| Where's
Saturn? Is that a UFO--or the ISS? What's the name
of that star? Get the answers from mySKY--a
fun new astronomy helper from Meade. |
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MORNING SHOW:
"I woke up early this morning, stepped outside and saw four
bright, beautiful objects in the twilight," reports Kenneith
Hui Ho-Keung of Hong Kong. "Venus, Mercury, Jupiter and
the Moon were lined up behind the wind turbines of the Ho Koon Education
cum Astronomical Centre." Photos: #1,
#2. Readers,
you don't need to be in Hong Kong to see this show. The planets
are on display at dawn all weekend long and all around the world.
Wake up and look: sky
map.
AURORA WATCH:
Would you like to see the Northern Lights this weekend? Take the
midnight flight from Los Angeles to London. Here is the view from
a port window on Feb. 29th:
"I was flying over the Hudson Bay en route from LAX to Heathrow,"
says photographer Jeff Hapeman.
"I always keep an eye on the aurora forecast before this flight
and pack my camera (a Canon
1D Mark III) if there is a good chance of a display."
The lights Hapeman saw were caused by a solar wind stream hitting
Earth's magnetic field. The solar wind continues to blow and NOAA
forecasters estimate a 30% chance of more geomagnetic activity tonight.
Observing tip: Pick a window seat.
February
2008 Aurora Gallery
[Interactive
World Map of Aurora Sightings]
[Aurora Alerts] [Night
Sky Cameras]
LUNAR LIBRATION:
A few days ago, NASA released new high-resolution radar
maps of the Moon's south pole, revealing a fantastic land with
peaks as high as Mt McKinley and craters four times deeper than
the Grand Canyon. But wait. How did NASA radars located in California
see the south pole of the Moon? The answer is lunar libration. As
the Moon goes around its orbit, it seems to nod
back and forth, tipping its north pole toward Earth one week
and its south pole toward Earth two weeks later. The effect is illustrated
in this composite photo of February's quarter moons:
"Two photos taken at first quarter and 3rd quarter were combined
to demonstrate the libration of the Moon," says photographer
Howard Eskildsen of
Ocala, Florida. "The Ptolemaeus group (three distinctive craters
near center of photo) were used as the anchor point."
Libration happens because the Moon's
orbit is slightly elliptical (5%) and slightly tilted (5°).
The two effects combine to provide a constantly changing point of
view as the Moon goes around Earth. It is often said that the same
side (i.e., the same 50%) of the Moon always faces our planet, but
libration allows us to observe not just 50% but rather 59%
of the Moon's surface.
Lunar
Eclipse Photo Gallery
[Interactive
World Map of Eclipse Photos]
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