Ok, so the t-ring is specific to your camera, but the t-adapter is a universal (I think?) thread dimension. The other side fits into a 1.25" eyepiece holder.
|T-ring and t-adapter assembled on Canon Rebel XT|
|T-ring for Canon EOS type, and universal 1.25" t-adapter|
|T-ring fits snug into lens coupling, and locks with the lens release|
|My setup that did not achieve focus. I think it's too long, so I'm going to cut out some pieces.|
I had my t-adapter nested into my 1.25" eyepiece holder because that's the only way that everything seemed to fit together. I tried taking my diagonal mirror off, and my other bits and pieces of tube and connectors - what a mess! I was trying to find a way to shorten my setup, because I figured that would compensate for my inability to focus any further 'up' the focuser tube.
|Venus out of focus at the limit of my focuser (butting up against optical tube)|
To resolve this (hopefully) I purchased a .965" telescope Basic Camera Adapter Japan T thread because it goes from .965" female to "T-thread" male (which should go directly into my t-ring female).
I also got some feedback on Instagram that I should get a Barlow lens, because not only will it give me about 2x magnification, but it will change my prime focus distance from the optical tube to within a range that my focuser can reach. I think I'll hold off on that until this guy comes in the mail. I'm not sure where a Barlow lens would fit exactly, and if they make a .965" to t-thread Barlow. I feel like I'm playing with a really expensive LEGO set and the pieces aren't matching up!
|As a consolation prize, however, I'm pretty sure my out of focus image of Venus corresponds to the phase of Venus last night, so that's pretty neat.|
I'll post updates here as I try to figure this out...
Update: I got it to work!