using six BalloonSats and
two radio trackers.
The EclipseCam is a
BalloonSat holding four
They point upward at 45
degree angles, which my
indicates will be the
sun’s elevation at totality.
I replaced two of the
camera’s hot mirrors so
they will shoot near
infrared (NIR) and left
two unmodified to shoot
RGB. The NIR cameras
will record the sun in a
part of the spectrum that
do not scatter. This
means the images will
appear as crisp black
and white images.
The remaining two
cameras have not been
modified and they’ll record the sun in
color, or as our eyes would see it.
The cameras are aimed 90 degrees
apart and the NIR cameras are
positioned opposite of each other. I
programmed the cameras to record
still images every five seconds.
As the moon covers up the last
bit of sun, its edge creates a
refraction pattern that appears as
wavy bright and dark bands
sweeping across the ground.
Astronomers call this phenomenon
shadow bands, and they are best
seen on white surfaces. The
BalloonCam will be an attempt to
record this in near space. It’s simply a
camera pointed up at the balloon
(the most convenient white surface in
I suspect that if they can be seen
on the balloon, then they’ll appear
straighter and less wavy because
there’s less atmosphere above the
balloon to affect them. Perhaps what
the BalloonCam might observe is
what shadow bands will appear like
to astronauts on the moon.
In addition to searching for
shadow bands, I’ll compare the
brightness of the balloon to the
brightness of the sky. The balloon’s
relative brightness might make a
good indicator of how much sunlight
the moon has obscured.
The PhotoSat is an eight-channel photometer based on
LEDs (the circuit for
converting light intensity from
current and into voltage was
developed and popularized
by Forrest Mims back in the
early 1990s). Photons of light
striking an LED produce a tiny
current. That current is
proportional to the number of
photons striking the LED and
therefore, proportional to light
produced in each LED
on top of the PhotoSat is
converted to a voltage,
and then digitized and
stored inside EEPROM
memory for download
after recovery. The
PhotoSat won’t record
the direction to the sun
(that’s a future upgrade),
so I expect to see some
wild swings in the
output. However, the
overall trend may be
telling — especially as
This is another
BalloonSat. It consists of
recording RGB and the
other NIR (a future
upgrade will incorporate thermal
infrared). The cameras in the
HorizonSat point in the same
direction towards the horizon and
record images every five seconds.
Perhaps they’ll see the moon’s
shadow as it sweeps across the
ground at speeds up to 2,000 MPH.
They’ll have a chance, since the
cameras will see the horizon over
APPROACHING THE FINAL FRONTIER
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Here’s looking at you baby, baby, baby, and baby. Four
cameras pointed at 90 degree angles should be enough
to capture some images of totality.
I added a camera boom to an older BalloonSat so that it
could record video of the balloon above.
All tethered up and ready for near space.
Eight LEDs protruding from the top will
record light intensity from infrared to
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