Spectroscopy is a demanding but unlimited field of astronomy where even amateurs can contribute valuable scientific data.The point-like light from stars is separated by the spectrograph into a broad band, in which each wavelength occupies a certain area. The resulting spectrum can be easily viewed in the eyepiece or imaged by a camera sensor. The latter then allows accurate analysis of the spectrum.
Photometry is used to measure brightness. The Sky Quality Meters from Unihedron, which can be used to systematically measure the night sky’s brightness, are useful in astronomy.