A rocket telescope spectrometer with high precision pointing control.

One second of arc pointing accuracy has been achieved by servocontrolling the secondary mirror of a Dall-Kirkham telescope flown in an Aerobee 150 rocket. The primary mirror is weight-relieved, mounted at its nodal line and can resolve 2 arc sec. An objective LiF prism mounted near the focal plane provides a lowresolution far uv spectrum suitable for studying planetary atmospheres. Solar blind photomultiplier tubes with pulse counting electronics provide a dark current background of less than 1 count/sec. Spectra of Venus, Jupiter and eta Ursa Majoris (U Ma) were obtained in a flight from White Sands, New Mexico, on 5 December 1967. Further flights are planned with the recovered package.