This document outlines the tools and processes involved in calibrating a RAMSES-ARC spectrometer manufactured by TriOS GmbH and used for measuring the atmospheric radiance in the Ultraviolet (UV), Visible (Vis) and Near Infrared (NIR) spectral ranges. Although calibration is essential for accurate measurements, it often involves high costs and specialized equipment. This document proposes a relatively simple, repeatable calibration procedure aimed at maintaining high accuracy while minimising costs. This work is particularly relevant for long term atmospheric monitoring in remote and harsh environments where consistency in calibration procedures are crucial. This document also shows how the instrument’s data are processed and the impact of the different calibration results on the...