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ZEISS DTI thermal imaging cameras. For more discoveries at night, and during the day.

Diascope and astro 1.25" eyepieces (1 Viewer)

Boogieshrew

Well-known member
Hi,

I have just ordered a Diascope 85 with 20-75 zoom and now just found this online:

http://binocularreviews.northernoptics.co.uk/user-guides-and-tutorials/how-to-connect-a-1-25-eyepiece-to-a-zeiss-diascope/

Do any of you use astro e/ps with a diascope. If so, which e/ps work best?

I am looking forward to having a zoom that goes to 75x but I also like wide field views so I would like a wide 20 or 25x eyepiece for watching flocks too.

I loved the 70* afov e/ps I used to use on my Pentax PF-65 EDAii.

Best wishes
BS
 
I used to own a straight 65 mm Diascope and experimented with both the Zeiss astro adapter and the Baader adapter. I gave the latter to a fellow BF member after replacing the Diascope with an ATM 65HD.

The Zeiss is probably a more precise fit but slower to change eyepieces as it uses a threaded ring to secure the eyepiece and adapter assembly to the male thread on the bayonet surround.

The focal length of the 85 mm Diascope is 502 mm, so divide this by the eyepiece focal length to get the magnification. Not all astro eyepieces will reach focus at infinity in the Diascope as in many cases the 1 1/4" barrels are too long. Despite the reference in your link, I doubt that 2" eyepieces could be used with the Diascope.

All Televue Plössls of 32 mm and less will work (50° AFOV) as should a 24 mm Panoptic (68° AFOV) for 21x magnification. Vixen LVs and NLVs work and possibly Baader Hyperions, but Pentax XWs might be a problem. My dealer used to shorten the barrels of 5 mm Vixen LVWs for 100x mag and had one customer, who used the set-up to check for cracks in wind machine blades. He could allegedly detect o,5 mm cracks at 100 m!

John
 
TV Delos should work.

David,

That is an expensive risk too. The 4,5 Delos' barrel is 1,1" long, The Plössls and 19 mm Panoptic 0,9" and the 24 mm Pan just 0,8".
If the Delos were parfocal when properly seated, it would need another 5 mm of infocus.

John

PS: Perhaps your friend could find a precision machinist to shorten the barrel of the Pentax XW.
 
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