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  1. #1
    Gordon Reid's Avatar
    Gordon Reid Guest

    Default Reflector vs. refractor telescopes



    Hello,

    We are trying to decide on a telescope for a 12 yr old. We are looking at 3
    different models (all in Sears Christmas Wishbook) - a 60 mm refractor, a
    76mm refractor or a 114mm reflector. The 114mm reflector has a 4mm and
    20mm eyepiece, a 3x barlow lens with 45x - 675x power range.
    The 60 and 76mm refractor telescopes each have 3 eyepieces (size not
    specified), a 3X Barlow lens and a magnification range of 35X - 525X.

    Would appreciate any comments on these telescopes. BTW, what is the Barlow
    Lens??

    Many thanks



  2. #2
    B's Avatar
    B Guest

    Default Reflector vs. refractor telescopes

    Any telescope that advertises a power range 45X-600x is junk. All the
    ones you mentioned at sears are poor quality. If your child is really
    interested in astronomy, a small refractor or Dobsonian (reflector) is
    best. To view the skys aperture is key. The larger the more light gets
    in and the more your can see. Dobsonians are cheaper in respect to the
    size of aperture you get. A refractor gives a sharper image on the moon
    or planets. Look at telescopes.com. It has a lot of info for beginners.

    Bruce

    Gordon Reid wrote:



  3. #3
    Yoesemite Sam's Avatar
    Yoesemite Sam Guest

    Default Reflector vs. refractor telescopes

    Hi Gordon,

    A barlow, when used in conjunction with an eyepiece, will either double (2x)
    or triple (3x) the normal magnification you get from the eyepiece. The
    problem is that a 3x barlow will give you way too much magnification with
    the telescopes you mentioned. As a general rule, you will not be able to
    magnify more than 50x per aperture inch. In other words you will only be
    able to magnify the 114mm scope to about 200x. Anything greater than that
    would not be useful, because you would only see a great big blurry mess. Of
    course at 200x you might still have difficulty seeing objects clearly if you
    have an unstable tripod. I think your best bet would be to get a Dobsonian
    telescope. It may not look like what you would normally expect a telescope
    to look like, but they are extremely stable and simple to use. One of the
    best ones out there for kids is the Orion SkyQuest XT4.5 Dobsonian
    Reflector. You can check it out at Orion's web page, www.telescope.com.
    Good luck!

    Jim



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  4. #4
    L.C.'s Avatar
    L.C. Guest

    Default Reflector vs. refractor telescopes

    None of the below!!!!!

    First advice:
    Get out of the Sears Wish List.
    Get out of department stores.

    Steer clear of anything that advertises
    more than 60X per inch of aperture

    ****************************************
    Here is a pertinent FAQ
    http://www.perkins-observatory.org/FAQ.index.html
    ****************************************

    Here are some suggestions, but read the FAQ and
    make your own choices.

    Dobsonians are the standard first scope.
    They will require that you help the child align the optics. It
    will be (or quickly become easy for you). Optically, they are the
    best bang for the buck. The larger ones can be bulky.


    Hardin has some good deals on Dobs.
    All sizes down to 6":
    http://www.hardin-optical.com/catalog1.html


    Here are some choices from Orion:
    A 6" Dob - Optically Ideal
    http://www.telescope.com/shopping/pr...roductID=14854

    A 4.5" Dob. A little small on aperture, but OK for a kid
    http://www.telescope.com/shopping/pr...iProductID=364



    Orion StarBlast
    A short tube reflector. This is strictly a low power scope.
    It gives wide field views
    It's embraceable
    It badly needs other eyepieces.
    (Could consider the Edmund Plossls and barlow, for this scope
    but stay clear of the current AstroScan telescope they sell)
    http://www.telescope.com/shopping/pr...&RS=1&keyword=



    An 80mm refractor
    (Will require a camera tripod and possibly a SloMo mount)
    This one won't show you anywhere near as much as the Dobs
    but there's no alignment:
    http://www.telescope.com/shopping/pr...&RS=1&keyword=

    Whatever you get, you will soon need more EP's.

    ***************
    What's a barlow?
    ***************
    A barlow is a lens that goes between the eye piece and
    telescope. Its functions:

    1) It raises the effective focal length, thereby increasing the
    magnification of any eyepiece you have. If you choose the
    barlow and eyepieces right, it's like doubling the number of
    eyepieces you have.

    2) In the case of the scopes you mention, the function of the barlow
    is to increase magnification so much, the image becomes dim and
    blurry.

    3) When properly uesed, a barlow is a way of increasing power
    without requiring an impractically small eyepiece hole. (They
    get smaller as eyepieces get more powerful.)

    4) When properly used, a barlow is a way of increasing power
    while allowing the viewer's eye to be comfortably far away
    from the eyepiece.


    Luck and Regards
    -Larry (Did I mention - get rid of that Catalog?) Curcio




    Gordon Reid wrote:



 

 

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