TAL eyepieces aren’t all equal!

[Chaz2b]

 I love my TAL eyepieces, I have seven but four are 25mm plossls. Now I want to use them in my Televue binoviewer and I’ve come across a small problem!
Not all the silver barrels are exactly the same in outside diameter, plus they are male threads whereas most other newer eyepieces are female. What that means is that I can’t swap, say a Celestron barrel as it’s a female barrel.

Not to be out done I tried all the TAL eyepieces to see which would fit and as luck has it, two do!

This meant I had to swap around the barrels so that I had two matching, as close as they can match, pairs to use with my binoviwer

I do have Televue plossls in pairs for binoviewing, but not 25 mm so this has sorted my little shortage.

What I can make of this is that TAL managed to change the diameter to the barrels, whether this was to do with their supplied diagonals I don’t know, but I might check that out as I have two TAL refractors and a Reflector.

chaz

Edited May 6, 2023 by Chaz2b
Added photos

[Roy Challen]

I'm fairly sure all the Tal 100 fracs use 1.25" eyepieces. The Tal 1 newt used slightly larger (32mm?) eyepieces in the early versions, then swapped to 1.25 later on. Not sure when the transition was.

Glad you found a solution 🙂

[John]

23 hours ago, Roy Challen said:

I'm fairly sure all the Tal 100 fracs use 1.25" eyepieces. The Tal 1 newt used slightly larger (32mm?) eyepieces in the early versions, then swapped to 1.25 later on. Not sure when the transition was.

Glad you found a solution 🙂

I agree. I had one of the very early TAL 100's (1999) and that was fitted out for 1.25 inch eyepieces. 

On the 25mm TAL Plossls, those can vary depending on the production run. Optically they seem to be uniformly good but the field stop diameter did vary so the AFoV could be from 55 degrees down to around 48 degrees.