Auroras
The Optical Remote Sensor Lab has developed an optical aurora detector. This instrument measures the brightness of auroral light and sends out cell phone text messages or emails notifying interested people of the opportunity to see an aurora (aurora.montana.edu).
We also rely on the old-fashioned approach of watching the sky and calling each other when something good is happening
We also rely on the old-fashioned approach of watching the sky and calling each other when something good is happening
Coronae and Iridescence
Coronae are colored rings that often form around the Sun or Moon
(or other light source) when light is diffracted by tiny cloud particles.
The angle into which light is diffracted is proportional to the
wavelength and inversely proportional to the dimension of the
scattering object. Therefore, the best coronae appear in clouds that
have tiny particles with relatively uniform size distributions.
Coronae are most often the result of diffraction by tiny liquid water
droplets in clouds. However, under certain conditions some clouds
can contain a narrow distribution of unusually tiny ice crystals.
This happens, for example, in wave clouds.
(or other light source) when light is diffracted by tiny cloud particles.
The angle into which light is diffracted is proportional to the
wavelength and inversely proportional to the dimension of the
scattering object. Therefore, the best coronae appear in clouds that
have tiny particles with relatively uniform size distributions.
Coronae are most often the result of diffraction by tiny liquid water
droplets in clouds. However, under certain conditions some clouds
can contain a narrow distribution of unusually tiny ice crystals.
This happens, for example, in wave clouds.
Rainbows
Coming soon.
All images are copyright. Joseph A. Shaw. Use only with permission.
