By the initiative of the Govt. of India, immediately after the independence, there was a flurry in scientific activities signaled by the establishment of a chain of national laboratories in the period 1947-1955. It was happy a coincidence that in the state of Uttar Pradesh a scholarly statesman was interested in nurturing the science of Astronomy - the mother of a number of other branches in fundamental sciences. Mainly, It was due to the initiative of the late Dr. Sampurnanand, cabinet Minister of Education, Uttar Pradesh and later the Chief Minister of the state, the Uttar Pradesh State Observatory (UPSO) came into existence.

In the year 1951, the Government of Uttar Pradesh decided to set up an Astronomical Observatory. In early 1952 a committee of experts was set up with Professor and Head, Department of Mathematics at the University of Lucknow, as a convener to recommend a suitable site for setting up the observatory at Varanasi and to formulate a plan to develop it into a full-fledged research center. At the initiative of Dr. A. N. Singh, till April 1954, a gravity driven 25-cm Cooke refractor, a set of Rhode and Schwarz quartz clocks, and some accessories had already been acquired or ordered for purchase at a cost of about Rs. 1,50,000.

In April 1954, through a formal administrative decision of the government of Uttar Pradesh, Dr. A. N. Singh, an eminent mathematician who was the Principal of the newly established D. S. B. Government College, Nainital was appointed as the honorary Director and was entrusted with the job of guiding the initial unsteady steps of UPSO. With the appointment of Dr. S. D. Sinvhal as Assistant Astronomer, the Observatory started functioning in the premises of the Govt. Sanskrit College (presently known as Sampurnanand Sanskrit Vishwavidyalaya), Varanasi on April 20, 1954.

Owing to a sudden heart attack, Dr. A. N. Singh prematurely expired at Varanasi in July 1954. The task of leading the UPSO on the path of growth to a matured institution came in November 1954 into the hands of Dr. M. K. Vainu Bappu - a youthful and enthusiastic Ph.D. from Harvard.

Dr. Vainu Bappu, appointed as Chief Astronomer, the senior most position at the UPSO, was responsible for the growth for the period 1954-1960. It was due to the vision, initiative and acumen of Dr. Bappu that the planning for the observatory was put on a sound footing. The first task, taken up was that of transforming UPSO into a modern center for Astrophysical Research. Poor observing conditions for astronomical observations at Varanasi were the main factors that necessitated a site survey at Nainital, Mussoorie and Dehradun. Finally, the present location at Manora Peak, Nainital was selected as the most prospective site.

In November 1955, the UPSO was shifted over from Varanasi to a small cottage at Debi Lodge, halfway up to Snow View from the Lake Bridge at Nainital. UPSO moved to Manora Peak (longitude 79^o 27' E, latitude 29^o 22' N, altitude 1951 meters), south-west of Nainital and situated at a distance of 9 km from the Nainital town. The boundaries of UPSO are defined by the road to Nainital which was a gravel one at that time.

Dr. S. D. Sinvhal took over the charge of Director in April 1960. Dr. Sinvhal hold the position till October 1978 and again from June 1981 till his retirement in May 1982. Dr. M. C. Pande worked as Director from November 1978 till May 1981 and then from June 1982 till his retirement in March 1995. In July 1996, Prof. Ram Sagar took over the charge of Director, and he continues till 2013.

Consequent to the creation of the state of Uttaranchal, on 09th November 2000, because of its geographical location within the boundaries of Uttaranchal, UPSO came under the administrative controls of the new government and was re-christened as the State Observatory (SO).

Aryabhatta Research Institute of observational sciencES (ARIES) was the new name when SO came under the Department of Science & Technology (DST), Govt. of India as an autonomous body. The ARIES came into existence on 22nd March 2004, following the decision of the cabinet of Ministers of the Govt. of India on 7th January, 2004.

The acronym ARIES also signifies the sun sign of the two important epochs separated by almost 50 years in the history of the Institute. First it corresponds to its creation on 20th April, 1954 and secondly it marks the beginning of a new phase on March 22nd, 2004; ARIES: a new 'AVATAR' in golden jubilee year that promises a bright future. Besides the work on the visual observations of comets, asteroids and double stars with the help of the 25-cm refractor at Sarnath near Varanasi, it was planned to start a national time service at Varanasi. However, the time service was almost simultaneously started at the National Physical Laboratory (NPL), Delhi and thus the dreams of Dr. Singh got fulfilled alternatively.

ARIES has 32.38 hectares of land at Manora Peak, Nainital on which functional and residential buildings are located. Functional buildings have covered area of 3435 square meters and residential buildings have covered area of 1963 square meters. For installation of new observational facilities another 4.48 hectare land has been acquired at Devasthal (longitude 79^o 41' E, latitude 29^o 23' N, altitude 2500 meters) situated at a distance of nearly 50 kms by road from Nainital. The site has about 200 clear nights in a year and the median ground level seeing is about 1".