Temperature Readings

[BlueBella]

Quick question here, so I have a Vivarium Electronics dimming thermostat designed for working with incandescent bulbs, that's probe is reading lower than my temp gun. I initially set the thermostat to 100 degrees for the basking rock, but when I checked the temps with the temp gun, the reading was 110-111 degrees, which is of course, too high. So I set the thermostat lower to like 95 degrees and get 97-101 temps with the temp gun, but I still don't know which is right. The probe for the thermostat is on the basking surface and not in the air. And also the temp gun temperature seems to fluctuate when I point at something and the temps change with how close it is. Is that normal? And what should I trust, the thermostat probe or the temp gun?

[kingofnobbys]

Quick question here, so I have a Vivarium Electronics dimming thermostat designed for working with incandescent bulbs, that's probe is reading lower than my temp gun. I initially set the thermostat to 100 degrees for the basking rock, but when I checked the temps with the temp gun, the reading was 110-111 degrees, which is of course, too high. So I set the thermostat lower to like 95 degrees and get 97-101 temps with the temp gun, but I still don't know which is right. The probe for the thermostat is on the basking surface and not in the air. And also the temp gun temperature seems to fluctuate when I point at something and the temps change with how close it is. Is that normal? And what should I trust, the thermostat probe or the temp gun?

Very likely the temperature gun is :
>>> not being used correctly ( if reading high you may be measuring ONLY surface temperatures and be introducing a systematic error due to the gun seeing the reflection of the basking globe on a "reflective" surface)

>>> incorrect emissivity setting programmed into the gun for the surface being measured by the , if the surface actually has a higher emissivity , the temperature measurement will be too low, and conversely if the emissivity of the surface is actually lower, the temperature will be too high :

and


The digital thermometer is the measurement I'd take as being reliable and accurate provided it's had time to reach thermal equilibrium and is either
>> in physical contact the surface if you want to measure the surface temperature
>> suspended in the media (air) if you want only radiant heat and air temperature.

and
>>> very common for amateurs to shoot the temperature from TOO FAR AWAY , it is very important that the area you to measure FILLS the measurement spot , if you are too far away , the gun will see & measure background too , which may be either a lot cooler (most likely in a viv) or a lot hotter , and it will simply indicate the average. SO if the gun has a spot specification of 12:1 , this means the spot is 1 inch in diameter at 12 inches from the surface, so your spot needs be larger than the measurement spot ( you come closer ) to ensure the spot is filled.

[BlueBella]

Thank you so much for the information! That helped out a lot. I have got the temps under control and picked up a 10 month old northern blue tongue today at a reptile expo!