Документ взят из кэша поисковой машины. Адрес оригинального документа : http://www.sao.ru/precise/Laboratory/Publications/1999/HSSI/TEXT/node4.html
Дата изменения: Tue Nov 24 21:18:57 1998
Дата индексирования: Sat Sep 11 22:06:39 2010
Кодировка:
Поисковые слова: orion nebula

SAO 6m observations

The first observations of a small subsample of HSS candidates were conducted in January 1995 with the SAO 6m telescope. The telescope was equipped with the 1024-channel photon counter detector (IPCS) mounted on the medium resolution spectrograph SP-124 in the Nasmyth-1 focus (Drabek et al. 1986). A 2'' diameter circular aperture was centered on the brightest part of the target galaxy or on the star-like candidate, and a similar aperture was placed 20'' off along the direction zenith-nadir to accumulate simultaneously the night sky spectrum. The latter was subtracted during the data reduction from the target spectrum. This set-up resulted in a spectral coverage of $\lambda$ 3700-5500 Å with a scale 1.8 Å/channel along the dispersion and a spectral resolution (FWHM) of about 10 Å. The exposure time varied between 3 and 5 minutes depending on the brightness. The signal-to-noise ratios of these spectra are $\approx$ 5 in the continuum at $\lambda$ 5000 Å. The seeing was about 2''.

During the night we have observed spectrophotometric standards from the KPNO list (Massey et al. [1988]) which were used to correct the spectra of the program galaxies for the system spectral response. An He-Ne-Ar lamp was used for the wavelength calibration. A flat-field was accumulated every night before and after the observations and all spectra are corrected for the flat field after azimuth and modulation correction of the original 1024-channel arrays.