David Brierley wrote: >For those of you who haven't heard, the Tycho data from the ESA >Hipparcos satellite has been reprocessed, resulting in a new catalogue >called Tycho-2 containing the positions and magnitudes of 2,539,913 >stars. It is claimed to have a cleaner cutoff than the first Tycho >catalogue, at around mag +11.5. It comes on a CD-ROM in one >uncompressed file of 515Mb. A while back I wrote a program to "compress" the SAO catalog of only 250000 stars into a file of 1MB so that a program (that I call "print near") could be used to print relatively inaccurate (0.01 degrees) positions and magnitudes for all stars "near" (about 1/2 to 1 degree) a given RA and Dec. A few months ago I did this for the first Tycho catalog. The resulting file was 3 bytes per star times 1200000 stars = 3.6MB. I will probably do this to this new catalog. 2500000 stars times 3 bytes = 7.5MB. I could also apply a magnitude cut-off to get a smaller file. Would anyone be interested in this? Typically only satellites above 5000 miles move so slowly and are so faint that such a catalog/program is needed to determine the observed position. If you are interested, probably you should email me directly: mikem@fc.net Mike McCants ----------------------------------------------------------------- Unsubscribe from SeeSat-L by sending a message with 'unsubscribe' in the SUBJECT to SeeSat-L-request@lists.satellite.eu.org http://www2.satellite.eu.org/seesat/seesatindex.html
This archive was generated by hypermail 2b29 : Mon Feb 14 2000 - 11:08:32 PST