DDO Standard Velocity Star Measures 1968–1984

The current Cassegrain spectrograph on the DDO 1.9m telescope was first used in 1966, but came into regular service in 1968. It is a fairly standard configuration with a Cassegrain collimnator and f/2 and f/5 Schmidt cameras. In practice, the f/5 camera with gratings which yield dispersions of 8A/mm and 12A/mm In the blue have been used almost exclusively, with the latter the more common. Interchangeable red- and blue-enhanced collimnators and Richardson image slicers were added in June, 1978. More than 1200 plates of IAU standard velocity stars have been taken with this spectrograph, of which measures of 956 were made by us, or were available from the DDO archives or were made available by other investigators. Ten of these plates were not used because they were taken with unusual grating and tilt combinations. Some of the plates left unmeasured were simply broken or of poor quality, but a depressingly large number were simply missing. Most of the stars of spectral type M have also not been measured, since a line list for this class has only recently been created. Of the plates used in this study 810 were with the 12A/mm dispersion, 110 with the 8A/mm, and 26 were taken at 16A/mm in the red. The latter are of less use in studying the IAU stars themselves, but are essential in calibrating the rather considerable number of velocities measured here in the red.