Datalord

Ok, I disassembled the entire thing. I thought I had an extra spacer for the g3, but it turns out to be a separate spacer for non-OAG mounting. But, when I disassembled, I noticed that the the telescopes thread was protruding into the OAGs thread, which blocked the tiny eyepiece(camera)-holder from going fully into the OAG. Adding the holder first, I can insert it longer into the OAG, saving valuable mm at the cost of a very tight connection between camera and scope. This is a different problem I must handle somehow. Anyways, with the new, low profile camera cap I bought, the new assembly, I got the following picture: Btw, I thinkn the focus distance is about 40mm, which doesn't match any other calculations, but if it works...

So, this makes total sense to me. This is what it really should be according to logic. Moravian: According to this, I should have 61.5mm backfocus. I can assure you I have tried absolutely everything, with every spacer known to mankind and absolutely nothing works. The only kind of success I have had is with an eyepiece within 10mm of the prism. Otherwise, nothing.

There is an extra 10mm spacer for the main camera I can put in, but how will this make the 120 go further out? I still don't know how this backfocus stuff works.

Nope, no workie. Next step is to saw off the tip to the minimum the eyepiece holder will still attach to. outside of that, I'm completely lost by now.

well, I found this: https://www.365astronomy.com/zwo-low-profile-cover-for-all-zwo-asi-cameras-except-the-cooled.html?gclid=CjwKCAjwlejcBRAdEiwAAbj6KROw7qZvBiJgWZBe224ipz_eqcLcFCWmVTHGYCTmOX_CQT41DKg6BxoClCEQAvD_BwE 5mm. Made an order.

Well, got my mount back this week and set it all up. I just spent 2 hours messing around with a big pile of extenders to no avail. Then I place an eyepiece on it, with little result. For whatever reason, I took off as much of the eyepiece I could, until only the lens was there. I placed this up to the holder on the OAG and lo and behold, it's full of stars. So the 61.5mm quoted in the manual turns out to be absolute nonsense, it's more like 5mm. Which gives me the problem of finding a T2 threaded piece that is ultra short.

God, the penny dropped. I was focusing on the wrong side instead of at the side where the camera is threaded. Thank you! Ordered a kit with a few different extenders so I can mess around.

Possibly. And it's cheap enough that I just made an order for it. That looks amazing. How did you make it?

OK, I'm lost. How would that baader piece fit on the eye piece holder? Everything in it is threaded, while none of my pieces are.

Yes, that's what I was trying to find, but I just don't know what to search for.

Hmm, that doesn't sound right. This thread is much smaller than the one on both ZWO and on the linked Baaders.

I just can't wrap my head around how I would make those Baaders fit with the OAG. I can see there is threading that might go into the camera, but which part would go into the OAG?

But the noise piece is about 30mm long, and this is maximum 29mm. I need something which can extend further than that.

it is totally worth it. In one of my other posts I started with 4 hours, then comparing to the final 17h shot. It's not even close. I don't think I'll even consider starting processing with less than 10 hours in the future.

I'm trying to get my ZWO120 to focus on the OAG for a G3-16200 and I've read that I need 61.5mm backfocus distance. So I need a spacer/extension for the ZWO, which I assume is 1.25". I'm too stupid to find something this simple. Seems to me I need something that is unthreaded in both ends, one male and one female and extensible somehow. What do I need to search for to find this thingimajig?