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Thread: 25mm 58 Degree Eyepiece Vs. 20mm 66 Degree Eyepiece

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    Default 25mm 58 Degree Eyepiece Vs. 20mm 66 Degree Eyepiece



    Is there a big difference in these two eyepieces with a 120mm f/8 refractor? Would you own the two?

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    Default Re: 25mm 58 Degree Eyepiece Vs. 20mm 66 Degree Eyepiece

    If you input all the numbers into this you can compare the TFOV and magnification: N.A.A. Telescope Math Calculator
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    Default Re: 25mm 58 Degree Eyepiece Vs. 20mm 66 Degree Eyepiece

    Hi,

    I prefer to use this site for comparisons: https://astronomy.tools/calculators/field_of_view/


    Here is the product from this site:



    Cheers,
    JT
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    Default Re: 25mm 58 Degree Eyepiece Vs. 20mm 66 Degree Eyepiece

    Here's a better image that may be more meaningful.



    Cheers,
    JT
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    Default Re: 25mm 58 Degree Eyepiece Vs. 20mm 66 Degree Eyepiece

    The fields are similar enough for me, I would lean then on the reputation of each. Which two EP's are we talking about here? I suspect one is an Expanse or clone of one, the other... BST maybe?
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    Default Re: 25mm 58 Degree Eyepiece Vs. 20mm 66 Degree Eyepiece

    Quote Originally Posted by jaetea View Post
    Hi,

    I prefer to use this site for comparisons: https://astronomy.tools/calculators/field_of_view/


    Here is the product from this site:



    Cheers,
    JT
    Thanks

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    Default Re: 25mm 58 Degree Eyepiece Vs. 20mm 66 Degree Eyepiece

    Quote Originally Posted by refractordude View Post
    Is there a big difference in these two eyepieces with a 120mm f/8 refractor? Would you own the two?
    Thanks

  8. #8
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    Default Re: 25mm 58 Degree Eyepiece Vs. 20mm 66 Degree Eyepiece

    Quote Originally Posted by Gabby76 View Post
    If you input all the numbers into this you can compare the TFOV and magnification: N.A.A. Telescope Math Calculator
    Thanks

 

 

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