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    Default Is there a performance difference between a long barlow and a shorty barlow?



    I have always liked my 2x meade telenegitive long barlow (two elements, I believe). In my 10" Orion f4.7. For me it's better than my Celestron Ultima sv series shorty and the Meade telenegitive shorty in performance. When I've used my various eyepieces in them. I have not tried the Televue powermate. I believe I read that a longer barlow out performed a short one. [I would like a single 7mm TMB eyepiece, instead of using my 15mm Panoptic & barlow]. Pat

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    MitchAlsup's Avatar
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    Default

    Bypassing the performance armument for a second:

    There is an optical difference between a shortie and a longie: the longer Barlow will alter the field curvature less than the shortie. For some scopes this FC change is good for others bad and for still others indifferent.

    Performance argument:

    Barlows fall into the catagory of optical devices for which optical execution is more important than optical design and/or the optical prescription. {Given the same optical prescription (glass type, surface curves, spacing) one company can produce a fabulous Barlow while another could produce a fairly good Barlow.}

  3. The Following 2 Users Say Thank You to MitchAlsup For This Useful Post:

    Indytom (11-02-2011),pat c (11-01-2011)

 

 

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