Tycho-2 Catalogue

The Tycho-2 Catalogue is a catalogue of more than 2.5 million of the brightest stars.

Catalogue

The astrometric reference catalogue contain positions, proper motions, and two-color photometric data for the 2,539,913 of the brightest stars in the Milky Way, of which about 9000 are visible to the naked eye. Components of double stars with separations down to 0.8 arcseconds are included. The catalog is 99% complete to magnitudes of V~11.0 and 90% complete to V~11.5. (, Table 1)

The Tycho-2 positions and magnitudes are based on the observations collected by the star mapper of the European Space Agency's Hipparcos satellite. They are the same observations used to compile the Tycho-1 Catalogue (ESA SP-1200, 1997). However, Tycho-2 is much larger and a bit more precise, because a more advanced reduction technique was used.

The U.S. Naval Observatory (USNO) first compiled the ACT (Astrographic Catalog/Tycho) Reference Catalog, containing nearly one million stars, by combining the Astrographic Catalogue (AC 2000) with the Tycho-1 Catalogue; the large epoch span between the two catalogs improved the accuracy of proper motions by about an order of magnitude. Tycho-2 now supersedes the ACT.

Tycho

Tycho may refer to:

People

Astronomy

Fiction

Software engineering

Tycho (musician)

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Tycho (pronounced like Tie-ko, with emphasis on the first syllable) is an American ambient music project led by Scott Hansen (born 1976 or 1977) as primary composer, songwriter and producer. Hailing from San Francisco, California, he is known as ISO50 for his photographic and design works. His music is a combination of downtempo vintage-style synthesizers and ambient melodies. The style of his music is very organic, typically incorporating clips of the human element into his songs (i.e. weather broadcasts, simple talking, or even breathing). His song, "Dictaphone's Lament", was used as the track on a music video entitled "Live Life to the Fullest", which was made by and featured on the action cartoon block Toonami. His song "Cascade" (originally made for an Adult Swim and Ghostly International compilation called Ghostly Swim) was played during the final moments of the original 11-year run of Toonami in 2008. As of December 2014, Tycho is signed to, and has released under, Ghostly International, but has also released music on Merck Records and Gammaphone Records.

Tycho (crater)

Tycho (/ˈtaɪkoʊ/) is a prominent lunar impact crater located in the southern lunar highlands, named after the Danish astronomer Tycho Brahe (1546–1601). To the south is the crater Street; to the east is Pictet, and to the north-northeast is Sasserides. The surface around Tycho is replete with craters of various sizes, many overlapping still older craters. Some of the smaller craters are secondary craters formed from larger chunks of ejecta from Tycho.

Age and description

Tycho is a relatively young crater, with an estimated age of 108 million years (Ma), based on analysis of samples of the crater ray recovered during the Apollo 16 mission. This age suggests that the impactor may have been a member of the Baptistina family of asteroids, but as the composition of the impactor is unknown this is currently conjecture. However, simulation studies give a 70 percent probability that the crater was created by a fragment from the same break-up that created asteroid 298 Baptistina; which was previously believed to be responsible for the formation of Chicxulub Crater and the extinction of the dinosaurs. However, that possibility was potentially ruled out by the Wide-field Infrared Survey Explorer in 2011.