how far can the camera see?

How far can the camera see?!

This is a question I get a lot! While it's mostly missing insulation that we look for, the world around us holds some interesting images for the infrared eye.

I took this shot early one morning in December 2010.

 

Notice anything interesting? Possibly not in this first image - it's a shot of the sky, with a tree in the foreground and clouds in the sky. The image has not been calibrated for temperature, but I've left the scale in anyway for interest - distance, emissivity of target, background temperature etc would all normally be measured (or estimated) and input in to the software where you hope to 'measure' temperature. Consequently lots of things can be wrong with your measurement, that's why thermal imaging is a great qualitative tool, but you have to be careful with the quantitative measurements. Don't always (ever?) believe the reported temperature on an infrared image - it's an apparent temperature based on emitted and reflected levels of infrared energy, with lots of variables.

 

Ok, so there it is the moon recorded during a solar eclipse, and a bit bigger below - digital zoom not optical - i.e. I've made each of the pixels bigger, but there is no more info. in the image.

 

The left hand side of the moon had just disappeared from view when the earth passed between the moon and the sun, and the right hand side was still illuminated as we usually see the moon. And that's what the thermal camera picked up too - as soon as the left hand side of the moon went dark, the apparent temperature dropped off. Another lesson here about imaging, the apparent 'heat' of the moon was actually (mainly) just reflected infrared energy from the sun. So we're not actually measuring moon surface temperature, but we are seeing energy reflected from the moon's surface. I was still amazed when I first took this image, and it took me a while to accept that my camera could 'see' up to 250,000 miles away, but then again why wouldn't it. Infrared energy and visible light are just energy from different parts of the electromagnetic spectrum, so if a detector (our eyes) can see one, why wouldn't a detector see the other? 

If an infrared survey of your world would help you understand something a little better, please give us a call on 01357 520557.