174mm-min connected to celestron OAG

heyjp

ZWO docs show the ASI174mm-Mini has a 1.25” barrel with a 28.5mm female threaded connector on the opposite end. I bought a T2-female to 28.5-male, but the 28.5 does not fit the mini barrel! Looks more like a 30-mm . What is the size of the 174’s thread if not 28.5s

how is everyone connecting their 174-mini to an OAG?

jim

w7ay

heyjp What is the size of the 174’s thread if not 28.5s

Looks like 28.5mm (1.25" filter's thread) to me.

Here it is with a 1.25" filter attached:

The Mini camera's barrel diameter is 1.25"(31.8mm) and the camera slides into a 1.25" helical focuser, like this one that ZWO sells for use with their OAG:

https://astronomy-imaging-camera.com/product/zwo-1-25″-helical-focuser

Chen

AstroDude42

heyjp i use the 174MM mini with the Celestron OAG (see image). The camera comes with a barrel, but in my case it’s not neccessary. I can get proper backfocus without it on an EdgeHD 8“.

heyjp

w7ay Chen: thanks for taking the time to measure and shoot the picture. So riddle me this! Why does my male adapter measure 28.3 (as it should) but my 174mm measure an ID OF29.3??

https://share.icloud.com/photos/0Qy4PHawQcnMH68CvGoVGWChw

okay, I guess I don’t know how to share an iCloud image here.

jim

heyjp

w7ay Chen:

My bad. Multiply me by zero. Apply full-stop Jim-filter. I had been playing with the different adapters that came with the 174-mini. When I added then removed the barrel extender, I also removed the thin end protector that changes the 174 ID from 29.5 to 28.5.

Problem solved. It screws onto my 28.5 adapter just fine.

sheesh,

Jim in Colorado

heyjp

AstroDude42 I’m using the Celestron large SCT-OAG adapter between the reducer and OAG which means I need a little more backfocus room from OAG to cameras. I can get 174-mini focus with a short 1.25 extender, but wanted to try a screwed adapter rather than barrel extension. I’m confused why I see an inside diameter of 29.3mm on my 174 threads rather than the expected 28.3. It doesn’t fit a 28.5 adapter??!!