Planetary Imaging with C11 & Barlow

[AstroAndy]

Hello all

I was wondering about the best & most practical (and least troublesome) way to set up my C11 for planetary imaging. The thing is, I have it perfectly set up for DSO imaging, and want to change this setup as little as possible.

What I would like to do is put my one of my Barlow lenses directly behind the filterwheel (in this case, a 1.25 Atik EFW2), as it connects beautifully to my ZWO ASI 120-s.

My questions are:

1) Is it feasible to put the Barlow lens (element) close to the focal plane, or at it (where the sensor would be), or would I need to set it for a wider dispersion?

2) What influence does a Barlow lens have on the backfocus of a system (Now, I'm set up perfectly with a backfocus distance of about 146mm, including the reducer, which I

    I would take out, as I understand the backfocus will be the same without it)? 

3) What adapter is needed to mate my 1.25" filterwheel to the Barlow (lens element) as there is no thread on the lens element.

 

My reasoning is this: Setting the Barlow-Cam. system behind the filterwheel (away from , and not towards the scope means I don't have to monkey around with the spacing before the filterwheel. It would also make focusing easier, since I probably have to start with a bigger sensor camera to get centered and focused, and gradually work my way to the smaller sensor camera (or Barlow Cam. combination), recentering and focusing in small increments.

Regards

Andy

Imaging train and Cam-Barlow combo: