Astrometric Research in the Southern Hemisphere

范·阿尔特纳博士将继续他的南方自行(SPM)计划。这些是第二个纪元观测，第一个纪元数据是在1965年至1974年之间获得的，这些数据是在阿根廷埃尔莱昂西托的耶鲁南方天文台获得的。该项目的目标是确定恒星相对于暗星系的绝对自行。这两个数据集的20年差异应该会导致对自身运动的高度精确的测量。绝对自行将被用来确定天琴座RR恒星的绝对星等，修正进动常数，确定希巴谷天文测量卫星的固定参照系，奥尔特常数B，以及研究银河系的局部结构。与建立惯性参照系相关的问题已经困扰天文学家几千年了。随着时间的推移和测量技术的改进，人们发现恒星并不是固定在天空中的，有必要将恒星的运动与地球极点的运动分开。目前，这种分离是通过观测太阳系天体，如太阳、行星和小行星来实现的。然而，一些太阳系观测的模式与正常恒星观测中使用的模式有很大不同，这种差异可能会危及动态定义的参照系和恒星系之间的联系。结果，天文学家在银河系中留下了恒星流、运动群和非圆周运动，这使得恒星运动模型和进动常数的修正公式变得复杂。确定相对于暗星系的自行的最初动机是确定进动常数的修正，从而改进基本星表系统。

Dr. Van Altena will continue his Southern Proper Motion (SPM) program. These are second epoch observations, the first epoch data were obtained between 1965 and 1974, which are taken at the Yale Southern Observatory at El Leoncito, Argentina. The goal of the project is to determine the absolute proper motions of stars with respect to faint galaxies. The 20-year difference in the two data sets should result in highly accurate measurements of proper motions. The absolute proper motions will be used to determine the absolute magnitudes of RR Lyrae stars, corrections to the constants of precession, a fixed reference frame for the HIPPARCOS astrometric satellite, Oort's constant B, and to study the local structure of the Galaxy. The problems associated with establishing an inertial reference frame have occupied astronomers for millenia. With the passage of time and improvements in measurement techniques, it was discovered that the stars are not fixed in the sky and that it is necessary to separate the motions of the stars from that of the Earth's pole. This separation is currently made through the observation of Solar System objects such as the Sun, the planets, and minor planets. However, some of the Solar System observations are made in modes that differ significantly from those used in normal stellar observatons, and this difference may compromise the connection between the dynamically defined reference frame and the stellar frame. As a result, astronomers are left with star streams, moving groups, and non-circular motions in the Galaxy to complicate the stellar motion model and the derivation of the corrections to the constants of precession. The initial impetus for determining proper motions with respect to faint galaxies was to determine the corrections to the constants of precession and thereby improve on the system of the fundamental catalogs.