tele extender help needed

[crystal_stars]

Hi all.

I have a question about tele-extenders. I bought a meade variable-projection camera adapter and a t-ring for my canon EOS (film), to try taking some pictures of the moon with my lightbridge. While I didn't get to try it out myself last night, my father borrowed it and put it on his saxon 70mm refractor and said that he could not get it to focus, the focuser was wound in as far as could go and was still not in focus yet. So I have a few questions.

A tele-extender shoud work with and without an eyepice in it, shouldn't it?

Could it be that my meade camera adapter will only work with my meade telescope?

Any other suggestions on what we could try or might be doing wrong would be appreciated.


Thanks.

C.

[Dennis]

Hi C

Typically, the tele extender optical train goes something like this:

Telescope focuser → tele extender + projection eyepiece → T2 ring → 35mm SLR camera.

The last time I did this, I used a 10mm eyepiece in the tele extender and on my ‘scopes, I had to wind the focuser out, rather than in, so I didn’t exhaust all my in-travel.

If your dad just put the tele extender tube in the optical train without a projection eyepiece, then it is highly likely he would run out of inward focus travel, as the tele extender is effectively eating up some 3 or 4 inches of inward travel.

Cheers

Dennis