... rgsspectrum creates an OGIP-compliant spectrum of counts for a single RGS exposure. ... background-corrected source spectrum . ... Note that although the spatial selection region for the background spectrum is not source-specific, the energy selection region is source-specific, and for this reason the background spectrum is technically source-specific. ... The above description of the BACKSCAL column applies only to Spectroscopy mode data; in HTR mode this column has nothing to do with exposure. ...

Next: Order Definition Up: Echelle Reduction Method Previous: Retrieving demonstration and . ... That is the mapping between the space wavelength, spectral order and the space sample x , line y in the raw image. ... Sections and describe the solution of this mapping. The second step in the reduction, described in Section , is to estimate the image background. ... In the rest of this Section the algorithms used in each step of the reduction are described. ...

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... The GHRS has the usual components of an astronomical spectrograph: entrance apertures, a collimator, dispersers, camera mirrors, and detectors. ... The collimator and camera mirrors are unexceptional and need no further description here (see ``The HST Focal Plane and the GHRS Apertures'' on page 73 for details). ... The first two first-order gratings, G140L and G140M, have their spectra imaged by mirror Cam-A onto detector D1, which is optimized for the shortest wavelengths. ...

... This is possible at modest cost due to the low moments of inertia of the telescope and enclosure. ... This same performance will be achieved in higher winds when the telescope enclosure is facing away from the wind, or by using wind screens. ... The telescope system (MILT) will be remotely operable with an on-site operator's assistance by an astronomer located at one of the ARC member institutions. ... Mean Wind Speed . ... Offsets > 10 deg: 1 arc sec rms max . ... 5 sec max, tracking to tracking . ...

... Telescopes . ... Diameter of circular antenna . ... Number of antenna elements . ... Geometrical area . ... Effective area of full circle . ... Wavelength range . ... Frequency range . ... 2 arcsec . ... Flux density limit . ... Absolute brightness temperature limit . 0.050 mK . ...