Which GSO 68º Superview for a Meade LB 10" dob?

[mark3d]

Hi all,

We have the Meade 26mm that came with the Lightbridge, and some other higher power EPs. We are looking at the GSO 68º Superview EP range for its value-for-money and the good eye relief. We want a nice, wide-field eyepiece and can't decide between a 32mm and 40mm GSO superview.

Is the Meade 26mm bad enough to consider replacing with the 32mm GSO? Or is it a better bet to get the GSO 40mm to give a wider variety of magnifications?

We could probably just get both - but to start with I am leaning towards the 40mm for relaxed wide-view viewing, just wondering what you knowledgable folks think?

Thanks
Mark

[Rigel003 (Graeme)]

If the scope is f/5, then the 40mm will give you an 8mm exit pupil which is larger than your eye can accomodate. I think you'll also find the view washed out and lacking in contrast, especially from suburban sites. The 32mm will give 6.4mm which is acceptable but still on the large side for aging eyes.

[ZeroID (Brent)]

I've got the 20 and the 15 mmm SV from GSO and they are good value. The 20mm is my 'wideview' and works well, the 15 mm gets me in closer without losing too much contrast. lets me define stars in globs.
I've thought about the 32mm but at that mag I just switch to my binocs.

[mark3d]

Thanks for the advice

I was hoping for crazy wide-field, like your binocs Brent.

Rigel003, I had not even considered exit pupil, and you're right, the 42mm would be a waste -- the wrong EP for the scope.

Might consider the 30mm Superview, otherwise stick with our current 17mm (75x magnification and 3.4mm exit pupil).

Learnt something - thanks again

[sopticals (Stephen)]

Hi Mark,
I have GSO Superviews 20mm,30mm,42mm. Using with my 4.5"f4.4,8"f5 and 14"f5.1 reflectors. The 42mm gives an exit pupil too big for scopes this fast. The 30mm with its 68deg field is okay for scopes of around f5 and slower with its wide field of view, is a great ocular for general sweeps and finding objects of interest.At f5 you have a 6mm exit pupil so though marginal for some older eyes this would be my recommendation.I use the 20mm with/without 2x barlow on my 4.5" and this works really well,(also to be recommended).

Stephen.

[ColHut (Colin)]

I have a GSO 30mm SV. It is fine for wide low-power views but sometimes I do notice the coma inherrent in an F5 scope.

[mark3d]

Thanks fellas, you twisted my arm on the 30mm SV, I shall look at getting one soon