Located in Cetus, NGC 246 is a medium-sized planetary nebula (4' x 3.5') having the well-deserved moniker, "The Skull Nebula"- two dark lobes for eyes and a curve of blue emission nebulosity for the mouth. The outline of the nebula is predominantly blue OIII emission with some Ha and Hb emission inside. No doubt there are fainter extensions to the roughly spherical nebula and one is faintly visible at 12 o'clock. Overall of mag 8.5 it has a central white dwarf star of 12th mag, easily visible in the image. The distance to NGC 246 is uncertain, estimated 1600-2500 ly.
The field contains many galaxies, in particular NGC255, a lovely face-on barred spiral to the lower right (70Mly away), two others, at 3 o'clock and 7 o'clock and many fainter ones on the left of the image.
|Camera:||SBIG STL11000M, Astrodon filters||Scope:||Takahashi TOA-130, f=1000mm, f7.7+flattner (fov 0.94° x 0.70°)|
|Mount:||Takahashi EM-200 Temma2||Guiding:||external, E-finder|
|Filters/Exposures:||L:R:G:B = 60:30:30:30min ≡ 2h30m||Location:||The Little Desert, Victoria, Australia|
|Dates:||November 2013||Processing:||CCDStack2, RegiStar and Photoshop CS5|