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Published online by Cambridge University Press: 12 April 2016
This paper describes the methods used with the Flagstaff 20–cm CCD transit telescope for determining the positions of planets and asteroids directly in the extragalactic reference frame. As a result, the observations are not affected by (optical – radio) zonal errors, which can be ±0.1 arcsec or greater in catalogs based on traditional fundamental observations. The telescope can observe objects as faint as V ~ 17.5 mag with an accuracy of σ ~ ±0.16 arcsec in each coordinate. As a result, a large number of asteroids and the planets Uranus, Neptune, and Pluto are being routinely observed so that their ephemerides can be improved, masses determined, and accurate predictions made for occultation events. These observations are considerably more accurate than most previous results.