A Brief Overview of the Absolute Proper motions Outside the Plane catalog (APOP)

Abstract

APOP is the first version of an absolute proper motion catalog achieved using the Digitized Sky Survey Schmidt plate material outside the galactic plane (|b|≥ 27(o) ). The resulting global zero point error is less than 0.6 mas/yr, and the precision better than 4.0 mas/yr for objects brighter than R_{F}=18.5, rising to 9.0 mas/yr for objects with magnitude in the range 18.5<R_{F}<20.0. The average position accuracy is about 150 mas (per coordinate) with a systematic deviation from the ICRS around 0.2 mas. The catalog covers 22,525 square degrees and lists 100,777,385 objects to the limiting magnitude of R_{F}̃ 20.8. Although the Gaia mission is poised to set the new standard in catalog astronomy, the methods and procedures used for APOP will be useful in other reductions to dispel astrometric magnitude- and color-dependent systematic errors from the next generation of ground-based surveys.