Development of Solar Differential Image Motion Monitor at IIA, for the NLST site characterization program

Abstract

The Indian Institute of Astrophysics is planning to setup a 2 m National Large Solar Telescope (NLST) in India. In view of this, a site survey program was initiated. A Solar Differential Image Motion Monitor (SDIMM) unit was received on loan from the National Solar Observatory, Tucson for starting the site survey program. In order to have parallel site survey work at three sites namely Hanle & Merak (at Pangong Lake) in Ladakh, and Devasthal in Uttarakhand, the in-house development of SDIMM, with suitably modified design, was taken up. One unit was built with a 14’’ Celestron telescope and two more units were built using 12’’ Meade telescopes. Following initial tests at Bangalore, the units were calibrated & tested using the NSO instrument and installed at different sites.