The US Naval Observatory (USNO) has a long history of providing accurate
astrometric data for millions of stars from their own observations plus other
data. The USNO CCD Astrograph Catalog (UCAC) project utiized the "redlens" 20 cm
aperture astrograph in an all-sky observing program between 1997 and 2004 (CTIO
in the south, NOFS in the north) with a limiting magnitude of about R = 16.5.
The previous release, UCAC4, became available in 2012.
The 1st Gaia data release provides proper motions for only about 2 million stars
(TGAS subset of the Tycho-2 stars) in the mainly 6 to 11.5 magnitude range. Gaia
DR2 which will contain proper motions of about a billion stars is scheduled for
release in April 2018. In the meantime the astronomical community would benefit
from proper motions of millions of stars fainter than the Tycho-2 limit, if a
substantial improvement in precision and accuraccy could be made beyond what was
available in the pre-Gaia era.
Re-reduction of UCAC + combine with Gaia DR1 provides proper motions for over
107 million stars on the 1 to 5 mas/yr level, strongly depending on magnitude.
UCAC observations (mean epoch 2001) provide positions with 10 to 70 mas
precision, and about 14 years of epoch difference to Gaia DR1.
If you use UCAC5, please cite both Zacharias et al. (2017)
and the dataset Digital Object Identifier (DOI): 10.26131/IRSA20.
|
UCAC5 Overview
IRSA Catalog Search Tool: UCAC5