Author Topic: Goto Kogaku Zoom Eyepiece from roughly 1957  (Read 178 times)

Cesar Rojas

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Goto Kogaku Zoom Eyepiece from roughly 1957
« on: December 28, 2017, 06:40:36 PM »
Hello all. This is my first post in these forums in a long time. Normally I would be reviewing modern equipment or Questars. However I am turning attention to a few of the telescopes I've acquired over the years and hope to learn a little more about them. I am the proud owner of a Model 105 that I believe came back from Japan with a US serviceman in 1957. There are no import stickers on the case. The scope has two pretty complete sets of eyepieces, Huygens and Orthos. The orthos include a 4mm so very nice indeed. There are number of other items that I've never given much thought to, but would love to present them to you and ask for guidance in their use. The first one is this marvelous zoom eyepiece that seems to more fit a spotting scope. However it fits nicely into the adaptor in the back of the drawtube and works well with the scope.  It says Zoom 10X-20X on the smaller ring and the larger ring is graduated from 10 to 12 to 15 to 20. There are some fairly complex lens movements within but magnification is smooth. You can also see a chrome knurled screw on the upper left that locks a ring, but there doesn't seem to be any function that it performs. Anyway that's the first item I would love to learn more about. I'm pretty sure Goto made it, but would love to know otherwise. Thanks for sharing views and opinions.

Stew




Artavius Murphy

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Re: Goto Kogaku Zoom Eyepiece from roughly 1957
« Reply #1 on: January 08, 2018, 04:22:15 AM »
Hi Stew,

Nice eyepiece! I will move the thread over to eyepieces as this thread will likely gain more traction there

bardeperdi

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Re: Goto Kogaku Zoom Eyepiece from roughly 1957
« Reply #2 on: January 11, 2018, 11:27:24 PM »
It appears to be a zoom microscope eyepiece. The thumbscrew tightens against the downtube of the microscope. The numbers are magnification powers - 10x to 20x, which translates to 12.5 - 25mm. I have a Unitron eyepiece that is very similar. It works quite well in a telescope, but the FOV is a bit narrow.

Charlie

proporasat

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Re: Goto Kogaku Zoom Eyepiece from roughly 1957
« Reply #3 on: January 12, 2018, 11:56:51 PM »
Unitron versionAttached Thumbnails


consurflola

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Re: Goto Kogaku Zoom Eyepiece from roughly 1957
« Reply #4 on: January 13, 2018, 11:58:26 PM »
Charlie,

Thanks so much! I use pairs of Unitron microscope eyepieces in a little Unitron microscope binoc that mounts in my Questar for binocular viewing. This makes perfect sense. Thanks for the picture of the Unitron counterpart. It is not marked Goto with either logo or name, so if anyone knows who made it .....

inovcomsett

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Re: Goto Kogaku Zoom Eyepiece from roughly 1957
« Reply #5 on: January 14, 2018, 02:46:48 AM »
I use many microscope eyepieces in a converted Zeiss bino head - works very well.

This Unitron zoom eyepiece is very, very sharp across the entire FOV - as sharp as my best .965 orthos. While the FOV is a bit narrower that fixed-focal length eyepieces, it is not that much different, and probably due to the small zoom range (2 to 1), the FOV doesn't change from the 10x to 20x settings. With an added Barlow, this eyepiece covers just about all the focal lengths I use in my classic scopes. I do need to find another one of these for the bino viewer.Attached Thumbnails


perpemucho

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Re: Goto Kogaku Zoom Eyepiece from roughly 1957
« Reply #6 on: January 18, 2018, 11:08:29 AM »
Could you post a few more photos of your eyepiece? It would make ID'ing it a bit easier.

Brian Olatunji

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Re: Goto Kogaku Zoom Eyepiece from roughly 1957
« Reply #7 on: January 21, 2018, 05:48:40 AM »
Here are some more pics. I was able to remove it from the compression tube adapter and you can see the bottom of the lens. Limited on size so will need to use a couple of replies.

Stew


tirafarpa

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Re: Goto Kogaku Zoom Eyepiece from roughly 1957
« Reply #8 on: January 21, 2018, 02:03:54 PM »
Another mid-zoom - notice gap with top of lens compared to previous.Attached Thumbnails

retaweawebs

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Re: Goto Kogaku Zoom Eyepiece from roughly 1957
« Reply #9 on: January 23, 2018, 03:05:00 PM »
And from bottomAttached Thumbnails


Vincent Reside

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Re: Goto Kogaku Zoom Eyepiece from roughly 1957
« Reply #10 on: January 26, 2018, 04:13:42 AM »
Thanks for the photos. The design looks nearly identical to my Unitron. The eye lens portion is at its highest at around the 12.5-13mm setting and lowest at the 10x & 20x settings. Perhaps they were made by the same manufacturer, with yours appearing to be an older model.Attached Thumbnails




pensranbafarc

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Re: Goto Kogaku Zoom Eyepiece from roughly 1957
« Reply #11 on: January 26, 2018, 06:19:50 AM »
And here's my Unitron microscope binoc head on the Questar.Attached Thumbnails


percufareg

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Re: Goto Kogaku Zoom Eyepiece from roughly 1957
« Reply #12 on: January 31, 2018, 02:22:47 AM »
From the backAttached Thumbnails

engoecircming

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Re: Goto Kogaku Zoom Eyepiece from roughly 1957
« Reply #13 on: January 31, 2018, 12:39:02 PM »
I would agree that they are the same design. I almost get the feel from the roughness of the tube that it might have been a prototype.

Stew

olexecin

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Re: Goto Kogaku Zoom Eyepiece from roughly 1957
« Reply #14 on: February 09, 2018, 04:09:32 AM »
Very nice Questar setup! I'll bet bino viewing with it is a real joy.