A program to match and subtract the images is currently being constructed. Once a supernova is found, there is still plenty to do. Once that is done, the supernova must be closely followed for the next four to six weeks so that its light curve may be constructed. Finally, the peak magnitude must be plotted to the Hubble diagram, along with other data from supernovae, and matched to a best fit cosmological curve. The spectroscopy is usually done at the same time as the follow-up period after finding the supernova.
Spectroscopy reveals the composition and redshift of the supernova.
For type I supernovae, an important distinguishing character is the lack of hydrogen lines in the spectra. Type II supernovae is quite abundant in hydrogen lines. Once that has been done, a best fit curve is constructed and the peak magnitude is determined. The calibration of the type I supernova is determined by various light curves. For instance, some light curves rise and fall from their peak magnitude quickly, while others rise and fall much slower.