Full moon rise tonight - well worth a look

[Jane H Jones]

Hi everyone!

Step outside tonight  to see the full moon rise in the East after 
sunset.  Sunset is at about 8:00 p.m. and moon rise is at about 8:30 
p.m. so depending on your horizons it may take you a little while to 
see the moon rise after 8:30 at your location.   Often when you 
observe the full moon rising, it "looks" bigger than it really is. 
It's an optical illusion that is easy to test and interesting to see.

"The full Moon of June 18th is a "solstice moon", coming only two 
days before the beginning of northern summer. This is significant 
because the sun and full Moon are like kids on a see-saw; when one is 
high, the other is low.

This week's high solstice sun gives us a low, horizon-hugging Moon 
and a strong Moon Illusion.

Sky watchers have known for thousands of years that low-hanging moons 
look unnaturally big. At first, astronomers thought the atmosphere 
must be magnifying the Moon near the horizon, but cameras showed that 
is not the case. Moons on film are the same size regardless of 
elevation: example. Apparently, only human beings see giant moons.

A fun activity: Look at the Moon directly and then through a narrow 
opening of some kind. For example, 'pinch' the moon between your 
thumb and forefinger or view it through a cardboard tube, which hides 
the foreground terrain. Can you make the optical illusion vanish?"

The above excerpted from the excellent Science at NASA's feature all 
about the moon illusion: 
http://science.nasa.gov/headlines/y2008/16jun_moonillusion.htm

Here is another good article about the moon illusion. 
http://www.msnbc.msn.com/id/25212851/

Both of these articles have some excellent graphics for you teachers 
(and students) out there.  And there is a full moon every month for 
you to practice this activity with your friends and family.

Since you're out looking at the moon, swing your head around to the 
West for a look at Mars and Saturn.  You'll see they are appearing 
closer and closer to each other.  On July 10 they'll fit in the same 
binocular view.

Jane
-- 
Jane Houston Jones
Senior Outreach Specialist, Cassini Program
JPL - 4800 Oak Grove Drive, MS 230-205
Pasadena, CA  91109  818-393-6435
jane.h.jones at jpl.nasa.gov
Cassini SOC http://soc.jpl.nasa.gov/index.cfm
What's Up? http://education.jpl.nasa.gov/amateurastronomy/index.html