I observed this PN in 2007 at San Pedro de Atacama, Chile, with the 18 '' dobson of Alain Maury ( http://www.spaceobs.com/en ), in a very good sky*: SQM 21,91, NELM ~ 7,25v.
Th PN is large, luminous, with a well defined shape*: the central part is a short rectangle, with a half circle on each side, elongation estimated a/b ~ 1,3 – 1,4.
The halo is rather bright, L4 on a scale of 1 to 10, homogenous, weakening on the circumference.
The central star is seen with adverted vision, weak, estimated m15 – 16v. I didn't see the outer ring as in Astrodon image.
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