at the 89th Annual Meeting of the AAVSO, October 28, 2000
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 spacecraft attitude determination and
control. Accurate information on multiplicity, spectral type and luminosity
class, and variability are also required to predict what the star trackers will
detect. The SKY2000Version 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, 4,684 entries had HD or HD Extension (HDE) identifiers
added, for a total of 210,062 entries with HD/HDE identifiers. A planned global
replacement of variable star names/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.
next planned update to the SKY2000 catalog will include a global
replacement of variable star names/identifiers and variability data. Catalogs
to be utilized will include, but are not limited to, the General Catalogue
of Variable 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 enhancements 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.