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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AN UPDATE FROM THE MOON: Earlier today, NASA's LADEE spacecraft completed a successful firing of its main engine to adjust its orbit around the Moon. This follows an earlier burn on Oct. 6th that put the spacecraft into lunar orbit in the first place. LADEE is now in a 4 hour elliptic orbit, with the perilune (low point) at the desired altitude for commissioning. A final burn is scheduled for Oct. 12th, which will settle the spacecraft into the commissioning orbit. LADEE is on a mission to study the Moon's exotic atmosphere, which is mightily affected by space weather.
CME IMPACT, GEOMAGNETIC STORM: An interplanetary shock wave, possibly the leading edge of a CME, hit Earth's magnetic field on October 8th at approximately 2015 UT (1:15 pm PDT). The impact sparked a G1-class geomagnetic storm (subsiding) and bright auroras around the Arctic Circle. Harald Albrigtsen sends this picture from Tromsø, Norway:
"This is a 10s exposure at ISO 1600," he says. Novice aurora photographers who wish to take similar pictures may find more photo settings here.
Earth is passing through the wake of the CME where a region of high-speed solar wind continues to buffet our planet's magnetic field. NOAA forecasters, who suspect that a second CME might arrive on Oct. 9th, estimate a 65% chance of polar geomagnetic storms during the next 24 hours. High-latitude sky watchers should remain alert for auroras. Aurora alerts: text, voice.
Realtime Aurora Photo Gallery
M-CLASS SOLAR FLARE: Solar activity is picking up. New sunspot AR1865 erupted this morning (Oct. 9th at 01:48 UT), producing the strongest solar flare in nearly two months. NASA's Solar Dynamics Observatory recorded the M2.8-class eruption: movie. Earth was not in the line of fire, but future eruptions could be geoeffective as the sunspot turns toward our planet in the days ahead. Solar flare alerts: text, voice.
JUNO SPACECRAFT BUZZES EARTH TODAY: NASA's Juno spacecraft will slingshot past Earth today, October 9th, for a velocity boost en route to Jupiter. At closest approach (19:21 UT, 12:21 PDT) the spacecraft will be only 347 miles above Earth's surface. This map shows the spacecraft's ground track:
During the flyby, Juno's science instruments will be activated to sample the Earth environment--a practice run for data-taking when the spacecraft reaches Jupiter in 2016. Despite the shutdown of the US government, "the flyby will continue as planned," says Juno principal investigator Scott Bolton of the Southwest Research Institute. "The commands associated with our instruments were already on board before the shutdown."
To celebrate this event, the Juno team invites amateur radio operators around the world to say "HI" to Juno in a coordinated Morse Code message. Juno's radio and plasma wave experiment, called Waves, should be able to detect the message if enough people participate. Please join in, and help spread the word to fellow amateur radio enthusiasts.
The spacecraft will not be visible to the unaided eye. Estimates of its maximum brightness range from magnitude +7.5 to +8.5. Such a faint object moving rapidly across the sky will be a challenge for even large backyard telescopes. There is a slim chance, however, that sky watchers could see a "Juno flare" if sunlight glints off the spacecraft's large solar arrays. Anyone who successfully photographs the spacecraft is encouraged to submit their images.
PS: If you want to see a really bright spacecraft, download our Satellite Tracker app and check out the International Space Station.
Realtime Space Weather Photo Gallery
GREEN COMET ISON: Comet ISON is brightening as it approaches the sun. At the moment it is glowing like a 10th magnitude star, too dim for naked eye viewing but an easy target for many telescopes on Earth. "This is what the comet looked like on Oct. 8th using the 0.8m (32 inch) Schulman Telescope," reports Adam Block from the University of Arizona Skycenter atop Mount Lemmon:
ISON's green color comes from the gases surrounding its icy nucleus. Jets spewing from the comet's core contain cyanogen (CN: a poisonous gas found in many comets) and diatomic carbon (C2). Both substances glow green when illuminated by sunlight in the near-vacuum of space.
"I am certain more images of Comet ISON will be coming out shortly as it increases in brightness during its dive towards the Sun," adds Block. "Here is hoping it survives that rendezvous on Nov. 28th and emerges as something spectacular on the other side!"
Although the comet is very faint, finding it is easy. Comet ISON rises alongside Mars in the eastern sky just before dawn. Amateur astronomers, if you have a GOTO telescope, enter these coordinates. Special dates of interest include Oct. 13-15 when Mars, Comet ISON, and the first magnitude star Regulus will be clustered in a patch of sky less than 3o apart. Red Mars and blue Regulus will form a beautiful naked eye "double star" in the early morning sky. Sky maps: Oct. 10, 11, 12, 13, 14, 15.
Realtime Comet ISON Photo Gallery
Realtime Aurora Photo Gallery