A broadband low-resolution spectrograph: SpectrumMate LR

Abstract

This article presents the development and application of SpectrumMate LR, a broadband, low-resolution spectrograph specifically tailored for use with small telescopes. SpectrumMate LR is designed to offer affordable and accessible spectroscopic capabilities for amateur astronomers, students, and educators, responding to the growing demand for versatile instrumentation in non-professional and educational settings. Employing a 300-grooves-per-millimetre diffraction grating together with 80 mm focal-length collimator and objective lenses, the system is optimised to analyse light across the entire visible spectrum. These optical parameters allow users to classify stars by spectral type, estimate stellar effective temperatures, and verify the transmission characteristics of astronomical filters. Laboratory and on-sky tests demonstrate SpectrumMate LR’s ability to record accurate, well-calibrated spectral data, validating its efficacy when observing a variety of both celestial and terrestrial light sources. Because all components are commercially available and assembly procedures are straightforward, the instrument fills an important niche for cost-effective spectroscopy, empowering a broader community to engage in detailed observational astronomy. By lowering financial and technical barriers, SpectrumMate LR promotes hands-on learning, encourages citizen-science contributions, and provides a practical pathway for schools, small observatories, and enthusiast clubs to expand their research and outreach activities. As a result, SpectrumMate LR stands out as an exemplary tool for introductory spectroscopy courses worldwide today.