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Thread: eye relief with lower magnification eyepieces

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    Default eye relief with lower magnification eyepieces



    Hi everyone. I just purchased a reflector telescope ( 10 inch F6) , and I am waiting for shipping delivery. Tentative shipping date is sep 30th. This is a much bigger aperture and focal length compared to my current scope ( 5 inch F5).


    So far, my lowest magnification eyepiece is a 20mm ES 68. This is the eyepiece that I use to spot objects/planets before switching to a higher magnification eyepiece . Because of my new scope, I am looking for a 30 to 35 mm eyepiece. I see online that most of these eyepeices have at least a 20 mm eye relief.


    I do understand the advantage and appreciate eye relief in the sense that it provides us with some "room " . But my question is which mark does eye relief starts getting tricky to centre the eye ? is there a limit that you guys will recommend that I should not exceed? In other words, at which value does eye relief starts getting disadvantageous? for example lets take the televue 35mm panoptic which has an eye relief of 24 mm. Is this eye relief too generous to the point where it gets tricky to centre the eye ? If yes, then what would be the visual impact? would my stars look like "birdies" similar to coma ?


    thanking you all in advance for your inputs and help !
    Last edited by mruhomau; 09-21-2016 at 01:37 PM.

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    Default Re: eye relief with lower magnification eyepieces

    I have some Baader Hyperions which have 20mm of eye relief. I've never noticed any problems. The only problem I ever had was trying to get a camera in the right spot for afocal images but other than that, it wasn't an issue.
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    Default Re: eye relief with lower magnification eyepieces

    Quote Originally Posted by Robrj View Post
    I have some Baader Hyperions which have 20mm of eye relief. I've never noticed any problems. The only problem I ever had was trying to get a camera in the right spot for afocal images but other than that, it wasn't an issue.
    do you have experience with eyepieces with eye relief more than 20mm ?

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    Default Re: eye relief with lower magnification eyepieces

    No. 20mm of eye relief is the longest I have. My most used eyepieces range from 10.5mm for my ES 5.5 100° to 17.5mm for my ES 24mm 82°. All of the Hyperions are 20mm. But most of the higher quality eyepieces will come with a suitable eye cup that helps you put your eye at the correct distance. Take a look at the reviews for any eyepiece you're interested in. That I'm aware of, the only real reason to go with a longer eye relief is if you wear glasses. If not, I would just look for something that's in a comfortable range and gets good reviews. For example, the Explore Scientific 30mm 82° eyepiece gets really good reviews and has 22mm of eye relief.
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