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  1. #1
    smokesha's Avatar
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    Default what is the largest apparent FoV in a 1.25" eyepiece



    Edit: title is misleading. I meant to say What is the largest True Field of View

    I want to get a really low power eyepiece for my 1.25" focuser but ran into the problem that 40mm eyepieces have less of an apparent FoV than the 32mm, giving almost the same True FoV. Should I settle on a 32mm or look for a bigger 40mm.

    the 32mm plossl I saw had a AFoV of 50 degrees while my 26mm EP has an AFoV of 60 degrees giving them the same TFoV. So it's not even worth getting that either. it seems that in order to get anything wider, I'd need a 2" focuser. Is there any other options out there for me?
    Celestron Astromaster 130eq - 130mm f/5 Newtonian on an equatorial mount. Viewing from New York, USA

  2. #2
    Kevin Z's Avatar
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    Default

    Baader makes an Hyperion aspheric lens. Comes with a 2 inch barrel and a 1.25 barrel.
    My biased opinion is that the Baader Hyperions are the best there is for the price.
    How the true field of view comes out is enough math to give me a headache, so I will let you figure that out.
    Eyepieces

  3. #3
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    Default

    Hello.,,.as Kevin said,. Baader EPs are the best in that price range.,.for more info about them go to AgenaAstro.com.,..they have detailed spec charts for these EPs..,.,and they are a great company to deal with.,.,,good luck.,,,O+O

  4. #4
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    Default

    Those eyepieces look very nice. It took me a bit to find the apparent field of view of them in the 1.25" barrel. But the 31mm has an AFoV of 55 degrees and the 36mm of 50. giving in my 130mm f/5 scope a True FoV of 2.62 and 2.77 respectively. Currently, my largest True Field of View eyepiece is 2.4 degrees. Is it worth spending 200 bucks for an extra .37 degrees?
    Celestron Astromaster 130eq - 130mm f/5 Newtonian on an equatorial mount. Viewing from New York, USA

  5. #5
    WWPierre's Avatar
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    In a word, no. You are already pushing the lower mag limits of your optical system. My Siebert 35mm gives very pleasing complete views of the Pleiades, and is crisp out to the edge of the FOV
    Last edited by WWPierre; 10-16-2009 at 07:22 PM.
    Meade 16" LightBridge; Celestron G-8N Bird-Jones/motorized EQ5;
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  6. #6
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    Default

    Further to my post above, I went looking for 1.25" 35mm eyepieces, (to compare prices and AFOVs) and they are pretty scarce.

    I did find this video, which is a pretty good demonstration of the optics. I think I made a good purchase.
    Meade 16" LightBridge; Celestron G-8N Bird-Jones/motorized EQ5;
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    49-41-37.03N 123-09-29.61W Calculated magnetic declination: 17° 39' East

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