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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SUBSIDING METEOR OUTBURST: Prof. Peter Brown of the University of Western Ontario reports that "the Andromedids are starting to fade from their peak of two days ago." Using the Canadian Meteor Orbit Radar (CMOR), Brown and colleagues have been monitoring an outburst of Andromedid meteors numbering as many as 20 per hour. Andromedid meteoroids come from Comet Biela, which broke apart in the 19th century. In recent years, Earth has been crossing through streams of debris from the doomed comet resulting in outbursts of meteors in 2011 and 2013. "Based on the radar data, I'd say activity will return to background levels later today," concludes Brown. "The best night for sky watchers to have seen Andromedids was probably Dec. 6-7."
COMET ISON UPDATE: Later this month, NASA plans to point the Hubble Space Telescope at Comet ISON to see if anything remains after the comet's death plunge through the sun's atmosphere on Nov. 28th. Note to Hubble: Don't expect to see much. Amateur astronomers are already searching the comet's position and setting hard limits on the brightness of any remains. Consider this image taken on Dec. 8th by Eric Allen of the Observatoire du Cégep de Trois-Rivières in Champlain, Québec:
The position of the comet--had it survived--is circled. "I unfortunately have to say that there is nothing down to about magnitude +16.5, not even a small condensation," says Allen. More information about Allen's observing techniques and image processing may be found here.
As Karl Battams of the Naval Research Lab comments in his blog on the Comet ISON Observing Campaign web site: "The evidence appears strong that at some point approaching perihelion Comet ISON likely began to completely fall apart. What remains of ISON now is going to be either just a cloud of dust, or perhaps a few very depleted chunks of nucleus. Either way, it's not going to flare up at this point and we should assume the comet's show is over."
Comet ISON Photo Gallery
AURORAS AND METEORS: A fast stream of solar wind is buffeting Earth's magnetic field. When the stream arrived during the late hours of Dec. 7th, a G2-class geomagnetic storm broke out around the poles and Northern Lights spilled over the Canadian border into several US states. Patrick Daigle sends this photo from Cameron, Montana:
"Just before bedtime I checked Spaceweather.com. That made me change my plans," says Daigle. "Instead of going to bed, I went out into the cold (-24 F) in search of Northern Lights. While I was snapping pictures, I noticed well over a dozen shooting stars. I believe the one pictured above is an Andromedid."
NOAA forecasters estimate a 40% chance of additional geomagnetic storms on Dec. 9th. High-latitude sky watchers should remain alert for auroras as the solar wind continues to blow. Aurora alerts: text, voice
Realtime Aurora Photo Gallery
COMET LOVEJOY'S ACTIVE TAIL: Amateur astronomers around the northern hemisphere are reporting activity in the tail of naked-eye Comet Lovejoy (C/2013 R1). In Nagano, Japan, astrophotographer Kouji Ohnishi could see big changes in less than an hour of monitoring:
Michael Jäger saw the same "disconnection event" from his observatory in Masenberg, Austria, on Dec. 5th. The disturbance could be caused by a gust of solar wind or perhaps an episode of vigorous outgassing in the comet's core.
Comet Lovejoy is now about as bright as a 4th magnitude star. It is visible to the unaided eye from the countryside and is an easy target for backyard telescopes even in urban areas. Monitoring is encouraged. Comet Lovejoy rises in the east just before the morning sun. Sky maps: Dec. 7, 8, 9.
Realtime Comet Photo Gallery
Realtime Space Weather 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 Dec. 9, 2013, the network reported 22 fireballs.
(20 sporadics, 1 Geminid, 1 sigma Hydrid)
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 December 9, 2013 there were 1445 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 |