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    Jay573's Avatar
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    Default Newbie - Barlow for Sky-Watcher Startravel 102



    I am curious to know what considerations to take into account before purhasing a Barlow lens for this telescope.
    The focal length is 500mm f/5 and it comes with a 20mm and 10mm eypiece.
    Are Barlow lenses difficult to use and do they make a significant improvement to magnification?
    Any tips or advice welcome.

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    Default

    Sorry about the delayed response.

    Think of a 2x Barlow as a focal length and focal ratio doubler. It will sort of turn your telescope into a 1,000mm, F/10 telescope.

    Having the longer focal length telescope will mean that you will get the same magnification from your Barlowed telescope and 20mm eyepiece that you now get from your 10mm. Once nice thing about that is that your eyepieces are likely Plossls and that means that the eye relief of your 20mm is likely much better than that of the 10mm and that means that you get the magnification of the 10mm with the eye relief of the 20mm.

    Use the Barlow with the 10mm and you'll pretty much max out the normal useful magnification of your telescope.

    Most of us do have Barlows for at least occasional use.

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    Default

    I'm kind of in the same situation. My scope is F4 with 400mm focal length, with the same size eyepieces as you.
    I'm thinking that a 2x barlow might be the best way to go.
    For now, that would get you up to 100x. Add in a 6mm eyepiece later, and that will give you 80x, and 160x with the barlow.

 

 

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