Data processing of Visible Emission Line Coronagraph Onboard ADITYA L1

TL;DR

This paper details the calibration and software algorithms development for the VELC instrument onboard India's Aditya-L1 mission, enabling automated analysis of solar corona images and spectra to detect energetic events and derive physical parameters.

Contribution

It introduces calibration procedures and image processing algorithms specifically designed for the VELC coronagraph to facilitate automated solar corona observations and event detection.

Findings

Calibration of detectors completed successfully

Algorithms developed for CME detection

Spectroscopic analysis methods established

Abstract

ADITYA-L1 is India's first dedicated mission to observe the sun and its atmosphere from a halo orbit around L1 point. Visible emission line coronagraph (VELC) is the prime payload on board at Aditya-L1 to observe the sun's corona. VELC is designed as an internally occulted reflective coronagraph to meet the observational requirements of wide wavelength band and close to the solar limb (1.05 Ro). Images of the solar corona in continuum and spectra in three emission lines 5303{\AA} [Fe xiv], 7892{\AA} [Fe xi] and 10747 [Fe xiii] obtained with high cadence to be analyzed using software algorithms automatically. A reasonable part of observations will be made in synoptic mode, those, need to be analyzed and results made available for public use. The procedure involves the calibration of instrument and detectors, converting the images into fits format, correcting the images and spectra for the instrumental effects, align the images etc. Then, develop image processing algorithms to detect the occurrence of energetic events using continuum images. Also derive physical parameters, such as temperature and velocity structure of solar corona using emission line observations. Here, we describe the calibration of detectors and the development of software algorithms to detect the occurrence of CMEs and analyze the spectroscopic data.