  Devasthal observatory, established over a time span of about 5 decades, is
located in central Himalayan region of Devabhumi in Nainital district of
Uttarakhand state, India. Operated and maintained by the Aryabhatta Research
Institute of observational sciencES (ARIES), its location was selected after an
extensive site survey. The first measurements of atmospheric seeing and
extinctions at Devasthal were carried out during 1997 to 2001. Since 2010,
three optical telescopes of 1.3 m, 3.6 m and 4 m apertures have been
successfully installed at Devasthal. Optical and near infrared observations
taken with these telescopes testify to the global competitiveness of Devasthal
observatory for astronomical observations. The article chronicles the
collaboration with the Tata Institute of Fundamental Research, beginning around
1996, for the purpose of establishing the observatory. A brief overview of the
main science results obtained so far, using these facilities, is also
presented.
