Swarovski CTS 85 Extendable Draw Tube Telescope (1 Viewer)

[ajfossey]

The Swarovski website states that this scope is “…compatible with two different SWAROVSKI OPTIK eyepieces”. These are the 20-60x and the 25-50x W.

I’d be interested to know whether the 20x or 30x fixed eyepieces would work? Perhaps there’s a technical reason as to why they aren’t an option?

The thought of carrying the CTS 85 fitted with the 20x appeals to me when walking my dog and not wanting to carry a tripod. Maybe the CTC 30x75 with the fixed eyepiece would be a better option?

 

[John A Roberts]

Hi AJ,

Although Swarovski's current publications don't address the previously offered single focal length 30x eyepiece (or the 20x or 45x ones),
it will work with the CTS.

See two pages from a 2005 catalogue showing the compatibility of the then S series eyepieces:



John

 

[William Lewis]

The Swarovski website states that this scope is “…compatible with two different SWAROVSKI OPTIK eyepieces”. These are the 20-60x and the 25-50x W.

I’d be interested to know whether the 20x or 30x fixed eyepieces would work? Perhaps there’s a technical reason as to why they aren’t an option?

The thought of carrying the CTS 85 fitted with the 20x appeals to me when walking my dog and not wanting to carry a tripod. Maybe the CTC 30x75 with the fixed eyepiece would be a better option?

The ctc 30/75 is a very good scope, I used one for a few years. This video's quite informative of the differences between the two. https://www.google.com/url?sa=t&sou...o7QBegQIDhAG&usg=AOvVaw3y14bvZZtFSTe4PTTXrSoF

 

[mbb]

Hi AJ,

Although Swarovski's current publications don't address the previously offered single focal length 30x eyepiece (or the 20x or 45x ones),
it will work with the CTS.

See two pages from a 2005 catalogue showing the compatibility of the then S series eyepieces:
View attachment 1549921


John

I noticed that both pages show that the cts-80 is compatible with the 30x, 45x, and zoom eyepieces, but they seem to suggest that the 20x is not compatible: it is not shown in the picture on the 1st page, and the specs of its combination with the cts-80 is left blank in the table on the 2nd page.
The bayonet is the same.
Would there be some field stop issue or something else, making it not possible to use it or only with reduced FOV?
Would the same apply to the older CT-75?
While I realize that the 20x was never as popular as the 30x, for a drawtube often used without tripod a 20x would make sense.

 

[ajfossey]

I noticed that both pages show that the cts-80 is compatible with the 30x, 45x, and zoom eyepieces, but they seem to suggest that the 20x is not compatible: it is not shown in the picture on the 1st page, and the specs of its combination with the cts-80 is left blank in the table on the 2nd page.
The bayonet is the same.
Would there be some field stop issue or something else, making it not possible to use it or only with reduced FOV?
Would the same apply to the older CT-75?
While I realize that the 20x was never as popular as the 30x, for a drawtube often used without tripod a 20x would make sense.

I noticed the same. 20x was likely my preference. The fixed eyepiece 75mm objective version I’d already discounted as I’m not sure they’d work well with my glasses.

The catalogue from John and video review from William were indeed both useful in researching these options.

 

[Tringa45]

Swarovski stated above that the ocular focal length was the same for all telescopes, where they meant the objective focal length (460 mm).
The 20x eyepiece had already been discontinued in early 2011, when my ATM 65HD was manufactured (no longer in the specifications) but my dealer had a NOS example which I was able to try out.
It was something of a disappointment and had shorter eye relief, perceived narrower AFoV and either pincussion or field curvature (no longer remember exactly).
The 30x W on the above scope is, in contrast, as near to perfection as it gets. With 20 mm ER and 65° it is essentially free of field curvature, astigmatism, rectilinear distortion and shows just a little unavoidable lateral colour.

John

 

[CharleyBird]

I have the 30x and 45x.
The 20x has never appealed as it is too close to my bins.
With 45x you get a very small exit pupil and atmospheric interference. I want the magnification but it needs a tripod.

The 30x on the CTS 85 works for me. Bright, big chunk of glass that's relatively easy to carry bandolier style.