M100 was the first target for testing the ZWO OAG. The result was impressive as the stars are very sharp.

There were a couple of challenges that I faced with focusing, as different filters requires different focus points. I’m not sure if I did the right thing but finding a bright guide star took me a while in adjusting the guide camera. I started with 2 seconds on the exposure but it’s not enough for PHD2 so I have to increase it to 4 seconds and increase the gain up to 98% for the camera.
The values were acceptable and PHD2 was able to track the star without any problem. I started only with 10secs, to 20secs and then 30 seconds. So far the results we’re good. With the setup, I was able to decrease the weight of the payload from a separate 80mm guide scope to an OAG that weight less than 1 lb. With the sudden decrease of the weight, I was able to use my Celestron AVX that is easier to setup.
Hi There,
I have watched your view. Very informative.
What intrigues me is that you have no visible shadow in the image of your main camera (cause by the OAG prism). I’m struggling with that.
Firstly this is my setup. Celestron 11″ SCT + Celestron f/6.3 Focal Reducer + Celestron T adapter + M48 – M42 adapter + ZWO OAG + 11mm spacer + T2 – T2 adapter + ZWO EFW mini + ASI 1600MM cooled. I use a ASI 120MC-S as my guide camera.
As soon as I lower the prism of the OAG to catch enough light, then there is significant shadow on the main camera.
Any guidance you can provide?
Best Regards,
Gerhard