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Eyepieces & LER


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Well, just about got decided on the telescope, now the eyepieces:icon_confused:

Have read the really useful guide on this site and have (I think!) managed to work out the focal lengths, magnifications, and even the true FOV :icon_eek:........so should be relative easy to then choose which to buy......but big sticking point on eye relief; as a glasses wearer, blind as a bat without, I believe from what I've read that that Long Eye Relief is essential - I can only find one set of Skywatchers that class themselves as LER and these don't cover the FL's I want.

Can anyone help with what constitutes LER? there may be other eyepieces that come in this category but which I don't recognise simply 'cos they don't call themselves LER in the marketing blurb, whereas others say suitable for glasses wearers but then don't say they have LER !

Any help on LER would be much appreciated :hello2:

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Eye relief is the distance that the eye needs to be from the top lens of the eyepiece so that the full field of view can be seen. Different designs of eyepiece offer diferent eye relief. I'm not a glasses wearer myself (when observing) but I understand that an eyerelief of something like 15mm or more is considered OK for those that do need to wear them. Longer focal length eyepieces (ie: lower power) tend to have longer ER anyway so it's less of an issue with those.

Some brands of eyepiece are designed to offer longer ER - the Skywatcher LER's are just one type (not very good ones in my experience). Others include the William Optics SPL's, Baader Hyperions, TS Planetary HR's, Meade 5000 plossls etc, etc. Just because they are not marked LER does not mean that they don't offer it !.

John

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Some don't claim LER, but looking at the specifications you can find the eye relief value. For someone using glasses around 12mm of eye relief should be fine.

On a wealthy budget you always have the Televues and Pentax.

On a average budget: The Sky Watcher Nirvanas are very well rated, have a wide FOV and have a good eye relief.

If you want good but cheape ones, I have 3 Agena SWAs and I'm very pleased with them. They have a good view to around 85% of the FOV with minor anomalies on the edge on my f/5.9 scope (slight coma). They are well rated for the price and I would recommend to someone on a budget with a scope with f/6 or above. Check them here: Agena AstroProducts - Telescopes, Eyepieces, Binoculars and Accessories for the Astronomy Enthusiast with FREE US Shipping

Review on the agenas WA, SWA and the higly rated William Optics SWAN

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That's very useful to know. Another reason to get a Barlow.

old_eyes

Yes, a good quality barlow is a good investment and provides more benefits than just increased magnification. By good I'm referring to ones like the Celestron Ultima SV 2x barlow or the Tele Vue 2x Barlow. A poor quality barlow (like the ones supplied with many scopes) should be avoided though - they cause more problems than they solve !.

John

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Many thanks for the info so far :icon_eek:

I thought choosing the scope was hard enough but the eyepieces and LER requirement present yet even more hours/weeks...maybe years:icon_eek:....of decision making.

The scope will be either Skymax 127 or Celestron 5SE (though I keep getting tempted to blow the budget and go for the 6SE!) They all come bundled up with an EP or two but I understand that these will need replacing with better quality ones asap, so all your views and expertise very much appreciated - can't wait to get the thing bought and start looking:)

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I'm not so sure how fast you need to replace them. The 25 and 10mm plossl that came with my scope are decent, and the ER isn't that bad.

I did rush into buying EPs and bought a couple too many, so take it easy and try out the ones that come with the scope. A visit to a local astronomy club may give you some hands-on experience and help you decide.

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