| T-Ring |
An accessory which is used to attach a camera to a telescope. |
| T-Ring Adapter |
A camera accessory for SLR type cameras. It replaces the removable camera lens assemble so that the camera can be attached to the optical line of the telescope. |
| T-Thread |
A photographic industry standard screw thread to attach a telescope's T-Ring to a camera's T-Ring Adapter. The 'T' stands for telescope. |
| Tarvos |
A moon of Saturn was discovered by John Kavelaars in 2000. Siarnaq also is designated as "Saturn XXI" and "S/2000 S4". In Gaulish mythology, Tarvos was the bull god. |
| Taurus |
Taurus (The Bull) is a zodiacal constellation, that is, it lies across the ecliptic, an imaginary line across the sky that the Sun, Moon and all the planets except Pluto seem to move along. Inside the constellation Taurus is the Crab Nebula (M1) and the star clusters Pleiades and Hyades. Also in Taurus is the bright, red, first-magnitude star Aldebaran located at the tip of one of the horns of Taurus. |
| Taygete |
A moon of Jupiter was discovered by Scott Sheppard and team in 2000. Taygete is also designated as "Jupiter XX" and "S/2000 J9". In Greek mythology, Taygete was a was a nymph and "Mistress of the animals." |
| Telescopium |
The constellation "The Telescope" |
| Telesto |
A moon of Saturn was discovered by Brad Smith, Harold Reitsema, Steven Larson and John Fountain on April 8, 1980. Telesto also is designated as "Saturn XIII" and "S/1980 S13". In Greek mythology, Telesto was daughter of Oceanus and Tethys and was the personification of "Success". |
| Terminator |
Boundary area between the lit and dark areas of the moon or planet. |
| Tethys |
A moon of Saturn was discovered by Giovanni Cassini in 1684. Tethys also is designated as "Saturn III". In Greek mythology, Tethys was a Titaness who was sister and wife to Oceanus and mother to the Rivers: nile, Alpheus and Maeander. |
| Thalassa |
A moon of Neptune was discovered by the Voyager Imaging Team in September, 1989. Thalassa is also designated as "Neptune IV" and "S/1989 N5". In Greek mythology, Thalassa was a daughter of Aether and Hemera. |
| Thebe |
A moon of Jupiter was discovered by Stephen P. Synnott on March 5, 1979. Thebe is also designated as "Jupiter XIV" and "S/1979 J2". In Greek mythology, Thebe was a nymph who was the daughter of the river god Asopus. |
| Thelxinoe |
A moon of Jupiter was discovered by Scott S. Sheppard and team in 2004. Thelxinoe is also designated as "Jupiter XLII" and "S/2003 J22". In Greek mythology, Thelxinoe was one of the three original Muses. |
| Themisto |
A moon of Jupiter was discovered by Charles T. Kowal and Elizabeth Roemer on September 30, 1975. Themisto is also designated as "Jupiter XVIII" and "S/1975 J1". In Greek mythology, Themisto was a daughter of the river god Inachus, and become the mother of Ister (the river Danube) by Zeus. |
| Thermals |
In reflecting telescopes, thermal convection currents originating from the primary mirror that are set in motion within the open main tube. |
| Three Star Alignment |
A procedure used by Celestron computerized telescope mounts to orient the computer to the celestial sphere without knowing what bright stars selected actually are -- the computer figures it out for you. Also see 'Two Star Alignment". |
| Thrym |
A moon of Saturn was discovered by Brett Gladman in 2000. Suttung, sometimes called Suttungr, also is designated as "Saturn XXX" and "S/2000 S7". In Norse mythology, Suttung was a frost giant who stole Thor's hammer. |
| Thunder Moon |
The name of the Full Moon usually in July. Specifically the first Full Moon after the Summer Solstice (June 22 by "The Maine Rule"). Sometimes known as the "Buck Moon" or the "Hay Moon." |
| Thyone |
A moon of Jupiter was discovered by Scott Sheppard and team in 2001. Thyone is also designated as "Jupiter Jupiter XXIX" and "S/2001 J2". In Greek mythology, Thyone, alsoo known as Semele, was the daughter of Cadmus and Harmonia and the mother of the goddess Dionysus. |
| Titan |
The largest moon of Saturn was discovered by Christiaan Huygens on March 25, 1655. Titan also is designated as "Saturn VI". In Greek mythology, Titans were giant brothers and sisters who gave birth to the gods. |
| Titania |
The largest moon of Uranus was discovered by William Herschel on January 11, 1787. Titania is also designated as "Uranus III". Titania is the Queen of the Faeries in William Shakespeare's play A Midsummer Night's Dream. |
| Transmission Coatings |
Coatings added to a lens to prevent light from being reflected away as light passes from air to glass. Examples of transmission coatings would be Meade's UHTC coatings and Celestron's XLT coatings. |
| Triangulum |
The constellation "The Triangle" |
| Triangulum Australe |
The constellation "The Southern Triangle" |
| Trinculo |
A moon of Uranus was discovered by Discovered by Matthew J. Holman, John J. Kavelaars, Dan Milisavljevic on August 13, 2001. Trinculo is also designated as "Uranus XXI" and "S/2001 U1". Trinculo is the drunken butler in William Shakespeare's play The Tempest. |
| Tripod |
A three-legged stand to hold a telescope mount |
| Triton |
The largest moon of Neptune was discovered by William Lassell on October 10, 1846. Triton is also designated as "Neptune I". In Greek mythology, Triton was a sea god and the son of Neptune. |
| Tucana |
The constellation "The Toucan" |
| Two Star Alignment |
A procedure used by computerized telescope mounts to orient the computer to the celestial sphere. Also see 'Three Star Alignment'. |
