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What’s up with my diagonal eyepiece??
I recently picked up a diagonal eyepiece for my TS (Topcon GPT-3005) for various reasons. The price tag for the manufacturers version running about $300. Since I don’t have a dire need for one and only plan on the occasional celestial observation, I thought I would purchase a Chinese knockoff at a considerable reduction. After it arrived I found I had to remove the eyepiece from the TS in order to thread the devise on the station. The treads matched fine but sighting through the eyepiece is impossible as all focusing is lost. I mean an instrument is just a fancy telescope right? Two lenses connected by a long tube. Remove one and there’s not much tele/micro scoping you can do.
Just wondering if anyone else had this kind of issue with a diagonal eyepieces.
Rob
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8 Replies
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Was this sold as matching the instrument or was it really made for astronomical telescopes?
I dont understand how all focusing ability can be lost. Isn’t there a focus ring separate from the eyepiece, that moves things inside?
I can see how it might nit provide for focusing on the crosshair reticle.
It is likely the optical path in the eyepiece is too long compared to the standard eyepiece and thus out of the range of a focus ring mechanism if you have one, especially for focusing to infinity.
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Do you know if a Sokkia diagonal eyepiece will fit? It might, as the companies are related, and I have one you could have for a small sum. This is a genuine, made in Japan piece. I would give it to you, but I’m clearing out the bosses back room for him and he might want a little something for it. It was bought for a SET series instrument specifically..
Let me know.
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This is made for Topcons using a model 10 eyepiece. The logo is silk-screened onto the little felt case it came with along with a sticky label ‘Tocon made in Japan’ on the devise. I’m sure it’s a knock off but it fits the dust cap threads fine. As to the eyepiece, removing it only gives a nice view of what I guess is the laser diode or EDM emitter mounted at the center of the scope tube. Same is true with or without the diagonal adapter on. In fact 90% of the field of view is this square diode.
All the Model 10’s I see online appear similar in physical dimensions so I don’t believe one with a deeper body to allow the reticle to remain in place is made.
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Thanks cf, in fact they are one and the same now. It might work if it’s the model 10 style but do you know if the eyepiece has to be removed on your Sokkia? I really don’t need to duplicate eyepieces, especially if I run into the same problem…
Rob
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The one I have for my older top cons also requires the removal of the eyepiece. Mine requires that I screw the eyepiece onto the end of the 90 deg tube. Focusing is still on the main ring at the scope and parallax/crosshair focus is at the eyepiece.
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Thanks Stephen!! What a moron I said to myself as I read your post. Why is it the obvious always eludes us. Threaded the eyepiece to the other end of the adapter (which also matched) and it works fine. I knew someone would steer me in the right direction.
Rob
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This is it: DE21A
I can’t say if it will work for your gun. I think it’s a few years old…
Oops – just saw your problem is solved!
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LOL, I almost didn’t post earlier because I didn’t want to offend you. Sometimes the obvious stuff is the hardest to spot.???
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