Meade LXD75 T-Adapter question
Posted 07 October 2005 - 11:51 AM
Posted 07 October 2005 - 02:21 PM
I don't know of what you speak but there are 2 alternatives I can think of.
The T-ring is usually held together by 3 small screws. Loosening one or 2 of these slightly should allow the outer ring to rotate separate of the camera mount. Frame your shot and than tighten the screws.
The other choice is why not use a basic camera adapter such as one of these...
I have used the AP unit when I had my VC200L. The adapter is a piece of machining wonder. Loosen a setscrew, frame the shot and tighten down. Nice part about it is it's a full aperture piece so little to no vignetting.
Posted 07 October 2005 - 02:51 PM
What I am using, is just the T-Ring part, which as you stated correctly has the three screws that allow it to be ratated. But these screws are tiny, and I am trying to find an easier way such as a thumb screw.
The AP unit you show also has a long barrel, and may cause some vignetting on my fast f/4 system at prime focus. I need something short, as I shoot film, and want to cover the whole 35mm frame with as much FOV as possible.
What I really could use is a T-Ring with THUMB screws!
Or just wait until I replace my focuser with a JMI unit that has the rotating T-Ring adapter built in.
Posted 07 October 2005 - 03:26 PM
The AP unit is basically a T-Ring with a barrel attached if I remember correctly. Would this really create an issue with your setup? I ask as I am contemplating the purchase of a 10" SN and am curious about such issues.
Sorry couldn't be more help.
Posted 07 October 2005 - 04:18 PM
The barrel will reduce the image field of view.
You'll be vignetted - and when you attach the camera right on the focuser with no barrel, you get the whole swatch on the film - from edge to edge... a HUGE view! Which is what I enjoy most!
Take a look at the field of view on this shot... This would not be possible through an extension.
Meade LXD75 8" f/4 SN
40 minutes hand guided on Fujichrome 400F Provia
Posted 07 October 2005 - 08:39 PM
Posted 07 October 2005 - 08:46 PM
Posted 07 October 2005 - 08:59 PM
My T-Adaptor (for the EOS) has those three tiny socket-head screws. I see no reason they couldn't be tapped out and replaced with thumbscrews. BTW, on mine, the inner ring is grooved, so the tightened adaptor should retain its focus even after being rotated.
Thank you for saying what I was trying to say Rusty. You did a better job than I did
Posted 07 October 2005 - 10:35 PM
The #TA2P which slides in the 2" eyepiece holder, and then has the T-Ring threads for my T-Ring. It's low, and I can use the 2" eyepiece holder thumb screws to allow the whole thing to be rotated..
Anyone else think this may do the trick?
Posted 08 October 2005 - 08:04 AM
Posted 08 October 2005 - 09:28 AM
Posted 08 October 2005 - 12:04 PM
Posted 09 October 2005 - 12:34 AM
Posted 09 October 2005 - 01:28 PM
Once the T-ring is adjusted and the nuts that hold it in the correct position are tightened, so that the camera is in a level position, why would you need to mess with the set-screws? I guess you might want a second T-ring adjusted for vertical, rather than horizontal shooting, but otherwise I never need to mess with the set screws. Perhaps I am not understanding the issue.
Celestial objects aren't level. When you frame M31, for instance, you want it to span your frame diagonally, so you can get the edges in. If your t-adapter position has it framed any other way, you want to rotate the camera, and that's where CF's question comes in.
Posted 09 October 2005 - 01:53 PM
Posted 09 October 2005 - 03:33 PM