I Wear Glasses - Eye relief?

[TomCrewe]

Hello all, I have just joined having had a telescope as an Xmas gift, It’s a Celestron Powerseeker 127 EQ. Some may have seen my question here about a new eyepiece (15mm Plossl). reading more and learning more I have more questions.
Eye Relief?? I have read that this effects glasses wearers. I wear glasses for distance and reading glasses, when I use binoculars, monoculars, magnifiers or cameras I remove my glasses!
Do people keep their glasses on?
Should I be keeping glasses on?
If so distance or reading glasses?
I would think I would remove glasses and rely on telescope optics.

[Ratlet]

I'm very short sighted and I don't wear my glasses when observing.  It depends on your prescription I think.  If you astigmatism and view without your glasses you'll still have astigmatism and the image will be affected.

With regarded to eye relief, it's basically how far away from the eyepiece your eye needs to be to see the whole image to the edge of the black circle.  If you wear glasses whilst observing you might not be able to get close enough to the eyepiece to see the entire view.

Edited January 5, 2023 by Ratlet

[jjohnson3803]

I'm nearsighted with astigmatism, so I usually wear my glasses when observing.  For me, I think about 10mm is the lower limit on eye relief.  I do observe occasionally without them, but the difference is quite noticeable.

 

[Graham Darke]

I always observe with my glasses on as I have astigmatism to go with my short-sightedness. For me the closer to 20mm of eye relief the better. I couldn’t observe at 10mm personally. Even at 15mm I struggle. 

[Carbon Brush]

Bottom line, check if your prescription includes astigmatic correction (cylinder).
If no, or small, you have a free choice on eyepieces.
Any short/long sight correction is dealt with simply turning the focusser.

If there is significant astigmatism, ask again. There various solutions.

HTH, David.

[RT65CB-SWL]

Hi @TomCrewe and welcome to SGL.

I asked my optician whether I should where glasses/spectacles and he said: "Unless your eyesight is extremely bad, then no!"

This article... https://televue.com/engine/TV3b_page.asp?return=Advice&id=87 may help.
If you think you have astigmatism then this... https://televue.com/engine/TV3b_page.asp?id=54

[dannybgoode]

Toric contact lenses are the solution for me. I can't stand wearing glasses when looking through any form of eyepiece, it never feels comfortable, but I a) I also hate constantly putting my glasses on and off (pretty short sighted so need them on even for things like changing eye pieces) and b) have an astigmatism.

Recently been trying toric multifocals and they're life changing for me. Tried them Erth binoculars the other night after wearing them for a day in the office and they're pretty much the perfect solution for me. 

[bryand2]

My normal glasses are varifocals which are useless for astronomy, so I got a cheap pair of distance-only single vision glasses for astronomy and archery. 

I got a chain so I can hang them round my neck which makes life a little easier.  I would put the glasses on for using the Telrad or another red dot sight, then take them off for using the eyepieces.

I also have astigmatism (-1.75 CYL in both eyes) and I have used TeleVue's Dioptrix with their eyepieces.  These work and do produce rounder, crisper objects but they are a bit fiddly to set up and have to be set for your individual eyes, so nobody else can use your scope.  This may or may not matter in your circumstances.

Edited January 6, 2023 by bryand2

[Geoffw]

This is a very interesting thread IMO as I have severe astigmatism and am long sighted.  So am I right to think it best to have a pair of distance only glasses for observing?  And then reading glasses to deal with the optics and the kit?

[Louis D]

Sounds like a plan.  It just might be a pain juggling two pairs of eyeglasses.  I'm lucky to have fixed focus at 8 to 12 inches, so I just look under my distance-only observing glasses to look at things up-close.  Surprisingly, my 2.0+ diopters of astigmatism isn't all that much of an issue at that distance.

[Merlin]

As a specs wearer, I get sufficient eye-relief with short-focus eyepieces by sawing and filling spare specs lenses down to a size so that they’ll sit in the eyepiece cup, held in with Blue Tack.

I filed two old specs lenses down to fit the eyepieces on the binoviewer. It pays to keep our old specs lenses!

[bosun21]

The simple answer is if you are long or short sighted, myopia etc then no glasses required. If on the other hand you suffer from astigmatism then yes to correct for this. The focuser will compensate for all the former shortcomings.

[michael.h.f.wilkinson]

I have quite strong astigmatism, so always use glasses when observing. This does require EPs with longer eye relief (16 mm minimum) for me

[TomCrewe]

We have had a clear spell early this morning and I tried with and without glasses and for me it's NO Glasses but thanks for all the help and explanations. Cheers.

[bomberbaz]

I have 6.5 diopters of astigmatism, I do not really like using glasses, never found myself comforatable with them, spoils the experience.

Solution A. I use a televue dioptrix down to 24mm when using the dob, beyond that I observe without glasses.  I know the view is affected by my astigmatism until I get down to lower exit pupils, but I prefer that to glasses. With my frac I never observe with glasses as the starting exit pupil is 2mm.

Solution B. Toric contact lens, I have some waiting to be used with the dob, just not tried them yet. I did use them last year on my giant bins and found them quite easy to get on with so I reckon they should be fine.