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. | | | FAINT ECLIPSE OF THE HUNTER'S MOON--UNDERWAY NOW: According to folklore tonight's full Moon is the Hunter's Moon. It gets its name from Native American hunters who once tracked their prey by autumn moonlight, stockpiling food for the winter ahead. This year's Hunter's Moon is special because it will pass through the outskirts of Earth's shadow, producing a dusky shading in the southern half of the Moon. The faint lunar eclipse will be visible to the naked eye during a 40 minute period beginning at 23:30 UT (7:30 EDT) on Oct. 18th. Sky watchers in Africa and Europe are favored with the best views. [details] [map] 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 Realtime Space Weather Photo Gallery NEW: 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. 18, 2013, the network reported 4 fireballs. (3 sporadics, 1 epsilon Geminid) 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 18, 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 | |