Current Science

B. Raghavendra Prasad ¹, Dipankar Banerjee ¹, Jagdev Singh ¹, S. Nagabhushana ¹, Amit Kumar ¹, P. U. Kamath ¹, S. Kathiravan ¹, Suresh Venkata ¹, N. Rajkumar ¹, V. Natarajan ¹, Madhur Juneja ¹, Pawan Somu ¹, Vaibhav Pant ¹, Nigar Shaji ², K. Sankarsubramanian ², Asit Patra ³, R. Venkateswaran ⁴, Abhijit Avinash Adoni ², S. Narendra ², T. R. Haridas ⁵, Shibu K. Mathew ⁶, R. Mohan Krishna ², K. Amareswari ², Bhavesh Jaiswal ²

Affiliations
1 Indian Institute of Astrophysics, 2nd Block, Koramangala, Bengaluru 560 034, IN
2 ISRO Satellite Centre, Old Airport Road, Vimanapura Post, Bengaluru 560 017, IN
3 Space Applications Centre, Jodhpur Tekra, Ambawadi Vistar, P.O., Ahmedabad 380 015, IN
4 Laboratory for Electro-Optics Systems, First Phase, Peenya Industrial Estate, Bengaluru 560 058, IN
5 ISRO Inertial Systems Unit, Vattiyoorkavu PO, Thiruvananthapuram 695 013, IN
6 Udaipur Solar Observatory, Near Fatehpur Lake, Shilpgram, Udaipur 313 004, IN

Abstract

Solar coronagraph mimics total solar eclipse by blocking the solar disk and enabling the observation of extended coronal atmosphere of the Sun. Visible Emission Line Coronagraph (VELC), on-board Aditya-L1 space mission, is an internally occulted solar coronagraph capable of simultaneous imaging, spectroscopy and spectro-polarimetry close to the solar limb. This payload is designed to study the coronal plasma and heating of the solar corona. Studying development, dynamics and origin of coronal mass ejections and measurement of coronal magnetic fields over active regions are other important science goals. VELC is designed to image the solar corona at 500 nm with an angular resolution of 5" over a field of view (FOV) of 1.05-3 R_o. It also facilitates simultaneous multi-slit spectroscopy at three emission lines, viz. Fe XIV (530.3 nm), Fe XI (789.2 nm) and Fe XIII (1074.7 nm) with a spectral resolution of 28 , 31 and 202 mÅ/pixel respectively, over an FOV of 1.05-1.5 R_o. The payload has a dual-beam spectro-polarimetry channel for magnetic field measurements at 1074.7 nm.

Keywords

Coronagraph, Coronal Mass Ejection, Payload, Solar Corona.

Full Text

   

P. Venkatakrishnan ¹, Shibu K. Mathew ¹, Nandita Srivastava ¹, A. R. Bayanna ¹, Brajesh Kumar ¹, Bireddy Ramya ¹, Naresh Jain ¹, Mukesh Saradava ¹

Affiliations
1 Udaipur Solar Observatory, Physical Research Laboratory, Udaipur 313 001, IN

Abstract

Multi Application Solar Telescope (MAST), a telescope for the detailed study of solar activity, was operationalized at the Udaipur Solar Observatory (USO) of Physical Research Laboratory (PRL), on 16 June 2015. This article traces the history of the conceptualization to realization of MAST and describes its salient features. MAST is an off-axis Gregorian-Coudé telescope with a 50 cm aperture. The first light backend instruments include a narrow band polarimetric imager to map the photospheric and chromospheric magnetic fields and a multi-slit spectro-polarimeter. An adaptive optics system is also being developed for the on-line corrections of the image distortions produced by atmospheric seeing. The main objective of MAST is to obtain high spatial and temporal resolution observations of solar photospheric and chromospheric activity, with the ultimate goal of predicting space weather.

Keywords

Adaptive Optics, Back-End Instruments, Dome, Solar Telescope.

Full Text