30mm GSO Superview - 2 versions

[ausastronomer]

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

[ving]

thanks john, i had no idea what the difference was between the 2. :)

I have a 15mm SV and its sharp edge to edge and very good on-axis, better than my 30mm SV... seems to be a lack of quallity control in that you can get good ones and mediocre ones :confuse3:

[mick pinner]

hi John, l have the long version and have a good chance to try it out in my 12" f/10 and it certainly compares favourably with much more expensive ep's, sharp to the edge and a good FOV.

[janoskiss]

I have the long version, Bintel branded. I noticed the current Bintel ones are short.

This explains why I get nearly 2.5x magnification in the 2" 2x barlow. It barlows to a 12mm effective FL. My eyepiece is lousy, as was confirmed by more experienced people at the Snake Valley camp last year. :( Seagulls a long way in from the edge, and refocusing does not help. Much better in the barlow though.

[Rodstar]

I feel very proud of my long GSO EP that appear in John's post. It tries very hard!

It would be very interesting to hear from Guang Sheng (sp?) what the explanation is.

[Starkler]

I was one of the unimpressed ones after looking through two samples, both being the longer type. Maybe my eyes are more sensitive to abberations than other people. I see seaguls in the outer field of a 12nagt4 at f5, where others do not :confuse3:

Thanks for the report John.

[asimov]

Wasn't overly impressed with mine either. Ended up selling it.

[iceman]

I wasn't a huge fan of the 30mm SV, but maybe like Geoff i'm just more critical of it. But for $70 I guess you can't get much better for the price.

I also wasn't a fan of the 15mm SV, in fact the stars weren't stars anywhere near the edge.. David your scope is an f/6 so it's a little more forgiving I guess.. but in my scope the wide FOV was just horrible as so little of the field was sharp.

[chunkylad]

I have to agree with Steve: my example is also lousy at F5. Same experience with the barlow and those nasty little sea birdies. Even my 2" GSO 26mm plossl is better, which is a bit of a dissapointment.:sad:

Dave W

[ausastronomer]

Dave,

I have not used the 26mm but I have used the 32mm 2" GSO Eyepiece. They are not plossls they are Kellners (I pulled it apart to find why it was so bad). I can say that the 32mm was sooooooooooo bad in my scope that the 30mm GSO Superview was in an entirely different league. That 32mm kellner was unusable from 40% off axis.

What this leads me to, is that there must be a large amount of quality variation amongst these cheaper eyepieces and not only from GSO, others as well. I am a pretty hard marker with edge performance and my 30mm GSO is good for 70% to 80% of the FOV and useable almost to the non existent field stop. I consider this to be exceptional performance considering the price. I also compared it against a University Optics 25mm MK70 at F10 in a Celestron C8 and at F5 in my own scope and it had better edge performance in both scopes. Rod's 30mm GSO was only a TAD behind mine and quite good. I have also used the 2" 30mm 1rpd in my F5 scope and I put it in the same class as the 2" GSO Kellners, terrible. I would rate the 30mm GSO Superview at 75% to 80% of the performance of my 27mm TV Panoptic.

I can only assume that not all 30mm GSO Superviews are created equal and its a lottery as to whether you get a good sample or a bad sample.

CS-John B

[ving]

probably right mike, or maybe just like the 30mm, my 15 is just a good one...

i used it last night for a bit, the seeing was shocking (2/10 or matbe worse) , the scope hadnt cooled, and it was windy as! and the EP performed well for 90% of the FOV... which is worse than usual...
go figure hey...

[chunkylad]

It's certainly looking that way. A very mixed bag of experiences with what essentially should be the same eyepiece.:confuse2:

We can only hope the Burgess Planetary ep's that are on the 'go' are much more homogeneous in their build quality:prey: . Having said that, I believe them to be in a different class altogether.
Dave W

PS: I will be more objective when next I use the 32mm SV and the 26mm Kellner side by side, as the 26mm (from memory) is much better than the poor >45% off axis performance you're getting with the 32mm version!!!

[ausastronomer]

Dave/Geoff,

The eyepiece you are saying is bad, is that a 30mm 2" GSO eyepiece or a 32mm 2" GSO eyepiece ? There are 2 entirely different animals involved here.

CS-John B

[rmcpb]

It would appear that these eyepieces are most useful in f6 and above scopes. Mine is a beauty in my f6 with about 90% of the FOV good. Not bad for the price :) and we have to remember the price when comparing these beasts.

[ving]

go the 8"ers hey rob! :D


btw, the GSO SV doesnt come in 32mm afaik...

[chunkylad]

For mine, it's the 2" 30mm GSO SuperView ( the same as the one on the LEFT in your photo) that's very ordinary, or at least, not as good as I'd hoped for: even for a 'budget' wide angle ep.
Dave

[ausastronomer]

Rob,

Mine does very well at F5. I know several guys who own F5 scopes that are also very happy with them. I think the problem is they are not all created equal.

CS-John B

[Starkler]

John I was referring to the 30mm gso superview.
I am familiar with the gso 2" kelner types and I owned the 26mm having originally paid $140 for it :scared:
I agree that the kelner series were bad for aberrations, diabolical even at f5. But, I found the contrast and transmission of the kelner far superior to the gso superview. All of the SV series I have viewed through remind me of viewing through dirty glass, they just dont seem clear.

FWIW, I tried the 20mm sv in my ed80 refractor (f7.5) and aberrations were still far from acceptable to me.