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    Default 2" lense or 1.25" whats the difference?



    Hi, I have just bought a 12" dob and it takes 2" lenses, i already have a 6" dob and this takes 1.25" lenses what the difference in the lenses? advantage, etc...

    thanks Dave.

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    Default

    The advantage of a 2" focuser like yours is that it can take both 2" and 1.25" eyepieces. (the lenses you're talking about)

    There's no difference in quality of 2" and 1.25" eyepieces, but 2" barrel allows for a wider field of view than a 1.25" barrel.

    For example, the ethos' 100 degree apparent field of view isn't possible on 1.25" eyepieces larger than the Ethos 13mm, so Televue uses 1.25" barrel on the 6, 8, 10, and 13mm ethos, and 2" barrels on the 17 and 21mm ethos eyepieces.

    The Ethos example is valid for any eyepiece, the barrel size is all about field of view of the eyepiece.

    Televue just doesn't use 2" barrels for the 13mm and below Ethos EPs because 100 degree field of view can be acquired with 1.25" barrel, so a 2" barrel isn't necessary in that case.
    Last edited by Leo; 06-05-2010 at 05:41 AM.
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    Default

    There are also other differences as well ..Main one being price ....2in. EP's cost a little more than 1.25in. EP's ...I bought my first 2in. EP a couple of years ago and although i love looking at the moon at high power i generaly just barlow a 2in. EP rather than use a 1.25in EP ... I like the big glass you get to look through as well as the massive size of 2in. EP's ...
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