EP's for astigmatism sufferers.

[bomberbaz]

Hi all, like the title says, unfortunately I have acute astigmtism and although I am not going to buy any EP's just yet, because of my affliction I feel it will be sooner rather than later otherwise my viewing pleasure will suffer as a result.

So question is, where do you get the lenses for people with my condition please. I read that there are special lenses that are more expensive but if these are what I need, then thats how it is.

If its seen as essential, I shall buy a mid/high and low range EP straight away, but I could do with some help first.

btw, I have an F5 Newt, so based on this, can anyone advise what the above would be also.

regards, steve.

[rowan46]

https://www.astronom...lenses_c91.aspx

and for an f5 scope you are probably looking at televue eyepieces

[Jon Sales]

Hi Steve,

I too suffer from acute Astigmatism in both eyes and I have found that it does not affect my observing at all.

No matter which eyepieces I use I still achieve perfect focus without using my glasses.

This is because you focus the eyepiece to suit your eyesight when using a telescope. One persons eyesight will differ to someone else's even with 20/20 vision so adjustments will need to be made.

My suggestion is try various eyepieces at your local astronomy club and you will see what I mean.

Where about's are you? If anywhere near Worthing in West Sussex I can recommend their help. I used to live there before moving to Cyprus and all the guys are good friends and very helpful to newcomers.

Hope this helps.

Jon

[bomberbaz]

Thanks Rowan and Jon. I had already seen this web page and if need be, one of those EP adaptors wouldnt be to bad at $99. Circa £65.

I am Northern based Jon but I am going to an observatory Saturday night and amongst the things I will be talking about is my astogmatism. Apparently they have a wide range of scopes and I am sure trying these out and seeking advice from the more experienced people there should give me the guidance I need. I have already tried without my glasses but results were not good. However differrent EP's might yield better results, so the juries still out on this one.

Again thanks for the help though guys.

Steve

[Eastridge]

Absolutely agree general short / long sight will not impact ability to focus but my expereince differs from above so I guess the level of astigmatism can make all the difference here.

Because of it I view with glasses but was still getting a little distortion due to the condition. An eye test showed the axis was slightly off ( either my eye had changed shape or the previous perscription was slightly out) and new glasses with a different axis ( but no change to other powers) I can focus exactly with no flares or spikes etc.

Personally I would rather wear the glasses and stick with high eye relief EP's than fork out for Televue EP's ( which is what my research / peoples advice on here concluded would be needed but that is mainly because there are 2 of us viewing so it's easier.

[bomberbaz]

Interesting comments there Eastridge. You say you have researched this subject and your findings point to a Televue EP but you are managing with high eye relief EP's

Which EP's are you using please. I am not intending rushing out and buying just yet because of the costs involved, so I need to be sure I make the right decission for me but I want as much info as possible.

I found these http://www.opticalvision.co.uk/astronomical_accessories/eyepieces/sky-watcher_long_eye_relief_ler_eyepieces and they look an interesting option.

Regards, Steve.

[Carbon Brush]

My solution for astigmatism is contact lenses.

Even if you don't get on with contacts for everyday use, or can't tolerate them for long periods, do consider them for astronomy.

You are free to use any type of eyepieces with any eye relief and the difference in view is significant.

With glasses, you get compromised on eye relief, stray light, etc.

My astig is <1D so not that bad. But the difference with a correct contact lens is well worth the effort.

Talk to your optician (not the counter staff) and explain the situation. Some lenses have only a limited range of correction angles and some don't have astig correction available at all!

Many opticians will do trials at little or no cost.

Hope this helps,

[fredster]

I have acute astigmatism in both eyes too. I find the lower power eyepieces really are unusable without my glasses. But with the high power eyepieces its less of a problem and i can observe with glasses off. I did consider briefly adding the TV Dioptrix to a Radian 14mm but that would make it a nightmare to observe with others. In the end i sold the Radian and the Hyperions, bought a set of ES 82's. The 24mm has plenty of eye relief while i'm happy to observe with glasses off using the 11mm and 6.7mm. But now i'm finding my newly purchased Celestron X-Cel LX 12mm to be superb with glasses on. Eye relief is pitch perfect and the eyepiece appears to be more or less a match for a Televue Radian optically. I've decided to now add more X-Cel LX's to my collection and then decide what to do with the ES's later.

[James]

Long/short sightedness is easily dealt with by focusing, astigmatism isn't unfortunately although using higher magnification eyepieces with their corresponding small exit pupil can help reduce the problem. Tele Vue do their Dioptrix lenses which go on some types of eyepiece but I haven't tried these yet.

With any eye problem it's probably best to get the best eyepiece you can to minimise any aberrations introduced by the eyepiece

James

[bomberbaz]

Thanks David. I tried contacts many years back and didn't get on with them. I will think about about this option but also think its a chat with my optician about spectacles specifically for using with a telescope might be an option.

I use varifocals and no doubt his wont be helping. So assuming I am using my strongest power when viewing through the scope, it might be worth looking into some single vision glasses purely for use for astronomy.

[bomberbaz]

I have acute astigmatism in both eyes too. I find the lower power eyepieces really are unusable without my glasses. But with the high power eyepieces its less of a problem and i can observe with glasses off. I did consider briefly adding the TV Dioptrix to a Radian 14mm but that would make it a nightmare to observe with others. In the end i sold the Radian and the Hyperions, bought a set of ES 82's. The 24mm has plenty of eye relief while i'm happy to observe with glasses off using the 11mm and 6.7mm. But now i'm finding my newly purchased Celestron X-Cel LX 12mm to be superb with glasses on. Eye relief is pitch perfect and the eyepiece appears to be more or less a match for a Televue Radian optically. I've decided to now add more X-Cel LX's to my collection and then decide what to do with the ES's later.

I have previously looked at these fredstar and so your comments are very interesting. Again I am hoping the observatory visit on saturday will give some useful results and that they have a range of EP's on thier scopes for me to try out.

My initial thoughts at this stage on any of these solutions for an F5 scope is low (25-28mm), medium/low (15-18mm) and med/high (9-12mm) lense with a 2 times Barlow but this is only my starting point. But given the costs of the Celestron X-Cel LX EP's and Barlows would set me back nearly £250. Even the lower costing skywatcher EP's as per above would be £150 so you understand why I am asking for other peoples experiences before I even consider buying.

Regards, Steve

[fredster]

Steve, I completely understand your desire to get it right first time of trying. Its a lot of money at stake. You could minimise the cost by perhaps looking secondhand.

Btw I use an F5 refractor and F4.5 Newtonian. I find the Celestron performs very well in both. Its edge correction is not far adrift of the illustrious TV Radian. Just the outer 10-15% suffers in the F4.5, where as the only the outer 5-10% suffered in the Radian. Contrast and sharpness are also excellent. I have observed Jupiter a few times the past week and the view was incredibly detailed when seeing allowed. Red Spot nicely defined and also the trail of disturbance behind it. A friend who uses a Baader Geniune Ortho 12.5mm was genuinely impressed by how close the 12mm X-Cel LX was to his beloved Ortho. I personally could barely detect any improvement in his Ortho. On axis the Celestron is incredibly sharp.

There's a few places selling the Celestron X-Cel LX brand new for under £60 delivered. Which is a very good price. I intend to add the 5mm as soon as funds allow.

[Carbon Brush]

Varifocals are (in my experience) awful for telescope use.

The lenses are all about compomise - especially when distance/near/astig are all added in. So they tend to give dodgy views that vary with the part of the lens you are using.

A set of lenses with fixed focal length (whether near or far correction) with astig correction would be better.

This is (in effect) the TV adapter offering.

Contact lenses have come a long way in recent years. Not only in comfort, but also in correction options. If the types offered to you a few years back didn't work, it is certainly worth looking again now.

If I'm only having a 'quick look' I tend to use uncorrected vision. That is no specs or contact lens. The focus travel takes care of distance correction and astig is tolerated.

However, for serious viewing where I want detail, contacts are the first choice.

But, like eyepeice choice. There is just as much personal preference in there are science.

[rowan46]

I have to confess I use varifocals I am astigmatic in only one eye consequently I take the glasses off. varifocals are not ideal for astronomy. I think you will find either corrective contact lenses or ordinary glasses and longer eye relief eyepieces your best option. Really your first point of call should be your optician.

[bomberbaz]

There's a few places selling the Celestron X-Cel LX brand new for under £60 delivered. Which is a very good price. I intend to add the 5mm as soon as funds allow.

Yeah been looking and bookmarking some pages for when I eventually decide to upgrade. On final question for you fredster, do you use a barlow wiht it and if so, how do you find the results.

Same question to anyone else who has used Celestron X-Cel LX lens......

Regards, Steve

[haitch]

The Televue Dioptrix is a lens for correcting astigmatism that sits over the end of the eyepiece and designed to fit Televue EPs. (I see it's already been mentioned but wasn't sure if it had been explained).

I only have mild astigmatism which has never bothered me viewing but I have often wondered whether it would be possible to get your optician to produce something similar to a dioptrix to sit/hold over the top of any EP.

[bomberbaz]

I read about that haitch, although having just checked out the costs of their lens, I shall not be persuing this option, far to expensive.

But seeing optician on Thursday as almost due my 24 monthly check. Hopefully they will be able to suggest a suitable single vision solution to make viewing a better experience.

Thanks, Steve

[fredster]

Yeah been looking and bookmarking some pages for when I eventually decide to upgrade. On final question for you fredster, do you use a barlow wiht it and if so, how do you find the results.

Same question to anyone else who has used Celestron X-Cel LX lens......

Regards, Steve

Steve, it barlows very well indeed. I use the Revelation (GSO) 2.5x Apo barlow, which for the money (£37) is excellent.

[Eastridge]

Absolutely agree general short / long sight will not impact ability to focus but my expereince differs from above so I guess the level of astigmatism can make all the difference here.

Because of it I view with glasses but was still getting a little distortion due to the condition. An eye test showed the axis was slightly off ( either my eye had changed shape or the previous perscription was slightly out) and new glasses with a different axis ( but no change to other powers) I can focus exactly with no flares or spikes etc.

Personally I would rather wear the glasses and stick with high eye relief EP's than fork out for Televue EP's ( which is what my research / peoples advice on here concluded would be needed but that is mainly because there are 2 of us viewing so it's easier.

Interesting comments there Eastridge. You say you have researched this subject and your findings point to a Televue EP but you are managing with high eye relief EP's

Which EP's are you using please. I am not intending rushing out and buying just yet because of the costs involved, so I need to be sure I make the right decission for me but I want as much info as possible.

I found these http://www.opticalvi...f_ler_eyepieces and they look an interesting option.

Regards, Steve.

Hi,

Before I answer your question I have to point out that many on here will say they are rubbish EP's for a fast scope, although I can't say I really notice there shortcomings I presume that is my inexperience. I have a very limited budget and that constrains me.

As I understand it lower power ER is usually quite good whatever the EP but I went for a GSO 32mm as a 'finder' on cost basis and cos it's ER is very good.

High power was more difficult to find a high ER EP within budget. In the end I went for a 10mm Hyperion with Fine Tuning rings for high power ( giving me 10, 8ish 7ish & 6ish focal lengths) cos the ER is good. I am told they are poor in fast scopes towards the edges and I am sure they are. But they do have a wide FOV (68) so there is quite a bit that is quite central and as I use it for planets which are viewed in the centre I am happy enough. The wide FOV is good for me with a manual Dob so that I have the planet in sight for longer so I can nudge it back to centre if I leave the scope for a few moments. But that EP has gone up a lot in price since I got it.

I am currently thinking about something in the middle for what I have ideally c. 15 - 18mm and from all that is said on here the 18mm excel LX seems to be the favourite & at 16mm ER it should be OK.

As others have said Contact Lenses have come on a lot in recent years, I have disposable ones which work out at about £1 a pair. When I get my contact perscription updated I will definately have a go with them. Specsavers will give you 5 free pairs to try so for the cost of a contact eye test that might be an option.

[Eastridge]

Sorry should have added that if I recall correctly the SW LER EP's you link to do not have a great reputation so they did not figure in my 'shortlist' but the 20mm ER is the sort of ideal figure.

The Williams Optics SPL 12.5 was the other option I looked at as that has 20mm.

[bomberbaz]

Thanks for the reply Eastridge. your comments are ver y useful. As metioned, I am not rushing out to buy new EP's just yet but when i do decide the time is right, information gathered here and my budget have narrowed me down to baader hyperions or Celestron X-Cel LX lens.

http://www.firstlightoptics.com/baader-planetarium/baader-hyperion-68-degree-eyepiece.html

http://www.firstlightoptics.com/celestron-eyepieces/celestron-x-cel-lx-eyepiece.html

I know that the Baader are the better lens but on prices I have seen, it will 3 for two by pricing on the Celestron compared to Baader. (have seen celestrons for £60 each)

The other thing better on the Baader are the sizes. Buying a 24, 17 and 10 with a Barlow allows for a good range of lens and no doubling up. With the Celestron I was thinking about the 25, 18, 12 which doubles up on the 12, well as good as.

Anyhow I think it might be a while so will see how the kitty stands when time comes round but I have some very good ground to take it forward.

Thakns for all the great info SGL'ers, I would be lost without it

Steve.

[cs1cjc]

I do not agree with all the comments on this thread to date. I have astigmatism and wear spectacles most of the time when observing. I am very shortsighted -11.25 in my left observing eye but happily with decreasing astigmatism, now down to -1 dioptre. Also at the age of 60 I have presbyopia so lack accommodation and I use varifocal glasses normally. However I have not found these to be good for observing and now have had a special pair made for observing with the left lens at infinity the right somewhat closer for looking at charts and other close work. My iris still works though and it opens to about 7mm. Floaters become an issue at small exit pupils. For small exit pupil sizes, astigmatism become irrelevant as shown in the table here:

http://www.televue.com/engine/TV3_page.asp?id=54&Tab=_Choose

This shows that for 1 dioptre of astigmatism, there should be no loss of definition with eyepieces giving an exit pupil of less than 2mm. For example in an F/6 telescope I can use eyepieces of up to 12mm to give full detail without spectacles. In practice I use spectacles almost all the time, except when trying to see most detail on planets. It is much more convenient and I normally observe in company when it is polite to leave the scope reasonably focused for the next person.

I respect of eye relief, I would not assume that you need 20mm to be able to see the full field with spectacles. Indeed I find there to be a poor relationship between published eye relief and useability with spectacles. In particular I have found all the following to be usable with spectacles, at night with a dark adapted eye:

Vixen NLV series, NPL 20mm and 30mm

TMB type Planetary (published eye relief between 12mm and 15mm)

Baader Hyperion 17mm and 36mm Aspheric (a very nice eyepiece)

Adler SWA 38mm has more than enough eye relief but too curved a field for my old eyes to accommodate

Antares (similar to BGO) Ortho eyepieces, 12mm and 9mm (marginal), but 6mm is not acceptable

ES68 24mm, 16mm (unusable in day time but marginal at night)

ES82 8.8mm, 4.7mm marginal and the 14mm unusable (even though all have 15mm published eye relief)

[GaryM]

Just come across this post and am also experiencing the same issue with astigmatism. I too normally wear varifocals which are no use to me when viewing. I have been using bins for the past year and have put up with the distortion they give [to me]. But now I am looking to buy first scope. Over the last few weeks I have tried contacts but could not get on with them. My Optician suggested a pair of distance glasses to use when viewing or the old bi vocals. The reason for the latter is that I could use the upper lense for viewing [corrected for distance] and the lower portion for reading / scanning any maps / notes etc... in theory the best of both? For the additional expense they could be a back-up to my varifocals too. Never realised I had an issue until I took up this hobby as during the day I have used bins glasses off / on for years. Now it's very frustrating. I have just ordered the bi-focals so hopefully I have made the right choice for me?

[Eastridge]

after a while please let us know how it goes with the bi-focals - I am really at the stage of needing them and if they work well for astro I would jump sooner rather than later.

[bomberbaz]

Gary and Eastridge. Only just tried them last night and results were ok but a little inconclusive. Viewing conditions were not that good because of full moon, cloud and aviation but I managed a couple of hours with them. I viewed the moon, jupiter and some larger stars and it all seemed good. Certainly the short distance element didnt cause a problem.

When I manage to get them and try out in better conditions, I should be able to let you know more.

However in general they performed ok. I have got Baader HP at 10, 13mm and Celestron X-cel LX 18, 25 mm wiht a barlow. The good thing about both of these is the high eye relief. With the Baader you can fold down the rubber cup to get a better view into the EP. Better still and a great selling point witht he X-cels is the rubber cup screws up and down to allow for much better adjustment.

One thing you must do, is get the anti reflective coating on your lens to avoid any reflections etc.

Hope this helps, Steve