I reprocessed the image, rotated it to match the orientation as seen in Stellarium. I downloaded all of the star catalogs available for Stellarium, which goes to mag 16.35. I'm guessing, but I believe there are magnitude 17 stars in this image. It appears that the supernova is indeed about magnitude 13, comparing the apparent brightness with similar magnitude 13 stars. This image was taken 6 days after the discovery, and the star exploded within 24 hours of the discovery. Of course I cant determine the exact magnitude, but I will be able to monitor the supernova as it dims out over time.
The streaks in the image are due to the proximity of Mars in this image, which is about a million times brighter than the supernova.
I will be using this image as a starting point to monitor the brightness of this supernova in the weeks to come.
This video explains exactly the significance of this study better than I can...
Video courtesy of DeepSkyVideos on Youtube.