Lampens, P. ; Frémat, Y.

published in Astrometry in the Age of the Next Generation of Large Telescopes, 338, pp. 276 (2005)

Abstract: We draw the attention to some bright, double and multiple visual systems with long-period orbits currently lacking high-quality astrometric data and we present arguments for resuming astrometric observations of these apparently very classical systems. When - for any good reason - a thorough study of these is being undertaken, the importance of the coverage of the critical phases in the orbit by follow-up observations should once more be stressed.

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