Zeiss 85FL and baadar eyepiece (1 Viewer)

What do I need to use a Baader fixed power eye piece on my Zeiss Diascope? Which eye piece would be a 30x equivalent?

Thanks

The Zeiss astronomical eyepiece adapter part 528384 (with a M57 screw collar)

http://www.adorama.com/ZSAA.html (out of stock)

or the Baader Diascope bayonet eyepiece adapter part 2454500 (which is a Zeiss bayonet fitting for 1.25" EP barrels).

http://www.baader-planetarium.com/pdf/hyperion_brief_description_e.pdf
http://www.baader-planetarium.com/pdf/hyperion-okulare_englisch.pdf

The Baader adapter is not sold in the US (AFAIK) but one might check with Alpine Astro even though it's not on their site

http://www.alpineastro.com/ordering_information.htm

The 85 FL has a 502mm focal length

http://www.zeiss.com/4125684700380D3D/ContentsWWWIntern/7ACD0757C0EAD3BD482571150029A163

502 / 30 = 16.73

So a 17mm EP is what you need.

Thank-you very much Kevin. Somewhere on the forum I read that someone had a problem so that they were unable to focus to infinity due to the adapter. Do you know anything about this?

No, I hadn't heard that. Can you provide a link to the discussion?

I believe Hyperion and the Celestron XCel will both reach focus in the Diascopes but not all eyepieces will.

berryns said:

Thank-you very much Kevin. Somewhere on the forum I read that someone had a problem so that they were unable to focus to infinity due to the adapter. Do you know anything about this?

Click to expand...

I think that may have been on a 65mm Zeiss scope. I had the Baader-Zeiss 1.25" adapter with Baader 17mm ep/Zeiss 85mm, and it worked fine. A lovely wide-field combo. I eventually tired of the yellow cast of the Zeiss scope (because I obviously haven´t enough to worry about), but it´s a great set-up, and even better with the Baader-Hyperion zoom ep, which according to experts, is now available in a waterproof version. I can´t remember where I got the 1.25" adapter, someplace in the UK - I´ll try and locate them and let you know.

Edit - found it! Rother Valley Optics in UK: http://www.rothervalleyoptics.co.uk/detail.php?id=2718

Thank you for the link and information.

berryns said:

Thank-you very much Kevin. Somewhere on the forum I read that someone had a problem so that they were unable to focus to infinity due to the adapter. Do you know anything about this?

Click to expand...

Thinking back I've used XCel EPs in both the 65mm and 85mm Diascope and they both focused on targets 50m away (and were not at the end of their focusing range). I didn't try further as this was just a test from my apartment and the sightlines are limited.

The issue is most likley not due to the adapter but due to the EP used not being able to get to the focal plane of the scope. I think the Baader adapter might let the EP get closer to the scope. It's also easier to get on and off if your also using the zoom. If you are just using the scope all the time with a fixed EP the Zeiss adapter is OK.

BTW, other posts on this topic mostly by John Russell

http://birdforum.net/showthread.php?t=156001
http://birdforum.net/showthread.php?t=145148
http://birdforum.net/showthread.php?t=72687
http://birdforum.net/showthread.php?t=46100

Astro EPs with long barrels are the problem.

You need to pay attention to how you place the EP in the adapter to optimize both infinity focus and near focus.

And I emailed Alpine Astro to see if they can supply the Baader adaptor in the US.

Having both adapters, my preference goes to the Baader. Bayonet system is easier and faster when you're exchanging eyepieces, specially in the country. Screw system can be a nightmare at low light and with cold hands.