The spectrum below of the comet ISON shows how easy it is for amateurs to study astronomical spectra. This wonderful spectrum of ISON using a just an 80 mm refractor, simple Star Analyser grating, and a DSLR. It clearly shows the green glow from glowing Carbon (the so-called “Swan bands” – Wikipedia link) This image was captured from a rooftop in Rajasthan, and then processed in the RSpec software.