Research facilities for solar astronomy at ARIES

Abstract

The solar observational facilities at ARIES (erstwhile U.P. State Observatory, UPSO), Nainital, began in the sixties with the acquisition of two moderate sized (25 cm, f/66 off-axis Skew Cassegrain and 15 cm, f/15 refractor) telescopes. Both these systems receive sunlight through a 45 cm and 25 cm coelostat respectively. The backend instruments to these systems comprised of a single pass grating spectrograph for spectroscopic study of the Sun and a Bernhard–Halle H α filter, coupled with a Robot recorder camera for solar patrolling in H α respectively. With the advancement in solar observing techniques with high temporal and spatial resolution in H α and other wavelengths, it became inevitable to acquire sophisticated instrumentation for data acquisition. In view of that, the above facilities were upgraded, owing to which the conventional pho- tographic techniques were replaced by the CCD camera systems attached with two 15 cm, f/15 Coude refractor telescopes. These CCD systems include the Peltier cooled CCD camera and photometrics PXL high speed modular CCD camera which provide high temporal and spatial resolution of ∼ 25 ms and ∼ 1.3 arcsec respectively.