Barlow question.

[SkyGuy228]

Does the f/stop of a telescope matter in choosing a barlow or can you use any 2x barlow in any telescope?

[The BFJ]

I could be wrong but, as long as it fits in your focuser tube and takes your eyepieces ok (ie 1.25in or 2in) it should be ok. Just bear in mind that doubling the mag won't always give you the best image. Sometimes all it will do is show up the flaws in the atmospheric conditions etc. It also may depend on what kit you have. What barlow and eyepieces will you be using? What scope will they be used with?

[damnut]

Just be careful that you do not exceed your scopes maximum mag usually calculated at 2*aperture in mm. Image will go very dark.