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    Scott M's Avatar
    Scott M is offline Junior Member
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    Default Barlow & SLR on Telescope



    Hi
    I have an interesting question...I took some photos for the 1st time through my christmas pressie telescope (8" reflector) using a DSLR with T-adapter screwed into the back of a 2X barlow. I took photos of the moon (as it was pretty much full and I couldn't see a lot else, besides, I had yet to buy batteries for the motor, so was limited to short exposures). I also took photos piggybacked using a 300mm lens.

    When I compared the piggybacked photos to the barlow photos, the moon was 10x bigger. This means that I was getting a focal length of 3000mm through the 2X barlow.

    Since it was a 2X barlow, and the telescope focal length is 1000mm, why wasn't I getting 2000mm??

    cheers

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    interstellaryeller's Avatar
    interstellaryeller is offline Bright Giants
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    All I can say is that a 2x barlow will double your power while cutting the light by 2x, and your t adaptor without a lens also acts like a barlow to some extent.
    Interstellaryeller: Celestron Classic 8: Meade DS2000

 

 

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