Eye Relief

[M4lcs67]

Hey Folks.

I know I should have probably put this in the eyepiece section, but when I have posted in previous times in what I think is the correct section, I only get a few answers (if any), so I thought I would cut straight to the chase this time.

I have a large selection of Hyperions and I love them for their versatility with the tuning rings. Effectively having 3 eyepieces in one is a great idea.

However I need to wear glasses full-time and having to take them on and off all the time when reading the hand controller then looking down the eyepiece is a colossal pain. Therefore my question is what are the best eyepieces with the longest eye relief? My Hyperions are billed as having long eye relief, but I still need to remove my glasses when looking through the scope.

I am predicting a very expensive answer. Tele Vue or something of that ilk?????

I would dearly love to be able to leave my glasses on (currently when looking through the eyepiece I have my glasses off and my eye virtually pressed against the lens of the ep) and that is where an eyepiece with the longest eye relief would really be the one for me. I have only been a glasses wearer for a year, but trying to juggle the hand controller while looking through the eyepiece is a very tough one.

[ronin]

The Hyperions say 20mm eye relief, and if that is insufficent I cannot think of easily getting much more.

I recall people complaining of too much eye relief when using 32mm plossls and they get about 20mm eye relief with a 32mm plossl.

I wear glasses and I use the BST's that have 15mm eye relief and find them acceptable.

I will say I often remove my glasses but that is simply as I find it easier not because of insufficent eye relief, I tend to whack them into  the eyepiece. However being short sighted it means I can remove them and then read the handset easier. I have to take mine off to read anything close, so just viewing without them simplifies it all.

[Naemeth]

I've found that the pair of glasses makes a huge difference to how much eye relief you need. With my old pair I could use 12mm of eye relief and have my glasses only slightly pressed up against the glass, whereas these ones need over 20mm eye relief (which is why I take them off). It may be cheaper to get lower profile frames for your glasses than a new set of eyepieces  . 

[astronymonkey]

Hi malc,

you only really need to wear your specs if you have astigmatism as this cant be corrected by focusing like near or far sightedness can.

I wear specs when viewing so only have eps with at least 15mm eye relief so 20mm you have should be enough unless youbhave huge frames or wear them on the end of your nose !

I pondered for a long time as to which eyepieces to get but in the end went for the type4 naglers for mid to low power, and then delos for high power and find these to be fine, despite being exoensive. I also have a william optics 28mm uwan for wide field use which is also fine.

cheers

[YKSE]

Hyperions have concave eye lens as shown here,

http://www.baader-planetarium.de/sektion/s26/download/hyperion-okulare_englisch.pdf

Eye relief is measured from the center of the Eye lens, so the available ER for hyperisons is shorter than 20mm. Televue Radians have 20mm ER and convex eye lens, and Pentax XWs (20mm ER) have flat eye lens, they should have available ER than hyperions.

[Astro Imp]

Have you thought of using a Barlow with the appropriate EP to extend the eye relief? Just a thought.

[RikM]

I own both Pentax XW and Hyperion eyepieces and have used a couple of the Delos range as well. These all state 20mm of eye relief and all feel about the same to me. I wear glasses to observe and don't quite need to press my glasses against the eyeguard to see the whole field but do need to get fairly close. If you are struggling to use the Hyperions, I don't think changing to Pentax, Delos or Radians will be the answer. I would go with the suggestion above and get some closer fitting frames for your specs.

I don't know if it is just me, but I don't find a barlow adds much extra eyerefielf when used with complex designs incorporating a Smyth lens group in the barrel. (Like Hyperians and Pentax). I do use a long type barlow rather than a shorty type and these do have less tendency to alter eyerelief as well.