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

Abstract

We present the design and testing of a compact stellar spectrometer developed for undergraduate and outreach applications. The spectrometer module, comprising an inexpensive 600 lines/mm diffraction grating, a CMOS monochrome sensor, and a 3D-printed mount, can be constructed at modest cost and integrated with reflecting telescopes commonly available at educational institutions. Calibration was performed using a helium emission source in the laboratory and Vega as a spectrophotometric standard, supported by a custom Python-based data-reduction 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 by institutions with existing telescope infrastructure, providing a practical framework for student-led astronomical instrumentation projects.

15 pages, 10 figures. Comments are welcome