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Thread: Reflecting telescope

  1. #1 Reflecting telescope 
    Forum Isotope (In)Sanity's Avatar
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    I just picked up a 125mm Bushnell scope. Used of course. I was wondering if anyone has any good advice on perfect alignment of the mirrors? I know your suppose to center everything with the center of the eyepiece, but somehow I think there must be more then one combination that appears to be ok.

    The tube on this thing is about 145mm, So I assume it's a 120mm or perhaps 125mm mirror. It's around 650mm plus a few long. Came with a nice tripod with the good micro adjusts and motor drive. Also have an NTSC camera that was included. I'll take a pic when I'm done fooling with it.


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  3. #2  
    Forum Radioactive Isotope cosmictraveler's Avatar
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    There's only one mirror, see link, that can be moved, the small one. If that has been somehow put out allignment then you'll have to know allot more than I can help with. Ususally the eyepiece is adjusted to bring the objects into focus. Perhaps it could be a bad eyepiece instead?




    www.northern-stars.com/reflecting_telescopes.htm


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  4. #3  
    Forum Isotope (In)Sanity's Avatar
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    I was a bit off on the size of this scope, it's a 114mm mirror (use able). The focal length is 650-675 (too lazy to remeasure).

    In any event using a film canister with that dead center hole drilled out I was able to align the system. First I cheated and removed the rear mirror in order to align the front mirror. I centered it exactly with the end of the scope (with the large mirror out). Once I got the front mirror aligned I was them able to adjust the rear (large) mirror so that everything was dead center.

    I found this site useful, while it's for a Meade 114 I still found it to be very useful and pretty much identical.

    http://homepage.ntlworld.com/robin.s...collimate.html

    I'll check out the scope tonight and see how it works out. I have some brand new Meade eyepieces that I purchased for my little 80mm refractor. The tripod on this Bushnell appears to be pretty good, it has the 3 micro adjusters for 3 different access points. Yaw, pitch and roll. The mirror also appear to be in perfect shape and very thick, I would say close to 3/4 inch of glass.

    Not sure what all I'll be able to see with a 114mm...but will be interesting to find out.
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  5. #4  
    Forum Freshman jgmaynard's Avatar
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    AS I recall, the best way to align reflectors is to take it out during the day, and view a small point of light with it (eg., a reflection off the corner of a car bumper in the distance) and then adjust the small mirror until it is the smallest point possible through the eyepiece.

    JM
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  6. #5  
    Forum Isotope (In)Sanity's Avatar
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    Quote Originally Posted by jgmaynard
    AS I recall, the best way to align reflectors is to take it out during the day, and view a small point of light with it (eg., a reflection off the corner of a car bumper in the distance) and then adjust the small mirror until it is the smallest point possible through the eyepiece.

    JM
    I've never read that one. Sort of makes a little sense...but I have to wonder about other things that also factor in.
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