The Lick Northern Proper Motion ( NPM ) program , a two-epoch ( 1947–1988 ) photographic survey of the northern two-thirds of the sky ( \delta \gtrsim - 23 \arcdeg ) , has measured absolute proper motions , on an inertial system defined by distant galaxies , for 378,360 stars from 8 \lesssim B \lesssim 18 .
The 1993 NPM1 Catalog contains 148,940 stars in 899 fields outside the Milky Way ’ s zone of avoidance .
The 2003 NPM2 Catalog contains 232,062 stars in the remaining 347 NPM fields near the plane of the Milky Way .
This paper describes the NPM2 star selection , plate measurements , astrometric and photometric data reductions , and catalog compilation .
The NPM2 Catalog contains 122,806 faint ( B \geq 14 ) anonymous stars for astrometry and galactic studies , 91,648 bright ( B < 14 ) positional reference stars , and 34,868 “ special stars ” chosen for astrophysical interest .
The NPM2 proper motions are on the ICRS system , via Tycho-2 stars , to an accuracy of 0.6 { ~ { } mas~ { } yr } ^ { -1 } in each field .
RMS proper motion precision is 6 { ~ { } mas~ { } yr } ^ { -1 } .
Positional errors average 80 mas at the mean plate epoch 1968 , and 200 mas at the NPM2 catalog epoch 2000 .
NPM2 photographic photometry errors average 0.18 mag in B , and 0.20 mag in B V .
The NPM2 Catalog and the updated ( to J2000 ) NPM1 Catalog are available at the CDS Strasbourg data center and on the NPM WWW site http : //www.ucolick.org/ { \thicksim } npm .
The NPM2 Catalog completes the Lick Northern Proper Motion program after a half-century of work by three generations of Lick Observatory astronomers .
The NPM Catalogs will serve as a database for research in galactic structure , stellar kinematics , and astrometry .