Who discovered 243 Ida and when was it found?
Austrian astronomer Johann Palisa spotted 243 Ida on the 29th of September 1884 from his post at Vienna Observatory. This marked his forty-fifth asteroid discovery in a career spanning decades.
Austrian astronomer Johann Palisa spotted 243 Ida on the 29th of September 1884 from his post at Vienna Observatory. This marked his forty-fifth asteroid discovery in a career spanning decades.
The name came later from Moriz von Kuffner, a Viennese brewer who also dabbled in amateur astronomy. He chose the name from Greek mythology where Ida was a nymph of Crete who raised the god Zeus.
The uncrewed Galileo spacecraft flew past 243 Ida on the 28th of August 1993 while en route to Jupiter. The probe approached within roughly 4,000 kilometers of the asteroid at speeds exceeding 14,000 meters per second relative to the target.
Mission member Ann Harch identified the moon Dactyl on the 17th of February 1994 while examining delayed image downloads from the spacecraft. She found it in forty-seven images recorded over an observation period of five point five hours in August 1993.
Ida measures 2.35 times longer than it is wide with a constricted waist separating two geologically dissimilar halves. A thick layer of regolith covers the surface acting as a blanket of pulverized rock about thirty meters deep.