NSSDCA ID: 1972-065A-01
Mission Name: OAO 3The primary objective of this Princeton telescope-spectrometer was to make quantitative observations of interstellar absorption lines with a resolution of about 0.05 A between 950 and 1450 A, and twice in first order between 1650 and 3000 A. The secondary objective was to observe UV spectra of selected brighter stars. The prime optical system was an 80-cm diameter Cassegrain telescope with a 16-m focal length (f/20). This telescope was coupled to a Paschen-Runge spectrometer with a concave grating which focused the spectrum on a 1-m Rowland circle, with a dispersion of 4.2 A per mm in first order. The entrance slit was 3 mm long and 24.2 microns wide, corresponding to 390 arc-s by 0.314 arc-s on the sky. The Bausch and Lomb grating was ruled with 2400 lines per mm, blazed for 2200 A in first order. The photons were detected by four phototubes, each equipped with its own exit slit and movable in pairs along the Rowland circle. A guidance error sensor attached to the prime optics controlled the spacecraft attitude to within 0.1 arc-s. This guidance system locked onto a star as faint as 7th magnitude. The overall system could make useful measurements on O-and B-type stars to 7th magnitude. For more details, see J. B. Rogerson et al., Ap. J., v. 181, p. L97, 1973; A. B. Wissinger, Opt. Eng., v. 14, p. 133, 1975.
Questions and comments about this experiment can be directed to: Coordinated Request and User Support Office
Name | Role | Original Affiliation | |
---|---|---|---|
Dr. John B. Rogerson, Jr. | Other Investigator | Princeton University | jbrogers@princeton.edu |
Prof. Lyman Spitzer, Jr. | Principal Investigator | Princeton University |