SN 185 (aka RCW 86) was a supernova which appeared in the year AD 185.
This "guest star" was observed by Chinese astronomers in the Book of Later Han, and might have been recorded in Roman literature.
It remained visible in the night sky for eight months. This is believed to have been the first supernova recorded.
The gaseous shell RCW 86 is probably the supernova remnant of this event and has a relatively large angular size of roughly 45 arc minutes (larger than the apparent size of the full moon).
The distance to RCW 86 is estimated to be 9,100 light-years.(WIKI)
This extremely faint nebula needed more than 6 Hrs of exposure in Ha to reveal it's structure.
Ha - RGB image
Ha - 6 Hrs bin 2
RGB 30 min each bin 2
total of 7:30 hrs
Imaged with the 16" f3.75 Dream Astrograph.
Apogee Alta U-16M camera.
Imaged from Tivoli farm in Namibia June 2014