Episode #11-40 "The Hunter’s Moon For 2011"
FIVE MINUTE EPISODE SCRIPT
DEAN: And I’m Dean Regas, Outreach Astronomer from The Cincinnati Observatory. We’re both here to help you be sure you know what you’re looking at when you go out to your back yard and look up. Let’s go.
JAMES: Get outside and look East any night next week about an hour or so after sunset. The first thing you’re likely to see is a big bright Moon. If you don’t see the Moon, just wait awhile. If the clouds are cooperating the Moon will be putting in an appearance. You’ll also see a bright point of light low on the horizon and that’s the giant planet Jupiter. Tuesday night October 11 the Full Moon will be very special. No, it won’t be the Harvest Moon, that was in September this year. What’s special about it is that this Hunter’s Full Moon will be the most distant Full Moon of the year. This means it will appear to be about 12 percent smaller than the largest Full Moon, which occurred on March 19 this past Spring.
DEAN: Since you don’t have that March Full Moon sitting by this one to compare, the difference isn’t obvious. All Full Moons look the same to the naked eye. Now the reason the Moon’s distance changes is that the Moon’s orbit around the Earth is not a perfect circle and next Tuesday the Full Moon will be about 31 thousand miles farther away than when the Moon was full in March. The Moon’s average distance is about 240 thousand miles from Earth but next week the Moon will be over 252 thousand miles away while back in March it was only about 221 thousand miles away. That’s a difference of over 30 thousand miles.
JAMES: The Full Moon looks awfully bright and it keeps us from seeing most of the stars but it’s not really all that bright. The Sun is almost 400 thousand times brighter than the Full Moon. Our eyes have an amazing ability to accommodate great ranges of light. The Moon shines only because it reflects light from the Sun and it’s not even very good at that. The Moon reflects only about 7% of the sunlight reaching it. That’s about the same as charcoal. Jupiter on the other hand reflects about half of the light reaching it from the Sun. And even with the bright moonlight in the sky nearby Jupiter will be quite easy to spot in the eastern sky next week. The Moon will move from one night to the next. Here it is on the 10th, then the 11th, the night of Full Moon, then the 12th, the 13th, closest to Jupiter, the 14th and so on. So the best nights for using the Moon to identify Jupiter will be Wednesday the 12th and Thursday the 13th.
DEAN: Another weird thing about the Moon is that it is much brighter at Full Moon than you might expect. Although the Moon looks half lit up at both First and Last Quarters, the Moon is not half as bright at First and Last Quarter as it is at Full Moon. At First and Last Quarter the Moon is less than 10% as bright as it is at Full Moon. The Moon only gets to be half as bright as the Full Moon when it’s about two and a half days before and two and a half days after Full Moon. This happens because the Moon is not a smooth uniform ball in the sky. The Moon is very rough on its surface and there are lots of shadows on its surface that don’t reflect light our way.
JAMES: So, let’s recap all this Moon info. We can see the Moon only because it reflects light from the Sun, the Moon does not shine on its own.
DEAN: The Moon’s orbit around the Earth is not a perfect circle. So sometimes the Full Moon is close and sometimes it’s far away. Next week it will be the farthest Full Moon of the year. When the Full Moon is close it appears to be larger and brighter. And when the Full Moon is far away it appears to be smaller and dimmer.
JAMES: The Moon’s brightening and dimming is not smooth and symmetrical. The Full Moon is much more than twice as bright as the half lit First and Last Quarter Moons. The Moon only gets to half as bright as a Full Moon when it’s about two and a half days on either side of the Full Moon.
UNISON: So think about all this Moon madness as you keep looking up!
Episode #11-40 M "The Hunter’s Moon For 2011"
ONE MINUTE EPISODE SCRIPT
JAMES: Get outside and look East any night next week about an hour or so after sunset. The first thing you’re likely to see is a big bright Moon. Close to the giant planet Jupiter. Tuesday night October 11 the Full Moon will be very special. This Hunter’s Full Moon will be the most distant Full Moon of the year. And it will appear to be about 12 percent smaller than the largest Full Moon which occurred on March 19 this year.
DEAN: Since you don’t have that March Full Moon sitting by this one to compare, the difference isn’t obvious. All Full Moons look about the same to the naked eye, but they’re really not.
JAMES: The Moon will move from one night to the next. Here it is on the 10th, then the 11th-, then the 12th, the 13th-, the 14th and so on. So enjoy the Hunter’s Moon and Jupiter while you
UNISON: Keep looking up!
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