Probably the most established field in space science, and in the entirety of science, is the estimation of the places of heavenly items. Verifiably, exact information on the places of the Sun, Moon, planets and stars has been basic in divine route (the utilization of heavenly articles to manage route) and really taking shape of schedules. Cautious estimation of the places of the planets has prompted a strong comprehension of gravitational irritations, and a capacity to decide past and future places of the planets with incredible exactness, a field known as heavenly mechanics. All the more as of late the following of close Earth items will take into account forecasts of close experiences or likely impacts of the Earth with those articles. The estimation of heavenly parallax of close by stars gives a crucial standard in the inestimable separation stepping stool that is utilized to quantify the size of the Universe. Parallax estimations of close by stars give an outright gauge to the properties of progressively inaccessible stars, as their properties can be looked at. Estimations of the outspread speed and appropriate movement of stars permits stargazers to plot the development of these frameworks through the Milky Way cosmic system. Astrometric results are the premise used to figure the appropriation of conjectured dim issue in the galaxy. During the 1990s, the estimation of the heavenly wobble of close by stars was utilized to recognize enormous extra solar planets circling those stars.