Purchased ASI183MC, my first dedicated camera (was using dslr before) at end of April this year. Have used on 2 different optical trains; 1) SV50307ED, and 2)Rokinon 135mm f/2. First light with 70ED showed noticeable focus issues in one corner only. Couple weeks of back focus testing and improved, just a little. Moved camera to Rokinon 135mm with zwo eos filter holder, and t2 tilter to fix my issue. All images, with either optical train have same area that is out-of-focus. I spent the better part of the summer, as weather permits, tweaking the zwo t2 tilter to correct. I did see a bit of improvement, but I could never get the offending corner, and it's opposite in focus simultaneously.
Yesterday I removed the protective cover and found the below image. Pretty easy to see why focus could never be achieved. My ASTAP and SIRIL tilt checks always showed outrageous tilt in one corner, guess they were spot on.
I removed the sensor board and tightened this myself. It had not come loose, it had never been fully tightened due to the tightness of the metal screw biting into the threads as I slowly turned. Once tightened, I reassembled camera, and first daytime terrestrial image were amazing, focus in all four corners looked good! This camera could have never tested good as delivered, but will wait for better weather to get some proper imaging done.
The purchase of the T2 tilter was unnecessary, and I spent a lot of time troubleshooting this obvious manufacturer defect.
Very disappointing first encounter with ZWO.
-Mark
