Spectroscopy provides information on the nature of our universe and brings us a lot of surprising information, beyond our expectations.
Spectroscopy
Analysis of Spectra in Astrophysics --- Visiting the Old, Learning
Successfully Starting in Astronomical Spectroscopy: A Practical
Astronomical spectroscopy
Spectroscopy and the Birth of Astrophysics (Cosmology: Tools)
Spectroscopy for Amateur Astronomers
How is Infrared Spectroscopy Used in Astronomy?
Amateur Astronomy Spectroscopy
Absorption and Emission
Sample Astronomy Projects – Field Tested Systems
Types of Spectra: Continuous, Emission, and Absorption
ESA - Spectroscopy with Webb
Astronomy Basics: What IsSpectroscopy?