From Astronomy Picture of the Day; October 17, 2025:
Ida and Dactyl: Asteroid and Moon Image Credit: NASA, JPL, Galileo Mission This asteroid has a moon. The robot spacecraft Galileo enroute to explore the Jovian system in 1993, encountered and photographed two asteroids during its long interplanetary voyage. The second minor planet it photographed, 243 Ida, was discovered to have a moon. The tiny moon, named Dactyl, is only about 1.6 kilometers across and seen as a small dot to the right in the image. In contrast, Ida is much larger, measuring about 60 km long and 25 km wide. In fact, Dactyl is the first moon of an asteroid ever discovered. But now many asteroids are known to have moons. Minor planet names Ida and Dactyl were taken from Greek mythology. Starship Asterisk* APOD Discussion Page for Today's Image
The APOD website is down due to the government shutdown, however new images are still being posted to the website’s discussion forum and mirror sites
