PROJECTS: Networked Meteor Camera
goal of characterizing the apparent point of origin
in the sky (the radiant), total number, and size
distribution of meteors entering our atmosphere.
Hundreds of thousands of meteor orbits have
already been logged through the work of citizen
scientists and, thanks to their dedicated work, it
won’t be long before we’re talking about millions
of orbits!
HARDWARE
Although the hardware required for imaging
meteors is fairly basic, there are a few things to
keep in mind when making a meteor camera.
First, meteors are typically faint and barely
visible with the naked eye, so the camera sensor
needs to be sensitive to very low light levels and
paired with a fast lens. Our favorite IP camera
modules, at the moment, use Sony’s ⁄" IMX291
and IMX307 sensors. Although these can be
bought for $35–$50, be aware that a current
shortage of certain HiVision SoC chips means that
prices fluctuate.
Lens-wise, a focal length of between 4 and
8mm gives good sky coverage while speeds faster
than f/1.0 allow faint meteors to be captured.
Choosing the best lens starts by calculating the
field-of-view for your sensor:
FOV = 57.3 / focal_length * binned_pixel_
size_mm * # pixels
and considering any obstructions (trees,
buildings, etc.) in your preferred pointing
direction.
A 4mm lens, for example, paired with an
IMX291 sensor (running at 1280×720) will have a
field of view of about 80°×45° (Figures
A
and
B
).
In practice, however, you’ll find that some
nominal 4mm lenses are actually 3.6mm and
you’ll get a larger field (88°×47°). Other possible
lenses and their properties are given in Table 1.
84 makercampus.com
A
The field-of-view of a 4mm lens on an IMX291
camera, projected onto a fisheye view of the sky as
visualized by Stellarium. The ideal pointing for most
locations will be at an elevation of about 45° in a
direction that overlaps with a nearby station.
M77_082-7_MeteorCamera_F1.indd 84M77_082-7_MeteorCamera_F1.indd 84 4/9/21 12:54 PM4/9/21 12:54 PM
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