In a six-month stretch during which one comet unexpectedly went poof and a second miraculously survived a solar swingby, it's nice to know that Comet Garradd (C/2009 P1) has continued its leisurely swing through the inner solar system.

Perihelion came and went on December 23rd at a point 1½ astronomical units (145 million miles) from Sun and far above the planetary plane. But in the weeks since, owing to its high orbital inclination, the comet has moved closer to Earth. It's remained reasonably bright, somewhere near 7th magnitude, which makes it an inviting target for binocular and small-telescope users.

Back in November, Comet Garradd made a sharp turn and headed up through Hercules. A few days ago, it slipped less than 1° to the west of the superb globular cluster Messier 92 in Hercules — a close encounter that didn't go unnoticed by astrophotographers.

The view above, captured by Rolando Ligustri using a remotely operated telescope in New Mexico, captures the pairing beautifully. The comet's faintly blue gas tail extends about 2° toward upper right, while a more compact dust tail points toward the cluster. Ligustri recommends that you download the full-size image "to appreciate the details of M92 and the incredible number of small galaxies in the image."

Few of us have access to remote-controlled telescopes under pitch-dark skies, so what For the next week or so, a nearly full Moon is going to subdue Comet Garradd's luster. But after that the prospects couldn't be better for northern observers. It's picking up steam as it heads even farther north and becomes circumpolar for those in the U.S., Europe, and at comparable latitudes.

Use the chart above (and the larger versions here) to find it high in the eastern sky before dawn. In mid-February it passes near the head of Draco and continues along the arc of stars marking the Dragon's back. Throughout all of this, the visitor should remain near 7th magnitude — hardly naked-eye bright, but then again something you should be able to pick up even with modest optical aid.

By early March, when Comet Garradd comes closest to Earth, it'll be poised over the Big Dipper's bowl and perched well above the horizon as soon as the evening sky gets good and dark. Will we still be enjoying good views of it a month from now? Check back here in a few weeks for an update! In the meantime, feel free to share your impressions of its appearance in the comments section below.

Georgia amateur Tim Puckett has a knack for spotting supernovae. But his latest find, SN 2012A in the irregular galaxy NCG 3239, is something special.

For one thing, word of the discovery came on January 9th, while Puckett was attending the 219th meeting of the American Astronomical Society. There colleagues and professionals immediately helped confirm and announce it. (It's currently about magnitude 13.4 and seems to be holding steady near maximum; recent magnitude estimates.)

Even better, a day later Puckett was awarded the Society's 2012 Chambliss Amateur Achievement Award. AAS president Debra Elmegreen made the announcement at the meeting and read the award citation: "To Tim Puckett for his Puckett Observatory World Supernova Search program that has discovered more than 200 supernovae".

His dedicated hunt for exploding stars began in 1998. Back then, Puckett mostly worked alone, using his custom built 60-cm Ritchey-Chrétien and 50-cm folded reflectors. Recently he was forced to close his observatory for personal reasons. But the popularity of his program has grown: it now comprises 20 amateurs who use four dedicated telescopes (the largest an amateur-built 24-inch) to record candidate galaxies and volunteers in five countries to analyze the resulting images.

Puckett built his first telescopes in the 1980s using machining skills learned from George Roberts, a retired naval engineer. He started out looking for comets but chanced upon SN 1994I by accident. Finding a supernova was exciting, but studying comets remained the priority. Puckett was even planning a project with famed planetary scientist Eugene Shoemaker.

But Shoemaker's untimely death in 1997, coupled with the advent of the LINEAR automated search for comets and near-Earth asteroids, changed the game. "At that point I was pretty disgusted and sad too," Puckett recalls. "With LINEAR, your chances of success were pretty slim." So he decided to focus instead on discovering supernovae, collaborating occasionally with amateur Alex Langoussis.

Puckett now treats the search like a second job. He works full time for Apogee Imaging Systems, but when time permits he shuttles around the country to attend conventions, scans his team's observations, and recruits volunteers. "Most of the time, I live out of a suitcase," he says.

All those supernova discoveries have earned him a reputation for credibility among amateurs and professionals. "The only thing that ever got us was a luminous blue variable," explains Puckett. "But we've made no other mistakes in reporting supernovae."

Puckett now hopes his Chambliss award, along with the buzz surrounding the discovery of SN 2012A, will encourage young amateurs around the world, especially high school students, to join the search. Most ambitiously, he'd like to take advantage of the growing popularity of citizen-science projects. "It will be nice to start something like Galaxy Zoo to scan for supernovae," Puckett says. He's also looking for a programmer who can help automate the searches. (Interested? Then contact him directly.)

As twilight deepened after sunset last Sunday, I was greeted with a darkening sky of jaw-dropping clarity. You know how it is — when the winter stars seem so bright and close that you can't take your eyes off them.

As it turns out, that was Day Two of this year's Globe at Night (GaN) campaign. Each year since 2006, amateur skywatchers around the world have taken stock of how dark their skies are by eyeballing the stars of Orion and comparing what they see with simple star charts. The resulting magnitude estimates provide a snapshot of how dark the night sky looks from backyards around the world.

Globe at Night is like an annual light-pollution checkup. I've been a dedicated participant in this effort, because I'm committed to keeping my observing site as dark as possible. In years past I've strained and squinted to glimpse every last star possible in the Orion region. I'm luckier than most: usually my backyard boasts a fairly dark limiting magnitude — my very best night ever was 5.4.

Sunday night was windy and bitterly cold, a climatic combo that seems to go hand in hand with pristine winter skies ("Why can't it be this clear in September?" I mutter to no one in particular.) So instead of gauging the stars by eye, I whipped out my Sky Quality Meter, a nifty hand-held gizmo that gives an instantaneous reading. It gave a reading of 19.38 magnitudes per square arcsecond, which corresponds to a limiting magnitude of 5.1. Nice!

Last year, Globe at Night's "citizen scientists" tallied 14,249 measurements from 115 countries. This year's effort, with a goal of at least 15,000 reports, has four observing windows: January 14-23, February 12-21, March 13-22, and April 11-20. "For the January through March campaigns, we will use the constellation of Orion," explains Connie Walker, who coordinates the program. "For the April campaign, we are going to use the constellation of Leo in the northern hemisphere and Crux in the southern hemisphere."

So what about you? Haven't you wondered how dark your sky is — and how many stars you've lost to light pollution? Joining Globe at Night is easy — no prior stargazing experience is necessary! Just download the comparison charts (for Orion, Leo, or Crux). spend at least 10 minutes out in the darkness (so your eyes can adapt), make your estimate, then report the results.

That's it! In less than a half hour, you'll not only know your backyard's rating but also have contributed to a global campaign to save the night sky. Won't you join me in this noble effort?

The first near-Earth asteroid to be discovered was 433 Eros in 1898. It made history then, in part by enabling the best determination of the astronomical unit and hence the scale of the solar system.

It made history again in 2000 and 2001, when NASA’s NEAR-Shoemaker probe took up orbit around it and then descended to its dusty surface. Eros is the second-largest near-Earth asteroid, after 1036 Ganymed, measuring 21 × 7 × 7 miles (34 × 11 × 11 km).

And now you have an opportunity to view this celebrated object telescopically, as it makes a swing past the Earth this month and next. This is Eros’s closest approach since the much-observed one in January 1975, when it reached magnitude 7.0, and it'll be its last close pass until January 2056.

Click here to download finder charts showing its path southward across Leo, Sextans, and Hydra as it brightens from magnitude 9.2 on January 12th to 8.8 on the 18th and then 8.6 from January 25th to February 13th. It fades back to 9.0 by February 25th. Eros passes its closest to Earth on January 31st, but even then it’s not very close as near-Earth asteroids go: 0.18 a.u., or 70 times the Moon’s distance.

On the charts, the ticks mark its position at 0:00 Universal Time on the indicated dates. This falls on the evening of the previous date in the time zones of the Americas. Interpolate to put a pencil dot on the track for when you plan to look. Stars are plotted to magnitude 9.0. In late January and early February Eros will be creeping along by almost 3′ per hour, so you can see its motion during an evening.

Updates:

• Amateurs and students can use position measurements of Eros to (re)compute the length of the astronomical unit. Read more and join the project .

• From Italy, Gianluca Masi at Bellatrix Observatory writes, "at the Virtual Telescope we will offer a live online observing session" of Eros's passage, in exchange for a 1-euro donation, starting at 0:00 February 2nd UT.

Update January 27: The supernova, now dubbed SN 2012A, seems to have reached a maximum brightness of about magnitude 13.4, which should be visible through moderate-sized amateur telescopes once the Moon is out of the way. See the Bright Supernova website for more information. The explosion has been classified as a Type II supernova, caused by the core collapse of a massive star. Also, in recognition of his long-running search for supernovae, the American Astronomical Society has given Puckett its 2012 Chambliss Amateur Achievement Award. See Shweta Krishnan's story here.

Here in Austin, Texas, attendees at the American Astronomical Society meeting are buzzing about the discovery of a possible supernova in the irregular galaxy NGC 3239 by amateurs Bob Moore, Jack Newton, and Tim Puckett.

The supernova showed up in this unfiltered CCD image that the trio took during an automated observing run on January 7th with a 16-inch (40-cm) reflector in Portal, Arizona. At that time the putative supernova was at magnitude 14.6; Puckett confirmed it at 14.4 the next day with the same scope. The most recent value is 13.9, and it might continue to brighten before the explosion reaches its peak.

Several professional astronomers at the meeting have already started putting out e-mails and calls for spectroscopic observations. They hope to catch the supernova early and gain important information about what kind of explosion it is and, perhaps, what its progenitor was. Nothing shows up at this position in images taken by Puckett two weeks ago — at least, nothing brighter than magnitude 19.

For now, the object’s designation is PSN J10250739+1709146. There's more info at the International Astronomical Union’s Central Bureau for Astronomical Telegrams.

NGC 3239 is roughly 30 million light-years away (estimates vary), in the constellation Leo. Puckett notes the object's position as 24.65 arcseconds east and 16.1 arcseconds south of the galaxy's center. You also can get a sense of the object's location in this image by Australian amateur Joseph Brimacombe.

By the way, Puckett's supernova search, begun in the 1990s, involves amateurs in several countries and has more than 200 discoveries to its credit.

Have you ever seen a single Quadrantid meteor? Astronomy guidebooks say the Quads are one of the richest annual meteor showers, with peak rates of 60 to 200 visible per hour under ideal conditions. But many lifelong skywatchers have never seen a single one.

The Quads have two problems. First, the shower is brief. Peak activity usually lasts just a few hours, and if the peak doesn’t fall between midnight and dawn for your part of the world, you lose out. The duration of the peak (when meteor rates are at least half the maximum) is variously quoted as 2 to 4 hours or 14 hours. The strength of the shower seems to vary from year to year, but perhaps less than the sometimes spotty observations suggest. Clearly the Quads could use more study.

The second problem is that you’re watching in the night’s coldest hours, in the year’s coldest time, under a wide-open clear sky that will also expose you to maximum radiational cooling. On top of that, if you’re lying motionless in a reclining chair or on the ground (or the snow), you’re not going to be generating much body heat.

So make it an adventure! This year the morning of January 4th offers very good circumstances for North Americans, especially in the East. The Quadrantids are predicted to peak around 7h or 8h Universal Time, which is 2 or 3 a.m. Eastern Standard Time. The waxing gibbous Moon sets about 3 a.m. local time wherever you are, leaving the sky fully dark until dawn begins around 5:30 or 6.

Plan a proper expedition. You want to be snug in many layers from head to feet with no pinches or thin spots. An electric hot pad buttoned inside your coat will help, with a long extension cord back to the house.

Meteor watching is especially fun if you take notes to make a proper count using standardized methods for reporting to the International Meteor Organization. (Read how.) If you use a voice recorder for notes, practice beforehand so you can work it in the dark with mittened hands. Batteries fail in the cold, but a pencil and clipboard won’t. Your mittened pencil notes don’t need to be pretty, just clear enough to read the next day. And be sure you can get to your watch and read it to mark off time intervals every half hour or so for separate counts.

The shower’s radiant (its apparent perspective point of origin) is in the antique constellation Quadrans Muralis about halfway from the end of the big Dipper’s handle to the head of Draco, as shown above. It’s reasonably well up in the northeast after about 1 a.m. local time and keeps rising higher until dawn. The higher a shower’s radiant, the more meteors appear all over the sky. Watch whatever part of your sky is darkest, probably straight up.

The meteors that arrive late in this shower tend to be brighter than the early ones. Minor activity has been reported as much as a week before and after the peak date; this needs to be monitored too.

Like the Geminid meteors of mid-December, the Quadrantids originate from an asteroid, not a comet. The asteroid is known as 2003 EH₁. Dynamical studies suggest that it may be a dead chunk of a comet that broke apart several centuries ago, and that the meteors are small bits of debris from this fragmentation.

The constellation Quadrans Muralis, the Mural Quadrant (an old naked-eye device for measuring positions of celestial objects) was added to the sky by the French astronomer Jérôme Lalande in 1795. Quadrans was still widely recognized when the meteor shower was identified in 1825, but it didn't make the cut when the International Astronomical Union created today's official list of 88 constellations and their borders in 1930. (Here are 49 other also-rans, from the Scepter of Brandenberg to Hirudo the Leech.)

After the Quads come and go, there won't be another good meteor shower until the Lyrids arrive in late April. Check out our list and description of all the major meteor showers of 2012.

As 2011 draws to a close, a comet that hadn't even been discovered a month ago is emerging as the celestial sensation of the year. NASA's Kepler spacecraft might be redefining how we view extrasolar planets, but Comet Lovejoy (C/2011 W3) likewise has forever altered our notion of what happens to comets as they near the Sun.

This 11th-hour interloper not only survived its December 16th perihelion (a scorching 116,000 miles from the Sun's surface), but in the days afterward it also held together and reformed its dust and gas tails. Armchair astronomers around the world watched anxiously as the comet distanced itself from the Sun in image sequences taken by orbiting spacecraft. And for those lucky enough to live deep in the Southern Hemisphere, viewing vicariously was soon no longer necessary.

Barely a day after perihelion, discoverer Terri Lovejoy managed to snap images of his namesake in daylight, when he estimated its brightness at roughly -1 in magnitude. Its brightness has fallen off somewhat in the days since, to perhaps 4th magnitude, but many observers now report being able to see Comet Lovejoy with unaided eyes in the predawn sky, its tails stretching upward into Scorpius. As of this morning the comet's nucleus was about 17° from the Sun, an elongation that will grow rapidly to 24° by Christmas Day and 40° by New Year's Eve.

"At long last the skies are clear in the Canberra region," reported Australian observer Dave Herald earlier today. "The nucleus for Lovejoy doesn’t rise for another half hour. But already the tail is visible to the naked eye, extending a full 10° above the horizon. The surface brightness is similar to the Magellanic clouds — even though they are higher in the sky."

Watching and photographing the comet from New Zealand's North Island, Ian "Coops" Cooper noted, "We always knew that this would be the day. Once the coma cleared the brighter part of astronomical twilight, we were in with a grin. Tail now out to 18°!" — and here is his proof!

Meanwhile, members of Brazil's Grupo Nevoeiro astronomy club scrambled to find a dark-sky site outside the city of Curitiba. Fernando Lopes managed to capture several images in the growing twilight that revealed Comet Lovejoy's thin gas tail. "Wonderful show — unforgettable moment," he exults.

In fact, the comet has now been viewed by observers with arguably the best-possible vantage: the International Space Station. Yesterday, ISS commander Dan Burbank captured a view of the comet rising from the color predawn twilight and airglow hugging Earth's limb. He posted a quick view of his snapshot via Twitpic, and within the hour NASA has released the full-resolution view. What a sight!

All the excitement over Comet Lovejoy has almost — but not quite — caused me to forget that we northern skywatchers are once again relegated to the sidelines by a wonderful "broom star" gracing southern skies. It's been five years, but I'm still grouchy that I didn't get to view Comet McNaught, C/2006 P1, in all its feathery glory. (So too is my science-writing colleague Daniel Fischer, who's still steamed that NASA managers didn't send the Space Station crew a head's up about that gorgeous cosmic visitor.)

Well, I can always dream: Seiichi Yoshida's list of future visual comets hints that one of PanSTARRS's comets, C/2011 L4, could conceivably blaze to magnitude 0 when it peaks in mid-March 2013. For those who care, that's just 448 days from now!

The year's two best meteor showers, the Perseids in mid-August and the Geminids in mid-December, always share the sky with the Moon in similar ways. Each year the Geminid peak comes just four days later in the lunar cycle than the peak of the Perseids. So if the sky is dark and moonless for one shower, it's usually that way for the other.

Or the reverse. This year the Perseids were largely wiped out by the light of the full Moon. So a waning gibbous Moon will also compromise the Geminid shower when it peaks on the nights of December 13-14 and 14-15. The Moon rises in early to mid-evening on those nights, before the shower's radiant rises high and meteor activity picks up, and it blazes brightly for the rest of the night.

Even so, you might still spot a few bright Geminids through the skyglow. If you see one of these "shooting stars," trace its path backward across the sky. If it was a Geminid, then this line, extended far enough, will pass Castor and Pollux in the constellation Gemini — well up in the eastern sky by mid- to late evening, and high overhead around 2 a.m.

During a meteor shower, Earth is crossing paths with a comet and plowing through a broad ribbon of particles shed all along its orbit. In the case of the Geminids, the comet is an object called Phaethon. Phaethon is classified as an asteroid (number 3200), but it's basically an extinct comet that has been heated by the Sun so many times that it's run out of gas. The particles that Phaethon spewed into space are still hanging around — and every year, in mid-December, we plow right through them.

By the way, you can learn more about the Geminids, along with other heavenly highlights for the coming week, by watching SkyWeek, S&T's great new weekly roundup.

This year's astronomical calendar included a total lunar eclipse on December 10th — and, given that another wouldn't occur until April 2014, observers were more determined than usual to see it.

The geometry wasn't very favorable for North America: everyone east of a line from Arizona to Hudson Bay missed out, and those in the west needed to get up before dawn. But the event was nicely placed in an evening sky for all of Asia, Australia, and the Pacific — and reports received by Sky & Telescope suggest that most observers in those regions (with the exception of southeast Asia) got to see it.

John Beyrau had a good view from Helena, Montana, where the predawn temperature had plunged to 1°F. "There was a slight ice fog in the area, which caused some light scattering," notes the self-described Curmudgeon of the Wild Frontier. "Such fogs are common in the Helena Valley when the temp gets down to 10° or less at this time of year."

Other observes had no such worries. "I saw last night's [eclipse] from Wailea Beach, Maui, under warm and relaxed conditions," reports German eclipse-chaser Jörg Schoppmeyer, who also witnessed last month's partial solar eclipse from South Africa. "The eclipse was a bright one; all parts in the umbra were easily visible at all time." (I'd sure like to have Schoppy's travel budget!)

The eclipse was "a welcome sight in Sydney," comments Aussie Sharon Grey, "not least given the unexpectedly clear skies for a few hours in an otherwise unremittingly sodden stretch of recent weather." But thunder and lightning rolled in at mid-totality farther south in Melbourne. "No eclipse visible at all," laments Alex Scutt. "Disappointing — though we did have success in June with a very deep early morning lunar eclipse."

Meanwhile, an international group of solar eclipse-chasers had gathered in India for a conference, timed in part to catch Saturday's celestial act. From a mountain camp near Ranikhet, Daniel Fischer, one of the attendees, had a great view. "Despite a little haze even at 1,800 m altitude, the stars and Milky Way around the eclipsed Moon were a sight to behold."

I would have missed this eclipse entirely from my home in Boston, but as luck had it I was visiting family and friends in the Los Angeles area this weekend. Although clear skies were forecast, things didn't bode well Friday evening when I looked up to find a beautiful, yet disquieting 22° halo surrounded the nigh-full Moon.

Fortunately, all that cirrus had moved on by dawn, and we gathered outside in time to catch the last bit of lunar limb slip into umbral shadow. At second contact the Moon was just 8° above the horizon, and I'd wondered whether totality would render it too dim to make out in the gathering light. Instead, it glowed pleasantly in the sky like a coppery coin, framed by the horns of Taurus above and by distant trees below.

The color and brightness were influenced by the Moon's far-southern path through Earth's umbra. This rendered the cratered southern highlands brighter than the already-dark maria that dominate the lunar disk's northern half. Also, it's been a while since large amounts of volcanic ash have erupted, so Earth's high-altitude atmosphere is relatively clear.

How about you? Were you able to see the eclipse? Post a comment below, and you can share any photos you recorded with other S&T.com viewers by adding them to our online photo gallery.

Coming up: May 20th's annular eclipse of the Sun, which will be visible along a track from Southeast Asia and Japan to the Far West states.

Update: See the latest SOHO images and movies of Comet Lovejoy's death plunge toward the Sun. It seems to be the brightest sungrazing comet that SOHO has ever seen.

If you want immortality as an amateur astronomer, there's no better way than to discover a comet — which then will be named after you. You can improve your standing by finding more than one such interloper. Even better would be to make sure one of your comets goes out in a blaze of glory after making a kamikaze plunge toward the Sun. And to really top the charts, be the only amateur ever to discover comets with telescopes on the ground and in space.

Such a person actually exists.

On November 27th (Universal Time), Terry Lovejoy was patrolling the southern sky from his observatory in Thornlands, a suburb of Brisbane, Australia, when his CCD camera snapped up a 13th-magnitude smudge gliding eastward through Centaurus. "It was the first comet I have found with my new equipment setup," Lovejoy relates in an online posting. "I now use a C8 Schmidt-Cassegrain scope working at f/2.1 with a QHY9 CCD camera. This gives me a field of view of a 4.5 square degrees."

The discovery images were buried among 600 images of 200 fields he'd recorded that morning. "On one set of images I noticed a rapidly moving fuzzy object," he recounts. "As I was unsure this was real, I noted the positions and wrote a brief comment 'Possible reflection' before proceeding to search more images." He recorded the mystery object again on the 29th. Still there — and obviously not a reflection. On December 2nd the IAU's Minor Planet Center made it official: Lovejoy had bagged his third comet, designated C/2011 W3.

This discovery comes 4½ years after the Aussie amateur's second and third finds, C/2007 E2 and C/2007 K5, which turned up on images he'd taken with a 200-mm lens. His first, C/1999 O1, doesn't bear his name but rather that of SOHO — the Solar and Heliospheric Obsevatory — because Lovejoy spotted the object passing near the Sun in SOHO's images.

What's got folks buzzing about the most recent Comet Lovejoy isn't how bright it is: a 13th-magnitude comet won't raise many eyebrows. Instead, observers are fixated on where it's headed in the days ahead. Perihelion will come on December 16th at a point just 0.005652 astronomical unit from the Sun's center, that is, a mere 116,000 miles (186,200 km) from the searing solar surface.

C/2011 W3 is what's known as a Kreutz sungrazer, named after the German astronomer who proved that they are all pieces of a much larger comet that broke up centuries ago. SOHO has recorded 1,100 comets passing near the Sun, a large fraction of which were sungrazers. But Lovejoy's find is the first discovery of a sungrazer from the ground since 1970! (For you numerologists, the MPC's discovery announcement came 16 years to the day after SOHO's launch on December 2, 1995 — an interesting coincidence.)

So what will happen to Comet Lovejoy over the next two weeks? For one thing, it's going to brighten a lot — but by how much? "Cometary brightness predictions are fraught with massive uncertainties," warns Timothy Spahr, the MPC's director. Still, there's a friendly little online competition among comet cognoscenti to predict the peak magnitude. The smart money is lining up for something between -2 and -4, by which time the comet will be much too close to the Sun to be seen visually.

But SOHO has no such problem with solar glare. The comet's trajectory should put it within view of the spacecraft's wide-angle (C3) coronograph on the 14th and its narrow-angle (C2) counterpart late on the 15th. It might first appear in the HI1 camera of STEREO-A, another orbiting sentinel, as early as the 12th.

Of course, all this speculation presumes that the comet actually survives to perihelion. Right now it's about 11th magnitude, putting it within telescopic range of far-southern visual observers. "C/2011 W3 appears to be only modestly condensed, at best, [and it lacks] any obvious stellar nucleus, even a very faint one," notes comet maven John Bortle. "In my mind this does not bode particularly well for this diminutive object."

We'll all find out soon enough. Comet Lovejoy won't likely match the amazing performance by Comet Ikeya-Seki in 1965, arguably the greatest sungrazer of the past century. But Bortle cautions, "Let's all keep in mind that C/2011 W3 is no more than a tiny cometary shard and apparently some 7 full magnitudes (!) fainter than Ikeya-Seki was intrinsically."

I suspect Terry Lovejoy would be thrilled just to see his namesake survive perihelion. In fact, I suspect he'll be thrilled regardless of its fate.

Last night was a special one here in Boston: crystalline skies, decent seeing, comfortably cool weather, and no wind. Taking advantage of all this, I homed in on Comet Garradd (C/2009 P1) with the exquisite 25-inch telescope at the Clay Center Observatory.

Despite interference from modest suburban light pollution and a first-quarter Moon, I had high expectations as I climbed to the eyepiece. Observers have been reporting that Comet Garradd is roughly 6½ magnitude, suggesting easy viewing even in binoculars or a small telescope. A recent image taken by Austrian astrophotographer Michael Jäger (shown here) shows that the comet now sports a strongly condensed coma, broad dust tail, and pencil-thin gas tail.

But the comet was not the boffo performer I’d hoped to see. It was certainly obvious through the 25-inch. I could see the dust tail’s extension away from its well-condensed nucleus. But the gas tail was a no-show, and I only barely glimpsed the comet at all in a piggybacked 7-inch f/9 refractor. Sadly, the light pollution and moonlight had taken a toll.

When observers report that a comet (or a nebula or a galaxy) is, say, 7th magnitude, they typically mean that the light from the entire object, if concentrated in a single point, would be as bright as a 7th-magnitude star. The more diffuse, or spread out, the light is, the more difficult the object will be to see — especially in a less-than-pitch-black sky.

So for those of you wishing to view Comet Garradd, try to do it when the Moon isn’t in the way. Fortunately, the comet has started moving northward through Hercules (where it’s resided since mid-September), and will soon be just as easy to see in the morning sky before dawn. As my S&T colleagues Alan MacRobert and Tony Flanders mentioned a few months ago, the best observing opportunities will tip in favor of predawn viewing in mid-December. But that’s also when the nearly full Moon shows up. So pick your times carefully.

The good news is that Comet Garradd will be around for several more months, and you can click here for a full-page, downloadable finder chart. The comet reaches perihelion on December 23rd, at a point 1.55 astronomical units (145 million miles) from the Sun — but this icy visitor won’t likely be at its best until February, when its estimated total magnitude should be at or slightly better than 6.0. In late January, Comet Garradd cruises along the east side of the Keystone in Hercules, and on the morning of February 3rd it’s just ½° from the globular cluster M92.

By the way, our online gallery contains lots of nice images taken by many talented amateurs. And Gary Kronk’s “Cometography” website has a great summary about the comet’s discovery (by Gordon Garradd more than two years ago) and its development since then.

Three partial solar eclipses happened during 2011, and the third act of this celestial trifecta occurred earlier today. Many of us associate solar eclipses with a blacking-out of the Sun, and so perhaps fittingly today's event fell on what's known as "Black Friday" in the United States. — so-called because businesses often ring up enough pre-holiday sales to put them "in the black," profit-wise, for the year.

In any case, no one in the U.S. saw the Moon take a bite of the Sun today, and in fact few people anywhere could see it. The path began well south of Africa, and from Cape Town the Moon's indentation on the Sun's disk was barely noticeable. Mid-eclipse occurred at 6:10 UT, at which time all of Antarctica was experiencing a partial event that covered 40% to 90% of the Sun's diameter (78% at the South Pole), depending on location. Observers in Tasmania and southernmost New Zealand also got a peek just before sunset.

Skies were generally clear at both ends of the track. Jörg "Schoppy" Schoppmeyer recorded nice views of the slightly dented Sun just after sunrise from his location in Cape Town.

Astronomer Jay Pasachoff (Williams College) observed with a small group from Invercargill, New Zealand, where the Moon's encroachment was a more substantial 30%. "About 5 minutes before the peak, the sky cleared," he reports, "and we saw the eclipsed Sun clearly, with clouds occasionally drifting by, for about 15 minutes." Later the Sun sunk into a low cloud bank. "After an in-and-out, off-and-on-rain day, we are very pleased," Pasachoff adds.

The weather wasn't as cooperative at at McMurdo Station on Antarctica. "The temperature is around 15°F, windy, and snowy," writes astronomer Chris Walker (University of Arizona). "Sounds like Thanksgiving weather all right — but wait: it's summer here!"

Clear skies prevailed at the South Pole, where a few of the researchers and support personnel ventured outside for a look at the eclipsed Sun. One was Kiell Kosberg, who had big plans for the event. "You should have seen my bag," she writes on her blog. "I looked like a one-woman band getting ready for a performance. A welding mask, blank CDs, hand warmers, aluminized mylar squares, a cup of coffee and a sieve borrowed from the kitchen. We went out to the ceremonial pole, cameras in hand."

This solar eclipse, occurring as it must at new Moon, is a warmup for a total lunar eclipse on tap for the full-Moon night of December 10th. That event, the Moon's last complete immersion until 2014, will be seen best from Australia, eastern Asia, and western North America.

If you're anywhere in central or western North America, mark your calendar to get up early on Saturday, December 10th. That morning the full Moon goes through its last total eclipse until 2014. (If you're on the East Coast or in Europe, you can sleep in that day.)

As the map shows, the farther west you are in the Americas, the better your prospects. From the Pacific time zone you can watch the Moon slip into Earth's shadow completely, while the Moon is sinking low in the west-northwest. In the Northwest you can even see the Moon start to emerge from our planet's shadow before moonset and sunrise end the show.

From roughly Arizona to the Dakotas, the Moon sets while still totally eclipsed — though horizon obstructions and the brightening dawn might end your view somewhat before then. In the Central time zone the Moon sets while still only partially eclipsed. Those farther east miss out completely.

Observers in the Pacific, Australia, and East Asia have it better. Seen from there, the whole eclipse happens high in a dark sky from start to finish. For Europe and Africa, the eclipsed Moon will be lower in the east during or after dusk on the evening of the 10th.

December 10th's Total Lunar Eclipse
Event	UT	CST	MST	PST
Penumbra first visible?	12:05	6:05 a.m.	5:05 a.m.	4:05 a.m.
Partial eclipse begins	12:45	6:45 a.m.	5:45 a.m.	4:45 a.m.
Total eclipse begins	14:05	—	7:05 a.m.	6:05 a.m.
Mid-eclipse	14:32	—	7:32 a.m.	6:32 a.m.
Total eclipse ends	14:57	—	7:57 a.m.	6:57 a.m.
Partial eclipse ends	16:18	—	—	—

When the Moon is totally eclipsed, it glows eerily orange, red, or dark bloody brown. Although the Moon is completely inside Earth's shadow at that time, it's still dimly lit by sunlight that skims the edge of Earth and is refracted into Earth's shadow by the atmosphere. What you're seeing on the Moon's face is light from all the world's sunsets and sunrises at the time that you're looking. How bright or dark an eclipsed Moon appears depends on the amount of cloudiness along Earth's sunrise-sunset rim and, especially, the amount of dust high in the upper air.

For this eclipse the Moon barely skims inside the southern edge of Earth's umbra, as shown at right. So we can expect the Moon's southern rim to remain brighter than the rest — creating a lovely 3-D effect and drama for photographers. To get a good image scale, use a wide-field telescope or a long telephoto lens.

Gorgeous photo of a similar dawn eclipse.

Cloudy? The next eclipse of the Moon will be only partial, happening before and during dawn next June 4th and visible from most of North America except the Northeast.

The next total lunar eclipse doesn't come until the night of April 14-15, 2014. But then the Moon will be high in a dark sky all across the Americas.

NEWS MEDIA: See our press release with graphics.

Five Observing Projects!

• Roger Sinnott continues to collect amateurs' crater timings — telescopic timings of when the umbra's edge crosses lunar craters — as part of a decades-long project tracking slight unpredictability in the umbra's diameter. Click here for crater maps, instructions, and where to report your timings.

• John Westfall seeks naked-eye timings of the eclipse contacts (when the partial phase begins and ends before and after totality) to help calibrate the historical timings made by mariners and others when this was one of the few ways to determine longitude at sea. Use the instructions here.

• Determine the magnitude of the fully eclipsed Moon (if it's in a dark sky at your location) using the reversed-binocular method, and report your result to Richard Keen of the University of Colorado.

• Estimate this eclipse's Danjon number (the traditional measure of a lunar eclipse's brightness or darkness) and report it to Richard Keen of the University of Colorado, to provide continuity with the Danjon numbers of eclipses running back many decades.

• International Measure the Moon Night "will offer a rare opportunity for students, teachers, and the general public to measure the Moon's distance and size duplicating the same techniques -- with a Digital Age twist -- used by Greek astronomers thousands of years ago."

Update: The flyby of asteroid 2005 YU55 generated a lot of interest among the news media and general public. Click here for details.

Roll out the red carpet! Earth is about to be visited by the largest close-approaching asteroid on record. Known as 2005 YU₅₅, it comes closest to us on November 8th at 23:28 Universal Time (6:28 p.m. EST), when it passes 198,000 miles (319,000 km) from Earth's surface — closer than the Moon's orbit. It will be visible from the Americas and Europe through much of the night.

Discovered nearly six years ago by Robert McMillan at Steward Observatory's Spacewatch Telescope in Arizona, 2005 YU₅₅ has been this way before. In April 2010 it passed close enough for detailed radar probing by the giant radio dish at Arecibo, Puerto Rico.

The Arecibo observations showed this asteroidal emissary to be a quarter mile (400 meters) across and remarkably round. Given its size and dimness, its surface must be quite dark and thus likely carbon-rich. Its rotation period is relatively long, 18 to 20 hours.

In the grand scheme of things it's more micro-planet than minor planet, but we've never knowingly had something this big come this close before. Were it to strike Earth, 2005 YU₅₅ would deliver a kinetic-energy punch equivalent to several thousand megatons of TNT. It's the kind of potential threat that outer-space sentries lose sleep over.

But fear not: the Arecibo observations allowed dynamicists to recompute the big rock's orbit with enough accuracy to ensure that it won't strike Earth within the next 100 years. (That said, it will pass just 175,000 miles from Venus in 2029, close enough to alter its orbit slightly. This adds uncertainty to predictions for its next close encounter with Earth in 2041, when the minimum distance could be anywhere from 200,000 to 30 million miles.)

So we might as well just enjoy this month's show. The asteroid will approach Earth from the sunward direction, so it will be a daylight object until just before the time of closest approach. A few hours later 2005 YU₅₅ should reach a visual magnitude of 11.1, within reach of backyard telescopes with apertures of at least 6 inches under fairly dark skies — though you'll be fighting light from the nearly full Moon. (By the way, that bright thing near the Moon tonight is Jupiter.)

The pass's track is especially favorable for western Europe and North America. But you'll need to know exactly where to look at exactly what time: the object will traverse the 70° of sky eastward from Aquila to central Pegasus in just 10 hours, clipping along at 7 arcseconds per second. Use the chart here to get a sense of what part of the sky it's in, then download our detailed finder chart for use between 9 and 10 p.m. November 8th Eastern Standard Time (2:00 and 3:00 November 9th Universal Time).

If you don't have a suitable scope, or if it's cloudy tonight, check out the live video webcast of asteroid 2005 YU55 from the 25-inch telescope at Clay Center Observatory in Massachuetts (continuously from about 6 p.m. to 3 a.m. EST). Another live webcast is available from Bellatrix Astronomical Observatory in Italy.

Amateur asteroid sleuths Brian Warner and Robert Stephens have mounted a campaign to obtain detailed photometry (brightness measurements) of the asteroid. You'll need at least a 10- or 12-inch scope, a CCD camera, and ideally one or more of the standard photometric filters commonly used by professional astronomers. Details.

Meanwhile, this visit by 2005 YU₅₅ is providing an unprecedented opportunity for high-reolution radar study. Astronomers have lined up extensive radar campaigns with Arecibo and with NASA's Goldstone facility in California's Mojave Desert, using big radio dishes in West Virginia and elsewhere as receivers. "The signal-to-noise ratios will be more than 1 million for Goldstone observations on November 8–9," explains Lance Benner (Jet Propulsion Laboratory). This SNR is heady territory for radar work, high enough to yield thousands of pixels across the object and to achieve surface resolution "comparable to what can be obtained by a spacecraft flyby mission."

So I hope you all get a chance to spot 2005 YU₅₅ as it zips past Earth.

Northern skywatchers are longing for a nice, bright comet to grace their skies — the kind of celestial spectacle that Comet McNaught (C/2006 P1) put on a few years ago for those Down Under.

When discovered last December, Comet Elenin (C/2010 X1) had the potential to at least crack the naked-eye-visibility threshold. OK, it was never going to be a McNaught or Hale-Bopp, but we're getting a little desperate up here north of the equator. The prediction was that Comet Elenin's inbound course would loop around the Sun at a distance of just 0.48 astronomical unit (45 million miles) on September 10th, followed by a quick climb into predawn skies for a couple weeks of nice visibility as it passed 0.23 a.u. from Earth in mid-October.

Alas, it was not to be. About 10% of such long-period comets randomly break apart on their first visits to the inner solar system, and Comet Elenin drew the short straw. By April the icy interloper was showing signs of pooping out, and it appeared to completely self-destruct about three weeks before perihelion.

"Disintegrating comets (as opposed to splitting ones) do not survive very long after the process has been observed to begin, which in the case with Comet Elenin was all the way back in the end of August," explains John Bortle, who's tracked the passages of these icy bodies for more than 50 years. "The decline/fade of Elenin was abrupt and dramatic."

Still, diehard observers have continued to look for the disrupted object's remains, with little success. Juan José González reports spotting a faint, diffuse cloud twice, on October 9th and 21st, from the summit of Alto del Castro (5,600 feet, 1,720 m) in northern Spain. It's a sighting claim that other comet observers, many armed with deep-probing cameras, dispute.

Putting the long-running "visual vs. CCD" debate aside, there's no question that Comet Elenin is — er, was — nothing like the Earth-threatening behemoth proffered by fringy pseudoscientists earlier this year. Using a remote-operated observatory in New Mexico, observers Ernesto Guido, Giovanni Sostero, and Nick Howes managed to record a wispy cloud at the comet's predicted location on October 21st and again on the 23rd. "The 'cloud' is roughly 40 arcminutes long with an extension of 6 arcminutes near the expected position of the comet," notes the report on their website.

In the meantime, comet-starved skygazers can always look to the stars of Hercules, where you'll find Comet Garradd (C/2009 P1) coasting along. It's not going to get much brighter than 7th magnitude, but on the other hand it'll stay nearly that brightness — and in the same region of sky —through January. So download S&T's finder chart, get those binoculars out, and have a look!