IM Normae is a recurrent nova in the constellation Norma, one of only ten known in the Milky Way. It has erupted in 1920 and 2002, reaching magnitude 8.5 from a baseline of 18.3. It was poorly monitored after the first eruption, so it is possible that it erupted in between these dates.
References
IM Normae Wikipedia(Text) CC BY-SA