Challan: Solar Full-Disk Imaging-Spectroscopic Telescope Using the Drift-Scanning Technique

• Published in: Journal of the Korean Astronomical Society, 58(2) Vol. 58; no. 2; pp. 175 - 183
• Main Authors: Heesu Yang, Maria S. Madjarska, Donguk Song, Hannah Kwak, Sung-Hong Park, Eun-Kyung Lim, Sujin Kim, Su-Chan Bong, Yeon-Han Kim, Seonghwan Choi
• Format: Journal Article
• Language: English
• Published: 한국천문학회 01.12.2025
• Subjects: 천문학; instrumentation: spectrographs— Sun: chromosphere— techniques: imaging spectroscopy
• ISSN: 1225-4614; 2288-890X
• DOI: 10.5303/JKAS.2025.58.2.175

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′′ and a spectral resolving power (R) of >43,000 in Hα and Ca ii 8542 Å 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.