Instrument Science Report NICMOS-98-010 NICMOS Parallel Thermal Background: Results from SMOV and Cycle 7. ... Parallel observations in NICMOS Camera 2 and Camera 3 are taken at different pointings and analysis of the data shows the HST thermal emission to be fairly stable, with an orbital variation of ~5% and a secular variation of ~8%. ... In this study, the thermal background measurements are presented as the average count-rate calculated over the entire chip. ...

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 . ...

Next: SAS processing Up: Maintenance procedures Previous: Maintenance procedures Contents . Suitable observations should be longer than about 20 ksec, cover all the considered time period, and have different background levels, in particular the highest ones, so the sample should include observations taken at the beginning and end of the science window. It is helpful to consider objects for which no RGS spectrum is expected or to look at the RGS monitor pages. ... Michael Smith 2011-09-20 ...

... In most astronomical observations the image intensity consists of contributions from both object and sky background. Depending on the complexity of the field and the type of object, different methods are used to estimate and subtract the background intensity. ... Non--linear filters are often used to remove stellar images and other sharp features (see Section ) while extended objects are very difficult to eliminate automatically. ...

... 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. ...

... 2000 January 14 . Chandra Resolves the Hard X-Ray Background . ... Chandra , NASA . ... In every direction at all times, the sky glows in X-rays . ... Yesterday results were released using data from the recently launched Chandra X-Ray Observatory that appears to have resolved much of this mystery. The above photograph shows that about 80 percent of the apparently diffuse hard X-ray background can be resolved into very many very faint sources. ... About APOD | ...

The Arecibo Galaxy Environment Survey (normally known as AGES) is using the Arecibo Telescope to search for galaxies in a number of quite different areas of the local universe. ... NGC 628 group (precursor) - published (Auld et al., ... NGC 1156 (isolated galaxy) - published (Minchin et al, 2010, AJ, 140, 1093) . NGC 7332/9 galaxy pair - published (Minchin et al, 2010, AJ, 140, 1093) . ... NGC 5523 (isolated galaxy) - completed (contact: Robert Minchin) . ... AGES team page - password protected . ...

... The J, H and K bands are characterized by a bright background, such a background is mainly due to the emission of atmospheric lines and of thermal radiation. ... If the source cover a large fraction of the slit, spectra off-source must be observed to adequately sample the sky background. ... The on chip integration time (time spent in each position of the slit) must not exceed 40 seconds in J and H bands and 60 seconds in K band. ... We suggest a sequence of 10 for each elementary integration time. ...

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) . ...