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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SLOW CME, INCOMING: Active sunspot AR1865 hurled a slow-moving (350 km/s) CME into space on Oct. 16th. The cloud appears set to deliver a glancing blow to Earth's magnetic field on Oct. 20th. Odds of a geomagnetic storm, however, are low because of the CME's relatively low mass and velocity. Aurora alerts: text, voice.
CHOOSE THE WINDOW SEAT: The next time you board an airplane with a northern flight path, choose the window seat. Photographer David Mayhew settled in next to the port wing of a flight from Denver to Iceland on October 14th, and this is what he saw through the glass:
"We were somewhere over the Hudson Bay," says Mayhew. "I rested the lens against the window and held a blanket over my head to reduce reflections - got plenty of odd looks from the other passengers!!"
NOAA forecasters estimate a 20% chance of polar geomagnetic storms on Oct. 17th. This means there is at least a 1-in-5 chance of a good view for Arctic fliers. Choose the window seat, indeed. Aurora alerts: text, voice.
Realtime Aurora Photo Gallery
COLORFUL CONJUNCTION: If you're awake at 5 am, go outside and face east. About halfway up the sky, the red planet Mars and the blue star Regulus are side by side, forming a 1st-magnitude "double star" in the pre-dawn sky. David Marshall photographed the colorful duo on the morning of Oct. 16th from Christ Church, Barbados:
Look carefully to the left of red Mars. The "duo" is actually a trio: Comet ISON is there, too. "Comet ISON, Mars and Regulus are quite a photogenic threesome!" says Marshall.
While Mars and Regulus are easily seen with the unaided eye, Comet ISON requires optics. The comet is far away, near the orbit of Mars, and glows like an 11th magnitude star. Marshall was able to photograph it by stacking 44 one-minute exposures from his Canon 7D digital camera.
Backyard telescopes reveal the comet much faster than a digital camera. Amateur astronomers, if you have a GOTO telescope, enter these coordinates. And while you're there, look up to enjoy the colorful conjunction. It's a nice way to begin the day.
Realtime Comet ISON 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 Oct. 17, 2013, the network reported 6 fireballs.
(5 sporadics, 1 southern Taurid)
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 17, 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 |