Celestron 11" SCT - Visual back

[Astrobod]

I've got an 11" Celestron Nextstar GPS.  The visual back is in two parts, removing the first part converts from 1 1/4" to 2" back, that's fine.  But there is another ring, about 3" in dia , can someone explain what it's for.

Thanks Ron

[Northern Soul man]

Hi Ron and a very warm welcome to the SGL mate.  Not sure but I think there is a difference between the 6 and 8's on one hand and the 11 to 14's - not sure where the 9.25 fits - but its the larger SCT's that have to accomodate a larger light path.  But to be honest I'm not too sure of this, I bought a Baader Click Lock to hold my 2" Diagonal and I think they do them in 2 sizes - 1 for the smaller (6-8 and I think the 9.25) and 1 for the larger (11 - 14) - so not sure if this is the case or not.  I bought the Click Lock a while ago and just removed the old VB and screwed the new Click Lock in place.

HTH Ron - but as said not to sure - you may have to wait for someone with a little more knowledge on this.

Paul.

[Astrobod]

Thanks Paul, Yes I've got the same Badder 2" click lock & 2" Badder diagonal.  I've removed the 2" to 1 1/4" visual back and screwed on a 2" Crayford fine focuser, then attached the Badder diagonal.   I'm using 1/14" eyepieces at the moment with a reducer, but I am concerned that the whole assembly only just clears the base mount when the tube swings between the fork arms.  If I go up to 2" eyepieces in the future they may be too long and cause the rear assembly to strike the base.

I thought there may be another Crayford fine focuser of a larger diameter where I could remove the other large reducer ring on the back of the tube assembly. I've got two photos of the setup but do not know how to add these to a message yet.

Also the tube is now rear heavy, so I need to counter balance some how. 

Ron

[Merlin66]

The larger 3"+ threaded section is the bottom of the internal baffle assembly.

There were adaptors which made use of this thread....

http://www.rothervalleyoptics.co.uk/peterson-eyeopener-ii-visual-back.html

HTH