Observing Comet Halley with Space Telescope

The NASA Space Telescope (ST) to be launched into LEO by STS in late 1985 is characterized, and its potential use for observations of Comet Halley shortly after the perihelion passage in February, 1986, is discussed. The ST comprises a 2.4-m MgF2-coated primary reflector (with maximum field of view 2.7 x 2.7 arcmin, wavelength coverage 120-1100 nm, and maximum tracking rate 0.21 arcsec/sec) and five first-generation scientific instruments (wide-field planetary camera, faint-object camera, high-resolution and faint-object spectrographs, and high-speed photometer). Planned ST observations of Halley include periods of continuous observation much longer than can be obtained from the ground, provision of supplementary data and navigation information to Giotto and other deep-space missions, emission spectroscopy, UV polarimetry, and possible detection of 124-nm H2O absorption. Before March 11, 1986, earth occultation or similar procedures will be required to observe Halley because it will be within the ST 50-deg solar-elongation-distance limit.