. List of supernovae sorted by Magnitude . This list of objects going back at least one year. Coordinates are in J2000.0 format, the date is the Discover date is actually the "Earliest Observation" date. The the "Last Mag" is the last observed magnitude. * = 30 days old, ** = 60 days old or older. Max Mag is the maximum observed magnitude. Last obs is the date the object was last observed (current year assumed). Max Date is the date of maximum observation. The "z", or red shift, is taken from the spectra