Recent Enhancements to and Future Plans for the "Sky2000 Star Catalog"

Our continuing efforts to improve the NASA "SKY2000" satellite attitude determination star catalog, previously known as "SKYMAP", to make it into a modern, high-quality comprehensive source of stellar data, have allowed us to complete Version 3 of the "SKY2000" catalog (2000 June). The present version of the catalog contains 299,160 entries and is reasonably complete to visual magnitude 9. As with previous versions of the "SKY2000" and "SKYMAP" catalogs, the most important data in the catalog are astrometry and photometry, because this information is essential for multiplicity, spectral type and luminosity class, and variability area also required to predict what the star trackers will detect. The "SKY2000 Version 3" catalog marks the global replacement of the Henry Draper (HD) spectral type data, as well as the global replacement of the photovisual (ptv) and photographic (ptg) magnitude data. During this process 4,784 entries had HD or HD Extension (HDE) identifiers added, for a total of 210,062 entries with HD/HDE indentifiers. A planned global replacement of variable star name/identifiers and variability data was not carried out because of resource constraints, but 311 variable star names/identifiers were added during analysis, bringing the total number of entries with variable star names or identifiers to 2,575. The next planned update to the "SKY2000" catalog will include a global replacement of variable star names/identifiers and variablity data. Catalogs to be utilized will include, but are not limited to, the "General Catalogue of Variabe Stars" (GCVS) (Kholopov et al. 1995) and the "New Catalogue of Suspected Variable Stars" (NSV) (Kukarkin et al. 1982). Completion of this updated version of the "SKY2000" catalog is anticipated in Spring, 2001. We intend eventually to utilize the AAVSO database to incorporate the highest quality data periods and amplitudes, particularly for long period variables, but this may not be possible for the next enhancement. This paper describes the current status after recent enhancement of the "SKY2000" catalog and outlines plans for future improvements. This edition ("SKY2000", version 3) and future editions of the catalog will be made available at Goddard's Flight Dynamics Web site: http://cheli.gsfc.nasa.gov/dist/attitude/skymap.html.