Abell 33 (Also called A33 or the Diamond ring nebula) is a faint spherical planetary nebula located 2700 light years away in the constellation of Hydra. It lies just behind the star HD 83535 which has no relation to the nebula. The star HD 83535 is also responsible for the “diamond ring” effect seen in the photograph.
The nebula gets its coloration from the Olll emissions (doubly ionized oxygen). The nebula is faint making it difficult to be seen using a telescope. The spherical shape of Abell 33 is mainly caused by its central star not having much of a spin. The nebula shares similar morphology to another nebula with the same spherical shape, the Owl Nebula (M 97) but is much darker than the owl nebula.

Telescope: Planewave CDK17 (FR) f4.5
Mount: Astro Physics 1600GTO
Camera: QHY16200A/ Integral FW
Guider: Agena Starguide II / ZWO ASI178MM
Filters: Astronomik 36mm LRGB

L: 52×10 mins = 520 mins, R: 24×10 mins = 240 mins, G: 24×10 mins = 240 mins, B: 24×10 mins = 240 mins

Total Imaging Time: 20h 40m

Data Imaged remotely on 10 nights during April, 2025.
Imaged from Observatorio El Sauce, Chile, in partnership with Fred Espenak.
Data acquisition & Processing by David Churchill.

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