How reliable is the temperature indicator in SGP?

How reliable is the temp reported by SGP?
I use a 1600MM and cool the cam to -20C when imaging.
I tested different temperatures from 5C to -20C and I don’t see much of a difference in the noise level in the subs making me doubt of the cooling.
Can I trust SGP for reorting the right values?

Is there another way to test the cooling of the camera than to rely on SGP reported numbers?



SGP will only report the temperature that the camera driver gives to it. You can trust that SGP is correctly displaying the temperature the camera reports. As for verify that the camera is correctly reporting the temperature, I suppose you could measure the temperature of the sensor directly with an IR thermometer.