Документ взят из кэша поисковой машины. Адрес оригинального документа : http://www.stsci.edu/ftp/instrument_news/FOS/pub/fos_isr088_a.txt Дата изменения: Wed Oct 11 23:48:19 1995 Дата индексирования: Sun Dec 23 05:12:42 2007 Кодировка: Поисковые слова: south pole

FOS FLATS FROM SUPER SPECTRA

D. Lindler, R. Bohlin, G. Hartig, and C. Keyes

FOS Instrument Science Report CAL/FOS-088
March 29, 1993

ABSTRACT:

A new algorithm for computing the FOS detector non-uniformities
(flat field response) uses spectra of stars taken in 9 different
positions in the 4.3 arcsec aperture. Despite some "ringing" at
frequencies corresponding to the constant offset of the star in
the dispersion direction, the new blue flat fields achieve our
accuracy goal of about 1% and are appropriate for FOS BLUE side
spectra taken in any aperture in 1992.
Ringing at a higher level of 1-2 percent in the RED data is
caused by the loss of two-thirds of the G191B2B data due to
observing problems. These RED side flats should be used only
for blemish location or for visual verification of potential
features in observed spectra.
Future flat field data should be collected with a newly
recommended set of locations of the star in the FOS 4.3 arcsec
aperture.