Tech Briefs Magazine - December 2022 - MD13

On the Hunt for Asteroids:
Positioning an Occultation Telescope
S
everal books and movies have been
made depicting an asteroid or comet
striking the Earth. There is a small chance
of such an event, but if it happens, the
results could be devastating, perhaps even
causing a mass extinction event such as
the one many believe killed off the dinosaurs
65 million years ago. It is potentially
the largest preventable natural disaster.
And that's why the Winer Observatory in
Arizona is working on planetary defense
by tracking NEOs (Near Earth Objects).
HEIDENHAIN donated encoders to assist
in the positioning for their newest
portable telescope project that will enable
Winer to do just that.
" Early detection of a NEO headed for
The digital video stream from the camera on TAOT is fed into software that can monitor the target star and
determine when it disappears and reappears. The drop in light from the star, though subtle, is easily detected
by the reduction software. The time of disappearance is shown by the red dashed line, and the reappearance
by the green dashed line. (Image: Vince Sempronio, Winer Observatory)
Earth would give us sufficient time to deflect
the threat, " said Vince Sempronio,
Lead Observer at Winer Observatory,
who specializes in observing planet (asteroid)
occultations and is also involved
with educating area groups on astronomical
science. An occultation occurs
when an astronomical body, such as
a NEO, moves in its orbit around the
Sun and comes between an observer on
Earth and a distant star. When the NEO
is directly between an observer and the
star, the star (usually brighter than the
NEO) winks out or is occulted by the
NEO. Those events provide information
about the orbit, size, and shape of the
asteroid that can be used to reduce the
chance of it hitting Earth.
The development of Winer's new telescope
took over a year in the making and
was designed to be uniquely transportable.
With a 16-inch diameter mirror set within
a relatively small structure on wheels, it is
an unusual tool for astronomers as it is an
extremely high accuracy telescope that
can be moved by car.
The structure includes two
HEIDENHAIN incremental encoders
that provide accuracy for the telescope's
movement and placement on the star(s),
meeting Winer's accuracy requirements
for each encoder count to represent 1 to
2 arc minutes on the sky.
The telescope named the
Transportable Asteroid Occultation
Telescope (TAOT) includes a video
camera located at its prime focus set
to record occultation events. Instead of
HEIDENHAIN donated two encoders to enable the new Transportable Asteroid Occultation Telescope (TAOT) at
the Winer Observatory to find and record occultation events. (Image: Vince Sempronio, Winer Observatory)
Motion Design, December 2022
an eyepiece, the TAOT uses a very low
light level surveillance TV camera taking
25 frames per second (PAL - the
European TV standard) or 30 frames
per second (NTSC - the American
standard). The video data is digitized
and recorded on a tiny computer. After
the event, the user can process the data
using analysis software sensitive to tiny
drops in the combined light of the star
and NEO that shows the event far better
than the human eye can simply by
watching the occultation.
TAOT's camera has a field of view of
a few arc seconds on a side. After aligning
the telescope on a couple of stars,
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Tech Briefs Magazine - December 2022

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