Attached is a photo of my new OAG, QHY OAG-M, setup. I tried it out Saturday night and could not get the guide camera, asi174mm, looking in good focus when viewing it in the Star Profile cross hairs with PHD2.
Researching for a camera, learning from previous experiences, I went the "Buy once, cry once" route and got an asi174mm.
I was totally amazed and happy I was getting a minimum of 7-8 guide stars for multi-star guiding, although I could maybe only see 1 to 3 stars in the main PHD2 screen.
I tried to focus on distant trees during the day and had the same problem that night. Would have to lower the guide camera in the guider base to get better focus.
However, it is at the maximum lowest level. Hence my problem.
The back focus of my flattener is 51.5mm +/- 5mm . With my previous setup I had 50.5mm back focus with just the camera adapter, shown separate in photo, connected directly to the flattener and a 1.5mm shim.
With trying to keep the same back focus, 50.5mm, and the OAG as far away from the camera as possible the distance from center of the prism to main camera sensor is 36mm.
The distance from the center of the prism up to the guide camera compartment, 36mm, puts it at the inside bottom of the guide camera compartment.
The guide camera stops 4mm from the bottom of the compartment and it still has another 8.5mm to reach the sensor for a total of 12.5mm extra focus length.
I've been reading everything I can on OAGs and know you keep the "sensor to prism to sensor" distance equal. Just don't know what to try.
If I add 12.5mm worth of spacers between the OAG and main camera, changing the "flattener to sensor" back focus distance above 50.5mm will it mess up my image focusing?
Or will I just need to adjust the main focuser in or out more?
Any thoughts or comments much appreciated!!!