model for the gravitational deformation of the TMRT. The e-OOF technique reduces the constraints on the telescopes. A radio telescope for the calibration of radio sources at 32 gigahertz. The main goal of the design and development was to provide a system that could yield the greatest absolute accuracy yet possible with such a system. The accuracy of the measurements have a heritage that is traceable to the National Institute of Standards and Technology. At the present time, the absolute accuracy of flux density measurements provided by this telescope system, during Venus observations at nearly closest approach to Earth, is plus or minus 5 percent, with an associated precision of plus or minus 2 percent.

Combining a cooled high-electron mobility transistor low-noise amplifier, twin-beam Dicke switching antenna, and accurate positioning system resulted in a state-of-the-art system at 32 GHz. This article describes the design and performance of the system as it was delivered to the Owens Valley Radio Observatory to support direct calibrations of the strongest radio sources at Ka-band.

Twenty-eight oral presentations were made and generous time allotted for useful discussions among participants. The goals of the workshop were to 1 summarize active groundbased observing programs and evaluate them in the context of current and future space missions to Mars, 2 discuss new technologies and instrumentation in the context of changing emphasis of observations and theory useful for groundbased observing , and 3 more fully understand capabilities of current and planned Mars missions to better judge which groundbased observations are and will continue to be of importance to our overall Mars program.

In addition, the exciting new discoveries presented from the Pathfinder experiments and the progress report from the Mars Global Surveyor infused the participants with satisfaction for the successes achieved in the early stages of these missions. Just as exciting was the enthusiasm for new groundbased programs designed to address new challenges resulting from mission science results. David Black, director of the Lunar and Planetary Institute, and the staff of the Institute's Publications and Program Services Department for providing logistical, administrative, and publication support services for this workshop.

Flux density variations observed for the first time at radio wavelengths are consistent with the typical optical patterns measured when partial occultations occurred. The flux density drops indicate a non-linear dependence with the percentage of overlapped area. Astronomers have discovered the strongest evidence yet found indicating that matter is being ejected by a medium-sized black hole, providing valuable insight on a process that may have been key to the development of larger black holes in the early Universe.

Black holes are concentrations of matter so dense that not even light can escape their powerful gravitational pull. The black hole in NGC is about , times more massive than the Sun. This puts it in a rarely-seen intermediate range between the supermassive black holes at the cores of many galaxies, which have masses millions to billions of times that of the Sun, and stellar-mass black holes only a few times more massive than the Sun.

Energetic outflows of matter are common to both the supermassive and the stellar-mass black holes, but the new radio observations of NGC provided the first direct image of such a suspected outflow from an intermediate-mass black hole. The outflows presumably are generated by little. FPGA applications for single dish activity at Medicina radio telescopes. FPGA technologies are gaining major attention in the recent years in the field of radio astronomy. At Medicina radio telescopes , FPGAs have been used in the last ten years for a number of purposes and in this article we will take into exam the applications developed and installed for the Medicina Single Dish 32m Antenna: In this paper, we report on the project, its current status, the key science goals, and plans for early science.

The Sardinia Radio Telescope SRT is a new major radio astronomical facility available in Italy for single dish and interferometric observations.

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The SRT combines a 64m steerable collecting area, one of the largest all over the World with state-of-the-art technology including an active surface to enable high efficiency observations up to the 3-mm band. Observations performed at offset positions suggest that the source of H2CO might be distributed. The H2CO abundance is on the order of 0. During the May observing period of comet Austin, two new species were detected for the first time in a comet: Preliminary estimates of their abundances are 1. Hosmer, Laura; Langston, G.

We present the web interface and astronomy projects that allow students and astronomers from all over the country to become Radio Astronomers. The 20 meter radio telescope at NRAO in Green Bank, WV is dedicated to public education and also is part of an experiment in public funding for astronomy. The telescope has a fantastic new web-based interface, with priority queuing, accommodating priority for paying customers and enabling free use of otherwise unused time. This revival included many software and hardware improvements including automatic calibration and improved time integration resulting in improved data processing, and a new ultra high resolution spectrometer.

This new spectrometer is optimized for very narrow spectral lines, which will allow astronomers to study complex molecules and very cold regions of space in remarkable detail. In accordance with focusing on broader impacts, many public outreach and high school education activities have been completed with many confirmed future activities. The 20 meter is now a fully automated, powerful tool capable of professional grade results available to anyone in the world.

Drop by our poster and try out real-time telescope control! Thermal behavior of the Medicina meter radio telescope. The preliminary results show that thermal gradients deteriorate the pointing performance of the antenna. Data has been collected by using: Two series of measurements were made, the first series was performed by placing the antenna in stow position, the second series was performed while tracking a circumpolar astronomical source. When the antenna was in stow position we observed a strong correlation between the inclinometer measurements and the differential temperature.

The latter was measured with the sensors located on the South and North sides of the alidade, thus indicating that the inclinometers track well the thermal deformation of the alidade. When the antenna pointed at the source we measured: The pointing errors measured on-source were arcsec greater than those measured with the inclinometer. High-precision pointing with the Sardinia Radio Telescope. We present here the systems aimed to measure and minimize the pointing errors for the Sardinia Radio Telescope: We show here the results of the tests that we have done on the Medicina 32 meters VLBI radio telescope.

These measurements show that we can obtain the needed accuracy to correct also the non repeatable pointing errors, which arise on time scale varying from seconds to minutes. Having the sharpest pictures always is a big advantage, and a sophisticated radio -astronomy technique using continent-wide and even intercontinental arrays of telescopes is yielding extremely valuable scientific results in a wide range of specialties.

That's the message delivered to the American Astronomical Society's meeting in Austin, Texas, by Mark Reid of the Harvard-Smithsonian Center for Astrophysics, a leading researcher in the field of ultra-precise astronomical position measurements. Very Long Baseline Interferometry provides extremely high precision that can extend use of the parallax technique to many more celestial objects.

That's helping us better understand many processes ranging from star formation to the scale of the entire Universe," Reid said. The observing technique, called Very Long Baseline Interferometry VLBI , was pioneered in , but has come into continuous use only in the past years. There are other VLBI systems in Europe and Asia, and large radio telescopes around the world cooperate regularly to increase sensitivity. VLBI observations routinely produce images hundreds of times more detailed than those made at visible-light wavelengths by the Hubble Space Telescope.

Several groups of researchers from across the globe use the VLBA to study stellar nurseries in our own Milky Way Galaxy and measure distances to regions where new stars are forming. The key has been to improve measurement accuracy to a factor of a hundred times better than that produced by the. Radio astronomy is important in the branch of the Astronomy that studies the celestial bodies through their emissions in the domain of the radio waves, to obtain information of these bodies, astronomers must design new types of telescopes that can capture radiation at different wavelengths, including radio telescopes.

This paper presents the construction of a prototype of an educational radio telescope , which is made using materials that are easily accessible and inexpensive. The issues that are addressed in the construction of this instrument, its use and the analysis of the data, are very varied and with a high content of multidiciplinariety, gathering basic topics in areas such as astrophysics, physics, electronics, computing, mechanics, which are necessary for Concrete the efficient use of this instrument. Alberto Quijano Vodniza and Dr. In addition to the construction of radiotelescope the final phase consists of the storage and analysis of data obtained with the observation of some celestial bodies that comply with The range in the 12 GHz band for study.

Laboratory will get the relayed information," Ghigo added. In Socorro, scientists will collect signals from Phoenix with antennas of the continent-wide Very Long Baseline Array VLBA , which produces the sharpest images of any astronomical instrument in existence. They will use the VLBA's ability to mark the position of objects in the sky with pinpoint precision to reconstruct the craft's location relative to other spacecraft at Mars to within about feet, despite its great distance from Earth.

This capability may be used to improve the navigational accuracy of future interplanetary missions. NRAO telescopes have contributed to the success of several previous space missions. The combined collecting area of the 27 VLA antennas and their sensitive receivers made possible a higher data-transmission rate from the spacecraft, thus enabling scientists to obtain more images of Neptune, its rings, and its moons. In , the VLA captured signals from the Galileo spaccraft's probe as the probe dived into the giant planet Jupiter's atmosphere.

Like Phoenix, the Galileo probe was designed to send its information to the main spacecraft, which would then relay the signal to Earth. However, the VLA's direct reception of the probe's signal measured the Doppler shift in the signal's frequency and made measurements of Jovian wind speeds 10 times more accurate than they otherwise would have been. The Doppler measurements of wind speeds made by NRAO and other radio telescopes provided the only wind data from the mission, because of a malfunction in communication.

When the European Space Agency's Huygens spacecraft makes its plunge into the atmosphere of Saturn's moon Titan on January 14, radio telescopes of the National Science Foundation's National Radio Astronomy Observatory NRAO will help international teams of scientists extract the maximum possible amount of irreplaceable information from an experiment unique in human history.

Huygens is the pound probe that has accompanied the larger Cassini spacecraft on a mission to thoroughly explore Saturn, its rings and its numerous moons. Along with other radio telescopes in Australia, Japan, and China, the NRAO facilities will add significantly to the information about Titan and its atmosphere that will be gained from the Huygens mission. A European-led team will use the radio telescopes to make extremely precise measurements of the probe's position during its descent, while a U. The radio-telescope measurements will provide data vital to gaining a full understanding of the winds that Huygens encounters in Titan's atmosphere.

Currently, scientists know little about Titan's winds. Data from the Voyager I spacecraft's flyby indicated that east-west winds may reach mph or more. North-south winds and possible vertical winds, while probably much weaker, may still be significant. There are competing theoretical models of Titan's winds, and the overall picture is best summarized as. The main function of the radio telescope control software is to drive the radio telescope to track the target accurately.

The functions of the software, communication mode and the user interface is introduced in this article. In what some scientists termed "a surprising, almost miraculous turnabout," radio telescopes , including major facilities of the National Science Foundation's National Radio Astronomy Observatory NRAO , have provided data needed to measure the winds encountered by the Huygens spacecraft as it descended through the atmosphere of Saturn's moon Titan last month -- measurements feared lost because of a communication error between Huygens and its "mother ship" Cassini.

Measurements of the frequency shift caused by the craft's motion, called Doppler shift, are giving planetary scientists their first direct information about Titan's winds. Now, with the ground-based telescopes providing the only information about Titan's winds, we are extremely proud that our facilities are making such a key contribution to our understanding of this fascinating planetary body," said Dr.

Early analysis of the radio-telescope data shows that Titan's wind flows from west to east, in the direction of the moon's rotation, at all altitudes. The highest wind speed, nearly mph, was measured at an altitude of about 75 miles. Winds are weak near Titan's surface and increase in speed slowly up to an altitude of about 37 miles, where the spacecraft encountered highly-variable winds that scientists think indicate a region of vertical wind shear. In the course of astronomical observations , with changes in angle of pitch, the large radio telescope will have different degrees of deformation in the sub-reflector support, back frame, main reflector etc, which will lead to the dramatic decline of antenna efficiency in both high and low elevation.

A sub-reflector system of the Tian Ma 65 m radio telescope has been installed in order to compensate for the gravitational deformations of the sub-reflector support and the main reflector. The position and attitude of the sub-reflector are variable in order to improve the pointing performance and the efficiency at different elevations. In this paper, it is studied that the changes of position and attitude of the sub-reflector have influence on the efficiency of antenna in the X band and Ku band.

A model has been constructed to determine the position and attitude of the sub-reflector with elevation, as well as the point compensation model, by observing the radio source. In addition, antenna efficiency was tested with sub-reflector position adjusted and fixed. The results show that the model of sub-reflector can effectively improve the efficiency of the 65 m radio telescope. The microwave holography system for the Sardinia Radio Telescope. Microwave holography is a well-established technique for mapping surface errors of large reflector antennas, particularly those designed to operate at high frequencies.

We present here a holography system based on the interferometric method for mapping the primary reflector surface of the Sardinia Radio Telescope SRT. SRT is a new m-diameter antenna located in Sardinia, Italy, equipped with an active surface and designed to operate up to GHz. The system consists mainly of two radio frequency low-noise coherent channels, designed to receive Ku-band digital TV signals from geostationary satellites. Two commercial prime focus low-noise block converters are installed on the radio telescope under test and on a small reference antenna, respectively. Then the signals are amplified, filtered and downconverted to baseband.

An innovative digital back-end based on FPGA technology has been implemented to digitize two 5 MHz-band signals and calculate their cross-correlation in real-time. This is carried out by using a bit resolution ADCs and a FPGA reaching very large amplitude dynamic range and reducing post-processing time.

The system was successfully tested during several holography measurement campaigns, recently performed at the Medicina m radio telescope. Two by maps, using an on-the-fly raster scan with on-source phase calibration, were performed pointing the radio telescope at 38 degrees elevation towards EUTELSAT 7A satellite. Very long baseline interferometry using a radio telescope in Earth orbit. The purpose of this experiment and the characteristics of the spacecraft that are related to the VLBI observations are described. The technical obstacles to maintaining phase coherence between the orbiting antenna and the ground stations, as well as the calibration schemes for the communication link between TDRSE and its ground station at White Sands, New Mexico are explored.

System coherence results and scientific results for the radio source observations are presented. The majority of pulsars' rotational energy is carried away by relativistic winds, which are energetic particles accelerated in the magnetosphere. The confinement of the winds by the ambient medium result in synchrotron bubbles with broad-band emission, which are commonly referred to as pulsar wind nebulae PWNe.

Due to long synchrotron cooling time, a radio PWN reflects the integrated history of the system, complementing information obtained from the X-ray and higher energy bands. In addition, radio polarization measurements can offer a powerful probe of the PWN magnetic field structure. Altogether these can reveal the physical conditions and evolutionary history of a system. I report on preliminary results from high-resolution radio observations of PWNe associated with G Their magnetic field structure and multiwavelength comparison with other observations are discussed.

The history of radio telescopes , Forged by the development of radar during World War II, radio astronomy revolutionized astronomy during the decade after the war. A new universe was revealed, centered not on stars and planets, but on the gas between the stars, on explosive sources of unprecedented luminosity, and on hundreds of mysterious discrete sources with no optical identifications. This paper traces the history of radio telescopes from through about , from the era of converted small-sized, military radar antennas to that of large interferometric arrays connected by complex electronics and computers; from the era of strip-chart recordings measured by rulers to powerful computers and display graphics; from the era of individuals and small groups building their own equipment to that of Big Science, large collaborations and national observatories.

An existing structure that is earmarked for this project, is a 32 m diameter antenna located in Ghana that has become obsolete due to advances in telecommunication. The first phase of the conversion of this Ghana antenna into a radio astronomy telescope is to upgrade the antenna to observe at 5 GHz to 6. The surface and pointing accuracies for a radio telescope are much more stringent than that of a telecommunication antenna. The mechanical pointing accuracy of such telescopes is influenced by factors such as mechanical alignment, structural deformation, and servo drive train errors.

The current research investigates the numerical simulation of the surface and pointing accuracies of the Ghana 32 m diameter radio astronomy telescope due to its structural deformation mainly influenced by gravity, wind and thermal loads. The Sardinia Radio Telescope. From a technological project to a radio observatory. Its active surface, comprised of separate aluminium panels supported by electromechanical actuators, will allow us to observe at frequencies of up to GHz. At the moment, three receivers, one per focal position, have been installed and tested: The SRT was officially opened in September , upon completion of its technical commissioning phase.

In this paper, we provide an overview of the main science drivers for the SRT, describe the main outcomes from the scientific commissioning of the telescope , and discuss a set of observations demonstrating the scientific capabilities of the SRT. As a result, the overall telescope performance has been significantly improved. As part of the scientific commissioning activities, different observing modes were tested and validated, and the first astronomical observations were carried out to demonstrate the science capabilities of the SRT.

In addition, we developed astronomer-oriented software tools to support future observers on site. In the following, we refer to the overall scientific commissioning and software development activities as astronomical validation. The astronomical validation activities were prioritized based on technical readiness and scientific impact. The highest priority was to make the SRT available for joint observations as. Control of active reflector system for radio telescope. According to the control requirements of the active reflector surface in the m radio telescope at QiTai QTT Xinjiang, a new displacement actuator and a new displacement control system were designed and manufactured and then their characteristics were tested by a dual-frequency laser interferometer in the micro-displacement laboratory.

The displacement actuator was designed by a scheme of high precision worm and roller screw structures, and the displacement control system was based on a ARM micro-processor. Finally, the S curve acceleration control methods were used to design the hardware platform and software algorithm for the active reflection surface of the control system. The test experiments were performed based on the laser metrology system on an active reflector close-loop antenna prototype for large radio telescope.

The accuracy standard deviation is 3. Furthermore, the active reflector integrated system was tested by the laser sensors with the accuracy of 0. The antenna, identified as DSS, is a meter diameter dish, 11 times the diameter of a ten foot microwave dish used for satellite television. Five-hundred-meter Aperture Spherical radio Telescope FAST is a Chinese mega-science project to build the largest single dish radio telescope in the world.



Its innovative engineering concept and design pave a new road to realize a huge single dish in the most effective way. Being the most sensitive single dish radio telescope , FAST will enable astronomers to jump-start many science goals, such as surveying the neutral hydrogen in the Milky Way and other galaxies, detecting faint pulsars, looking for the first shining stars, hearing the possible signals from other civilizations, etc.

The idea of sitting a large spherical dish in a karst depression is rooted in Arecibo telescope. FAST is an Arecibo-type antenna with three outstanding aspects: The feasibility studies for FAST have been carried out for 14 years, supported by Chinese and world astronomical communities. The project time is 5. This review intends to introduce the project of FAST with emphasis on the recent progress since In this paper, the subsystems of FAST are described in modest details followed by discussions of the fundamental science goals and examples of early science projects.

System performance testing of the DVA1 radio telescope. It has a feed-high offset Gregorian optical design with a primary effective diameter of 15 m. DVA1 has been undergoing mechanical and astronomical system tests since The clean shaped optics, careful attention to feed design, and high sensitivity of the L band receiver Trx 6 K yield a system with high aperture efficiency 0. Observations of 21 cm atomic hydrogen lines towards standard sources demonstrate the low stray radiation pickup of the antenna.

Ku band holography has measured the effective surface accuracy and stability of the dual-reflector antenna. The effective RMS of 0. Our study of the Sun, an object that provides life to this planet but also is a serious threat to the existence we now enjoy, is frequently limited in hands-on activities by the unavailability of the necessary observational tools.

While small optical telescopes are more easily obtained, telescopes that work the other regions of the electromagnetic spectrum, such as the radio frequencies, are unusual. Radio emissions from solar storms, however, can be "viewed" by a student constructing a simple, tunable and inexpensive radio telescope designed to receive the most common radio frequencies broadcast from the Sun during such a storm.

The apparatus employs normally available materials and technology in new purposes. Utilizing this telescope , students have the ability to test and modify its design for changes in frequency and signal amplitude, and therefore examine a wide spectrum of radio emission emanating from our star. This engaging introduction to radio electronics not only involves the study of the electrical circuit involved, but also sets the student up for detailed study in the form of specific research projects focusing on solar activity in the radio wavelengths.

So far, my students have been actively involved in varying the electrical properties of a simple one-transistor circuit that selects the observational frequencies of the solar radio telescope they have constructed. Student research projects also have examined antenna design in terms of directionality and signal strength gain.

In the future, collaboration is possible to link student observers in different locations on this planet, allowing for significant peer evaluation and cooperation. NASA's "Project Jove", a program that Sonoma Valley High School and Robert Ferguson Observatory have been connected with since about the year , already has a worldwide collaboration network in place for similar student-operated radio telescopes for primarily studying Jupiter. Because of the higher frequencies with. Radio Observations of Organics in Comets.

A major observational challenge in cometary science is to quantify the extent to which chemical compounds can be linked to either interstellar or nebular chemistry. Recently, there have been complimentary observations from multiple facilities to try to unravel the chemical complexity of comets and their origins. Incorporating results from various techniques can gain further insight into the abundances, production rates, distributions, and formation mechanisms of molecules in these objects [I].

Such studies have provided great detail towards molecules with a-typical chemistries, such as H2CO [2]. Multiple parent volatiles e. We will present a comparison of molecular abundances in these comets to those observed in others, supporting a long-term effort of building a comet taxonomy based on composition. Previous work has revealed a range of abundances of parent species from "organics-poor" to "organics-rich" with respect to water among comets [3,4,5], however the statistics are not well constrained. Remote observing capability with Subaru Telescope.

Subaru telescope has three observing -sites, i. Our remote observing system is designed to allow operations not only from one of three observing -sites, but also from more than two sites concurrently or simultaneously. Considering allowance for delay in observing operations and a bandwidth of the network between the telescope -site and the remote observing -sites, three types of interfaces protocols have been implemented. In the remote observing mode, we use socket interface for the command and the status communication, vnc for ready-made applications and pop-up windows, and ftp for the actual data transfer.

All images taken at the telescope -site are transferred to both of two remote observing -sites immediately after the acquisition to enable the observers ' evaluation of the data. We present the current status of remote observations with Subaru telescope. SN eaw is a rare type IIP that did not show prompt radio emission after initial explosion.

We will present our analysis of the current data and discuss the implications for the pre-explosion evolution of the progenitor star of SN eaw. Ideas for future large single dish radio telescopes. The existing large single dish radio telescopes of the m class Effelsberg, Green Bank were built in the s and s.

With some active optics they work now down to 3 millimeter wavelength where the atmospheric quality of the site is also a limiting factor. They use advanced technologies as carbon fiber structures and flexible body control. We review natural limits to telescope design and use the examples of a number of telescopes for an overview of the available state-of-the-art in design, engineering and technologies. Without considering the scientific justification we then offer suggestions to realize ultimate performance of huge single dish telescopes up to m. We provide an outlook on design options, technological frontiers and cost estimates.

Spectra of both comets were obtained at and MHz 18cm wavelength with a beam resolution of 7. In spite of their close approaches to Earth, we only detected OH spectral lines with the telescope beam centered on the nucleus of the comets, so we are unable to make a direct constraint on collisional quenching, but using estimated quenching, we can obtain estimates for gas production rates. Spectral line widths and derived gas outflow velocities are low compared to other comets at these heliocentric distances, particularly for HMP, with best-fit water outflow velocities of 0.

Best-fit velocities for TGK in mid-March, averaged 0. We will present gas outflow velocities for each detection and gas production rates or upper limits, as derived from best fits of Monte Carlo simulations. This paper describes several attempts to utilize various radio telescopes in a manner that we term "parasitic," that is in a manner that does not interrupt or seriously impact the standard astronomical observing programs in progress at the radio observatories.

In the extreme case, only recorded astronomical data are accessed off-line, after the fact, without any burden on the observatory at all. This paper describes several attempts to utilize various radio telescopes in a manner that is termed 'parasitic', that is in a manner that does not interrupt or seriously impact the standard astronomical observing programs in progress at the radio observatories. The Molongo Radio Telescope , a large cylindrical paraboloid interferometer located near Canberra in Australia, has been redeveloped with a digital receiver system and optic fibre transmission network leading to a hybrid signal processor incorporating a GPU supercomputer and programmable-logic chip based filterbanks.

The new configuration is 10 times more efficient than the previous system with substantially increased sensitivity and bandwidth centred on MHz and a field of view of about 8 square degrees. The mechanical infrastructure has been retained; hence the angular resolution remains at 43 arcsec. The key science goals of the new instrument include increasing the Fast Radio Burst discovery rate by an order of magnitude or more over our long term rate with the Parkes Telescope , pulsar timing and commensal imaging of diffuse radio sources. Novel methods of RFI excision have been demonstrated.

The talk will present the elements of the new system and some recent science results. New infrared telescopic observation of Vesta. We were able to obtain 5 different observations in 5 day, at two different epochs. The obtained spectra do not exhibit Reststrahlen bands and show only weak features attributable to the Christiansen peak and to the transparency feature compatible with a fine grain size regolith. Astronomical studies of celestial sources at low radio frequencies 0. In a companion paper [Basart et al. For relatively little cost for a space mission, great strides can be made in deploying arrays of antennas and receivers in space that would produce data contributing significantly to our understanding of galaxies and galactic nebulae.

In this paper we discuss an evolutionary sequence of telescopes , antenna systems, receivers, and u,v plane coverage. The telescopes are space-based because of the disruptive aspects of the Earth's ionosphere on low-frequency celestial signals traveling to the Earth's surface. The evolutionary sequence of telescopes starts with an Earth-orbiting spectrometer to measure the low-frequency radio environment in space, proceeds to a two-element interferometer, then to an orbiting array, and ends with a telescope on the lunar farside.

The sequence is in the order of increasing capability which is also the order of increasing complexity and cost. All the missions can be accomplished with current technology. We report on a search for the presence of signals from extraterrestrial intelligence in the direction of the star system KIC No narrowband radio signals were found at a level of Jy in a 1 Hz channel, or medium band signals above 10 Jy in a kHz channel.

Foundation design for a radio telescope on the moon. A foundation design for a m diameter dish-type radio telescope on the moon is presented. An axisymmetrical finite element code of the uppdated Lagrangian formulation was used. Interface slip elements were also used. The nonlinear hyperbolic stress-strain model parameters for the regolith were derived from load-deflection characteristics of astronauts' bootprints and the Rover tracks.

Design and Performance of a Wideband Radio Telescope. This educational program currently uses a meter antenna, DSS12, at Goldstone for classroom radio astronomy observations via the Internet. The current program utilizes DSS12 in two narrow frequency bands around S-band 2. The DSS28 antenna has a meter diameter main reflector, a 2. The antenna was designed for high power and a narrow frequency band around 7. The performance at the low end of the frequency band desired for the educational program would be extremely poor if the beam waveguide system was used as part of the feed system.

Consequently, the meter antenna was retrofitted with a tertiary offset mirror placed at the vertex of the main reflector. The tertiary mirror can be rotated to use two wideband feeds that cover the 0. By using both a wideband feed and wideband amplifiers, the entire band from 0. VGOS is a challenge for all fields of a new radio telescope. For the future software and hardware control mechanisms, it also requires new developments and solutions. More experiments, more data, high-speed data transfers through the Internet, and a real-time monitoring of current system status information must be handled.

Additionally, an optimization of the observation shifts is required to reduce work load and costs. Within the framework of the development of the new A basic infrastructure should enable these, e. Solar polar orbit radio telescope for space weather forecast. Radio emission from density plasma can be detected at low radio frequencies. An image of such plasma clouds of the entire inner interplanetary space is always a wanted input for space weather forecast and ICME propagation studies.

To take such an image within the ecliptic plane may not fully explore what is happening around the Sun not only because of the blockage of the Sun, also because most of the ICMEs are propagating in the low-latitude of the Sun, near the ecliptic plane. It is then proposed to launch a solar polar orbit radio telescope to acquire high density plasma cloud images from the entire inner interplanetary space.

Low radio frequency images require a large antenna aperture in space. It is, therefore, proposed to use the existing passive synthetic aperture radiometer technology to reduce mass and complicity of the deployment system of the big antenna. In order to reduce the mass of the antenna by using minimum number of elements, a zero redundant antenna element design can be used with a rotating time-shared sampling system.

A preliminary assessment study shows the mission is feasible. A multipath mechanism similar to that used in Australia sixty years ago by the Sea-cliff Interferometer is shown to generate correlations between the periods of oscillations observed by two distant radio telescopes pointed to the Sun. The oscillations are the result of interferences between the direct wave detected in the main antenna lobe and its reflection on ground detected in a side lobe. The Web address is: This data base is made possible thanks to the help of R. Williams MPC who sends the observations of the faint outer satellites of the giant planets gathered as asteroidal observations and D.

Pascu who made efforts to complete the reduction of his data. Astrometric observations of visual binaries using inch refractor during at Pulkovo. We present the results of astrometric observations of visual binaries carried out in at Pulkovo observatory. Telescope automation and weather monitoring system installation allowed us to increase the number of observations significantly. Visual binary and multiple systems with an angular distance in the interval 1. The results were studied in detail for systematic errors using calibration star pairs.

There was no detected dependence of errors on temperature, pressure, and hour angle. The dependence of the inch refractor's scale on temperature was taken into account in calculations. The accuracy of measurement of a single CCD image is in the range of 0. Mean errors in annual average values of angular distance and position angle are equal to 0. The results are available here http: In the catalog, the separations and position angles per night of observation and annual average as well as errors for all the values and standard deviations of a single observation are presented.

We present the results of comparison of 50 pairs of stars with known orbital solutions with ephemerides. Optical Astrometric Catalog Observing Programs. UCAC3 G yes Astrometric Research of Asteroidal Satellites. Several observational methods have been applied in order to detect asteroidal satellites. Some of them were rather successful, such as the stellar occultations and mutual eclipse methods. Recently other techniques such as the space imaging, the adaptive optics and the radar imaging inferred a great improvement in the search for these objects.

However several limitations appear in the type of data that each of them allow us to access. We propose to apply an astrometric method in order as well to detect new asteroidal satellites as to get complementary data of some already detected objects mainly their orbital period.

This method is founded on the search of the reflex effect of the primary object due to the orbital motion of a possible satellite. We have applied such a method for several asteroids. A periodical signal appears in this analysis, leading to data compatible with a first detection of a probable satellite made previously Arlot et al.

The accurate measurement of the motions of stars in our Galaxy can provide access to the cosmological signatures in the disk and halo, while astrometric experiments from within our Solar System can uniquely probe possible deviations from General Relativity. This article will introduce to the fact that astrometry has the potential, thanks also to impressive technological advancements, to become a key player in the field of local cosmology.

For example, accurate absolute kinematics at the scale of the Milky Way can, for the first time in situ, account for the predictions made by the cold dark matter model for the Galactic halo, and eventually map out the distribution of dark matter, or other formation mechanisms, required to explain the signatures recently identified in the old component of the thick disk.

Final notes dwell on to what extent Gaia can fulfill the expectations of astrometric cosmology and on what must instead be left to future, specifically designed, astrometric experiments. Continued acquisition and analysis for short-exposure observations support the preliminary conclusion presented by Monet et al. BAAS v36, p, that a second exposure in 1. A single solution for mapping coefficients appears to be valid over spatial scales of up to 10 arcminutes, and this suggests that numerical processing can proceed on a per-sensor basis without the need to further divide the individual fields of view into several astrometric patches.

Should these results be confirmed, the expected astrometric accuracy after 10 years of LSST observations should be around 1. Observations were made in approximately one hour on the evening of May 1, The observers determined that the separation of STF was Seminar members then used the spectral type, parallax, and proper motion vectors of the two stars to determine if they are a line-of-sight optical pair or physically bound by gravity.

Due to large errors in the parallax and the proper motion vector for the secondary star, the results were inconclusive. Through this experience, the students learned the skills needed to observe , analyze, and report on double stars. The launch of the Hipparcos satellite in and the Hubble Space Telescope in revolutionized astrometry. By no means does this imply that not much progress was made in the ground-based techniques used exclusively until then.

On the contrary, the s to s saw an intense development of new or highly improved instruments, including photoelectric meridian circles, automated plate measuring machines, and the use of chargecoupled device CCD detectors for small-field differential astrometry for a review of optical astrometry at the time, see Monet In the radio domain, very long baseline interferometry VLBI astrometry already provided an extragalactic reference frame accurate to about 1 milliarcsecond mas Ma et al.

Spectacular improvements were made in terms of accuracy, the faintness of the observed objects, and their numbers. However, there was a widening gulf between small-angle astrometry, where differential techniques could overcome atmospheric effects down to below 1 mas, and large-angle astrometry, where conventional instruments such as meridian circles seemed to have hit a barrier in the underlying systematic errors at about mas. Though very precise, the small-angle measurements were of limited use for the determination of positions and proper motions, due to the lack of suitable reference objects in the small fields, and even for parallaxes the necessary correction for the mean parallax of background stars was highly non-trivial.

Linking the optical observations to the accurate VLBI frame also proved extremely difficult. New data and comparison of different measurement techniques. From April to August Mars Express carried out 74 Phobos flybys at distances between and km. Images taken with the Super Resolution Channel SRC were used to determine the spacecraft-centered right ascension and declination of this Martian moon. Image positions of Phobos were measured using the limb-fit and control-point measurement techniques.

Camera pointing and pointing drift were controlled by means of background star observations that were compared to corresponding positions from reference catalogs. Blurred and noisy images were restored by applying an image-based point spread function in a Richardson-Lucy deconvolution. Here, we report on a set of Phobos astrometric observations with estimated accuracies between 0. Control point measurements yield slightly more accurate results than the limb fit ones. Our data can be used for the maintenance and update of these models.

Space Based Astrometric Observing. The completion of a complementary optical emission-line survey of the nebulae associated with Wolf-Rayet stars in the southern sky is reported, along with the completion of a survey the large-scale environments of Wolf-Rayet stars using IRAS Skyflux data. Additionally, a physically consistent BRDF and radiation pressure model is utilized thus enabling an accurate physical link between the observed BRDF and radiation pressure model is utilized thus enabling an accurate physical link between the observed photometric brightness and the attitudinal Astrometrical observations of Pluto-Charon system with the automated telescopes of Pulkovo observatory.

The space probe "New Horizons" was launched on 19th of January in order to study Pluto and its moons. Spacecraft performed close fly-by to Pluto on 14th of July and obtained the most detailed images of Pluto and its moon until this moment. At the same time, observation obtained by the ground-based telescopes may also be helpful for the research of such distant system.

Thereby, the Laboratory of observational astrometry of Pulkovo Observatory of RAS made a decision to reprocess observations obtained during last decade. These observations were processed by means of software system APEX-II developed in Pulkovo observatory and numerical simulations were performed to calculate the differences between positions of photocenter and barycenter of Pluto-Charon system.

We focused on estimating whether the positioning accuracy determined from direct astrometry could compete with that derived from photometric observations of eclipses, for dynamical purposes. We present the analysis of 35 observations of Amalthea and 19 observations of Thebe realized with the 1-m telescope at the Pic du Midi observatory during three nights in , January and April. The images were reduced through an optimal process that includes image and spherical corrections using the Gaia-DR1 catalogue to provide the most accurate equatorial RA, Dec.

Using the Gaia-DR1 catalogue allowed us to eliminate systematic errors due to the star references up to mas, or km at Jupiter, by comparison with the UCAC4 catalogue. Lunar occultation of Saturn. IV - Astrometric results from observations of the satellites. The method of determining local lunar limb slopes, and the consequent time scale needed for diameter studies, from accurate occultation timings at two nearby telescopes is described.

Results for photoelectric observations made at Mauna Kea Observatory during the occultation of Saturn's satellites on March 30, , are discussed. Analysis of all observations of occultations of Saturn's satellites during indicates possible errors in the ephemerides of Saturn and its satellites. Astrometric observations of Saturn's satellites from McDonald Observatory, Observations of Saturn's satellites were reduced by means of secondary reference stars obtained by reduction of Palomar Sky Survey PSS plates.

This involved the use of 39 SAO stars and plate overlap technique to determine the coordinates of 59 fainter stars in the satellite field. Fourteen plate constants were determined for each of the two PSS plates. Comparison of two plate measurement and reduction techniques on the satellite measurements demonstrate the existence of a serious background gradient effect and the utility of microdensitometry to eliminate this error source in positional determinations of close satellites. Images of the binary star system were measured using AstroImageJ software.

Twenty observations of WDS were measured and analyzed. The calculated mean resulted in a position angle of These measurements were consistent with the previous values for this binary system listed in the Washington Double Star Catalog. Observations of Saturn's satellites have been reduced by means of secondary reference stars obtained by reduction of Palomar Sky Survey plates.

This involved the use of 29 SAO stars and plate overlap technique to determine the coordinates of 59 fainter stars in the satellite field. Comparison of two plate measurement and reduction techniques on the satellite measures appears to demonstrate the existence of a serious background gradient effect and the utility of microdensitometry to eliminate this error source in positional determinations of close satellites.

Std Z to address the question of binarity. Based on an astrometric analysis of the data, binary reflex motion is detected in the primary and, by Measurement Results 96 5. The next-generation large aperature and large field-of-view telescopes will address fundamantal questions of astrophysica and cosmology such as the nature of dark matter and dark energy. For a variety of applications, the CCD mosaic detectors in the focal plane arrays require astronomic calibrationat the milli-arcsecond mas level. The existing optical reference frames are insufficient to support such calibrations.

To address this problem, deep optical astronomic fields are being established near the Galactic plane. In order to achiev a mas or better positional accuracyfor the Deepp Astrometric Standards DAS , and to obtain bsolute stellar proper motions for the study of Galactic structure, it is crucial to link these fields to the International Celestial Reference Frame ICRF.

Relative astrometric positions were derived for these sources at a milli-arcsecond accuracy level. The detection of the optical counterparts of these extragalactic radio sources will allow us to establish a direct link to the ICRF locally in the GOT field. The PHEMU15 catalogue and astrometric results of the Jupiter's Galilean satellite mutual occultation and eclipse observations made in Van Den; Vandenbruaene, H. We focused on processing the complete photometric observations data base to compute new accurate astrometric positions.

We used our method to derive astrometric positions from the light curves of the events. We developed an accurate photometric model of mutual occultations and eclipses, while correcting for the satellite albedos, Hapke's light scattering law, the phase effect, and the limb darkening. Presented here are the details of the astrometric reductions from the x, y data to mean right ascension R.

For these new reductions we used over , CCD exposures. Errors up to about mas have been corrected using complex look-up tables handling multiple dependences derived from the residuals. The overall magnitude equation is derived from UCAC calibration field observations alone, independent of external catalogs.

The Tycho-2 catalog is used to obtain final positions on the International Celestial Reference Frame. Residuals of the Tycho-2 reference stars show a small magnitude equation depending on declination zone that might be inherent in the Tycho-2 catalog. We present an astrometric method for the calculation of the positions of orbiters in the GEO ring with a high precision, through a rigorous astrometric treatment of observations with a 1-m class telescope, which are part of the CIDA survey of the GEO ring. We compute the distortion pattern to correct for the systematic errors introduced by the optics and electronics of the telescope, resulting in absolute mean errors of 0.

The Tycho-Gaia Astrometric Solution. Gaia DR1 is based on the first 14 months of Gaia's observations. This is not long enough to reliably disentangle the parallax effect from proper motion. For most sources, therefore, only positions and magnitudes are given. Parallaxes and proper motions were nevertheless obtained for about two million of the brighter stars through the Tycho-Gaia astrometric solution TGAS , combining the Gaia observations with the much earlier Hipparcos and Tycho-2 positions. In this review I focus on some important characteristics and limitations of TGAS, in particular the reference frame, astrometric uncertainties, correlations, and systematic errors.

All measurements were compared with historical measurements from the Washington Double Star Catalog. Our astrometric results compare favorably with other recent observations. Breakthrough in orbit determination of a binary. There exists a very classical inverse problem regarding orbit determination of a binary system: How do we determine the orbital elements from observations? It is reviewed with some related topics. While dozens of stellar-mass black holes BHs have been discovered in binary systems, isolated BHs have eluded detection.

Their presence can be inferred when they lens light from a background star. These events were selected because of their long durations, which statistically favors more massive lenses. Astrometric measurements were made over one to two years using laser-guided adaptive optics observations from the W. The OB light curve is well fit by a single-lens model, while both OB and OB light curves favor binary lens models. Using the photometric fits as prior information, no significant astrometric lensing signal was detected and all targets were consistent with linear motion.

The significant lack of astrometric signal constrains the lens mass of OB to 0. Fits to OB yielded a reduced Einstein crossing time and insufficient observations during the peak, so no mass limits were obtained. Two degenerate solutions exist for OB, which have a lens mass between 0. Follow-up observations of OB will further constrain the lens mass. Based on our experience, we use simulations to design optimal astrometric observing strategies and show that with more typical observing conditions the detection of BHs is feasible.

The Astrometric Gravitation Probe AGP is a concept of space mission aimed at tests of Fundamental Physics in the Solar system, using Fizeau interferometry and coronagraphy techniques to implement differential astrometry among superposed stellar fields. The main goal is verification of the General Relativity GR and competing gravitation theories in the weak field of the Solar System by high precision measurement of the light deflection in the vicinity of the Sun at observation of four regions close to the Solar limb and in opposition; coronagraphic techniques are applied on the elementary sub-apertures.

The star displacement due to light deflection is derived by differential astrometry on images taken in different deflection conditions e. The instrument design is focused on systematic error control through multiple field simultaneous observation and calibration. The metrology system requirements related to the science goals are discussed, and the technical aspects of possible implementations are investigated.

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The potential benefit of auto-collimation and cophasing techniques derives from monitoring comparably large sections of the optical system common to the stellar beams. The performance at microarcsec level is verified by simulation. Astrometric surveys in the Gaia era. The Gaia first data release DR1 already provides an almost error free optical reference frame on the milli-arcsecond mas level allowing significantly better calibration of ground-based astrometric data than ever before.

Gaia DR1 provides positions, proper motions and trigonometric parallaxes for just over 2 million stars in the Tycho-2 catalog. These data are very helpful in the interim period but will become obsolete with the second Gaia data release DR2 expected in April The era of traditional, ground-based, wide-field astrometry with the goal to provide accurate reference stars has come to an end.

In optical SETI OSETI experiments, it is generally assumed that signals will be deliberate, narrowly targeted beacons sent by extraterrestrial societies to large numbers of candidate star systems. If this is so, then it may be unrealistic to expect a high duty cycle for the received signal. This can enormously lessen the amount of sky that needs to be searched. In addition, this is an attractive approach for the transmitting society because it both increases the chances of reception and provides a large reduction in energy required.

With good astrometric information, the transmitter need be no more powerful than an automobile tail light. To ensure the full capabilities of the Gaia's measurements, a programme of daily observations with Earth-based telescopes of the satellite itself - called Ground Based Optical Tracking GBOT - was implemented since the beginning of the Gaia mission for more details concerning GBOT operating see Altmann et al. These observations are carried out mainly with two facilities: The constraint of 20 mas on the tracking astrometric quality and the fact that Gaia is a faint and relatively fast moving target its magnitude in a red passband is around 21 and its apparent speed around 0.

This work extends earlier studies dealing with one-dimensional detectors and stationary sources Mendez et al. Astrometric "Core-shifts" at the Highest Frequencies. We detail the reasons that astrometrical observations of 'core-shifts' have become critical in the era of VLBI We detail how this new method allows the problem to be addressed at the highest frequencies and outline its superior compensation of tropospheric errors. Detailed Astrometric Analysis of Pluto. Abstract 2, Maximum Characters: Pluto is the main representant of the transneptunian objects TNO's , presenting some peculiarities such as an atmosphere and a satellite system with 5 known moons: Charon, discovered in , Nix and Hydra, in , P4 in and P5 in Until the arrival of the New Horizons spacecraft to this system july , stellar occultations are the most efficient method, from the ground, to know physical and dinamical properties of this system.

The ephemerides and occultations results was then compared with the astrometric and photometric reductions of CCD images of Pluto around images. Two corrections were used for a refinement of the data set: The first is due to the mean color of background stars beeing redder than the color of Pluto, resulting in a slightly different path of light through the atmosphere that may cause a difference in position of 0. It became more evident because Pluto is crossing the region of the galactic plane.

The objective is to separate these two gaussian curves from the observed one and find the right position of Pluto. The method is strongly dependent of the hight of each of the gaussian curves, related to the respective albedos of charon and Pluto. A detailed analysis of the astrometric results, as well a comparison with occultation results was made.

Unrecognized astrometric confusion in the Galactic Centre. The Galactic Centre is a crowded stellar field and frequent unrecognized events of source confusion, which involve undetected faint stars, are expected to introduce astrometric noise on a sub-mas level. This confusion noise is the main non-instrumental effect limiting the astrometric accuracy and precision of current near-infrared imaging observations and the long-term monitoring of individual stellar orbits in the vicinity of the central supermassive black hole.

We self-consistently simulate the motions of the known and the yet unidentified stars to characterize this noise component and show that a likely consequence of source confusion is a bias in estimates of the stellar orbital elements, as well as the inferred mass and distance of the black hole, in particular if stars are being observed at small projected separations from it, such as the star S2 during pericentre passage.

Furthermore, we investigate modelling the effect of source confusion as an additional noise component that is time-correlated, demonstrating a need for improved noise models to obtain trustworthy estimates of the parameters of interest and their uncertainties in future astrometric studies. The OWL-Net consists of five optical tracking stations. Brightness signals of reflected sunlight of the targets were detected by a charged coupled device CCD.

A chopper system was adopted for fast astrometric data sampling, maximum 50 Hz, within a short observation time. The astrometric accuracy of the optical observation data was validated with precise orbital ephemeris such as Consolidated Prediction File CPF data and precise orbit determination result with onboard Global Positioning System GPS data from the target satellite.

In the optical observation simulation of the OWL-Net for , an average observation span for a single arc of 11 LEO observation targets was about 5 min, while an average optical observation separation time was 5 h. We estimated the position and velocity with an atmospheric drag coefficient of LEO observation targets using a sequential-batch orbit estimation technique after multi-arc batch orbit estimation. Post-fit residuals for the multi-arc batch orbit estimation and sequential-batch orbit estimation were analyzed for the optical measurements and reference orbit CPF and GPS data.

The post-fit residuals with reference show few tens-of-meters errors for in-track direction for multi-arc batch and sequential-batch orbit estimation results. The Future of Astrometric Education. Astrometry is poised to enter an era of unparalleled growth and relevance due to the wealth of highly accurate data expected from the SIM and GAIA space missions. Innovative ground-based telescopes, such as the LSST, are planned which will provide less precise data, but for many more stars.

The potential for studies of the structure, kinematics and dynamics of our Galaxy as well as for the physical nature of stars and the cosmological distance scale is without equal in the history of astronomy. It is therefore ironic that in two years not one course in astrometry will be taught in the US, leaving all astrometric education to Europe, China and Latin America. Hipparcos and the HST were astrometric successes due only to the dedicated work of specialists in astrometry who fought to maintain the astrometric characteristics of those satellites and their data pipelines.

We propose a renewal of astrometric education in the universities to prepare qualified scientists so that the scientific returns from the investment of billions of dollars in these unique facilities will be maximized. The funding agencies are providing outstanding facilities. The universities, national and international observatories and agencies should acknowledge their responsibility to hire qualified full-time astrometric scientists to teach students, and to supervise existing and planned astronomical facilities so that quality data will be obtained and analyzed.

A temporary solution to this problem is proposed in the form of a series of international summer schools in Astrometry. The Michelson Science Center of the SIM project has offered to hold an astrometry summer school in to begin this process. A one-semester syllabus is suggested as a means of meeting the needs of Astronomy by educating students. Astrometric exoplanet detection with Gaia.

We provide a revised assessment of the number of exoplanets that should be discovered by Gaia astrometry, extending previous studies to a broader range of spectral types, distances, and magnitudes. Our assessment is based on a large representative sample of host stars from the TRILEGAL Galaxy population synthesis model, recent estimates of the exoplanet frequency distributions as a function of stellar type, and detailed simulation of the Gaia observations using the updated instrument performance and scanning law.

We use two approaches to estimate detectable planetary systems: Due to the relatively large number of optical Earth Observation missions at ESA, this area is interesting for new space technology developments. In addition to their compactness, scalability and specific task customization, optical MEMS could generate new functions not available with current technologies and are thus candidates for the design of future space instruments. Most mature components for space applications are the digital mirror arrays, the micro-deformable mirrors, the programmable micro diffraction gratings and tiltable micromirrors.

A first selection of market-pull and techno-push concepts is done. In addition, some concepts are coming from outside Earth Observation. Finally two concepts are more deeply analyzed. The first concept is a programmable slit for straylight control for space spectro-imagers. This instrument is a push-broom spectroimager for which some images cannot be exploited because of bright sources in the field-of-view.

The proposed concept consists in replacing the current entrance spectrometer slit by an active row of micro-mirrors. The MEMS will permit to dynamically remove the bright sources and then to obtain a field-of-view with an optically enhanced signal-to-noise ratio. The second concept is a push-broom imager for which the acquired spectrum can be tuned by optical MEMS.

This system is composed of two diffractive elements and a digital mirror array. The first diffractive element spreads the spectrum. A micromirror array is set at the location of the spectral focal plane. The second diffractive element then recombines the light on a push-broom detector. Dichroics filters, strip filter, band-pass filter could be replaced by a unique instrument. Gamma astrometric measurement experiment -science and implementation. A space based telescope, looking close to the Solar limb thanks to coronagraphic techniques, may implement astrometric measurements sim-ilar to those performed in the solar eclipse of , when Dyson, Eddington and collaborators measured for the first time the gravitational bending of light.

Simulations show that the final accuracy of GAME can reach the level. GAME will be a decisive experiment for the understanding of gravity physics, cosmology and the Universe evolution. The observations leading to Dark Matter e. Also, high precision astrometry makes accessible other appealing measurements, e. GAME may also carry out measurements on selected astrophysical targets, e. GAME, also thanks to high-cadence, high-precision photometry on transit-ing exoplanet systems, will thus improve on our understanding of the actual mass distribution and multiplicity of sub-stellar companions.

Very long baseline interferometry VLBI observations of the maser emission provide a unique tool to probe the innermost layers of the circumstellar envelopes in AGB stars. The simultaneous multi-channel receivers of the KVN offer great possibilities for astrometry in the frequency domain. This is the first successful demonstration of source frequency phase referencing for millimeter VLBI spectral-line observations and also where the ratio between the frequencies is not an integer. Astrometric observations of radio source occultations by solar system bodies may be of large interest for testing gravity theories, dynamical astronomy, and planetary physics.

Simple Ephemeris With Tables of Aspect for Astrology Phoenix 2015-2019

In this paper, we present an updated list of the occultations of astrometric radio sources by planets expected in the coming years. Such events, like solar eclipses, generally speaking can only be observed in a limited region. A map of the shadow path is provided for the events that will occurr in regions with several VLBI stations and hence will be the most interesting for radio astronomy experiments. More than a century ago, astronomers using transit telescopes to determine precise stellar positions were hampered by an unexplained periodic shifting of the stars they were observing.

With the advent of CCD transit telescopes in the past three decades, this unexplained motion, termed 'anomalous refraction' by these early astronomers, is again being observed. The cause of this tilting has often been attributed to atmospheric gravity waves, but this cause has never been confirmed. Although theoretical models of atmospheric refraction show that atmospheric gravity waves are a plausible cause of anomalous refraction, an observational campaign specifically directed at defining this relationship provides clear evidence that anomalous refraction is not consistent with the passage of atmospheric gravity waves.

The source of anomalous refraction is found to be meter-scale, slowly evolving quasi-coherent dynamical structures in the boundary layer below 60 m above ground level. The satellite was launched in June It will allow recording simultaneous solar images from ground. Previous works have revealed a dependence of the Sun radius measurements with the observation conditions Fried's parameter, atmospheric correlation time s They are complemented by standard sun-photometers and a pyranometer for estimating a global sky quality index. It gives estimations of the coherence parameters characterizing wave-fronts degraded by the atmospheric turbulence Fried's parameter, size of the isoplanatic patch, the spatial coherence outer scale and atmospheric correlation times.

This paper presents an overview of the ground based instruments of PICARD and some results obtained from observations performed at Calern observatory in The astrometric detection and characterization of extrasolar planets presents considerable technical challenges, but also promises to greatly enhance our understanding of these systems.

Nearly all currently confirmed exoplanets have been discovered using transit or radial velocity techniques. The former is geometrically biased towards planets with small orbits, while the latter is biased towards massive planets with short periods that exert large gravitational accelerations on their host stars. Astrometric techniques are limited by the minimum detectable perturbation of a star's position due to a planet, but allow for the determination of orbit inclination and an accurate planetary mass.

Here we present astrometric solutions for five nearby stars with known planets: Observations have baselines of three to thirteen years, and were made using the 0. We provide improved parallaxes for the stars and find that there are no planets of several Jupiter masses or brown dwarfs orbiting these stars with periods up to twice the length of the astrometric coverage. In the broader context, these results are consistent with the paucity of super-Jupiter and brown dwarf companions we find among the roughly red dwarfs searched in our astrometric program.

Optical Observations of Space Debris. This viewgraph presentation reviews the use of optical telescopes to observe space debris. It will present a brief review of how the survey is conducted, and what some of the significant results encompass. The goal is to characterize the population of debris objects at GEO, with emphasis on the faint object population. Because the survey observations extend over a very short arc 5 minutes , a full six parameter orbit can not be determined.

Recently we have begun to use a second telescope, the 0. With a long enough sequence of observations , a full six-parameter orbit including eccentricity can be determined. The project has used STK since inception for planning observing sessions based on the distribution of bright cataloged objects and the anti-solar point to avoid eclipse. The ODTK analysis results indicate that temporal variations in the solar perturbations, possibly due to debris orientation dynamics, can be estimated in the OD process. Additionally, the best results appear to be achieved when solar forces orthogonal to the object-Sun line are considered.

The concept addresses the major issues for ultra -precise astrometry: Technology "close" to complete. Focal plane geometry to 2e-5 pixels and centroiding to approx 4e -5 pixels. On the detection of other planetary systems by astrometric techniques. A quantitative method for astrometrically detecting perturbations induced in a star's motion by the presence of a planetary object is described. A periodogram is defined, wherein signals observed from a star show exactly periodic variations, which can be extracted from observational data using purely statistical methods.

A detection threshold is defined for the frequency of occurrence of some detectable signal, e. Possible effects of a stellar orbital eccentricity and multiple companions are discussed, noting that assumption of a circular orbit assures the spectral purity of the signal described. The periodogram technique was applied to 12 yr of astrometric data from the U. Naval Observatory for three stars with low mass stellar companions.

Periodic perturbations were confirmed. A comparison of the accuracy of different astrometric systems shows that the detection accuracy of a system is determined by the measurement accuracy and the number of observations , although the detection efficiency can be maximized by minimizing the number of data points for the case when observational errors are proportional to the square root of the number of data points. It is suggested that a space-based astrometric telescope is best suited to take advantage of the method.

We present astrometric results of near-Earth objects NEOs targeted in fourth quarter and in This time is divided up into two hour observing runs approximately every other night for astrometry and frequent half-night runs approximately several times a month for spectroscopy see poster by M.

Observations were made using 2 x 2 binning.

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Special emphasis has been made to focus on the smallest NEOs, particularly around m in diameter. As of August , we have detected NEOs for astrometric follow-up, on point with our goal of providing astrometry on a thousand NEOs per year. Astrometric calculations were done using the interactive software tool Astrometrica, which is used for data reduction focusing on the minor bodies of the solar system.

The program includes automatic reference star identification from new-generation star catalogs, access to the complete MPC database of orbital elements, and automatic moving object detection and identification. This work is based on observations done using the 3. Astrometric properties of the Tautenburg Plate Scanner. In our poster, we reported on tests and preliminary results of its astrometric properties. The essential components of the TPS consist of an x-y table movable between an illumination system and a direct imaging system. All components are mounted on a massive air-bearing table.

Scanning is performed in lanes of up to 55 mm width by moving the x-y table in a continuous drift-scan mode perpendicular to the CCD line. The pixel map is produced as a series of optionally overlapping lane scans. Subsequent high-level data processing is performed off-line on other computers. During the scanning process, the geometry of the optical components is kept fixed. The optimal focussing of the optics is performed prior to the scan.

Due to the telecentric lens refocussing is not required. Therefore, the main source of astrometric errors beside the emulsion itself are mechanical imperfections in the drive system, which have to be divided into random and systematic ones. This accuracy is comparable to. StreakDet data processing and analysis pipeline for space debris optical observations.

We describe a novel data processing and analysis pipeline for optical observations of space debris. The monitoring of space object populations requires reliable acquisition of observational data, to support the development and validation of space debris environment models, the build-up and maintenance of a catalogue of orbital elements. In addition, data is needed for the assessment of conjunction events and for the support of contingency situations or launches. The currently available, mature image processing algorithms for detection and astrometric reduction of optical data cover objects that cross the sensor field-of-view comparably slowly, and within a rather narrow, predefined range of angular velocities.

By applying specific tracking techniques, the objects appear point-like or as short trails in the exposures. The scope of the ESA-funded StreakDet Streak detection and astrometric reduction project is to investigate solutions for detecting and reducing streaks from optical images, particularly in the low signal-to-noise ratio SNR domain, where algorithms are not readily available yet.

For long streaks, the challenge is to extract precise position information and related registered epochs with sufficient precision. Although some considerations for low-SNR processing of streak-like features are available in the current image processing and computer vision literature, there is a need to discuss and compare these approaches for space debris analysis, in order to develop and evaluate prototype implementations.

In the StreakDet project, we develop algorithms applicable to single images as compared to consecutive frames of the same field obtained with any observing scenario, including space-based surveys and both low- and high-altitude populations. The proposed processing pipeline starts from the. Astrometric Discovery of GJ B. Automatic Astrometric and Photometric Calibration. Astrometric and photometric calibrations have remained the most tiresome step in the reduction of large imaging surveys.

SCAMP has been written to address this problem. The program efficiently computes accurate astrometric and photometric solutions for any arbitrary sequence of FITS images in a completely automatic way. An empirical astrometric model includes terms for: The size of these atmospheric distortions is not closely related to the seeing. Remaining detectable error contributors are mas RMS from unmodelled stray electric fields in the devices, and another mas RMS from focal plane shifts between camera thermal cycles. Astrometric Telescope Facility isolation and pointing study.

It fits within the available annular region between the PPS and the ATF while meeting power and weight limitations and providing the required roll motion, payload data and power services. By contrast, the passive base isolator system must have an unrealistically low isolation bandwidth on all axes to meet ATF pointing requirements and does not provide roll about the line of sight. Astrometry from space is capable of making extremely precise measurements of the positions of stars, well below 1 uas microarcsecond at each visit. A hundred such visits over a period of several years could result in a relative astrometric precision for the mission of 0.

Stellar photometric fluctuations on timescales of months to years introduce astrophysical noise in radial velocity and astrometric measurements of stars. These fluctuations are dominated by rotation and evolution of magnetic surface features sunspots and faculae. We describe a dynamic model of starspot noise which is consistent with the power spectrum of the Sun and several other stars. We use the model to predict the noise in astrometric and RV observing campaigns for this small sample of stars.

We also use empirical stellar activity models to estimate the astrometric and radial velocity jitter for a much larger sample of nearby solar-type stars. We find that for most of these stars, starspot noise does not significantly interfere with astrometric detection of habitable zone planets down to well below an Earth mass. Improvements in Ross type astrometric objectives. It is shown that aspheric deformations of the first and fourth elements of the four element Ross objective can be introduced to permit one to obtain improved color corrections for astrometric purposes.

The usual monochromatic aberrations are as well corrected as for the standard Ross lens. In addition, one can eliminate or reduce additional aberrations, such as secondary spectrum, chromatic spherical aberration, chromatic coma and chromatic distortion. The resulting objectives are suitable for use as intermediate and long focus astrometric objectives covering large angle fields.

We report on observations of three nearby stars Trappist-1, GJ and Wolf that possess exoplanets located in their respective habitable zones to search for optical signals generated by an advanced alien civilization. Using the photon data collected with the Berkeley Visible Image Tube attached to the 10m Southern African Large Telescope, we searched for very high amplitude events in the pulse height distributions that statistically could only be produced by non-astrophysical means such as an optical laser used for communications purposes.

Assuming that a purported ET civilization has access to an orbiting 10m mirror and an optical laser to send signals over the three sight-lines to Earth, we derive upper limits to the output power of their l lasers which might be used for inter-stellar communication.

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We present preliminary results to demonstrate that our method for detection and location of Space Debris SD in the geostationary Earth orbit GEO ring, based on observations at the OAN of Venezuela is of high astrometric precision. A detailed explanation of the method, its validation and first results is available in Lacruz et al. As reported by Kikwaya et al. However, the astrometric method cannot be applied to any binary system of asteroids. It depends strongly on the mass ratio of the two bodies and the distance between them Kikwaya et al.

Pluto-Charon provides a good test of this method. Previous works based on direct imaging of Charon show that its period is 6. Using archived photographic observations and CCD observations from US Naval Observatory, Flagstaff station , Bordeaux observatory and Mc Donald Observatory , we are analyzing the position of Pluto to see if its wobble effect due to Charon amplitude around 95 mas can be detected and if the orbital period of Charon can be recovered through a spectral analysis.

If successful, this will reinforce the ability of our astrometric method to find asteroid satellites. Optical MEMS for earth observation payloads. A summary of this review will be presented. Following the review two space-instrument design concepts were selected for more detailed analysis. The concept is potentially of interest for any mission using imaging spectrometers.

A spectrometer concept was selected and detailed design aspects and benefits evaluated. The second concept developed uses MEMS devices to control the width of entrance slits of spectrometers, to provide variable spectral resolution. This paper will present a summary of the results of the study. In this poster, we present the prospect that astrometric shifts can be used to identify blended microlensing events in crowded fields.

Moreover, by measuring an astrometric shift, one can determine the position of the true lensed star with respect to the local field with very high precision. Optical Chopper Assembly for the Mars Observer. The OCA is unique because of its constant accurate rotational speed, low electrical power consumption, and long-life requirements.

These strict and demanding requirements were achieved by use of a number of novel approaches. We report on a continuing program of optical photometric measurements of faint orbital debris at geosynchronous Earth orbit GEO. These observations can be compared with laboratory studies of actual spacecraft materials in an effort to determine what the faint debris at GEO may be. GEO objects discovered in a survey with the University of Michigan's 0.

A smaller sample of high area to mass ratio AMR objects discovered independently, and acquired using predictions from orbits derived from independent tracking data collected days prior to the observations. Our optical observations in standard astronomical BVRI filters are done with either telescope, and with the telescope tracking the debris object at the object's angular rate. Observations in different filters are obtained sequentially. A total of 66 of these sequences have 3 or more good measurements in all filters not contaminated by star streaks or in Earth's shadow.

Most of these sequences show brightness variations, but a small subset has observed brightness variations consistent with that expected from observational errors alone. The majority of these stable objects are redder than a solar color in both B-R and R-I. There is no dependence on color with brightness. For a smaller sample of objects we have observed with synchronized CCD cameras on the two telescopes. The CCD cameras are electronically linked together so that the start time and.

An astrometric precision of 10 to 15 mas for those stars is estimated from frame-to-frame comparisons. External comparisons reveal an accuracy of about 15 mas for those stars in a 20' field of view. This paper provides a description of the Java software framework which has been constructed to run the Astrometric Global Iterative Solution for the Gaia mission. This is the mathematical framework to provide the rigid reference frame for Gaia observations from the Gaia data itself. This process makes Gaia a self calibrated, and input catalogue independent, mission. The framework is highly distributed typically running on a cluster of machines with a database back end.

All code is written in the Java language. We describe the overall architecture and some of the details of the implementation. The most stringent astrometric performance requirements on NASA's SIM Space Interferometer Mission -Lite mission will come from the so-called Narrow-Angle NA observing scenario, aimed at finding Earth-like exoplanets, where the interferometer chops between the target star and several nearby reference stars multiple times over the course of a single visit.

Previously, about 20 pm NA error with various shifts was reported.

Since then, investigation has been under way to understand the mechanisms that give rise to these shifts. In this paper we report our findings, the adopted mitigation strategies, and the resulting testbed performance. Establishing Alpha Oph as a Prototype Rotator: We also use photometry from these observations to derive a model-based estimate of the companion mass. We achieve our astrometric alignment by solving first for the ionospheric dispersive contributions using wide-band centimeter-wavelength observations.

Second, we solve for the tropospheric non-dispersive contributions by using fast frequency-switching at the target millimeter-wavelengths. These solutions can be scaled and transferred from low frequency to the high frequency. The Gaia catalogue second data release and its implications to optical observations of man-made Earth orbiting objects. Abstract and not the Final Paper is attached. The Gaia spacecraft was launched in December by the European Space Agency to produce a three-dimensional, dynamic map of objects within the Milky Way.

Gaia's first year of data was released in September Common sources from the first data release have been combined with the Tycho-2 catalogue to provide a 5 parameter astrometric solution for approximately 2 million stars. The second Gaia data release is scheduled to come out in April and is expected to provide astrometry and photometry for more than 1 billion stars, a subset of which with a the full 6 parameter astrometric solution adding radial velocity and positional accuracy better than 0.

In addition to precise astrometry, a unique opportunity exists with the Gaia catalogue in its production of accurate, broadband photometry using the Gaia G filter. In the past, clear filters have been used by various groups to maximize likelihood of detection of dim man-made objects but these data were very difficult to calibrate.