... 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. ...

... The orbits as follows are considered: INTERBALL Tail Probe (IB_TAIL) & Auroral Probe (IB_AUR), GEOTAIL (NASA/ISAS), and POLAR (NASA). ... The situation investigation aim is to select the following favourable spatial positions (FSP) : . ... FSP3 : That part of the FSP1 & FSP2 time intervals, which corresponds to the magnetic conjugations of the any couple of the considered spacecraft. ... The polar diagram plot . ... The geocentric distance (GCD) of the 4 spacecraft as a function of the time. ...

... 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. ...

Position Switching Separation Tolerance with Arecibo in L-Band Travis McIntyre The University of New Mexico July 2010 Revised December 2013 Abstract The blocked telescope aperture at Arecibo creates standing waves in the bandpass around 1MHz. ... Test observations with Arecibo in L-Band show that position switching effectively removes standing waves for separations of one half FWHM or less. Standing waves remain for separations of one FWHM, increasing the rms of the baseline by 20%. ...

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. ...

... 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. ...

Databases (NSDC) of the Natural Planetary Satellites. ... NSDC: Database of astrometric observations of Natural Planetary Satellites . ... They are thoroughly looking for observations in different sources, creating their owndatabases which are then mostly inaccessible to other researchers. ... In the file "content" with explications, the reference is given to the data source as well as the bibliographic reference. ... Data sources. ... Why a specific bibliographic database for Natural satellites? ...

Next: Program use Up: Description of program searchdup Previous: Description of program searchdup . Parameter input is done with a graphic user interface. ... Input file: Name of the input catalog file. It has to be formatted, one record per source/observation, according to the format used in the Arcetri observations and source archives. ... Minimum number of observations per source Source with less than this number of independent observations are not included in the output file . ...

This thread illustrates how to evaluate if your RGS observation is affected by pile-up; if so, how to deal with it in some special cases; and how to prevent it occurring. ... Pile-up will cause two coincident first order . ... Thus, pile-up may differ between RGS1 and RGS2 and may abruptly vary between CCD locations due to the nominal event pattern distribution variations over the detectors. ... Migration of photons from 1st to 2nd order (or from 2nd order to 3rd order) . ...

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 . ...

... RJMCMC Similar to Richardson Green 1997 Knowledge of the PSF makes things easier Insensitive to e.g. posterior for ten sources with = 3: Number of Components 9 10 11 12 0.141 0.222 0.220 0.157 0.022 0.029 0.027 0.021 Mean SD 7 0.029 0.018 8 0.058 0.019 13 0.082 0.014 Simulated Data Source region (2 SD) is about 28% of the area and contains about 41% of the observations Positions (-2, 0), (0, 1), (1.5, 0) with intensities ... Approximate the number of sources (2 in this case) 2. ...

Next: Catalog Construction Up: Observations and Analysis Previous: Source Detections . ... It was assumed that the highest signal gives the most likely position of the source. ... Comparing the summed map with the maps from the individual energy ranges, the one which produced the smallest error box was chosen to represent the source position, as long as was greater than 4, a level chosen to reflect a reasonable degree of confidence in the detection. ...

... astro-ph . ... Statistical Characterization of the Chandra Source Catalog . ... The first release of the Chandra Source Catalog (CSC) contains ~95,000 X-ray sources in a total area of ~0.75% of the entire sky, using data from ~3,900 separate ACIS observations of a multitude of different types of X-ray sources. ... In addition to these traditional catalog elements, for each X-ray source the CSC includes an extensive set of file-based data products that can be manipulated interactively. ...

These observations are aimed at fully charactering FORS1 photometric system (UBVRI zero-points, color-terms and extinction coefficients) for the Tektronix 2048x2048 pixel CCD (24µm px) . To this aim, the two Landolt/Stetson photometric fields SA95 and SA101 will be observed on a number of epochs and at different airmasses during February and March 2007. ... SA101 . ... OBs for SA101 have to be observed during evenigh twilight (exceptions are expected for the second half of March) . ...

... 8, ``Celestial Mechanics'', 2002 Estimation of masses of some minor planets from observations of perturbed bodies O. M. Kochetova Institute of Applied Astronomy, St. Petersburg, Russia The most straightforward method of mass determination of minor planets is the dynamical one which uses the gravitational perturbations produced by minor planet in the motion of other bodies. ... The values of the masses of minor planets (15), (29) and (65) appear to be rather close in both papers. ...

... 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. ...

Atmospheric influence on the different radio-engineering system functioning . ESTIMATION OF ATMOSPHERIC OPTICAL CHARACTERISTICS AND REMOTELY SANSED IMAGE CORRECTION . ... Direct transmittance estimation results for 12 channels of the spectrometer CHRIS. ... We have managed to develop a direct method of estimating the discrete Normalized Atmospheric Point Spread Function (NAPSF) from available images alone, not using any external sources of information about the atmosphere. ... IRE RAS 1996-20 11 ...

... Comet Tutorial . ... On July 1, 1993 an image was taken with the Hubble Space Telescope (HST) that clearly shows at least 15 individual fragments in one image frame of the train. ... This made an accurate orbit (or orbits) difficult to determine; however, after numerous observations of the comet, astronmers determined that the comet had passed within 96,000 kilometers (60,000 miles) of the center of Jupiter or 25,000 kilometers (16,000 miles) from the cloud tops during the July 8, 1992, approach. ...

Astronomy Discussion Forums . ... I Think What You're Saying Is Not A Deeply-considered Position . ... Post Message | ... Posted by M.W.Pearson on October 16, 2002 19:36:09 UTC . ... I think there is more to it than dismissing Dr. Dick's position. ... http://www.astronomy.net/forums/god/messages/23110.shtml . ... www.astronomy.net . About Astronomy Net | ... Forum posts are Copyright their authors as specified in the heading above the post. "dbHTML," "AstroGuide," "ASTRONOMY.NET" & "VA.NET" . ...

... If you have centered the object on the chip the pattern will put the object in each of the 4 quadrants of the chip. ... They are the offset in arcseconds for the x and y inst plane offset, the exposure time in seconds, and the number of exposures at each position. ... A point about offsets should be made here. The dither program uses absolute instrument plane offsets, so you should use object plane offsets to center up on the chip so that the script starts from where you centered up. ...