SBIG ST-4000XCM
8x15min
Imager Temp -20C
APM/TMB 130/780
Field Flattener
Full Frame
Link to Larger JPEG

I thought that Jones-Emberson 1 was dim, well this one was processed from a set of data in which the nebulosity seemed to be visible by sheer imagination alone. Here's a link to the central part of a single 15 minute exposure of Abell 31. Can you see it? Here's another imager (Stefan Binnewies) remarking about the same thing. He was using a more sensitive ST-10 camera, while I was using a one-shot-color imager.

Abell 31 (PK 219+31.1), (Sh2-290) in the constellation Cancer at a distance of 1000 light years, is a large planetary nebula spanning 16.8 x 15.6 arcmins - larger than the Helix Nebula. The nebula is extremely dim with a mean surface brightness of only 26.9 Mag/arc-sec². It is similar in appearance to Jones-Emberson 1 (PK 164+31.1) in Lynx, however that nebula measures 6.3 x 6.3 arcmin - small by comparison.

Abell 31 was discovered in 1955 by George Abell on the POSS plates and shows the typical red shell/blue center of many planetary nebulae.

January 13, 2010