依巴谷卫星扫描观测不均匀性的研究

以观测时间T=0.5年,四种不同的旋转角ξ=30°、36°、43°和50°,计算了依巴谷卫星对50颗全天均匀分布的恒星模拟观测次数。发现随着黄纬的增加,观测次数逐渐增加。当|β|=40°～60°时,观测次数分布达极大。而|β|=0°～10°之间,观测次数约只有极大值的1/2。计算符合Hoyer等人的理论估计,即在|β|=90°—ξ附近观测次数最多,在黄道面附近的恒星观测次数最少。本文指出依巴谷卫星对|β|为50°～60°区域内的恒星观测精度高。原因是在这一区域内,依巴谷扫描观测的次数最多。

A Study on the Non-uniformity of HIPPARCIS' Scanning Observations

The simulated number of observations for the fifty stars distributed on the whole sky are calculated with four different revolving angles (30°,36°,43° and 50° and the observing period of half year.It is found that the number of observations goes up with increasing β.It reaches the maximum as the observed star located between 40° and 60°in the ecliptic latitude.But the number of observations for the stars between 0°and 10° is about half of the maximum.The results is consistent with the previous theoretical estimates by Hoyer's group.It is pointed out by this paper that the enhanced accuracy near 60° latitude is due mainly to more scanning observations.