thermal images. However, after
looking at over a hundred of them,
I’ve concluded that the eclipse didn’t
affect the thermal imager’s view of
the horizon. That’s because there’s
no obvious heat signature of the
moon’s shadow in the images.
There are two complicating
factors regarding the thermal images.
First, air molecules don’t have as
large a thermal mass as the ground
does. So, only when the thermal
imager is looking across the horizon
through tens of miles of atmosphere
does the air’s temperature begin to
affect the quality of the camera’s
images (the image details get washed
out). Now compare this to images
taken from an imager looking straight
down; these do show variations in
The second complicating factor
is that the thermal imager scales its
color palette to match the
temperature extremes observed. The
ground is always warm (around 40
degrees); however, the temperature
variations observed across the
ground only amount to 10 or so
Near space, on the other hand,
has a temperature of -90 degrees,
according to the thermal imager.
Whether the temperature variation
observed in a thermal image is 10
degrees or 140 degrees, the thermal
imager uses the same color palette to
map the temperature range.
Therefore, while a temperature
change of 10 degrees observed
looking straight down is easily
detected in a thermal imager, the
same 10 degree change in
temperature becomes impossibly
small to observe when the
temperature range becomes 140
degrees, as it does in an image taken
of the horizon.
50 December 2017
After passing over the balloon,
the moon’s shadow is now seen
going east towards Idaho Falls.
The lake visible in this image is
Lake Lowell, and is located just
south of the towns of Nampa and
The entire moon’s shadow is visible in this image. The distance to the
horizon is over 250 miles and the moon’s shadow is 70 miles across.
The moon’s shadow approaching the balloon at a speed of 2,000 MPH.
This image was taken around 43,000 feet and is looking west over