- What is the expected maximum apparent magnitude of supernova SN 2014J?
- When will it attain peak brightness?
According to this website the peak visible magnitude will be about 10.5 around February 2nd. Earlier estimates had been a little brighter around the same date.
The AAVSO data seems to indicate that it might have already peaked, at around 10.5 (visual). The infrared is quite a bit brighter, partly because it penetrates dust better.
Sky and Telescope says it peaked on Jan 31.
In retrospect, we now know that the peak brightness was indeed 10.5 during the first week of February, 2014: