Astrometric and photometric studies of star clusters

Abstract

Astrometry is the science of studying positions and motions of the celestial objects. Astrometry, by its definition, can be considered to be started with the first naked eye observations of the night sky. Thus, it is one of the oldest divisions of Astronomy. The sources concerned in astrometry include stars and star clusters of the Milky Way. To a greater extent, it aims to study positions and motions of other galaxies and even the cluster of galaxies. Astrometric measurement techniques had reached a saturation level of accuracy and the astrometric studies were on a back foot for decades in the last century until recently when they became vital again owing to the new developments like invention of CCDs, launching of HIPPARCOS space mission, Hubble Space Telescope and uses of CCDs Wide Field Images etc. The astrometric accuracies being achieved these days are far better and the field is expected to revolutionize further with the take off of the GAIA space mission.