Stationkeeping for near halo orbits in the Earth-Moon-Sun system is studied. The full solar system is considered as a perturbation of the restricted three body problem. The families of halo orbits and the motion near them is studied. The general equations of motion are integrated to get the final nominal quasi-periodic orbit. The on/off

Infrared photometry is reported from 1.25 to 10 micrometers for 10 Seyfert 1.8 and 1.9 galaxies identified by Osterbrock and his collaborators and drawn originally from the Markarian lists. The three objects whose infrared colors are the most nonstellar in nature are objects whose ultraviolet or optical spectra preclude heavy reddening of either

Not Available

A ≡7-hr observation of the central part of the Coma cluster of galaxies has been performed with the EXOSAT LE telescopes and CMA detectors. Five serendipitous sources are detected within the inner 35 arcmin radius of the field. Optical spectroscopy shows that four of these are background AGN not associated with the cluster. At the sensitivity level

Project Cassini is concerned with a potential collaborative mission to Saturn and Titan. The project has been the subject of a joint ESA/NASA Technical Assessment Study from April 1984 to July 1985. The spacecraft consists of a Saturn Orbiter and a Titan entry Probe. Science objectives with respect to Titan include a determination of the abundances

IAUC 4115 available at Central Bureau for Astronomical Telegrams.