In ancient times, the Romans or ancient Greeks were already observing "new stars", which they called stella novae. These are transient astronomical events that cause a sudden brightness increase of a stellar object up to 6 to 19 magnitudes, which then slowly fades over weeks or months. Such nova eru...

Since decades observational astronomy uses broadband imaging with several filters to obtain information about the spectral energy distribution of cosmic objects. This energy distribution is an indicator of both the chemical composition of a celestial body as well as the physical processes on which t...