Back Focus Issue?

SpaceChef

Hello, went out last night to test out a new setup and couldn't get focus for the life of me. The attached picture was as focused as I could get with the scope fully extended. I followed the ZWO set up exactly and had was measured to be 55mm from the flattener glass to the sensor, but im clearly missing something. Scope is an ED127, 3inch .7 reducer/flattener, OAG, filter drawer and ASI2600

Tech@ZWO

SpaceChef Both the guide camera and main camera can not get focus, or only guide camera?
From your pic, the adapter on the flexible focuser is needless. otherwise the guide camera can not get focused.

1 You may need to decrease 3mm back focus if you add this adapter.

If both cameras can not get focus, is there any other adapter between the reducer and telescope?

SpaceChef

Tech@ZWO
Hello, I also posted on cloudy nights and the collective was there needed more focal length before the reducer/flattener. So I found some extensions and need to see if that helps. Do you think there is an issue after the FR, with the total spacing being 58mm not 55? With the OAG and filter drawer I dont see where that could be made up. I also realized the OAG was set up incorrectly, I haven't focused it yet but I believe the configuration is correct now.

SpaceChef

Tech@ZWO
I was able to get a daytime focus on both cameras with a spacer attached before the FR. Do you think that extra 3mm with still be an issue?

Tech@ZWO

SpaceChef As the back focus requirement of the reducer is 55mm, 58mm may cause the star on the images look like this.