Unitron 102mm F1500mm scope ?

[DavidU]

I have a nice Unitron 102mm achromat and I am fabricating the collematable cell and tube. I hoped someone has one of these scopes so they can measure the distance from the crown/flint air gap to the eye piece (lens) in mid travel so I can cut the tube to the correct length.
Then I can laser cut the baffles etc.
Thanks !

[astronut]

David,
I'll check mine tonight and post it here, OK?:)

[DavidU]

Awesome ! thanks:thumbsup:

[astronut]

David,
The measurement from the air gap to the focuser fully extended (without the extension tube) is 1.45metres.
If you need further info, please let me know.

Cheers, John:)

[gts055]

Hii, I have measured the distance from an estimated location of the air gap between the objective elements, to the eyelens of a 25mm unitron eyepiece at the "in focus" position as being 154cm. This is viewing straight thru, ie no diagonal. The Unitrons use a draw tube to get rough focus and then with a very short, approx 25mm rack, you get final focus. I guess u will need to deduct the length of the diagonal light path and make allowance for the focuser assembly u will be using. That 154cm distance is the critical figure for you. If you need any other information just ask :) Mark

[DavidU]

Thanks fellas ! I will now make some progress.