Stellar Spectroscopy Using Diffraction Grating, CMOS Monochrome Sensor, and Reflecting Telescopes

TL;DR

This paper describes a low-cost, compact stellar spectrometer designed for educational use, utilizing diffraction gratings, CMOS sensors, and reflecting telescopes to capture spectra of bright stars.

Contribution

The paper introduces a novel, affordable spectrometer setup suitable for undergraduate and outreach projects, with detailed calibration and spectral analysis methods.

Findings

Successfully recorded spectra of bright stars including Vega and Betelgeuse.

Demonstrated the feasibility of low-cost spectroscopy for educational purposes.

Provided a practical framework for student-led astronomical instrumentation.

Abstract

We present the design and testing of a compact, low-cost stellar spectrometer developed for undergraduate and outreach applications. The instrument employs a 600 lines/mm diffraction grating, a CMOS monochrome sensor, and a 3D-printed mount integrated with reflecting telescopes. Calibration was performed using helium emission sources in the laboratory and Vega as a spectrophotometric standard, supported by a custom Python-based image-processing pipeline for wavelength calibration and spectral stacking. The spectrometer successfully recorded usable spectra of bright stars including Vega, Sirius, Procyon, Capella, and Betelgeuse, covering spectral types A through M. The results demonstrate that meaningful stellar spectroscopy can be achieved with accessible, low-cost equipment, providing a practical framework for student-led astronomical instrumentation projects.