Shine On, Harvest Moon

Tomorrow night just after sunset, the Full Harvest Moon will rise in all her glory and we're once again the fortunate humans who will witness the autumnal equinox as it shows off.  Thanks to the great Caesar, Julius, we have two extra months in the year so farmers had enough time to harvest their crop - hence the name "harvest moon".  For centuries untold, farmers worked by the light of Luna Maria, shining as if it were a great powerful beam of the softest, most ethereal heavenly glow.  There's nothing that comes close to the way moonlight looks on people and things, I say.  And to that, I'd like to add a few interesting facts:

Did you know that moonlight "steals" color from whatever it touches?  If you look at a rose under moonlight, it's brightly lit and casts a shadow but the red is gone, replaced by shades of pale gray.  The whole landscape is that way!

And if you stare at the gray landscape long enough, it turns blue.  The best places to see "blueshift" is in the countryside, far from artificial lights.  As your eyes become adapted to the dark, that's when the blue appears.  Film makers often use blue filters over their lens when filming night scenes to create a more natural feel.  Artists add blue paint for nightscenes for the same reason.  Yet if you look at the moon, it is certainly not blue. 

Moonlight won't let you read!  Open a book beneath the full moon - it seems bright enough.  Yet when you try to make out the words, you can't.  And if you stare at the page too long, the words may just disappear!  Moonlight blurs your vision and creates a little blind spot.

This is all very strange, yes?  Actually, moonlight is no more exotic than sunlight reflected from the dusty surface of the moon.  The only difference is intensity:  moonlight is about 400,000 times fainter than direct sunlight.  So why does this all happen?  The reason is our eyes:

The RETINA is like a digital camera.  We have two kinds of "pixels"called rods and cones.  The cones allow the eye to take in colors, like red roses, and fine detail, like words in a book.  This all works only in bright light.  After dark, the rods take over.  They are 1000 times more sensitive than the cones.  They allow us to see at night, yet rods are colorblind!  Thus, roses at night appear blue.  The basic principle is, when we think we see color, we're actually seeing the effects of light - reflected, refracted, absorbed, etc.  It is the explanation for what appears to be a "blue" sky or ocean, yet pick up a handful of the sea and it's colorless.  Just as our atmosphere is. 

I've left out alot of information about the composition of the eye and why things appear as they do, but the moon is still a very mysterious and incredible object which most believe was once part of planet earth.  Whatever our feelings about Luna Maria, she is still a wonder to behold!

Basic info courtesy of Skywatcher Alert, Sky & Telescope

CAVEAT LUNAR:  This is a generalization about how people perceive things under the full moon, but as with all things human, there are exceptions.  Some people can read by moonlight, others have no trouble seeing the red petals on a moonlit rose.  These people have "MOONVISION" which is caused by having extra rods or extremely sensitive cones.  Maybe YOU'RE one of them?  Find out tomorrow night!