How to connect 2" diagonal to Celestron Edge 9.25 HD?

[zenith]

Hi all,
I have a lend of a Celestron Edge HD 9.25" scope, it was bought second hand by a friend 18 months ago and not used. It came with a few bits and bobs, but I think there is something missing preventing me from using 2" accessories.

The first image shows a 1.25" attachment which connects to the scope and will accept 1.25" accessories. All good.

The next image shows the 2" diagonal, part number 93519, however in the online images of this part the end that attaches to the scope is different to the one I have. Online it has a female thread which would screw onto the back of the scope, however mine has a larger male thread. This part of the diagonal can be removed leaving a standard 2" chrome barrel.

The third image is a 2" extender.

What would be my best option here? Try to purchase the correct part to suit the 2" diagonal that I have? Purchase a baader click lock 3.25" to 2"? Purchase an sct focuser? Purchase some kind of extension tube/adaptor with a 2" female thread on one end and thumb screws on the other?

Thanks in advance for the help and suggestions.
Tim.

[Wavytone]

Call Bintel.

[raymo]

There are two types of diagonal for SCTs/Maks. One is a 1.25" or 2" diagonal which has a female thread which screws directly onto the male thread on the back of the scope. The other has the standard 1.25"or 2" chrome plated barrel
which slides into the 1.25" or 2" visual back which screws onto the rear of the scope. You need a 2" visual back, which the chrome barrel on your diagonal will slide into, or alternatively, a 2" diagonal with the female thread. The diagonals that screw directly onto the scope are better because there is
no barrel that can slide out and fall to the ground damaging your precious
eyepiece. I think you'll pick up a 2" visual back pretty cheaply on ebay.
raymo

[Don Pensack]

It depends on how much clearance your diagonal will have with the base, but I would argue the 'refractor-style' diagonal (NOT the threaded-on SCT style) is the best 2" diagonal to use, and for several reasons:
1) It is threaded on the front for 2" filters. No need to change filters from one eyepiece to another when changing eyepieces.
2) It is very easy to turn it to the side when the scope points low by simply loosening the thumbscrew that holds the diagonal in. This enables your chair to have less seat height adjustment requirements.
3) It can be easily transferred to a refractor in case you have another scope. Hence, less expense for you.
4) the refractor style diagonals almost always have a larger clear aperture all the way through, so less vignetting of the edge of the field in low power eyepieces with large fields.
5) When removed, a 2" tube exists on the back of the scope, which allows accessories to be inserted, such as Lymax SCT cooler or even just an eyepiece when collimating the scope.
6) Barlows can be used in front of the diagonal for higher magnification if desired.

You have a scope that has correction to the edge of a large field. It behooves you to get an adapter to use the 2" diagonal you have. It will cost you less and have the advantages I mention.

[el_draco]

Better yet, get a Baader click lock adapter for SCT. Locks it in like its been welded with no effort at all. Expensive, but definitely worth it.

[Camelopardalis]

+1 for the Click-Lock :thumbsup:

Note that the 9.25" EdgeHD is a 3.25" thread like the C11 and C14, whereas the 9.25" XLT is 2" like the C8.

[zenith]

Thanks for the help guys, I went the inexpensive option the other day and ordered the Bintel 2" visual back for $39 (since it's not my scope, otherwise I'd probably have gone for the click-lock).
Main idea is to suss out the scope (collimation, focus, mirror lock etc as I've not used one of these before) and then try my DSLR on it in the 'usual' configuration before getting fancy and reading up on the hyperstar that came with it.
Cheers.