AlexAntao

2 hours ago, Louis D said:

What about a simple 42mm to 37mm step down ring?  Have you tried that yet?  A T-mount thread is simply M42 (42mm x 0.75mm tp).  Here's the same link on ebay UK.

Thank you !!!! I was looking for it a whole day and found almost nothing.... 

Sorry to raise this old topic, but I found it because I have the same problem here. 

Have a CElestron 7-21mm eyepiece and a T-Ting for my NIkon. I'm Almost shure the T-Ring has M42 internal thread, I think the pitch is 0.75mm, but I'm not shure. I'll try to include pictures.

Eyepiece hass about 37mm thread, so I think it 's M37...  but i know there's the question about the pitch of the thread... 

Did you found a solution ???