Abell 33 (or, as it is usually known, A33) is a planetary nebula in the constellation Hydra. This nebula shows several remarkable aspects. The star HD 83535, located in the lower right rim, gives the nebula the aspect of a “diamond ring” (this nebula is also known with this name). This foreground star is accidentally aligned with the nebula’s rim, and adds to its beauty. The nebula’s color is mainly due to OIII emission. Its color and its faint magnitude (+12.9), make this nebula a difficult target. The central star is double and, as of 2014, it was not known whether they form a physical pair or a chance alignment. The fact that the nebula has the unfrequent spherical form is mainly due to the absence of spin of the central star.
This image has been taken with narrowband filters (OIII -mapped as green and blue- and Halpha -mapped as red and, partially, blue)), RGB frames have been taken only for the stars.
Name(s): Abell 33
Type: Planetary Nebula
RA: 09h 39m 59.8s
Dec: -02º 53’ 11.8”
Size (arcmin): 4.5×4.3
Distance: 2,700 ly
Date: 2015-12-31 thru 2016-01-12
Location: iTelescope.net, SSO near Coonabarabran, NSW Australia
Size (arcmin): 35×35
Telescope: Planewave CDK 20” f/6.8
Camera: SBIG STX16803 (4096x4096pix)
Guiding: Astrodon MonsterMOAG off-axis guider
Total exposure: 15.5 hours (Ha: 6 hours; OIII: 8 hours; RGB: 1.5 hours)
Processing: CCDStack, Photoshop CC 2015.5 and PixInsight