Barlow and DSLR pointless or not?

[CedricTheBrave]

I have a 2" x 2 barlow that i have never really used mainly because i cannot get the camera to focus with it.

is this what would be expected and i am flogging a dead horse trying to get it to focus?

SW200PDS OTA

[timwetherell]

I use a 2x 2" barlow for imaging sometimes and a focus is achievable  but that's on a refractor with a long focuser range. I presume you're using your  200p Newtonian? which probably has a more limited focus travel. If the barlow is pushing the focus point further out you might be able to use an extension tube?

[Carbon Brush]

A suggestion before spending on an extension tube.

In daylight, point your scope to the horizon. Offer the DSLR camera + barlow up to the focus tube and move the camera by hand. Use live view or a separate screen.

If you see that to obtain focus the camera is in mid air, you have demonstrated that you need an extension tube and you have an idea of the length.

If you only need a millimetre or two. Is there enough space to pull the main mirror back a little?

I have had the opposite problem (on different scopes) and had to lift the main mirror or swap to a low profile focusser.

Hope this helps,

David.