[ausastronomer (John Bambury)]

I have attached a photograph showing 2 different versions of
the 2" 30mm GSO Superview Eyepiece. I have mentioned this
before but never had both on hand together to take a pic or
compare them optically.

In the picture you will see that one is about 30mm shorter than the
other one, this is about 20mm in the body itself and 10mm is an
extension of the body housing between the eye lens and the rubber
eyeguard. The chromed barrels are identical. The short one has
longer eye relief and is a little more comfortable to use with
glasses on. The shorter one is my own, it was one of the 1st samples
ever produced. An Aussie dealer brought it back from the GS factory
in Taiwan in Jan 04 and gave it to me to test. After I tested it I
kept it as a great eyepiece for school viewings etc. I also have a
27mm TV Panoptic but don't like the thought of chocolate coated
fingers on that one. The taller sample is about 6 months old. I
compared them both optically albeit briefly in my F5 scope and the
performance was very similar. My own sample was marginally sharper on
axis but I believe this could be from sample to sample variation and
quality control rather than any design differences, there certainly
wasnt a lot in it. Personally I think the 2" 30mm GSO Superview is
about the best "budget" 2" widefield for use in fast scopes, based on
3 samples I have used in my own 10"/f5. They all performed very well
and FOV is useable at F5 almost to the edge of the FOV. Funnily
enough I have heard reports from a couple of people on forums who
rate it as very average. Maybe they got a bad sample of the eyepiece
or a bad pair of eyes, I dunno. I will also add that I have tried
both the 15mm and 20mm 1.25" GSO Superviews in my F5 scope and was
very dissappointed in their performance. I could not recommend those
for use in a fast telescope and felt they were considerably inferior
optically to their larger brother.

Clear Skies
John Bambury