中国与丹麦合作的水平子午环在建立惯性坐标系中的作用

The Role of Observation With Horizontal Meridian Circle in China for Establishing an Inertial Frame

预计Hipparcos测定星位的精度要远好于地面仪器的结果。对于从事地面仪器测量的天体测量学家来说,必须回答:地面仪器还能发挥什么作用?我们认为,地面仪器在未来建立惯性坐标系中仍起着重大作用。因为:1.地面经典仪器有相当长的观测历史,因此,在自行方面,有较好地面仪器观测历史的天体其精度并不亚于Hipparcos的结果。2.地面仪器观测可研究与地球物理有关的问题.3.空间卫星不可能包罗全部课题,仍有大量的课题需要地面仪器去观测。4.地面仪器研究课题的运转周期短。一般来说,空间观测的课题要10年以上的周期。5.地面仪器的改造,使得效率和精度有相当大的提高,特别是CCD探测器在天体测量上的应用。中国与丹麦合作的水平子午环,其有效口径为240mm,可观测到13~m.5的天体,因此我们的仪器将在惯性坐标的建立中发挥作用。根据本仪器的特点,可在下列课题发挥其作用:1.观测射电星,作参考系联结的工作。2.观测较暗的小行星,进行坐标系分点改正的工作。3.进行IRS星的绝对测定。4.观测射电源周围的天体,作为观测射电源的定标垦。5.改进FK5星的位置精度。本文发表于IAU141讨论会,1989年10月,列宁格勒。

What can we do in the future for ground-based instruments while HIPPA-RCOS is expected to measure positions and proper motions of stars with far bet-ter accuracy than those obtained by ground-based instruments? The ground-basedobservations are still important for establishing inertial frame because of the longhistory of such observations and the improvements of the instruments. Moreover, itis necessary to have the data from ground-based observations for the research su-bjects related to the Earth. The honizontal meridian circle jointly developed byDenmark and China (DCMT) is expected to have advantages over the classicalmeridain circles. The DCMT will be asembled and tested this year. It will work inthe following fields: 1. observations of radio stars. 2. observations of the minorplanets. 3. obsolute determinations of IRS stars.