[Dasman56 (Wayne)]

I thought i would post a new thread explaining some troubles i have had with fan vibration on my camera as it may be of some interest to others that run into similar issues.

I bought a second hand QHY163c and was using it on a Hyperstar + 9.25HD for a little while with what seemed like no issues. But when i switched to the Native F10 focal length i was getting streatched stars. Which i first thought might be collimation or back focus. Now a lot of advice was saying you need a OAG at F10 or else. But you don't get streatched stars with 1 sec exposures. Now i had come across some info on people having fan vibration issues with ZWO cameras, and sure enough as soon as i disconnected the 12v power on the QHY perfect sharp round stars.

So here is what i did. The first thing i tried was a new fan with no improvement. Removing the filter draw did make a noticable improvement, my imaging train without the draw is a solid billet macined assembly. Whilst a major effort was made to isolate the fan it did not completely solve my problem. I finally got nice round stars but they still looked slightly bloated.

Now without the more extreme distortion at the start i probably would not have questioned my stars. But they were still not as sharp as with the fan off. My fix was to add a 50ohm resistor to slow the fan, along with the isolating and my problem is solved. . I wonder how many people experience slight star bloating from fan vibration and don't even know?