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Published online by Cambridge University Press: 03 August 2017
A combination of the HIPPARCOS catalogue with fundamental catalogues, such as the basic FK5, shall provide, for the common stars, proper motions (and derived positions) which are significantly more accurate (by a factor of up to 5) than those in the original catalogues. For many other stars, the ground-based observations would also be suited for improving the HIPPARCOS proper motions considerably.