I have 2 STX Guiders, one in New Mexico and one in Canada, great devices. Recently I interchanged the 2 along with the cameras, and the one I installed in Canada gives me problems when temperatures dip below -15C. I know that they can operate well below this as before the switch I had no problems down to -30C. The problem has been going on for 3 months or so. I suspected that it was only when it got very cold, but now I am sure. My sessions start off well but as the temperature drops the guide image intensity starts to vary. The star appears and disappears from frame to frame. I changed out the HDMI cable, no affect. The main camera is working fine. I started increasing the exposure time and it helped but the as the temperature drops more that failed too. Then I noticed that certain stars, not all were affected separately, leading me to think that the shutter was blocking part of the frame. Then I noticed that when the stars were bright there was a solid clicking of the shutter, and when the clicking was softer or even hard to hear, and delayed, the stars were gone. I think the shutter gets weak as the temperature drops. I have attached 3 pics that illustrate the problem. It is connected to an STXL 11002 that is only +-8 months old (they were purchased together). Running Maxim 6.20 on windows 10Pro, all drivers and firmware are up to date. Thx for your help.