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. | | | ORIONID METEOR SHOWER--STILL ACTIVE: Earth is passing through a stream of debris from Halley's Comet, source of the annual Orionid meteor shower. Last night NASA's All-Sky Fireball Network detected 15 Orionid fireballs over the United States. After sunrise, the Canadian Meteor Orbit Radar (CMOR) continued to record echoes from Orionids in broad daylight. This CMOR sky map shows the Orionid radiant (ORI) clearly active at 1445 UT on Oct. 21st: Forecasters expect the shower to peak on Oct. 21st with about 20 meteors per hour. However, Halley's debris stream is broad, so Orionid activity could spill into Oct. 22nd. 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] 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 SUNSPOTS OF INTEREST: Two large sunspot groups, AR1875 and AR1877,have emerged over the sun's eastern limb and they are turning toward Earth. NASA's Solar Dynamics Observatory captured this three-day movie of their approach: AR1877 is large, and AR1875 is rapidly growing to match it. Both sunspot groups have 'beta-gamma' magnetic fields that harbor energy for M-class solar flares. So far, however, neither one is actively flaring. Perhaps this is the calm before the storm. NOAA forecasters estimate a 25% chance of M-flares in the next 24 hours. Realtime Space Weather 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 Aurora 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. 21, 2013, the network reported 34 fireballs. (15 Orionids, 13 sporadics, 4 Leonis Minorids, 2 epsilon Geminids) 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 21, 2013 there were 1434 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 | |