Supernova SN 2011dh was spotted on May 31st, when French amateur Amédée Riou noticed a previously absent 14th-magnitude star in CCD images of the Whirlpool galaxy, M51, roughly 31 million light-years distant. The image shows two views of M51 taken in Victoria, one well before and the other shortly after the supernova appeared.
Details
both images taken at Observatory Hill using the Victoria Centre Obsrvatory 14" Meade SCT on Paramount ME mount and were processed in Images Plus and Photoshop.
Left Side
Date and location:- 2008-06-22 with modified Canon 350D camera.
Exposure:- 18 light and 14 dark frames all at ISO 1600 for 120 s.
Right side
Date and Location 2011-06-03 with Canon T1i camera.
Exposure - 17 60 sec frames at ISO 3200 with matching dark frames.