Astrometric Techniques for the Observations of Planetary Satellites

An historical overview of astrometric techniques used to study planetary satellites is presented. Visual methods used for orbital adjustment based on the timing of phenomena such as eclipses, occultations, and shadow transits or on heliometer, filar micrometer, or photographic observations of positions in the tangent plane are discussed. The Struve method in which positions of satellites relative to one another are used in orbital adjustment is outlined. Modern photographic techniques are described, and the future of spacecraft imaging techniques and earth-based radar techniques in astrometric studies is assessed. The instruments used in each technique are examined, and sources of error are considered.