Eyepiece extension to allow more in focus?

[parallaxerr]

Hi all,

I have a Baader Hyperion Zoom fitted to my scope with the 2" nosepiece.

I wish to extend the nose piece, such that the focuser moves in, allowing a little more mount clearance and a few more degrees Alt on my Goto (currently restricted to 64°).

I have 25mm of draw tube exposed so I think a 20mm extension should suffice. Focus is achieve across all EP FL's with minimal focus adjustment so I should have 4mm in focus remaining.

I have discovered many different threads whilst researching, but assume I need a filter thread extension. Can someone confirm if this is the right extension for the job?...

http://www.altairastro.com/20mm-spacer-2-barrel-m48-filter-thread.html

Also, are there any issues associated with this approach, such as reducing field of view etc?

Thanks in advance,

Jon

[YKSE]

M48 x0.75 thread is the standard filter thread for 2" eyepieces, you should be able to connect to the Baader Zoom's 2" nosepiece.

Have you checked that 20mm extended 2" nosepice doesn't hit the diagonal mirror when you insert the Zoom?

[parallaxerr]

Hi YKSE,

Thanks, that confirms the thread form I need.

I just checked my diagonal and there's a lip to stop the nose piece hitting the mirror. I thought this is what the Zoom was resting against but it's not, the zoom bottoms out on it's lower body ring. There's another 10-15mm before the lip in the diagonal so I may actually get away with a normal 30mm push fit extension.