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  1. #1
    patpaa's Avatar
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    Default Choice between two low-power EP's



    I'm thinking about expanding my EP set with a low-power unit and would appreciate your input before I buy.

    My scope is an Omni XLT 102mm refractor, focal length 1000mm, f/10. I currently have a high-power (10mm) EP, the 25mm that came with the scope and a 2x Barlow. I'm looking for a third EP that gives me as wide TFOV as possible.

    I'm looking at the Celestron Omni Plössl's which seem to be allright for their low price tag. Would you choose either
    1. a 32mm, 52deg AFOV, 22mm eye relief (31x, 1.66deg AFOV and 3.2mm exit pupil), or
    2. a 40mm, 43deg AFOV, 31mm eye relief (25x, 1.72deg AFOV and 4mm exit pupil).


    Price difference is essentially none (the 40mm is a little bit cheaper). The 40mm seems better as it gives a (slightly) wider field of view and larger exit pupil, but I'm wondering if that's all there is to it?

    Any thoughts or other EP recommendations?

    Cheers /Patrik
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  2. #2
    Joe Lalumia's Avatar
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    Default

    I would go with the 32mm -- clear skies to you.
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  4. #3
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    Default

    Obviously, the 40mm does give you a slightly larger True FOV, but does it at a very low magnification level.

    I'm with Joe, I think the 32mm is the more balanced eyepiece.

    That said, I'd choose neither of those Celestron Omni Plossls.

    I'd go to Agena Astro and get this: GSO 1.25" Plossl Eyepiece - 32mm

    It appears to be the identical eyepiece. The Celestron was probably made by GSO. . .

    But if you get it through Agena Astro you get a slightly lower price, a bolt case for the eyepiece, and free shipping.

    I'm cheap. I'd get it through Agena Astro even though the Celestron looks purtier.

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  6. #4
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    Default

    The 32mm is the way to roll. There is a limit to how wide of a view you can get before there is a compromise in viewing. Since I don't know much about that I'll wait for someone with more knowledge to shed some light on the issue.

    The 32mm EP is probably right about where you want to be.
    -Nick

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  8. #5
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    Default

    In your refractor IF YOU DO NOT USE A 2 INCH Diagonal I actually would prefer the 40 mm "slightly" over the 32

    Actually I own a f/6 100mm 600 mm refractor as well as a F/9 127 mm 1200 refractor and I tend to use a 40 more then I do the 30 (I do not own a 32) ...

    If you use a 2 inch diagonal Then I'd go with the 32 because a 40 would be very demanding on where you actually place your eye to avoid the black outs ...

    Bob G.
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  10. #6
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    Default

    I would also consider how the ep with barlow fits in with other eps. Would a 20 mm or 16 mm fit best? The 32 mm plus barlow would make a very nice 16 mm ep.

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  12. #7
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    Default

    Quote Originally Posted by OleCuss View Post
    Obviously, the 40mm does give you a slightly larger True FOV, but does it at a very low magnification level.

    I'm with Joe, I think the 32mm is the more balanced eyepiece.

    That said, I'd choose neither of those Celestron Omni Plossls.

    I'd go to Agena Astro and get this: GSO 1.25" Plossl Eyepiece - 32mm

    It appears to be the identical eyepiece. The Celestron was probably made by GSO. . .

    But if you get it through Agena Astro you get a slightly lower price, a bolt case for the eyepiece, and free shipping.

    I'm cheap. I'd get it through Agena Astro even though the Celestron looks purtier.
    Thanks for the tip! I was actually planning to buy from Sweden this time, but I would save a few extra bucks ordering from the US, so it might just be worth the extra hassle...

    CS /Patrik
    Celestron Omni XLT 102 refractor, Celestron UpClose 10x50 binoculars.

  13. #8
    patpaa's Avatar
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    Default

    Quote Originally Posted by kencrowder View Post
    I would also consider how the ep with barlow fits in with other eps. Would a 20 mm or 16 mm fit best? The 32 mm plus barlow would make a very nice 16 mm ep.
    Good point! I did actually consider this earlier but forgot to include it in my first post. The 32mm would indeed fill some gaps in my magnification range below 100x. My current setup gives 40x, 80x, 100x, 120x, 200x (and 300x). The 32mm would yield 31x, 62x and 93x, and the 40mm 25x, 50x and 75x.

    CS /Patrik
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  14. #9
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    Quote Originally Posted by Bob327 View Post
    In your refractor IF YOU DO NOT USE A 2 INCH Diagonal I actually would prefer the 40 mm "slightly" over the 32

    Actually I own a f/6 100mm 600 mm refractor as well as a F/9 127 mm 1200 refractor and I tend to use a 40 more then I do the 30 (I do not own a 32) ...

    If you use a 2 inch diagonal Then I'd go with the 32 because a 40 would be very demanding on where you actually place your eye to avoid the black outs ...

    Bob G.
    That's interesting. Why do you prefer the 40mm over the 30mm? Because of the larger TFOV? It seems like the extra eye relief of the 40mm could be a nuisance, but perhaps it isn't?
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  15. #10
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    Default

    I also give my vote for the GSO 32 mm plössl. It is very good for that price. I bought it with an eyepiece kit under the TS brand.
    Carl Sagan's fanboy.

 

 
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