OBSERVATIONS OF QUASI-STELLAR AND HARO-LUYTEN BLUE OBJECTS.

Abstract

be installed at Yerkes Observatory. The spectrograph has a threeinch optical bundle, a perforated grating, and an f/2 folded Schmidt camera. This camera was designed and constructed so that the focus is 0.5 inch beyond any obstruction. This is sufficient to permit the image tube to be placed in a uniform magnetic field of a solenoid with a special pole face. The Schmidt is provided with a field flattener, but the flattener is not in optical contact with the image tube face. Four dispersions are available in factors of two from 50 to 400 Â/mm. Because of a loss of resolution in the image tube and photographic transfer system, these dispersions correspond approximately in resolution to classical spectrograms with approximately one-half the dispersion. In February 1966 the spectrograph was used on the 82-inch telescope of the McDonald Observatory to secure spectrograms of quasi-stellar objects and Haro-Luyten blue objects. The wavelength region covered depended somewhat on the colors of the sources but was generally between 3800 and 7000 Â. A nominal dispersion of 200 Â/mm was used throughout the program. Three of the spectrograms are shown in Plate I. The image tube itself is capable of giving significantly higher resolution, but with the introduction of the transfer lenses and photographic emulsions not only is the resolution reduced but the spectrograms lose the crispness usually associated with classic spectroscopy. The nineteen Haro-Luyten objects were selected according to observing convenience, without reference to their colors, from a set of finding charts kindly supplied by Dr. E. J. Wampler. Only two of them, both shown in Plate I, showed emission lines. An additional 16, which are listed in Table