Barlow focus and DMK

[Earl]

I can focus my DMK fine with a 50mm extension on my 8" newt.

But what ever i do, extensions or not I cant get focus with a Barlow, I know im centred ok and double check it visually every time i change it round.

Any ideas?

[Earl]

Any ideas?

[GazOC]

A Barlow pushes the focal point away from the scope, you may need another extension piece.

[riklaunim]

Focuser -> Barlow -> Camera or something other + camera. It won't probably focus if you put extension between the focuser and Barlow.

[Earl]

Humm so do i need to extend after the barlow?

[riklaunim]

You don't by default unless you need more power of the Barlow (if you add a spacer after the Barlow it will work as a stronger Barlow).