Wide angle eyepice for f5 dob and older eyes

[Eastridge]

Looking to replace the SW 25mm supplied with scope with a wide field eyepiece around the £100 mark. I can read about what is best generally but know

1. our 250 f/5 Dob needs an eyepiece that minimises egde distortion - so no Baader Hyperion for example.

2. Our older eyes only have 5mm exit pupil so understand anything more than 25mm / mag of 50 will just be a waste of light / money with olu scope. Many have 30- 40mm so are no good to us with our scope.

3. I have astigmatism so need long eye relief to view with my glasses, looking for high teens / 20mm eye relief but many dont have this.

Ideas?

Thanks.

[cs1cjc]

Hi,

Have you checked that you only have a 5mm iris once you are fully dark adapted. This is easy to do with a partner putting a ruler to your eye. The 5mm is a guide only and I find that at 60 my iris still goes to 7mm, giving much more choice over eyepiece. Also although light outside the iris is "wasted", you are getting the brightest image possible and have the opportunity for a wide true field of view without an excessive cost, weight or apparent field of view.

I use a ES68 24mm (1.25") and also a generic (Adler) SWA 38mm, both of which are fine with spectacles.

[Damo636]

Getting edge to edge perfection in an f5 (I think your scope is actually f4.7) is not easy for £100, especially in a widefield eyepiece. If you could stretch your budget this might be worth keeping an eye on...

Televue 24mm Panoptic Eyepiece Boxed And Mint Tele Vue EPO-24.0 | eBay

The 24mm Pan is arguably one of the best eyepiece's ever produced at this focal length. Whether or not the 15mm of eye relief is enough I'm not sure.

[Moonshane]

I agree with Damo

I think you have three options:

1) keep the same budget and accept the field edge issues with cheaper options and buy one of those that gives adequate eye relief

2) keep the same budget and buy e.g. a Televue 25mm plossl which will fulfull all of your requirements other than wide field

3) increase your budget and buy one of the premium brands but this will not be cheap especially with 20mm of eye relief.

sorry to be negative but your requirements are quite challenging.

[cs1cjc]

Do not be persuaded that only mega-bucks will give you a good solution! It might be worthwhile looking at this review of 25mm 1.25" eyepieces.

24-26 mm Eyepiece Comparison - Review

Also if you want to go to 2", the Aero 30mm and Baader Aspheric 31mm are only just outside your price range.

I should perhaps add that I use the GSO coma corrector which does a vey good job in reducing newtonian aberrations.

[Moonshane]

Do not be persuaded that only mega-bucks will give you a good solution! It might be worthwhile looking at this review of 25mm 1.25" eyepieces.

24-26 mm Eyepiece Comparison - Review

Also if you want to go to 2", the Aero 30mm and Baader Aspheric 31mm are only just outside your price range.

I should perhaps add that I use the GSO coma corrector which does a vey good job in reducing newtonian aberrations.

Chris, I think we agree? The issue here is the wide field not the budget necessarily.

[Eastridge]

Thanks guys I will have a re-think, I know it's going to be a question of comprimise it's just getting to a 'shortlist' to decide which comprimise to make. Also, I have just taken delivery of a Hyperion 10mm + fine tuning rings for planetry use & on first view the edge distortion doesn't appear as horrific as people warned me it would be. So that might be the comprimise I make.