Fan Vibration

I recently installed a 14” RC on an MX mount with a SBIG STXL attached. All the images I’ve taken have elongated stars with aspect ratios typically running from 20-60%. The long axis of the stars is mostly in a north-south direction over the entire field of view. After spending a considerable amount of time eliminating collimation as the cause I started looking at vibration as the issue. Observing on windless nights and turning mirror fans on and off had no effect in reducing the image aspect ratio. I then used the SkyX camera add-on to turn the SBIG fan on and off. It was like night and day, with the fan on very poor stars, fan off nice round stars. I had notice this problem with my previous telescope but it is much worse with the 14”. I’m assuming the fan is causing resonance somewhere in telescope/mount system. Any help in finding a solution to this problem would be most appreciated!

Ed Michaels

 

Hi Doug-

Thanks for the quick response. The 14” is a large scope for the MX but it is well within the maximum weight limit of the mount. As I indicated, I used a much lighter scope on the MX and the same problem existed. I do mostly serial photometry so slightly oval images were not a big issue but the problem has become extreme with the 14”.

I found the menu in CCDOps for controlling the fan speed but that setting is not saved in the firmware when the program is closed. Is there another way to set the fan speed? I use MaxIm for camera control but have not found a fan speed setting.

Ed

 

Thanks, found it... The only problem is the "Fan Spd" adjustment is grayed out therefore I'm unable to adjust the fan speed. This is the case with and without the Enable "Fan Box" checked. Is there any other settings I may have overlooked?

 

Doug, I got it work. I was going through Setup Camera to get to Advance settings. First connecting to camera then going through the Expose tab worked. Thanks for your help!