... The experience of determination of the link between radio sources and dynamical reference frames is presented. To obtain this connection we used a series of very long baseline interferometry (VLBI) observations of the spacecraft Phobos-2 and angularly nearby quasars. ... The dynamical reference frame is determined by equator and equinox of these ephemerides. ... References . ... The relative orientation of the radio and dynamical reference frames can be described by a sequence of three rotations . ...

. Comment on J1225+1253 . Early 2.3 GHz VLBI observations (Jones, Terzian & Sramek 1981) indicate an elongated source structure in the N-S direction, in agreement with our image. Giovannini, Feretti & Comoretto (1990) measured a 180 mJy correlated flux density at 1.6 GHz on the shortest VLBI baselines. VLBApls home page . Last modified: 16 Oct 2000

Nowadays at the Department the experimental and theoretical investigations, including astronomical and ionospheric observations, active experiments with space vehicles are taking place. ... Solar Corona physics and erruptive phenomenae. ... Stellar astronomy. ... The Department has organized and put into practice more then 50 expeditions for observation of Solar ecllipces, aurorae polaris, comets, meteor streams, controlled space experiments, and also for investigations of geophysical characteristics. ...

Next: Rotation Periods of ZAMS stars Previous: T Tauri Stars . ... The first attempts to directly measure periodic modulation of T Tauri stars occurred in the early 1980s. Rydgren & Vrba (1983) observed four PMS stars using photoelectric photometry over a period of seven consecutive photometric nights. ... Because the spot lifetime is much longer than the rotational period, the observed effect will be a modulation of the light from the star synchronously with the rotation period. ...

Not everyone accepted Parker's theory of the solar wind when it was first published in 1958, and it was debated until observations confirmed it. ... Lower-velocity solar wind comes from regions in between sunspot regions and coronal holes . ... It was therefore expected that the solar wind above the Sun's poles would be relatively fast and smooth-flowing. ... The Ulysses mission has its own home page on the web, leading to many related files. ... Exploration" home page (index) Glossary . ...

Next: Emission molecular bands Up: Optical spectrum of IRAS04296 Previous: Optical spectrum of IRAS04296 . We have obtained spectra of IRAS04296 with the CCD (1140 1170 pixels) equipped echelle spectrometer PFES mounted at the prime focus of the 6m telescope of SAO RAS (Panchuk et al. ... Figure: The IRAS04296+3429 spectrum near . Next: Emission molecular bands Up: Optical spectrum of IRAS04296 Previous: Optical spectrum of IRAS04296 Klochkova V.G. 12/20/1999 ...

... Future seminars . P a s t seminars . Seminar council . Optical afterglow of GRB030329: first results and new approaches to observations " . A. Pozanenko (IKI), V.Rumyantsev (CrAO), M. Ibrahimov (UBAI), S.Bondar' (Kosmoten), G.Beskin (SAO) on behalf of large collaboration . ... Despite a successful GRB030329 afterglow observation, the problem of a search GRB optical counterpart (Optical Transient in place of GRB) still remains. ...

... They are concerned with Attitude Control System of the spacecraft, satellite visibility from tracking stations, limits on the satellite autonomous operations during the orbit, and needs for auxiliary operations with the spacecraft. ... Among the operational constraints the most important one is the number of programmed slews per orbit, which determines the maximum number of radio sources to be observed during one orbit. ... System temperature (K) . ... Progress of the RadioAstron Project in Pictures...

... Science . ... The Local Sphere of Influence (LSI) survey is a deep near-IR (H-band) survey of galaxies residing in the Local Sphere of Influence ( D < 10 Mpc). The images with a typical surface brightness limit 4 mag fainter than 2MASS (24.5 mag arcsec -2 < SB lim < 26 mag arcsec -2 ) have been obtained with IRIS2 on the 3.9~m Anglo-Australian Telescope. 11 of the observations have resulted in non-dections or the images were saturated by foreground stars. ... Copyright 2007 Emma Kirby. ...

... Polarizer efficiency is defined as , where and are the respective measured signals for a polarizer oriented parallel and perpendicular to the axis of a fully polarized beam... angle 12.2 . Polarizer position angle as measured from the NICMOS Aperture Offset Angle of , about the aperture center toward the +U3 axis.. IDL 14.1 . IDL (Interactive Data Language) is an interactive analysis and visualization program written by Research Systems, Inc.... resolution. ...

RADIOASTROPHYSICAL DEPARTMENT • INSTITUTE OF SOLAR-TERRESTRIAL PHYSICS RAS SB . General information Main characteristics of the Radio telescope Observing programs General view of the antenna array Main research areas Principle of generation of radio images Radio telescope 's beam Receiving systems Main characteristics of the base receiving-recording complex Calibrations Data archive and databases Publication SSRT - Siberian Solar Radio Telescope . ...

... the time of observation . ... Observing the Changing Position of the Sun To Establish Cardinal Directions . ... Observations of the Sun's apparent movement across the sky and its pattern of rising and setting in the east and west horizon helped to establish the cardinal directions. ... The final stage of the Sun's return was marked by the observation that the Sun had reached its highest altitude when the full width of your mitted hand could fill the gap between the Sun and the horizon. ...

... Julian Date Flux Densities (mJy) Julian Date Flux Densities (mJy) 2440000:0 A1 A2 B C 2440000:0 A1 A2 B C 8930.9968 153.8 134.6 59.8 22.6 9021.6846 154.0 137.0 59.0 22.9 8939.7717 163.7 146.0 66.1 22.9 9024.6766 151.4 134.6 58.4 22.1 8940.8936 153.2 135.8 59.2 22.6 9030.5334 156.7 139.1 59.0 22.4 8944.7380 161.7 142.2 63.7 23.1 9032.6650 151.8 136.5 57.7 22.6 8951.8637 148.4 131.3 58.3 21.7 9036.7067 155.1 137.1 58.8 ...

Spacecraft STP Data 1. ... This CD-ROM contains solar flare reports, sunspot numbers and regions histories, total solar irradiance, and solar bursts. ... MAGSAT - 2 discs. ... A Compilation of 1963-1999 Solar Wind Field and Plasma Data, Near Earth and Deep Space - 3 discs. This CD-ROM contains the interplanetary magnetic field (IMF) and solar wind plasma (SWP) data from several spacecraft which have explored the near-Earth and deep space regions over the last three decades. ...

... Archive of publications: . ... 2005 . ... S.V.Shestov , A.M.Urnov , S.V.Kuzin , I.A.Zhitnik , S.A.Bogachev , . Electron Density Diagnostics for Various Plasma Structures of the Solar Corona Based on Fe XI - Fe XIII Lines in the Range 176-207 A Measured in the SPIRIT/CORONAS-F Experiment Astronomy Letters, V. 35, No. 1, pp. ... Download in format .pdf, 747 113 B . I.A.Zhitnik , S.V.Kuzin , A.M.Urnov , I.L.Beigman , S.A.Bozhenkov , I.Yu.Tolstikhina , . ... Download in format .pdf, 422 738 B . ...

... Old World First Asteroid Radar Echo. ... It testifies that 4179 Toutatis is a double object like asteroid 4769 Castalia. ... Interference of Radar Echo from the Binary Asteroid 4179 Toutatis. ... An analysis of the 6-cm radar data revealed quasi-harmonic oscillation of the echo’s “central” Doppler frequency with a period of about 14 sec and a deviation of about (0.7*B) Hz, where B is the echo bandwidth, which for 4179 Toutatis was equal to 2.1 Hz and 1.9 Hz for 1992 Dec 8 and 9, respectively. ...

... Dept. for Astrometry & Space Geodynamics . ... Dept. for Physics of Stars&Galaxies . Dept. for Space Plasma Physics . ... Solar telescopes . ... 2016,MNRAS, 2016MNRAS.tmp.. ... 2016,MNRAS, Vol.455 ,is.1,p.357-369. ... 2016,MNRAS, Vol.456 ,is.1,p.181-191. ... WASP- 22, WASP-41, WASP- 42 and WASP- 55. ... 2016,MNRAS, Vol.456 ,Is.1,p.990-1002. ... Observations . ... In 2002 regulary observations of comets with using of CCD camera S1C started at Andrushivka Astronomical Observatory, near Zhytomyr. ...

... After all we cannot send a probe to the star Altair to confirm that it is 17 light years away. ... The "Bessel determined that the star 61 Cygni was about ten light years away" Earth goes around the Sun in one year, so in six month it is in the opposite position in its orbit. ... In 1838 Bessel determined that the star 61 Cygni had a parallax of 0.314 arcseconds and therefore the star was about ten light years away (today the distance is more precisely measured to be 11.4 light years). ...

Astronomy Discussion Forums . Forums: . ... TIME DILATION . ... Time dilation is what we take to be the disagreement in the total time of an event as measured by a moving frame and stationary frame. ... Imagine a car 100km from a stationary observer and which is positioned such that it would travel 200km on a straight line in a direction away from the stationary observer. ... Therefore the total time of motion of the car as measured by the stationary observer is T= t- 100km/C + (100km+200km/C). ...

The database contains references to the papers, data files and links to the Internet resources related to measurements and calculations of the optical constants in the wavelength interval from X-rays to radio domain. ... References to some useful books and reviews on the subject (e.g. the classical handbooks edited by E.D.Palik) and links to Internet collections of optical constants and personal WWW pages with related software were also placed in the database. You have arrived at our welcome page. ...