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 RADIATION STORM: A solar radiation storm in progress around Earth is slowly subsiding. It currently ranks S2 (moderate) on NOAA storm scales, which means that satellites in Earth orbit could experience "single event upsets" in their electronic systems. The radiation storm is also a source of noise in spacecraft cameras, giving their images a snowy appearance (see below).
M5-CLASS EXPLOSION: The ongoing radiation storm got started on May 22nd when the magnetic canopy of sunspot AR1745 exploded. The blast produced an M5-class solar flare and hurled a magnificent CME over the sun's western limb:
Credit: the Solar and Heliospheric Observatory (SOHO)
The movie of the CME is very "snowy." That is caused by high-energy solar protons striking the CCD camera in SOHO's coronagraph. Each strike produces a brief snow-like speckle in the image. This hailstorm of solar protons is what forecasters mean by "radiation storm."
Although the explosion was not squarely Earth-directed, the CME will likely be geoeffective. The expanding cloud appears set to deliver a glancing blow to Earth's magnetic field on May 24th around 1200 UT. According to NOAA forecast models, the impact will more than double the solar wind plasma density around Earth and boost the solar wind speed to ~600 km/s. High-latitude sky watchers should be alert for auroras. Aurora alerts: text, voice.
Realtime Space Weather Photo Gallery
THE SHOW BEGINS: The long-awaited sunset sky show of May 2013 is beginning. In only a few days, Venus, Jupiter and Mercury will form a tight triangle in the western sky, visible to the unaided eye around the world. On May 20th, Fred Espenak of Portal, Arizona, photographed the trio in the early stages of convergence:
"The three planets were easily visible to the naked eye in spite of the bright twilight glow," says Espanel. "Mercury should be even easier to spot in the coming days as it climbs higher into the sky. "
In the nights ahead, the line of planets will collapse to form a triangle. At closest approach on May 26th, they will fit within a circle less than 3o wide. Start watching tonight--it's a great way to end the day. [full story] [video]
Realtime Planet Photo Gallery
A BIG ASTEROID APPROACHES: Near-Earth asteroid 1998 QE2 is approaching the Earth-Moon system for a flyby on May 31st. There's no danger of a collision; at closest approach the asteroid will be 3.6 million miles away. Even at that distance, however, the 1.7-mile-wide space rock will be an easy target for mid-sized backyard telescopes. Using a 14-inch Celestron, Alberto Quijano Vodniza of Narino, Colombia took this picture of 1998 QE2 on May 17th:
The sunlit side of the asteroid will turn more squarely toward Earth during the first week of June. At that time it will reach a maximum brightness of 11th magnitude.
NASA radars will be monitoring the flyby, too. "Asteroid 1998 QE2 will be an outstanding radar imaging target at Goldstone and Arecibo and we expect to obtain a series of high-resolution images that could reveal a wealth of surface features," says radar astronomer Lance Benner of JPL. "Whenever an asteroid approaches this closely, it provides an important scientific opportunity to study it in detail to understand its size, shape, rotation, surface features, and what they can tell us about its origin."
Stay tuned for updates and observing tips.
Realtime Aurora Photo Gallery
Realtime Comet Photo Gallery
Realtime Noctilucent Cloud Photo Gallery
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