... Astrometry with the FGS, by contrast, proceeds in the reverse order; the positions of the individual objects are found first, and then a virtual plate is constructed with the help of data from the guide stars and check stars. ... Corrections based on guide star data are referred to as POSITION mode dejittering , and those based on check star data are called drift corrections . ... The adjustments to the astrometry centroids from this POSITION mode dejittering correction are typically about 1 mas. ...

Start Data Acquisition - Selected Wavelengths - 22/Apr/2014 16:06:46.063 Observation Type - Target Images - 22/Apr/2014 16:06:46.088 22/Apr/2014 16:06:48.128 Begin Iteration #1 of 2 - Number of Frames : 17 - 22/Apr/2014 16:06:48.144 Filter : 6563 (Position 3) | ... Acquisition Time : 22/Apr/2014 16:06:48.273 | ... ExpTime (sec) : 0.030 | Stokes : I Filter : 6563 (Position 3) | ... Stokes : I Begin Iteration #2 of 2 - Number of Frames : 17 - 22/Apr/2014 16:06:50.942 Filter : 6563 (Position 3) | ...

... 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 . ...

... To plot the data (and model, here xitau.model), I have read the model, computed the model values for the ASTROMETRY, and used Plot|ASTROMETRY to produce the ASTROMETRY plot widget. ... First, plot the data and with Util|Ellipse and the mouse buttons interactively define an apparent ellipse to fit your data as best as you can. ... Under Util|Orbit, there is a Thiele-Innes procedure to estimate the orbital elements using your apparent ellipse and Kepler's laws! ... Back to tour page . ...

Pulkovo Database of Observations of Visual Double Stars . ... Catalog of relative positions of visual double stars, based on photographic observations performed since 1960 in Pulkovo on the 26-inch refractor (A.A.Kiselev, O.A.Kalinichenko, O.V.Kiyaeva, N.A.Shakht, L.G.Romanenko, I.S.Izmailov, O.P.Bykov, K.L.Maslennikov, E.A.Grosheva, D.L.Gorshanov), 2010 . ... Enter either ADS or WDS number. Click here to display full list of visual double stars observed at Pulkovo. ADS . ...

Pulkovo NEO Page . ... NEA Accuracy Estimation . ... The estimation of accuracy of the current CCD observations of asteroids and comets is constantly performed at Pulkovo Observatory. ... The (O-C) values, so called "Observed" minus "Calculated" positions, characterize numerically the observations of any observatory, both professional and amateur, during a short period (one or several close nights). ... So the (O-C) values for these objects nearly entirely define the errors of observations. ...

... 8, ``Celestial Mechanics'', 2002 CCD observations of planetary satellites and occultations and close approachments of stars by asteroids with 26­ inch refractor of Pulkovo observatory T. P. Kiseleva, I. S. Izmailov, M. A. Mozhaev Pulkovo Observatory, St. Petersburg, Russia ST--6 CCD camera has been used with 26-- inch Refractor at Pulkovo for ob­ servations of ... These estimates are \Sigma0:015 arcsec and \Sigma0:014 arcsec for X and Y correspondingly. ...

... The HST uses an onboard model of its orbit to perform in real-time various control functions relating to spacecraft operations and observation support. ... New coefficients for the ephemeris are updated every other day, and are archived as FITS keywords for each HST observation data set. Using these coefficients,an observer can perform a variety of calibration and characterization calculations relating to the orbital position and velocity of the telescope. ...

... A document window is shown, with 8 lines (numbered 1 to 8), each 24px high. The text of the "outer" box (at the end of line 1, halfway into line 2, and halfway into line 3) is shifted upward 12px. The text of the "inner" box, thought shifted upward as well, has been relatively positioned so that it lies in its normal flow position at the end of line 2. ... The lines, as they appear in the image, contain: Start 1 Beginning of body contents. 2 of outer contents. Inner contents. ...

... We publish 16 Doppler imaging temperature maps for the years 1994-2002 of the active RS CVn star II Peg. ... Through Doppler imaging we want to study the spot evolution of the star and in particular compare this with previous results showing a cyclic spot behaviour and persistent active longitudes. ... The derived temperature maps are quite similar to th