When is the best time to see auroras? Where is the best place to go? And how do you photograph them? These questions and more are answered in a new book, Northern Lights - a Guide, by Pal Brekke & Fredrik Broms.
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ORIONID METEOR SHOWER: Earth is passing through a stream of debris from Halley's Comet, source of the annual Orionid meteor shower. Forecasters expect the shower to peak on Monday, Oct. 21st, with about 20 meteors per hour. The best time to look is during the hours before local sunrise when the constellation Orion is high in the sky. [meteor radar] [sky map]
Lunar interference will be a problem during the peak. All but the brightest Orionids will be wiped out by glare from the waning full Moon. Fortunately there are some bright ones. NASA's All Sky Fireball Network captured this Orionid fireball shining through the moonlight over Georgia on the morning of Oct. 20th:
For more information about what NASA cameras are seeing, scroll down this page to the all-new section "All Sky Meteor Network." Meanwhile, amateur photos of Orionds are available in the gallery.
Realtime Meteor Photo Gallery
FAINT ECLIPSE OF THE HUNTER'S MOON: As Oct. 18th came to a close, a dusky shadow fell across the southern half of the full Hunter's Moon. It was a faint "penumbral" lunar eclipse. Observing from the Canary islands, Frank A. Rodriguez Ramirez photographed the Moon (left) two hours before and (right) at the moment of maximum eclipse:
"We had bad weather for the eclipse," says Rodriguez Ramirez. "I captured these pictures between small holes in clouds."
A penumbral eclipse happens when the Moon passes through the pale outskirts of Earth's shadow. It is much less dramatic than a total lunar eclipse. In fact, when observers are not alerted beforehand, they often do not realize an eclipse is underway. Nevertheless, the subtle shadow of Earth is visible to the naked eye if you know it's there. Scan the gallery for more examples.
Realtime Space Weather Photo Gallery
MOONLIGHTS: "For five nights in a row we have seen amazing auroras above Abisko National Park," reports tour guide Chad Blakley of Abisko, Sweden. "Last night I spent most of the evening on the shore of Lake Torneträsk. I was able to capture several thousand images of the Northern Lights dancing over the lake while the glow of the full Moon illuminated the nearby mountain peaks." After daybreak, he put the images together to make a must-see video:
"I have spent countless nights out under the auroras but there was something very special about listening to the waves gently crash along the shore as the lights played overhead," says Blakley. "I think I have the best job in the world!"
The auroras could continue dancing in the nights ahead--especially on Oct. 21st when a solar wind stream is expected to reach Earth. NOAA forecasters estimate a 20% chance of polar geomagnetic storms when the stream arrives. Aurora alerts: text, voice.
Realtime Aurora Photo Gallery
GREEN COMET, RED PLANET: Comet ISON, which will fly through the atmosphere of the sun on Nov. 28th, is now flying past the planet Mars. The green comet and the Red Planet are just 1o apart in the eastern sky before dawn. Parks Squyres photographed the odd couple from his private observatory in SaddleBrooke, Arizona, on Oct. 16th:
Mars is almost as bright as a 1st-magnitude star, easy to find in the constellation Leo near the blue star Regulus. The comet, on the other hand, is invisible to the unaided eye. Mid-sized backyard telescopes are required to see it.
"I used a Celestron 11-inch telescope," says Squyres. "The image is a stack of 80 15-second exposures."
The comet is green because its vaporizing nucleus emits diatomic carbon, C2, a gas which glows green in the near-vacuum of space. Mars is red because its rocky surface is widely rusted. The two colors make a heavenly ensemble. Amateur astronomers, if you have a GOTO telescope, enter these coordinates, and let the exposures begin.
Realtime Comet ISON Photo Gallery
Every night, a network of NASA all-sky cameras
scans the skies above the United States for meteoritic fireballs. Automated software maintained by NASA's Meteoroid Environment Office calculates their orbits, velocity, penetration depth in Earth's atmosphere and many other characteristics. Daily results are presented here on Spaceweather.com.
On Oct. 20, 2013, the network reported 28 fireballs.
(17 sporadics, 8 Orionids, 1 chi Taurid, 1 southern Taurid, 1 Leonis Minorid)
In this diagram of the inner solar system, all of the fireball orbits intersect at a single point--Earth. The orbits are color-coded by velocity, from slow (red) to fast (blue). [Larger image] [movies]
Potentially Hazardous Asteroids (PHAs
) are space rocks larger than approximately 100m that can come closer to Earth than 0.05 AU. None of the known PHAs is on a collision course with our planet, although astronomers are finding new ones
all the time.
On October 20, 2013 there were potentially hazardous asteroids. Notes: LD means "Lunar Distance." 1 LD = 384,401 km, the distance between Earth and the Moon. 1 LD also equals 0.00256 AU. MAG is the visual magnitude of the asteroid on the date of closest approach.
| ||The official U.S. government space weather bureau |
| ||The first place to look for information about sundogs, pillars, rainbows and related phenomena. |
| ||Researchers call it a "Hubble for the sun." SDO is the most advanced solar observatory ever. |
| ||3D views of the sun from NASA's Solar and Terrestrial Relations Observatory |
| ||Realtime and archival images of the Sun from SOHO. |
| ||from the NOAA Space Environment Center |
| ||the underlying science of space weather |