“2-D Frutti” Spectra of B Supergiants in the Milky Way and the LMC

Extract

Digital spectra of 7 B-type supergiants in the Milky Way and 15 B-type supergiants in the Large Magellanic Cloud (LMC) were obtained in December 1986 using the “2-D Frutti” detector (2-DF) and the Carnegie Image Tube Spectrograph on the 1-m telescope at the Cerro Tololo Inter-American Observatory. The 2-DF is a photon counting, 2-dimensional Shechtman-type detector, now available on both the 1-m and 4-m telescopes at CTIO. The detector/spectrograph configuration used for the December observing run yielded spectra covering the classical blue region, 3800-5000 Å, with a resolution of approximately 3 Å. The typical observing procedure was to obtain spectra for each star at several locations along the slit. The individual spectra were then averaged (to reduce the detector fixed pattern noise) resulting in S/N ratios of 50-60 in the 4300 Å region.