Possible Supernova PSN J16525897+0224255 in NGC 6240 Narrowfield L - May 20

Possible Supernova PSN J16525897+0224255 in NGC 6240 Narrowfield L - May 20, a photo by Joseph Brimacombe on Flickr.

Via Flickr:
SUMMARY
SN seen north of the nucleus at Mag 18.9 L.
DISCOVERY
Adam Block: 2013.4.11.396; Mag 18.1
TECHNICAL INFORMATION
Total exposure 110 min (11 x 10 min, luminance filter; binned 2x2, scale 0.91 asec/px)
Time: 2013.5.20.231
Astrometry: RA 16 52 58.94 Dec +02 24 24.5
Photometry: 18.92 +/- 0.22 L (V for ref)
These data were collected remotely using a 51-cm RCOS and STL11K camera at New Mexico Skies, Mayhill, New Mexico by Joseph Brimacombe, Coral Towers Observatory, Cairns, Australia.
FITS file available on request from jbrimaco@bigpond.net.au