- Upload tycho catalogue for skychart software#
- Upload tycho catalogue for skychart license#
- Upload tycho catalogue for skychart free#
Upload tycho catalogue for skychart license#
This project has a Creative Commons License that allows you to freely download, use, and/or distribute the work for non-commercial purposes. It is now hosted on Cloudy Nights, one of the most popular astronomy communities on the web.
Upload tycho catalogue for skychart free#
Put the catalog.dat and index.dat files in a subdirectory data/ to the directory pointed to by the TY2_PATH environment parameter or the ty2cd variable in libwcs/ty2read.c.Andrew L Johnson started the Free Mag 7 Star Atlas Project on his personal web site, but it proved too popular, and it needed a more robust server. Add the carriage returns to the files using the unix2dos -ascii command.
Upload tycho catalogue for skychart software#
The resulting files will differ from the files on the CD-ROM in that they will end lines with only a linefeed, while the CD-ROM version for which WCSTools software was written terminates lines with a carriage return and a linefeed. After retrieving them and the index.dat file, combine the gzipped files into catalog.dat. The following FTP sites make the Tycho-2 catalogue available as 20 gzipped files. Tycho-2 File Formats WCSTools software uses the files catalog.dat and index.dat. imty2 lists the Tycho-2 stars within an IRAF or FITS image using the world coordinate system defined in its header.Ī Perl program for extracting data from the catalogue is available from. sty2 lists Tycho-2 stars by number or sky region. To enable rapid access of specific stars in the catalogue, WCSTools software numbers each star using its Guide Star region number (0001 to 9537) and a five-digit star number within each region, separated by a decimal point. Photometric accuracy for stars brighter than Vt=9 is 0.013 magnitude for all stars it is 0.10 magnitude. The observational period was from 1989.85 to 1993.21 and the mean satellite observation epoch is 1991.5. The overall error for all stars is 60 milliarcseconds. For stars brighter than Vt=9, the astrometric error is 7 milliarcseconds. There were only about 100,000 stars for which proper motion could not be derived. Proper motions precise to about 2.5 milliarcseconds per year are given as derived from a comparison with the Astrographic Catalogue (AC 2000) and 143 other ground-based astrometric catalogues, all reduced to the Hipparcos celestial coordinate system. Naval Observatory (USNO) first compiled the ACT Reference Catalog, (Astrographic Catalogue / Tycho) containing nearly one million stars, by combining the Astrographic Catalogue (AC 2000) with the Tycho-1 Catalogue the large epoch span between the two catalogues improved the accuracy of proper motions by about an order of magnitude. However, Tycho-2 is much larger and a bit more precise, because a more advanced reduction technique was used. They are the same observations used to compile the Tycho-1 Catalogue (ESA SP-1200, 1997).
The Tycho-2 positions and magnitudes are based on the observations collected by the star mapper of the European Space Agency's Hipparcos satellite. The catalogue is 99% complete to magnitudes of V~11.0 and 90% complete to V~11.5. Components of double stars with separations down to 0.8 arcseconds are included. The astrometric reference catalogue contain positions, proper motions, and two-color photometric data for 2,539,913 of the brightest stars in the Milky Way, of which about 9000 are visible to the naked eye.
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