Need advice!

[perfrej]

Currently, I image with an Explorer 250 on NEQ6 and a Canon EOS 1000D without IR filter. Apart from vignetting, even with a newly collimated scope, I wonder how I should screw things together in order to use a 2x Barlow with all this.

Order of things:

Telescope <- short 2" extension tube <- LPF <- Coma corrector <- T-adapter <- Camera

Now, introducing the Barlow into this makes me a little confused. From what I understand, the coma corrector is designed to be 55 mm from the film plane, which it appears to be in my non-Barlow setup. Using the Barlow, however, should I even use the coma corrector?

Another problem is threads. The parts don't really mix that well, but I guess that can be sorted out when I learn the roght order of things.

HELP!

/p

[Merlin66]

I assume the barlow would give you around f10.

I definately try it without the CC

[perfrej]

OK, that's a start. Collimating again - 30 or so attempts... Difficult to get that vignette out of the picture.