Telesto is known as a Tethys Trojan because, together with Calypso, it circles Saturn in the same orbit as the moon Tethys Telesto orbits about 60 degrees ahead of Tethys and Calypso orbits behind Tethys by about 60 degrees. Telesto is the leading Trojan. Calypso is the trailing Trojan.
Telesto is about 24 km (15 miles) across and appears to have a smooth, icy surface. It does not show the signs of instense cratering seen on many of Saturn's other moons.
Telesto was discovered in 1980 using ground-based observations by Brad Smith, Harold Reitsema, Stephen Larson, and John Fountain
How Telesto Got its Name:
Telesto [tah-LESS-toh] is a daughter of the Titans, Oceanus and Tethys in Greek mythology. It was originally designated S/1981 S1.