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One of the oldest of natural sciences is astronomy. It was actually originated due to the religious, mythological, and astrological practices in the ancient times. Astrological prediction used astronomical data by some civilization. Astronomy can be defined as the study of celestial objects and phenomena that is created outside the Earth's atmosphere. Evolution and motion of celestial objects, as well as the formation and development of the universe are the main subject matter of astronomy. It deals with subjects like meteorology, chemistry, and physics. Early civilizations such as the Babylonians, Greeks, Chinese, Indians, and Maya, Egyptian monuments, Nubian monuments and Stonehenge, are historical astronomical artifacts that performed Methodical observations of the night sky. In the modern science, telescope has brought wide innovation and could transform astronomy as one of the important subject of modern science. Various disciplines like observational astronomy, the making of calendars, astrology Astrometry, and celestial navigation formed part of astronomy in the olden days where as today astronomy is nothing but astrophysics.

Professional astronomy got divided into observational and theoretical branches at some stage in 20th century. In observational astronomy, celestial objects are observed and data is collected and then principles of physics are used to study the data where as in the case of Theoretical astronomy, astronomical objects and phenomena are explained by focusing more on the development of computer or analytical models. Even though the method used in both cases are different but still the results of one can be used for the other. Ancient astronomy believed that the positions of celestial bodies affected human affairs and it was often confused with astrology. But today it is clear that they are two different subjects even though some methods and their origin are common. The visible light or usually electromagnetic radiation is the main source for getting information regarding celestial bodies and other objects.

Observational astronomers collect data according to the observed region of the electromagnetic spectrum where some portions are observed from the Earth's surface while others are apparent from high altitudes or space. Analytical models like polytropes used to approximate the behaviors of a star and Numerical models (computational numerical simulations) are some of the methods used by the Theoretical astronomers. A clear idea as to what is happening insight is got through Analytical models while Numerical models expose the existence of invisible phenomena and effects. The fundamental theories of physics, Big Bang, Cosmic inflation, and dark matter contained in Lambda-CDM model are different, commonly acknowledged studied theories and models. It is well known that the contribution of Amateur astronomers in astronomical discoveries is immense.