Abstract:
A major project called the National Large Solar Telescope (NLST) has been proposed for pursuing Solar Astronomy at
High Altitude. The project envisages the development of a state-of-the-art 2-m class telescope to carry out high-resolution
studies of the solar atmosphere. This project is led by the Indian Institute of Astrophysics and has national and international
partners. Its geographical location will fill the longitudinal gap between Japan and Europe and is expected to be the largest
solar telescope with an aperture larger than 1.5 m till ATST and EST come into operation. NLST is an on-axis alt-azimuth
Gregorian multi-purpose open telescope with the provision of carrying out nighttime stellar observations using a spectrograph
at the Nasmyth focus. The telescope utilizes an innovative design with low number of reflections to achieve a high
throughput and low polarization. High order adaptive optics is integrated into the design that works with a modest Frieds
parameter of 7-cm to give diffraction limited performance. The telescope will be equipped with a suite of post-focus
instruments including broad and narrow band imagers, a high-resolution spectrograph and a polarimeter. A comprehensive
site characterization programme has demonstrated the presence of at least two excellent sites for setting up observational
facilities for solar astronomy at high altitude in India.
