Science Filter Characterization of the Solar Ultraviolet Imaging Telescope (SUIT) on board Aditya-L1

TL;DR

This paper characterizes the spectral transmission properties of the filters used in the SUIT instrument on Aditya-L1, ensuring their performance meets scientific requirements for solar observation across 200-400 nm.

Contribution

It provides detailed experimental characterization of SUIT filters, including spectral variation, tilt angle dependence, and out-of-band transmission, which was previously unreported.

Findings

All filters meet expected spectral performance.

Out-of-band transmission is below 1% for most filters.

Filters effectively capture solar features in the targeted atmospheric layer.

Abstract

The Solar Ultraviolet Imaging Telescope (SUIT) on board the Aditya-L1 mission is designed to observe the Sun across 200-400 nm wavelength. The telescope used 16 dichroic filters tuned at specific wavelengths in various combinations to achieve its science goals. For accurate measurements and interpretation, it is important to characterize these filters for spectral variations as a function of spatial location and tilt angle. Moreover, we also measured out-of-band and in-band transmission characteristics with respect to the inband transmissions. In this paper, we present the experimental setup, test methodology, and the analyzed results. Our findings reveal that the transmission properties of all filters meet the expected performance for spatial variation of transmission and the transmission band at a specific tilt angle. The out-of-band transmission for all filters is below 1% with respect to in-band, except for filters BB01 and NB01. These results confirm the capabilities of SUIT to effectively capture critical solar features in the anticipated layer of the solar atmosphere.