A word of caution about this channel. You will notice that it
looks a lot different at nighttime than at daytime. This is
because
the sensitivity of this channel is in the "near" IR, that is, it is
very
close to the visible spectrum, and has some visible
characteristics.
One of these is that when the sun illuminates the scene, solar IR
photons
are reflected (just like visible light) and detected, while at night,
only
earth radiated IR photons are sensed. Interesting effects can be
seen during this transition when the terminator goes across the image
during
sunrise or sunset. - Dan
Birkenheuer