Quote:
Originally Posted by kon1966
Hi all, have attached a photo of what I need. Please see photo, is there a short replacement available or even a whole new 2 inch diagonal with shorter ends. I have a 8SE.
Regards
Kon
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The shortest 2" diagonals are the SCT thread-on variety (as in your picture).
These are usually short enough to clear the base on the 8SE.
Something you should know about the SE:
You can loosen the bolt that holds the OTA on the arm and slide it forward. The limit is when the rear cell of the scope hits the plastic cover on the arm.
If you file a deeper notch in the plastic cover of the arm, you can slide th OTA even farther forward.
Doing so gives you even greater clearance between the 2" diagonal and the base.
By doing so, I've been able to slide the OTA far enough forward that a 2" diagonal easily clears the base--even the refractor style of 2" diagonal wherein the forward-projecting tube on the diagonal slides into a 2" tubular adapter threaded onto the back of the scope.
The threaded-on 2" diagonals cannot hold a 2" filter on their front ends, typically have several millimeters less of clear aperture, and are significantly harder to rotate to the side (which makes the scope much easier to use when the scope is pointed near the horizon).
So the obvious answer is not a shorter diagonal, but sliding the OTA farther forward in its cradle. If you look closely, you'll see that the part that holds the scope is a pair of angled aluminum clamps. The plastic of the arm is merely cosmetic.
If you have a Dremel tool, the plastic on the arm can be notched a few centimeters deeper in only a few seconds, and allow you to slide the OTA forward to increase the clearance with the base.
I am not certain why Celestron chose to limit the forward movement of the scope so much, but at least the owner of the scope can rectify that.
Let me know if my explanation is not clear.
Even if it is clear and you would prefer to have a threaded-on diagonal, they are generally available from many on-line retailers.
