It's a clear and slightly chilly night expected in Monrovia. The
crescent moon will be out early, and later Jupiter might clear the trees
to the east.
While tonight's sky is expected to be very transparent (dark), the other
atmospheric feature that affects astronomy is scintillation, a measure
of how turbulent the air is. Astronomers have a technical term for this:
"seeing." The seeing tonight is not expected to be very good, because of
different layers of air temperature and upper level winds.
That's what gives the slightly watery effect you notice when you view
the moon or planets through a telescope, and it gives stars more of a
twinkle when you look up at the night sky.
Notice the brightest star Sirius tonight due south, and see how it
flashes and changes color as its light passes through the turbulent air.
It's a little like looking up at the sky from the bottom of a deep
swimming pool.
But "seeing" is highly variable! If you look for a while, you will have
moments when you're looking through air that isn't turbulent, and you
can see fine detail: mountain peaks and lava tubes on the moon, cloud
belts and swirls on Jupiter.
Come take a look if you can.
Jane and I have a family engagement tonight so we won't be there, but
Todd and Dave and maybe some others are planning to set up from about
6:00 'til 8:00.
Best regards,
Mojo
--
Morris Jones
Monrovia, CA
http://whiteoaks.com