Sep 3, 2010

What’s Up for September 2010: The moon

What’s Up for September?

The moon


Hello and welcome. I’m Jane Houston Jones at NASA’s Jet Propulsion Laboratory in Pasadena, California.

September 18 is International Observe the Moon Night.

This annual event is inspired by last year’s Lunar Reconnaissance Orbiter’s journey to and orbit insertion around our moon. Images from its first year include all six manned lunar landing sites and close-ups of the lunar surface.

You can join astronomers around the world at lunar observing events and observe the ten-day-old moon. This is a night when many of the most recognizable lunar features are visible. Or you can even hold your own Observe the Moon event. And you don’t even need a telescope.

The moon takes about 29 days to go around the Earth once. And it also takes the moon about 29 days to spin once on its axis. This causes the same side of the moon to always face the Earth.

We can see the moon’s far side only from spacecraft.

Sometimes the moon’s far side is referred to as the dark side of the moon in poetry and songs. But this isn’t accurate.

As the moon orbits Earth, the portion we see illuminated changes. The first phase, called the new moon, is just a sliver. It’s difficult to see at first, but each night it gets bigger and brighter.

The next phase is called the first quarter, because the moon has traveled one quarter of its 29-day orbit around Earth.

International Observe the Moon Night falls halfway between the first quarter and the full moon.

A full moon is the next phase, on the 14th day of the lunar cycle. Don’t miss the full moon of September, called the Harvest Moon[1]. It rises in the east just before Jupiter on September 23rd.

Then the illuminated portion visible to us shrinks to the last quarter.

Use this moon observing journal[2] to record the lunar phases for yourself.

Be sure to check out the International Observe the Moon Night website[3] and join me, along with thousands of other amateur astronomers on September 18 sharing the moon views with your community.

That’s all for this month. I’m Jane Houston Jones.

[1] Harvest moon
The full moon that appears nearest to the autumnal equinox (秋分).
For more information, please visit

[2]Moon Observing Journal
Download the moon observing journal at

[3]International Observe the Moon Night
For the event of "International Observe the Moon Night", please visit

[4]Moon Map
Download the Moon Map at

[5]Star Chart
Download the Star Chart at
or (Use for September 18, 2010 only.)

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