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-   -   Help needed ~ Zoom eyepiece for vintage spotter (https://www.birdforum.net/showthread.php?t=382036)

ctom99 Sunday 6th October 2019 19:31

Help needed ~ Zoom eyepiece for vintage spotter
 
1 Attachment(s)
Hello - I have a vintage (early 80s) spotting scope that has sentimental value to me in that it was a gift from my wife when I was a poor college student. It's a fixed power Japanese made 25x60mm Tasco World Class model 25T. At the time, Tasco offered a variety of accessory eyepieces for the scope. Here's an old print advertisement I found that describes the spotter and its accessories.

I'm interested in finding out whether someone here could point me to a vendor that might have a used 20-45X Tasco eyepiece (model 6651).

Alternatively, I'd like to know whether you all think I could possibly mount a currently available zoom eyepiece by a different manufacturer on this scope. Thanks in advance for the assistance!

Binastro Sunday 6th October 2019 20:00

Hi and welcome.

Probably just as cheap to find another similar scope with the zoom eyepiece and use that eyepiece on your scope.

Otherwise, what is the internal size of the eyepiece mount on the body?
Is it screw thread or bayonet?

It may be that an old Opticron zoom eyepiece might fit.

Regards,
B.

ctom99 Sunday 6th October 2019 20:16

Quote:

Originally Posted by Binastro (Post 3904079)
Otherwise, what is the internal size of the eyepiece mount on the body? Is it screw thread or bayonet? It may be that an old Opticron zoom eyepiece might fit.

Binastro - appreciate the reply. The scope takes threaded eyepieces, and I measured the ID of the threads at 1.088" or 27.64mm. Does that ring a bell for you? Thanks.

jring Sunday 6th October 2019 21:14

Hi,

I just measured the inner diameter of the threaded eyepiece mount of my ancient Kowa TS-9 - it also had 27.65 mm or so - very fine pitch thread. I only have a 20x fixed EP for it, but 11-33x zooms are around. All the threaded EPs of the old Kowa single digit TS series should be the same (TS-1 to TS-9).

Some speculation exists that some old EPs for Opticron and other scopes might fit the Kowa too - see https://www.birdforum.net/showthread.php?t=58475

Beware of the single digit TSN-1/2/3/4 models - they're great but these take modern style small body bayonet EPs - as do the TS-611/2/3/4.

Joachim

Binastro Sunday 6th October 2019 21:54

The Opticron MM2 has a small thread of about 28mm, but the eyepieces are smooth and fit on with an outer bayonet.

40933 HR2 3x zoom Opticron eyepiece is smooth outer front barrel. I haven't fitted this to anything, but it was low price secondhand.

However, I have a 20x #78-2220 eyepiece Made in Japan, amber coated. Also low price secondhand.
No makers name. In small box typical of Japanese orthos and Kelners.
Concave field lens outer surface. Convex eyelens rear surface.
Good high powered magnifier.
About 27.7mm external thread, but I don't know the thread it fits on the body.
I don't know what scope it fits.
But well made.
Fine thread, but I can't remember if I have a thread gauge.

B.

P.S.
The 20x No name Japan eyepiece has a slightly smaller thread than the Opticron MM2 inner thread.

I don't know when Opticron switched from Imperial thread to metric thread.

ctom99 Sunday 6th October 2019 22:44

1 Attachment(s)
Biastro & jring. Yall's info has been very helpful - I appreciate it! I found a pic of the Tasco 6651 20-45X eyepiece. See attached. My Tasco 25T appears to be simply a rebranded Opticron, as both scopes appear to have the exact same exterior shape.

I am almost certain that an Opticron zoom eyepiece will attach to some short secondary male threads that are concentric above the main threaded hole for fixed eyepieces. On my scope, these secondary male threads have an OD of 1.375" or 34.93mm.

Based on that, do you tend to agree about Tasco's / Opticron's compatibility? Thanks again.

Binastro Sunday 6th October 2019 23:25

One really needs thread gauges for Imperial and metric.
At the time I suppose both British and U.S. scopes used Imperial threads, but I am not sure.

Or one takes a chance on an old zoom that looks right.

B.

pete_gamby Monday 7th October 2019 12:24

The external thread dimension will match with Opticron zoom eyepieces but as binastro says, the question is whether the Tasco you have is metric or imperial. The chances of finding a second hand imperial thread zoom are slim to none.

There may be some ex-demo or otherwise used zoom eyepieces in our US stock - you could contact my colleague Kyla Burgess at [email protected] and she can let you know what she has available. Your risk would be the cost of postage both ways.

HTH

Cheers, Pete

ctom99 Thursday 10th October 2019 03:36

Quote:

Originally Posted by pete_gamby (Post 3904286)
There may be some ex-demo or otherwise used zoom eyepieces in our US stock - you could contact my colleague Kyla Burgess at [email protected] and she can let you know what she has available.

Pete - I appreciate your 'across-the-pond' lead. I just emailed Kyla. Hopefully she'll come back with a zoom eyepiece I can try out. Thanks again for the suggestion!

ctom99 Saturday 19th October 2019 19:10

Quote:

Originally Posted by pete_gamby (Post 3904286)
The question is whether the Tasco you have is metric or imperial. The chances of finding a second hand imperial thread zoom are slim to none

Pete - just sent you a Private Message. Thanks - ctom99

richard866945 Friday 25th October 2019 12:15

I think you will find the same eyepieces were and still are used on the Helios Natureclose; older Hawke Naturetrek; Bushnell Spacemaster as well as the Tasco scopes.
16x-48x (on 65mm OG) zoom eyepieces still available as well as MK25 and ME19 fixed mag ep's.
I'm not supposed to advertise so search ActionOptics on the internet.

ctom99 Saturday 26th October 2019 21:41

richard866945 - just sent you a PM


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