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    Default Wrong focal length on Bushnell* Sky Chief II?



    This is my first post here, so play nice.
    I was given a used Bushnell* Sky Chief II and am trying to get it working. I pointed it at the moon and couldn't get it to focus on the big blur of light in the eyepiece. I cleaned the objective lens, eyepieces, and diagonal mirror. Now they all look near perfect. The moon was still blurry.
    This is how I got it focused: I put the focusing tube as long as it would go, then looked through the eyepiece as I pulled it out about 1.5 inches. Everything became perfectly clear! How is this possible? And how can I fix it?

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    Ryouko's Avatar
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    Default Re: Wrong focal length on Bushnell* Sky Chief II?

    For more info, the scope's nameplate says it has a 60mm aperture, 800mm focal length. I measured from the lens to where the eyepiece is and only get about 740mm.

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    Default Re: Wrong focal length on Bushnell* Sky Chief II?

    Ryouko, looks like no one with experience in your telescope has chimed in yet so I will. Mine isn't a Bushnell, but I experienced the same thing you did. My focuser tube was all the way out, but it was still blurry. Only until I pulled out my eyepiece by about 20mm OUT the focuser was when the stars came into focus. The reason for this was because my telescope had an upgraded focuser which was SHORTER than the original focuser. To solve this, I bought a 35mm extension tube (https://www.astronomics.com/astro-te...be_p17010.aspx).

    It looks like you are missing 60mm of back focus so you can get the 50mm or 80mm extension tube. Hope that helps.
    -- Michael
    Telescopes: Sky-Watcher 12" Flextube | Nikon 8x40 Action VII Bino
    EP's: ES 82° 24mm, 18mm, 14mm, 11mm
    My Blogs: http://newastronomer.com


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