Challan: Solar Full-disk Imaging-Spectroscopic Telescope using the Drift-Scanning Technique

TL;DR

Challan is a multi-site solar telescope using drift-scanning to provide continuous, high-resolution spectroscopic imaging of the Sun, aiming to study solar flares, filament eruptions, and small-scale chromospheric events.

Contribution

It introduces a novel multi-site, modular solar telescope with drift-scanning for continuous 24-hour solar observations with high spectral and spatial resolution.

Findings

Designed for continuous 24-hour solar monitoring

Achieves high spectral resolution (>43,000) in key chromospheric lines

Scheduled for deployment at Big Bear Solar Observatory in 2025

Abstract

The Challan instrument is a solar full-disk imaging spectroscopic telescope planned to be installed at three sites with a 120-degree longitudinal difference, enabling continuous 24-hour observations of the Sun. It will take data every 2.5 min with a spatial resolution of $2-3^{\prime\prime}$ and a spectral resolving power (R) of >43,000 in H$\alpha$ and Ca II 854.2 nm bands simultaneously. Challan is composed of two modules, each dedicated to a specific waveband. This modular design is beneficial in minimizing the scattered light and simplifying the structure and engineering. The primary scientific goal of Challan is to investigate solar flares and filament eruptions. It is also expected to detect small-scale events in the solar chromosphere. In 2025, Challan will be installed at the Big Bear Solar Observatory for test observational runs, followed by scientific runs in 2026.