Phase Retrieval Measurements of Antenna Surfaces Using Astronomical Sources Bojan Nikolic, John Richer, Richard Hills Mullard Radio Astronomy Observatory, Cavendish Laboratory, Cambridge, U.K. Abstract We present a novel technique for accurate measurement of the largescale errors in an antenna surface using astronomical sources and detectors. Out-of-focus images of compact astronomical sources contain a wealth of information about the telescope optics. ...

... Previous: Generalized Linear Multi-Frequency Imaging in VLBI . ... At Astronomical Observatory of Valencia University (OAUV), CCD observations of asteroids and big planets satellites are obtained since 2001 with a big format camera and several telescopes. ... Software for comparison of single and overlapped CCD fields obtained at different epochs has been developed. ... After images measurement in CCD field, catalogue stars are identified and adjusted with images. ...

SAI 175 anniversary . ... Moscow University . Search for in SAI Moscow University Search for in Russian astronomical resources . ... SAI Astronomical Databases . ... Browse SAI Software archive(ftp.sai.msu.su) . ASTRONET.RU - Russian Astronomical Network (available in translit also) . ... SAI Supernovae Research Group . ... Department of the Galaxy and Variable Stars (in Russian) . Sternberg Astronomical Institute Seminars . ... All-Russian Astronomical Olympiad (in Russian) . ...

... Donate to Support Science Literacy . ... 2016 Annual Awards . The ASP is accepting nominations for the organizationтАЩs national annual awards which recognize special achievements in astronomy research, technology, education, and public outreach. ... Shop the AstroShop . ... The Astronomical Society of the Pacific (ASP) is accepting nominations for the organizationтАЩs national annual awards which recognize special achievements in astronomy research, technology, education, and public outreach.. ...

To main of Laboratory . The research work and design of optical and optical-electronic devices are carries out by laboratory staff: . ... Lens: . ... In the layout 1 prism systems perform functions of dispersive element, corrector of aberrations, optical reducer. ... Spectral range 200 - 400 nm; . ... Back Forward . ... The main corrector's function are compensation of field aberrations of the main spherical mirror of a telescope (diameter of 600 mm, f'=1200 mm) and increase aperture ratio. ...

Next: Some theory Up: userhtml Previous: Calibration . By many measures, the ATCA 3-mm observing band is a completely different domain to the other ATCA bands. ... Not surprisingly many aspects of the data reduction are also different. This chapter reviews the theory behind some of the differences, and then considers a practical approach to calibration. ... Antenna gain considerations and flux calibration . Instrumental phase . Atmospheric phase and phase calibration considerations . ...

... The Science Operation Department is composed of Astronomers, Telescope Instruments Operators(TIOs) and Data Handling Administrators(DHAs). ... Astronomers have proposed several methods to quantitatively measure the amount of turbulence above the telescope, which the most common ones is Differential Image Motion Monitor (DIMM). In optical testing, the Hartmann test is the common method to test the quality of optical components. ... Hartmann mask consists of 48 lenses. ...

... Multiple exposures with small offsets in the pointing of the telescope are usually necessary or recommended for NICMOS observations. ... Dithering or chopping to measure the background associated with an -astronomical source. Mosaicing to image a source larger than the NICMOS field of view. ... Background images will be obtained by offsetting the telescope from the target to point to an "empty" region of the sky. ... Two distinct type of telescope motion are defined: . ...

Observations of stellar magnetic fields is a powerful method to study of different non-stationary effects in our Galaxy and behavior of plasma under astrophysical conditions. ... Investigations of stellar magnetism by means of Zeeman measurements of polarized spectra of different stars are one of the most significant observational programme on the 6-m telescope BTA of our Observatory. ... Laboratory for the Stellar Magnetism Study . ... Laboratory for the Stellar Magnetism Study of SAO of the RAS . ...

... Contact A Problem of an estimation of accuracy of the asteroid CCD observations . The Minor Planet Center supported by the Interntional Astronomical Union is the main office for keeping observational data of the small Solar System bodies and their investigations. ... At Pulkovo Observatory we are estimating an accuracy of the CCD asteroid observations obtained by amateurs and professional astronomers all over the World using the MPC database. ...

... During the week from the 14th of June to the 18th of June I have been on work experience in the Armagh Observatory. During the course of these 5 days, the main task which I had been set was to, using the Faulkes Telescope in Hawaii and the Faulkes Telescope in Australia, capture images of various different asteroids, and afterwards measure their position. ... The near-Earth asteroid 2010 DW1, in images obtained on 2010 Jun 15 using the Faulkes Telescope North, operated by Las Cumbres Observatory. ...

... The extinction in terrestrial atmosphere. ... A star was observed at different zenith distances during one night at the Engelgardt's Astronomical Observatory in the program of atmospheric extinction study at blue. ... Calculate the air mass for given zenith distances in 1st 54.9 11800 column, and write the result into the 2nd column. ... Spectral observations. ... Calculate the radial velocity Vr of the star on each date, the results of measurements and write calculations into the table. ...

Quasar VLBI network observatories as co-location sites A. Ipatov, I. Gayazov, S. Smolentsev Institute of Applied Astronomy, Saint Petersburg, Russia ... supposes: 1. installation of different observational techniques at sites (co-location) 2. combined processing of different types of observations (collocation) IAA activity in space geodesy · Quasar VLBI network : ­ VLBI observations ­ GPS /GLONASS observations ­ DORIS ( ...

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... Астрономическая неделя с 11 по 17 апреля 2016 года . ... Александр Козловский . ... День открытых дверей на Пущинской РадиоАстрономической Обсерватории 09 апреля 2016 года . ... Полное солнечное затмение 9 марта 2016 года . ... Полное лунное затмение 28 сентября 2015 года . ... Затмение, которое произойдет 28 сентября 2015 года, является повторением через сарос (цикл повторений затмений равный 6585 дней или 18 лет 11 дней) полного лунного затмения от 16 сентября 1997 года с максимальной фазой 1,20.....

... Archives . ... Diab Jerius follows up on LOESS techniques б with a very nice summary update and finds LOCFIT to be very useful, but there are still questions about how it deals with measurement errors and combining observations from different experiments: . ... LOESS has been succeeded by LOWESS and, finally LOCFIT, which is the 800lb gorilla of local regression fitting. The LOCFIT algorithm uses local regression (i.e. fits over samples of the data) to generate smooth curves. ... Chandra Blog . ...

June 28, 2010 Wider Bandwidths and a New 12m Antenna will keep . the Arecibo Radiotelescope at the cutting edge of . ... 12m reference antenna Photos by: Tony Acevedo . V ery Long Baseline Interferometry (VLBI) is the technique used to combine signals from radio telescopes separated by distances that can span different continents, or even reach between the Earth and an orbiting . ... Arecibo 305-m telescope is an active participant in both of these forms of VLBI. ...

Next: CCD data Up: Special problems Previous: Marginal nights . If the program complains that you have negative intensities, this is usually due to misidentifying star observations as sky. ... Another problem with sky occurs when the program cannot find a suitable sky observation to subtract from a star datum. ... Finally, as the sky-modelling algorithm does not try to model twilight, it uses the ``nearest-neighbor'' method to correct star observations made during twilight for sky. ...

. Pulkovo Observatory of Russian Academy of Sciences is situated . near Saint-Petersburg. It was founded in 1839. 196140, Saint-Petersburg, Pulkovskoye chaussee 65/1 . English version . Russian version . This page has been accessed times since May 1, 1999.

... ESO, the European Southern Observatory . ... ESO Acronyms . ... Survey Telescopes . ... Star Clusters . ... Stars@ESO . ... ESO 3.6-metre telescope . ... MPG/ESO 2.2-metre telescope . ... Demonstrates in a schematic way, how the images of two stars of different angular size (left) will look like, with a single telescope (middle) and with an interferometer like the VLTI (right). Whereas there is little difference with one telescope, the fringe patterns at the interferometer are quite different. ...