33 is a large round planetary nebula that lies very close to a 7th
magnitude star. An OIII or UHC filter really helps bring it
out. Once the bright star (HD 83535) has been located, look to
the northeast for a very faint glow. Use low magnification
(less than 100x).
Stathis Kafalis reports
seeing a "Faint diffuse homogenous glow" in a 10-inch at
93x with OIII filter. Dave Aucoin detected it in a 13.1"
with averted vision and UHC filter.
The best view in my
18-inch came at 94x with an OIII filter in place. It appeared
as a big round glow with one edge intersecting the bright star.
The glow appeared faint, but averted vision was not required to see
it. If it weren't for the bright 7th magnitude star nearby it
would be much easier to detect. I was able to detect the glow
without the OIII filter, but this required some work and averted
vision. The edge of the glow appeared neither sharp nor
diffuse. The impression of a darker center was quite strong,
although I could not pin it down for certain. Apparently I
wasn't seeing things because Steve Gottlieb also notes that it
appears to have a "slightly darker center (partially
The field in an 12-inch at
60x. North is down and east is to the right.