10" GSO and DSLR focus

[bindibadgi]

If I buy the GSO 10" dob from Andrews (the super deluxe version with 10:1 Crayford etc), will my Canon DSLR come to focus on it, or will I need to swap the focuser out with a low profile one?

I'm planning on getting a Baader MPCC as well at some stage, so I don't know if that makes a difference.

[davewaldo]

Hi Bindibadgi,

I used to own a GSO 10" dob which I moddified to come to focuse with my 20D. Here is a a couple of links describing it:

Part 1: http://www.iceinspace.com.au/forum/s...ght=dob+reborn

Part 2: http://www.iceinspace.com.au/forum/s...ght=dob+reborn

The MPCC will help as I belive it pushes focus a centimeter or so back. But I think you may still need to move your primary mirror up.

The best way to test is to setup with the MPCC in place and point the scope at the moon. Holding tracing paper over the focuser opening, you can see where the focus point is by moving the paper back and forth. Once you know where the focus is, you can make measuments to decide how much you need to adjust the primar mirror.

I would imagine you will need to move the primary about 30mm.

Hope this helps.

Dave.

PS. If you go to the trouble of cutting your tube, its worth taking the extra time and money to repaint the inside with good black paint or flocking. And maybe even get it powder coated like I did. Makes a huge difference.