THE NPM AND SPM CONTRIBUTIONS TO THE HIPPARCOS PROPER-MOTION LINK

I Platais, V Kozhurina-Platais, T Girard, W Van Altena, R Hanson, A Klemola, B Jones, C Opez, H Macgillivray, D Yentis, J K O V Alevsky, L Lindegren
unpublished
We describe the use of the Lick Northern Proper Motion NPM program and its southern-sky complement , the YaleeSan Juan Southern Proper Motion SPM program to determine the Hipparcos proper-motion link to the extragalactic reference system de-ned by galaxies. Particular attention is given to the presence of systematic errors in the NPM and SPM proper motions which bias the spin solutions.
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