Photo Credit: Dan Bush
Look for the full Harvest Moon tonight and tomorrow - September 22 and 23, 2010. Nature cooperates during the months of autumn to make the Harvest Moon unique.
September 22nd, 2010 - Astronomy Essentials
In the U.S., in 2010, the best nights for seeing the 2010 Harvest Moon are September 22 and September 23. The crest of the full Harvest Moon will come on September 23 at 4:17 a.m. CDT (9:17 Universal Time).
Why is the Harvest Moon special?
Harvest Moon is just a name. It’s the name for the full moon nearest the autumnal equinox. In the northern hemisphere, you’ll always see the Harvest Moon in either September or October. In the southern hemisphere, a moon with these same characteristics always comes in March or April.
Everything you need to know: Autumnal equinox of 2010
It’s more than just a connection to the season of harvest. In fact, nature is particularly cooperative during the months of autumn to make the Harvest Moon unique.
Here’s what happens. On average, the moon rises about 50 minutes later each day. But near the time of the autumnal equinox, the moon rises only about 30 minutes later each day. Why? The reason is that the ecliptic – or path of the sun, moon and planets – makes a narrow angle with the evening horizon during the autumn months. The narrow angle of the ecliptic in on autumn evenings results in a shorter-than-usual rising time between successive moonrises around the time of the autumn full moons.
These moonrises are what make every Harvest Moon special. Every full moon rises around the time of sunset. Around the time of this full moon in autumn, you’ll see the moon ascending in the east close to the time of sunset for several evenings in a row. There’s a short time between successive moonrises as described in the paragraph above. Because of this, it seems as if there are several full moons – for several nights in a row – around the time of the Harvest Moon.
Want to know the time of moonrise in your location? My favorite source of that information is this Custom Sunrise Sunset Calendar. Once you get to that page, be sure to click the box for ‘moon phases’ and ‘moonrise and moonset times.’
Is the Harvest Moon bigger, or brighter or more colorful?
No. The Harvest Moon has the reputation of being especially big and bright and orange. But it isn’t really. It’s no bigger, brighter or oranger than any full moon.
Still, you might think it is. That’s because the Harvest Moon has such a powerful mystique. Many people look for the it shortly after sunset around the time of full moon. And after sunset around any full moon, the moon will always be near the horizon – it’ll just have risen. It’s the location of the moon near the horizon that causes the Harvest Moon – or any full moon – to look particularly big and particularly orange in color.
The orange color of a moon near the horizon is a true physical effect. It stems from the fact that – when you look toward the horizon – you are looking through a greater thickness of Earth’s atmosphere than when you gaze up and overhead. The atmosphere scatters blue light – that’s why the sky looks blue. The greater thickness of atmosphere in the direction of a horizon scatters blue light most effectively, but it lets red light pass through to your eyes. So a moon near the horizon takes on a yellow or orange or reddish hue.
The bigger-than-usual size of a moon seen near the horizon is something else entirely. It’s a trick that your eyes are playing – an illusion – called the Moon Illusion. You can lengthy explanations of the Moon Illusion by googling those words yourself.
How the Harvest Moon got its name
So why is this moon – the moon closest to the autumnal equinox – called the Harvest Moon?
The shorter-than-usual time between moonrises around Harvest Moon time means there is no long period of darkness between sunset and moonrise. In the days before tractor lights, the light of the autumn full moon helped farmers bringing in their crops. As the sun’s light faded in the west, the full moon would rise in the east to illuminate the fields for several more hours of work.
Who named the Harvest Moon? That name probably sprang to the lips of farmers throughout the northern hemisphere, on autumn evenings, as the autumn full moon aided in bringing in the crops. The name was popularized in the early 20th century by the song below.
|Taken with my Kodak Easy Share camera|
|The constellation " Pegasus" showing on the IPhone|
|I took a photo of Husband's IPhone showing the Harvest Moon information |
Jupiter's is special tonight also
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On September 21, Jupiter’s closest opposition since 1963Tonight is
Sep 23, 2010
Courtesy U.S. Naval Observatory Email
Print September 21st, 2010 - Tonight
Comet Hartley 2 might brighten to binocular object by late September 2010
In 2010, Jupiter came closest to Earth on September 20 – yesterday – at 21 hours Universal Time (4 p.m. Central Daylight Time). Then Jupiter was only 368 million miles away.
Today Earth passes between the sun and Jupiter, placing Jupiter opposite the sun in our sky. Astronomers call this event an opposition of Jupiter. The 2010 opposition is Jupiter’s closest since 1963. Plus, Jupiter is near tonight’s moon.
The giant planet is now lighting up the September night from dusk until dawn. It will remain close and bright throughout the second half of September. Although it’ll dim slightly by October, more people will notice Jupiter next month, because it will appear in the east already as the sun is setting in the west.
Why is Jupiter closer at some oppositions than others? It’s because Jupiter’s orbit – like Earth’s orbit – isn’t perfectly round. Jupiter happens to be near its closest point to the sun in its 12-year orbit around the sun. That closest Jupiter-sun distance will come in March 2011. We’re passing between Jupiter and the sun – so Jupiter is closer to us than usual at this year’s opposition. Jupiter won’t come this close to Earth again until the year 2022.
Jupiter comes to opposition every 13 or so months, as Earth takes this long to travel once around the sun relative to Jupiter. Jupiter’s closest approach to Earth for the year always falls on or near this planet’s opposition date. In 2010, Jupiter came nearest to Earth on September 20, at 21 hours Universal Time (4 p.m. Central Daylight Time).
However, Earth flies in between the sun and Jupiter today at 12:00 Universal Time. That is 7 a.m. Central Daylight Time on September 21. When it is opposite the sun, astronomers say that Jupiter is in opposition. The king planet now rises in the east at sunset, and sets in the west at sunrise. At midnight, Jupiter climbs highest in the sky.
And, because it’s opposite the sun around now, you can see Jupiter at any time of night. For example – as today’s chart shows – you can see it in the south at midnight tonight, when the sun is below your feet. At dawn tomorrow, you’ll see Jupiter low in your western sky. At opposition, Jupiter shines at its brightest in our sky.
You would need at least 80 Jupiters – rolled into a ball – to be hot enough inside for thermonuclear reactions to ignite. In other words, Jupiter is not massive enough to shine as stars do. But Jupiter is the largest planet in our solar system. So when the sun goes down on these September 2010 nights, you might – if you’re fanciful enough – imagine bright Jupiter as a tiny sun all night long.
Jupiter’s greatest distance from us will come when Jupiter is behind the sun from Earth in April 2011. Let’s see . . . closest in late September . . . farthest a bit more than six months later in early April 2011. You might see that Jupiter’s distance from us, as well as its location in our sky, is being driven primarily by Earth’s year-long orbit around the sun.
That’s because Earth travels around the sun in an orbit that’s closer to the sun than Jupiter. Our orbit is smaller, and we move faster in orbit than does the solar system’s king planet. Earth travels at a speed of about 18 miles per second in orbit, in contrast to about 8 miles per second for Jupiter.
Be sure to look for Jupiter near the moon tonight. They will be beautiful on this night of Jupiter’s opposition. And remember, this September 2010 opposition of Jupiter counts as extra special – Earth’s closest encounter with Jupiter since the year 1963!
I love the moon and look for it always!
Shine On Harvest Moon!