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The following new features are available in version 3.20 of "Astrometrica":
Download
Registered users can download an update (247 kB, EXE and README files only) to version 3.25. A complete version (357 kB) is available here.
Users of older versions than 3.2 must also contact the author to receive their personal license file as e-mail attachement.
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The USNO-SA has data on about 55 million objects, extracted from the USNO-A catalog to produce a spatially uniform net of faint (mainly 16mag to 19mag) reference stars with a density of about 1300 objects per square degree. The astrometric positions of both the USNO-A and the USNO-SA are said to be accurate to about 0.25", and the new version 2.0 of both catalogues have been reduced to ACT reference frame, so they are probably the most accurate high-desnsity star catalogues available today. The single CD-ROM USNO-SA 2.0 catlog is available for free from the Astrometry Department of the U.S. Naval Observatory.
Important Note: While the USNO-SA catalog is generally available at no cost, but individuals who need USNO-A must provide a sufficient and succinct scientific justification for why their need is not satisfied by USNO-SA when contacting the Astrometry Department of the U.S. Naval Observatory!
Note:"Astrometrica" can not access the Hipparcos/Tycho data on the Celestia 2000 CD-ROM (no information on the file format is available).
According to Sean E. Urban, the U.S. Naval Observatory has run out of ACT CD-ROMs. The complete catalog is, however, available for download in the U.S.A., Europe, and Japan. So one can eventually write his orher own ACT CD-ROM.
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If you encounter any problems using the graphics display of "Astrometrica", check the list below for possible reasons and solutions:
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