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3/29/08:

SUNSPOT SUNSET: A few evenings ago, Mark Walters of Four Crosses, Wales, trained his Personal Solar Telescope on the western horizon--"I was hoping to catch the new sunspots before nightfall," he says--and took this dramatic photo:

"The sun was setting behind trees almost a mile away," he explains. The branches look almost frosted compared to the furnace behind."

In the photo, sunspots 987 and 988 are the light-and-dark blotches just above the treetops. These old-cycle spots are putting on a good show for amateur astronomers with solar telescopes--no trees required!

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3/26/08:

SOLAR ACTIVITY ALERT: With little warning, three big sunspots have materialized and on March 25th one of them (989) unleashed an M2-class solar flare. This is the biggest flare of the year and it signals a significant increase in solar activity. The eruption also produced a coronal mass ejection (CME), but auroras are unlikely because the cloud is not heading toward Earth: movie.

"It's March Madness," says Greg Piepol who photographed the three sunspots from his backyard observatory in Rockville, Maryland:

LISTEN: During the M2-flare, radio astronomer Thomas Ashcraft heard a curious "heaving sound" coming from the loudspeaker of his 21 MHz radio telescope in New Mexico: listen. "It was a Type II solar radio burst," he explains. Such bursts are generated by shock waves at the leading edge of CMEs.

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3/18/08:

LOOKING FOR SATURN? Tonight it's easy to find. Go outside after sunset, locate the Moon (you can't miss it), and note the golden star beside it. That "star" is Saturn. One quick slew takes your telescope from lunar craters to icy rings and back again--it's all good! [sky map]

LUNAR IMPACT: On March 13th, amateur astronomer George Varros of Mt. Airy, Maryland, was monitoring the dark limb of the Moon using his 8-inch Celestron telescope. With no warning, an explosion ensued:

The flash in this short movie is a meteoroid hitting the Moon with about as much energy as ~100 kg of TNT. "This gives new meaning to 'shoot the Moon'," says Varros. "The flash was also seen by three NASA telescopes in Alabama and Georgia."

Since 2005, careful monitoring by astronomers at NASA's Meteoroid Environment Office has shown that space rocks hit the Moon with surprising regularity and the resulting flashes are visible in ordinary backyard telescopes. Varros has recorded three impacts this year alone.

The best time to look is during a meteor shower, but sometimes a random meteoroid associated with no known shower plummets to the ground. Such was the case on March 13th. "It seems to have been a sporadic meteor," says Varros. "It struck at lunar coordinates 78oW, 23oS, [not far from crater Darwin]."

Readers, are you ready to join the hunt? Start here.

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2/20/08

PACIFIC FIREBALL: On Tuesday morning, Feb. 19th, at approximately 5:30 a.m. Pacific time, people in Washington, Oregon, Idaho and Montana witnessed a spectacular fireball. It exploded not once but twice in midair, casting shadows and rivaling city lights. Many onlookers wondered if spy satellite USA 193 had been shot down. No, it was a small asteroid breaking up in Earth's atmosphere, a surprisingly common event. Reports of meteorites hitting the ground remain unconfirmed; stay tuned for updates.

TOTAL LUNAR ECLIPSE: On Wednesday evening, February 20th, the full Moon over Europe and the Americas will turn a delightful shade of red. It's a total lunar eclipse—the last one until Dec. 2010. When should you look? Click here for an animated timetable.

As explained in a recent Science@NASA story, red isn't the only color to look for when the Moon glides through Earth's shadow. Observers of several recent lunar eclipses have reported a flash of turquoise. For example, note the upper left corner of the above photo taken by Jens Hackmann during the European lunar eclipse of March 2007.

The source of the turquoise is ozone. Earth's ozone layer absorbs red sunlight while allowing blue rays to pass. This has the effect of turning Earth's shadow turquoise-blue around the edges. Look for it during the first and last minutes of totality (10:01 pm EST and 10:51 pm EST).

• live webcasts: from the Canary Islands; from Norway; from Iran; from Columbus, Georgia; from the Netherlands; from Belgium;
• timetables: (pick your time zone) GMT, AST, EST, CST, MST, PST, Alaska, Hawaii
• discussion: chat about the eclipse
• NASA links: worldwide visibility, full story

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WEEKEND PLANETS: This weekend you can tour the solar system in only a few minutes. Go outside at sunset and look west; Mercury, Venus and Saturn form a line almost perpendicular to the horizon. Look up; there's the Moon. Look behind your back; Jupiter is rising in the east. On May 23th, Peter Rosen of Stockholm, Sweden, photographed all five worlds in one observing session: Take the tour!

ISLANDS ON TITAN: On May 12th, the Cassini spacecraft swooped over Saturn's moon Titan and scanned its surface by radar. One of the images captured a dark sea of liquid methane dotted with islands, bays and other features typical of terrestrial coastlines:

The utter darkness of this sea suggests to Cassini mission scientists that the depth of liquid exceeds tens of meters. The islands may, in fact, be the peaks of partially submerged mountains akin to Catalina Island off the coast of Southern California.

While this view resembles Earth, it is utterly unEarthly. The surface temperature of Titan is -180^o C. That's why the seas are not made of water, which would freeze. Instead, Titan has methane (CH₄), a liquid which is colder, lighter and less viscous than H₂O. How would you design a boat for such a sea? Could a water bug skitter across its surface? Is there such a thing as a methane rainbow? Science@NASA has the answers.

SOLAR SOUNDS: On May 19th at 12:52 Universal Time, a magnetic filament erupted on the sun. The blast sent shock waves billowing through the sun's atmosphere; those waves, in turn, generated strong Type II solar radio emissions. Amateur astronomer Thomas Ashcraft heard them in the loudspeaker of his 21 MHz ham receiver. Click on the image to listen:

Dynamic spectrum courtesy UFRO and RadioJove

"It was 6:52 am here in New Mexico, and the sun was just rising over the mountains," says Ashcraft. "I was lucky to catch the full power of the radio emission, which was peaking at the heart of my observing frequencies."

The sun has been remarkably "radio-active" lately. Want to tune in? Visit NASA's RadioJove site to learn how you can build your own radio telescope.

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3/18/07:

SOLAR ECLIPSE: On March 19th around 0230 UT, the Moon will pass in front of the Sun producing a partial solar eclipse visible from Russia, India, China and the northern reaches of Alaska: map. In those places the normally-round Sun will turn into a crescent and cast strangely-curved shadows on the ground. During a similar eclipse in Oct. 2005, Sylvain Weiller of St Remy les Chevreuse, France, took this picture:

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11/29/06:

PLANETARY ALIGNMENT: Mark your calendar. On Dec. 8th though 11th, (Kislev 17 thru the 20th) the planets Jupiter, Mercury and Mars will converge, forming a tight triangle in the early-morning sky. All three planets will fit together in the field of view of ordinary binoculars. Don't miss it! Sky maps: Dec. 8-11.

RING-SHAPED SUNSPOT: A new sunspot has materialized--and it's an odd one. Sunspot 927 is shaped like a ring. John Nassr of the Philippines photographed it this morning:

The ring is about twice as wide as Earth and makes an easy target for backyard solar telescopes. It's worth watching. The magnetic field of this 'spot might be arranged in an unusual way, leading to instabilities and eruptions. Stay tuned.

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METEOR ALERT: Earth is about to skirt the dusty tail of Comet Thatcher, and this will cause the annual Lyrid meteor shower. Forecasters expect 5 to 15 meteors per hour--modest, but pretty. The best time to look is during the hours before dawn on Saturday morning, April 22nd: full story.

The Moon will also encounter the comet's tail on April 22nd, which raises an interesting possibility: Amateur astronomers may be able to see flashes of light on the Moon when comet debris hits the lunar surface and explodes. All that's required is a backyard telescope and patience.

See photo HERE of simulated lunar Lyrid impacts.

Want to try? Train your telescope on the dark side of the Moon; Lyrids will be raining down on the northern third of the visible disk. Watch for point-like flashes. They are fleeting and easy to miss. Better yet, let a video camera do the work for you. Brian Cudnik, who coordinates amateur observations of lunar impacts for the Association of Lunar and Planetary Observers, explains how.

SUN SERPENT: Yesterday, astrophotographer Gary Palmer of Los Angeles, California, claims to have spotted the Loch Ness Monster--on the Sun. You decide:

Click HERE for photo!

This fluffy solar filament does indeed resemble a sea serpent. In a few days, though, it'll look like something utterly different. The sun's rotation is carrying the filament toward the sun's limb. Soon, it will hang out over the edge, blazing bright against the black space beyond, transforming a dark serpent into a hot glowing ... what? Stay tuned!

SOLAR ACTIVITY: Things are heating up on the sun. The growth of sunspot group 865 continues; it now stretches more than 10 Earth diameters from end to end. The spot has a twisted and possibly unstable magnetic field that harbors energy for M-class solar flares.

Meanwhile, flame-shaped prominences are dancing around the sun's limb, as shown in this six-hour movie recorded by amateur astronomer Andrew Chatman of Pittsford, New York:

CLICK HERE FOR PHOTO.

Although they look like flames, prominences are not fire. They are enormous clouds of gas held aloft by solar magnetic force fields. The best way to see them is through H-alpha telescopes tuned to the red glow of solar hydrogen.