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Thread: Usable Eye Relief Difference between Explor Sci 68* 28mm and 82* 30mm?

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    Default Usable Eye Relief Difference between Explor Sci 68* 28mm and 82* 30mm?



    I have very deep set eyes and, now that I have to wear my glasses to observe due to astigmatism, I can't see through the eyepieces I collected in the mid-2000s. To replace my "find the darned fuzzy thing" eyepiece, I'm considering the Explore Scientific 68* 28mm and the 82* 30mm. Both are listed as having long eye relief, but the real world could tell a very different story. Can anyone speak to having used both with eyeglasses on? Does one offer meaningfully more eye relief in actual use?

    I don't think it'll matter for this question, but someone always asks, so the host scope will be a 10" f/4.9 dob.

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    Default Re: Usable Eye Relief Difference between Explor Sci 68* 28mm and 82* 30mm?

    I've got the 82° 30mm, but I've not tried it with glasses on (I wear contact lenses when observing). Eye relief is quite sufficient in that regard, but that doesn't help your decision process.

    I will suggest, however, that this eyepiece may offer a very large exit pupil (about 6mm) with that particular scope, and this may cause the central obstruction (secondary mirror) to display a darker splotch (shadow) in the center of the FOV, especially on brighter objects.

    I get a similar effect in my 12" f/5 dob. It puts up a 6.02mm exit pupil with my scope and I do notice the loss of light with this eyepiece. As a result, this eyepiece doesn't spend a lot of time in my dob. It is absolutely amazing in my 127mm refractor.

    I find that the 82º 24mm is much better in the capacity as a "finder" eyepiece as it loses less light than the 30mm. It puts up an excellent and bright image with my dob.

    Again, though, that doesn't help you with your eye relief question, but will hopefully pose another aspect of your decision that you may not have considered. You may not be concerned about that at all, but just wanted you to be aware that it could pose an issue for you.
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    Default Re: Usable Eye Relief Difference between Explor Sci 68* 28mm and 82* 30mm?

    I have a 26mm 70* AFOV eyepiece now that I used to use happily. When I pull away from it, I can see that the bright object (such as the sun today for the eclipse) is a donut, but when I finally get my eye down to the right spot, I don't see any problems with the image. I was hoping the 28 and 30 were each close enough to 26 for the situation to continue to be ok. I have no real experience to base that hope on, though.

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    Default Re: Usable Eye Relief Difference between Explor Sci 68* 28mm and 82* 30mm?

    I observe with glasses on. I did not have a chance to use Explore Scientific 68* 28mm and the 82* 30mm, but for shorter focal lengths it was easier to see full field of view in ES 68 and Meade 5000 UWA then in ES 82.

 

 

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