Another new-Moon weekend has arrived, and that means astrophotographers will head for local hilltops in quest of the "old Moon in the young Moon's arms." The Moon is technically new when it passes the Sun at 8:18 a.m. Eastern Daylight Time on Monday, May 5th. So on Saturday morning before sunup, and on Tuesday evening after sundown, the thin crescent will be an especially inviting spectacle. And Tuesday's crescent will appear just a few degrees from Mercury.

But veteran Moon-and-planet watcher Robert C. Victor points out that this new Moon offers something quite special. Because the Moon is passing north of the Sun and is also at perigee, hence moving most rapidly along its orbit, there's a chance for North Americans to spot an ultrathin crescent Moon on Sunday morning in the east, and then again on Monday evening in the west — on consecutive days. Only a tiny handful of skilled observers have ever managed to see such "opposing crescents" before.

Clear skies and unblocked views of the horizon are crucial to success, of course. You also need to know exactly where in the sky the Moon will be, and when. Have binoculars handy — they can help! Without careful planning on your part, failure is almost guaranteed.

Victor points out that the Sun and Mercury can play important roles for skywatchers in the US and southern Canada this weekend:

(1) To prepare for glimpsing Sunday morning's crescent Moon, watch the sunrise on Saturday morning and note the time when the Sun has climbed 5° above the horizon. This tells you that on Sunday morning, some 60 minutes earlier, the Moon will also be 5° up and 1° or 2° to the right of where the Sun was.

(2) For the even-more-difficult thin crescent on Monday evening, check Mercury on Sunday evening. Follow Mercury in the western sky until its altitude has gone down to 4°. Then on Monday evening, about 50 to 55 minutes earlier, the Moon will be at almost exactly that same spot.

These rough guidelines may not be accurate enough. So Victor strongly recommends refining the times for your own location, using any planetarium software that gives the altitudes and azimuths of celestial bodies for your location.

"Folks in the East will have a very hard time seeing the young Moon on Monday evening," Victor warns. "For Boston and Miami, when the Sun is 5° down at 8:14 p.m. EDT, the Moon will be at nearly a record-young age of 11 hours 56 minutes."

For further details, check out the handy Abrams Planetarium Sky Calendar for May. My own articles in the February Sky & Telescope, page 72, and also here have more about the techniques and special conditions needed for spotting a very young Moon.

As an added inducement, this new Moon coincides with the peak of the Eta Aquarid meteor shower. So if you live south of latitude 35° N, keep an eye open for Eta Aquarids while you're preparing to look for the pre-dawn Moons on Saturday and Sunday.

Most people have never knowingly seen Mercury. That's a pity, because viewing the innermost planet is very rewarding, whether you use a telescope, binoculars, or just your unaided eyes.

The problem with Mercury is that it never strays far in the sky from the Sun, so it's usually visible only very close to the horizon in bright twilight. But people at mid-northern latitudes (the US and most of Canada, Europe, and Asia) have an extraordinarily good opportunity to view the elusive planet on evenings in May 2008. Throughout most of the month, Mercury is high above the western horizon a half hour after sunset, and it's still reasonably high even an hour after sunset, when the Sun's glow is quite subdued.

As always when it's visible in the evening, Mercury is brightest at the beginning of the apparition, fading from magnitude -0.8 on May 1st to 0.3 on May 12th. That's nearly a threefold decrease, but magnitude 0.3 is still dazzlingly bright.

Mercury fades rapidly after mid-month, making it a challenging target for the unaided eye. But this is also when the planet is at its best through a telescope, swelling in apparent diameter and thinning to a crescent as it starts to come between Earth and the Sun. Following Mercury with a telescope throughout an entire apparition is surprisingly satisfying.

Mercury makes interesting patterns with other astronomical objects on two occasions in May. From May 1–3, it passes just to the left of the Pleiades. The planet will be easy to see, but you might need binoculars to spot the Pleiades when they're so low in the sky. In any case, the cluster and the planet will fit easily in a single binocular field of view.

Then on Tuesday, May 6th, North Americans can watch Mercury make a spectacular pairing with a 1½-day-old crescent Moon. It's almost identical to the scene shown at right, except that the positions of the bodies will be reversed, with Mercury to the Moon's lower left.

Did you get to see the crescent Moon occult the Pleiades last Tuesday night? Conditions here in Boston were pretty iffy, but things worked out alright in the end.

Both the National Weather Service and the Clear Sky Chart had good forecasts, so I felt confident scheduling a little observing party in our local park with my family and a couple of friends. But thick clouds began to cover the sky at sunset, and prospects were looking grim. Fortunately, the clouds thinned out, leaving just a medium-heavy haze by the time the Moon neared the Pleiades.

Because of the haze, the cluster was completely invisible to the unaided eye, and I could see only the brightest stars through my 10×30 binoculars. But my 15×70 binoculars, 70-mm refractor, and 7-inch Dob all had enough power to show dozens of stars, so three people got to watch each occultation simultaneously. Every disappearance was greeted with little cries of delight. Overall, the 15×70 binoculars probably provided the most aesthetically satisfactory view.

Saturn and Mizar provided icing on the cake, particularly for one friend who had never seen Saturn before. Which all goes to show that even haze and heavy light pollution don't have to stop you from having a great observing experience.

If you have any stories of your own, please submit them as comments below.

The first time I knowingly saw the zodiacal light, it was so bright that I couldn't believe I'd never seen it before. I was in Chile, across the valley from the professional observatories at Cerro Pachon and Cerro Tololo. I commented to my host, the superb astrophotographer Daniel Verschatse, that the light pollution from nearby La Serena was unbelievably intense. The light in the west was washing out even the Sagittarius Milky Way, which was quite high in the sky at the time.

"Look again," said Verschatse. "That's not light pollution; it's the zodiacal light! See its tall, triangular shape? See how it leans to the right, following the ecliptic?" (In the north, the evening zodiacal light leans left, as shown at right.)

Now that I know what to look for, I see the zodiacal light quite often. I've even seen it — just barely — from my astronomy club's observing field in the outer Boston suburbs. But it's much more prominent if you're far from any artificial light pollution. It's well worth the trip.

The zodiacal light is brightest and broadest near the Sun. But the very brightest part of all can never be seen from Earth, because it's overwhelmed by the Sun's glare. So your best opportunities come right before the onset of morning twilight and after the end of evening twilight, when you can see the sky quite close to the Sun, but the Sun's light is blocked by our own planet.

And since the zodiacal light follows the ecliptic, it's easiest to see when the ecliptic runs highest in the sky near twilight, as shown at right. In the Northern Hemisphere, that happens during the evening from mid-February through mid-April, and in the morning from mid-August through mid-October. (The situation is reversed in the Southern Hemisphere, which is why I could see the zodiacal light so easily on an October evening in Chile.)

Most people prefer to view in the evening, so late winter and early spring are the ideal time. Find spot as far as possible from any artificial lights that has a low western horizon. Go there shortly after sunset on a moonless evening and watch for the zodiacal light to appear as twilight fades.

What are you seeing? The zodiacal light is the combined glow of countless tiny particles (debris from comets and asteroid collisions) that orbit the Sun. Like the dust in an unswept room, their mass is minuscule but their combined surface area is quite large, so they reflect a lot of sunlight. In fact, if it could be condensed into a single point, the zodiacal light would handily outshine all the planets, including even Venus.

As an interesting side note, Brian May, founding member of the rock group Queen, completed his doctoral dissertation on the zodiacal light in 2007, obtaining a PhD in astrophysics from Imperial College in London. He had started the thesis in 1970, but took a 35-year break to become a rock celebrity.

Have you seen the zodiacal light? Then share your impressions below with the rest of our readers.

Did you know that Venus is still visible in the morning sky? I have it on the best authority. There's a chart showing planet visibility in the middle of every issue of Sky & Telescope, and the one on page 47 of the April issue says that Venus is visible just before dawn through April 12th.

But wait a second! Things can't be as simple as that. Venus barely changes from day to day, so it can't just sit there in plain view on the 12th and disappear completely on the 13th. The transition must be subtle.

Moreover, any planet's visibility depends on your latitude, the clarity of the air, your level of experience, and the equipment that you use. Just what does this chart mean when it says Venus is visible?

As author of the chart, I can answer those questions. First of all, we're talking about visibility to the unaided eye. With a telescope, you can see all the bright planets just about any time they're above the horizon when the sky is clear — even during broad daylight.

And unless otherwise stated, all articles and diagrams in our magazine are intended to be precisely accurate for the "S&T standard location: 40° N, 90° W, 55 miles southwest of the proverbial Peoria, Illinois.

Finally, I know perfectly well that visibility isn't an either/or situation, but I have to put down some date. I have a formula based on a planet's brightness and its altitude above the horizon at the beginning or end of civil twilight that predicts when it should be visible to an experienced observer with good-to-excellent conditions. And I'm constantly tweaking this formula based on my own and other people's observations.

That's where you come in. My formula predicts that Venus should be visible very low in the east 15-20 minutes before sunrise through mid-April. Please go out, look for yourself, and report any positive or negative sightings to us. The key to a successful observation is finding a location with a completely unobstructed eastern horizon. And binoculars are extremely helpful, because Venus is bright and bold in binoculars even when it's barely visible to the unaided eye.

The morning of Friday, April 4, is a particularly good oppoprtunity, because Venus will be right next to a thin crescent Moon.

Please submit any reports as comments to this article or e-mail them to observers@SkyandTelescope.com. Include your location, the sky conditions, and the time accurate to one minute.

For instance, I went to my local park (42.1° N, 71.1° W) on the morning of Wednesday, April 2nd. The sky was clear though slightly hazy, with a few wispy clouds to the east. I found Venus in binoculars at 6:03, and it was consistently visible to the unaided eye from 6:05-6:10 — though pretty faint and subtle. I caught my last naked-eye glimpse at 6:20, just before I left, but by that time I was seeing it less than 5% of the time. It was still bright and bold in binoculars, and no doubt would have stayed that way until sunrise.

Incidentally, I was also following Jupiter, far off to the south. It was still quite obvious to the unaided eye at 6:20 — as long as I looked in exactly the right spot. I lost track of Jupiter once and spent several minutes searching for it with binoculars.

And two last questions — which you're also welcome to answer in e-mail or (better) as a comment to this article. Our planet-visibility chart is intentionally optimistic; it says when planets are likely to be visible — even if just for a few minutes — given ideal circumstances. Does this lead to unrealistic expectations? Would you prefer to know only when the planets are likely to be easy to see?

Finally, do you like the format of the planet-visibility chart? Does it tell you everything that you need to know? How would you like to see it changed, if at all?

When I posted that blog about the Sun back on Tuesday, I knew I was jinxing things. Sure enough, Tuesday afternoon was cloudy here. Wednesday brought more lousy weather, and they're calling for rain tonight. So I was shocked when I saw a brief break in the muck over Boston this morning.

Knowing a good sucker hole when I see one, I rushed to my H-alpha solar scope and peered in to see what I had missed since my last observations. Wow! First off, the spots have certainly evolved. But much more impressive than the spots (at least more impressive to me), was the appearance of a dark filament across the Sun's disk. It looked to my eye as if there was a crack on the Sun's surface. A funny idea for sure, but if I didn't know better, I might have been fooled.

My colleague Sean Walker also managed to see the scene from his home in New Hampshire. He stayed home a bit longer than usual this morning to capture the image above. According to his report, I wasn't the only one peering through holes in the clouds.

What do you guys think? Anyone else having as much fun with these spot groups as we are? Share your observations below, and feel free to submit images to the photo gallery.

Oh, and I can't forget to remind everyone to only look at the Sun with a safe solar filter. Us astronomy writers all take a blood oath to include that passage in every solar story we write.

It's so nice to have an active Sun again. Clear skies! (Or at least clearer than mine will be for the next 48 hours.)

P.S. These spots are not the start of the much-awaited next solar cycle. Their magnetic orientation (with south pole leading as the Sun rotates), and their very low latitude, peg them as last gasps of the old Solar Cycle 23. . . even though the first spot of Cycle 24 (at high latitude, with north pole leading) appeared in January. We're still in the minimum-activity period between the old and new solar cycles.

One of the things I like best about working at Sky & Telescope is that nobody thinks twice if you take 10 minutes out of your day to do a little solar observing. I presume the same is true for watching a baseball game while at Sports Illustrated.

Anyway, my office has a beautiful view of the rising Sun in the morning. And as you might expect, perched at my window is my little solar telescope. Its hydrogen-alpha filter allows me to observe the Sun at that specific wavelength. Whenever it's clear, I make sure to take a "morning coffee break" just to see what's up. To be honest, March was pretty boring. But this week has changed all that.

If you have a solar filter or another way to safely view the Sun, be sure to check out the latest group of sunspots that's popped up on the disk. The larger spot is developing and will be fun to keep tabs on over the next few days. And feel free to comment below to let us know what you think of this group.

The world's largest set of opera glasses is operational.

The Large Binocular Telescope (LBT) in Arizona achieved an important milestone in January when both of the telescope's 8.4-meter mirrors pointed toward the spiral galaxy NGC 2770. Last week the LBT folks released the images.

This critical step means we're not far from having another full-time telescopic giant producing incredible observations and scientific discoveries. And it poses the question: Is LBT the largest telescope in the world?

If you ask me, I say no. When the images are combined, the two LBT eyes have the light-collecting area of a single 11.8-meter mirror. And they ride on the same mount and always point in the same direction. But it still takes two separate primary mirrors and two separate optical systems to make the magic happen. The largest binoculars? Sure. The largest telescope? The purist in me still gives the title to the 10-meter Kecks. The 10.4-meter GranTeCan in the Canary Islands isn't quite up and running yet, but it should be soon. When that happens, in my book it will take the crown.

And I don't count Hobby-Eberly Telescope or the Southern African Large Telescope because they can't point all over the sky, and not all of the primary mirror is working at a given time.

So let's start the debate. Do you think the LBT should rank as the "world's largest largest optical telescope"? If you read their press release, that's what they're calling it.

What do you think?

Here in Sky & Telescope country — light-polluted, often-cloudy Massachusetts — the weather turned better than predicted for a change, giving all of us here a crystal-clear view of the lunar eclipse in a clean, starry, ice-cold sky.

I had a visitors at my observatory alternating between views of the slowly progressing eclipse and sights elsewhere using my 12.5-inch reflector under the unnaturally dark full-Moon sky (the Orion Nebula was a chaos of detail, the E and F stars in the Trapezium were easy, so was Rigel B, no sign of Sirius B, markings were still slightly visible on Mars).

The eclipse was a moderately bright one, with the Moon showing pastel orange and red around mid-eclipse. Early Danjon-number estimates that we're getting range from 2.5 to 3.

Roger Sinnott, our lunar-eclipse data master, used the reversed-binocular method to get a preliminary brightness estimate at mid-eclipse: magnitude –3.4. (His final value awaits his calibration of how much the binoculars actually diminish light when reversed, done by comparing stars.) In Brazil, experienced lunar-eclipse observer Willian C. de Souza used the same method and got magnitude –2.4 at mid-eclipse, though with cloud interference. John Bortle got magnitude –3.2.

Images are pouring in to our photo gallery for this event. Post yours too! And did you have any cool observations or experiences to share? Comment below.

Amateur astronomers throughout the Americas and Europe are now planning their photographs, image sequences, or even time-lapse movies of Wednesday night's total lunar eclipse. But don't overlook the scientifically useful projects that are just begging to be carried out. You don't need anything but clear skies and some very simple equipment.

Color

Total lunar eclipses come in a great variety of brightnesses and hues. In February 1860, Irish amateur Mary Ward likened the Moon to "a red-hot penny" in the sky. But the famously dark eclipse of December 1963 was so dim that some skywatchers could not find the Moon when they stepped outdoors near mid-totality!

To help in comparing reports from various observers, even years and cultures apart, French astronomer André Danjon devised a five-point scale that is still used today. To learn how to give this eclipse a Danjon L rating, go here.

Brightness

For 21 years Brazilian astronomer Helio C. Vital has led a very active group of observers in monitoring the brightness of the eclipsed Moon, not only as it moves across the shadow but also from one eclipse to the next. He expects this will be a fairly bright one, which is typical of lunar eclipses taking place when Earth's atmosphere is nearly free of aerosols. "This seems to be a very good assumption, since the most recent volcanic eruption that could have caused some effect (though a very small one) occurred on October 6, 2006, on Mount Rabaul in Papua New Guinea," Vital writes.

"Based on eclipses our group has observed from Brazil since 1986, we predict that the Moon will be shining at total magnitude –2.6 ± 0.4 during mid-eclipse." That's between Jupiter and Venus in brightness.

More about the work of Vital's group can be found (in Portuguese) on their website. For the 2008 eclipse, they list the visual magnitudes of several convenient stars and planets to be used in judging that of the Moon.

So how do you make an estimate? If you wear thick glasses you can try taking them off so the Moon and bright planets or stars look like equal-size blobs. Looking through the wrong end of binoculars also helps.

Size of the Umbra

Timings of celestial events offered early mariners a way to find their longitude far from home. This method was used by Christopher Columbus, who timed the start and end of a lunar eclipse in 1504 during his fourth trip to the New World. When astronomers tried to refine this method, however, they quickly found that the dark center of the Earth's shadow, called the umbra, was larger than pure geometry indicated by about 2%, because our atmospheric sheath adds to Earth's effective diameter.

To time when the Moon's edge enters or leaves the shadow is often iffy. Instead, it's more accurate to time when individual spots and craters cross the shadow's edge. For example, from 697 crater timings sent in by Sky & Telescope readers, I derived an enlargement of 2.1% for the July 1982 eclipse. But for a similar event only six months later, 298 timings gave 1.7% enlargement. In each case the probable error was less than 0.1%. So the enlargement definitely varies slightly from eclipse to eclipse, for reasons not yet understood.

The Moon photo above has prominent features labeled on it, and you can click here for our predictions of their entrance and exit times in the umbra. Before making your timings, set a watch to accurate radio time signals. Write down the time (to the nearest 5 seconds) when the edge of the umbra crosses the center of the crater or other feature. It's as simple as that! (The shadow edge is a little fuzzy, so try to judge the point where light is falling off most rapidly and adopt that for your timings. Use a 2.4-inch or larger scope.)

If you carry out any of these simple projects at Wednesday night's eclipse, please e-mail the results to me. I'm collecting them for later analysis.

But no matter what you do, set aside a little time to sit back and enjoy the eclipse, too!

By now you've probably heard news reports about a super-secret spy satellite, designated USA 193, that will tumble uncontrolled from orbit within the next few weeks. The National Reconnaissance Office, which owns the doomed bird, has been mum on its mission and description.

But in a remarkable press conference on February 14th, a deputy national security adviser announced that President Bush has agreed to let the U.S. Navy try to destroy the satellite prior to its reentry by slamming a ship-fired SM-3 into it.

Apparently, DoD computer models have shown that, if left alone, more than half of USA 193's roughly 5,000-pound mass would survive the atmospheric plunge and reach the ground. In particular, there's a 20-inch diameter tank containing about a half ton of the highly toxic propellant hydrazine. So the decision was made to break up the satellite if possible.

You'll notice that I didn't say "shoot it down," as I've seen in many news reports. USA 193 isn't some aircraft that will simply drop from the sky if hit. Nor will some of the resulting fragments end up in long-lasting orbits that will threaten other spacecraft, as others have speculated.

None of the debris will survive more than a few weeks. That's because while, conceivably, the fragments' orbital apogees (high points) might end up somewhat higher, their perigees (low points) will not — and those perigees are already so low that fairly rapid decay is assured. All else being equal, breaking up the satellite will actually hasten reentry because virtually all the pieces will have higher area/mass ratios that the intact satellite did.

Whether this concern for public safety is genuine, or the NRO spooks don't want souvenir hunters combing through whatever wreckage might land on solid ground, or the Navy wants a good excuse for target practice isn't why I'm telling you all this.

Instead, I want you to go spot this satellite while you still can. The first interceptor missile won't be fired until sometime after February 20th. (There's some evidence that it'll come about 3:30 UT on the 21st, which coincidentally is during totality of that night's lunar eclipse.)
Until then, USA 193 will be left alone — and, as spy satellites go, it's easy to spot if you know where and when to look.

Right now the satellite's altitude is averaging just 163 miles (262 km), and it'll lose another 10% of altitude by the time the shooting starts. Because its orbit is inclined 58½° to the equator, USA 193 passes over virtually every city and town on Earth. If it were to pass directly over you after sunset or before sunrise, it might be as bright as a 1st-magnitude star. That should make it easy to spot with your eyes alone even from a light-polluted urban setting. Even better, right now the satellite is making a series of favorable early-evening passes over North America and Europe.

To determine where and when to look for it, you can get free predictions from our Satellite Tracker. After selecting your location and time zone, you'll be able to create predictions customized for your location. We utilize orbital parameters derived by Canadian satellite sleuth Ted Molczan from amateur sightings. Because the orbit is evolving rapidly, be forewarned that the predicted times might be off by a minute or two.

Good luck! If you succeed in spotting it, add a comment below to let me know how accurate the prediction was for your location.

It seems like yesterday, but back in November 2003 I boarded a chartered jet that carried about 80 of us out over the frozen wastes of Antarctica to witness a total eclipse of the Sun in midair. At the time I took a mental tally of how many others might have seen it too. I came up with about 500 in all — counting a second chartered jet, an icebreaker off the coast, and an expedition to a Japanese research station.

But my experience pales compared to the lengths that French eclipse-chaser Xavier Jubier went to for February 7th's annular eclipse. He decided to view it from atop Vinson Massif, whose summit (16,062 feet or 4,897 meters) is the highest in Antarctica.

To get there, he first flew on an Ilyushin IL-76 jet from Punta Arenas, at the southern tip of Chile, to the Patriot Hills "depot" in Antarctica, and from there he took a Twin Otter flight to the Vinson base camp. A couple of staging camps later, he was ready for the arduous trek to the summit, where temperatures near -40°F (-40°C) awaited him. And, yes, he did make it, as the following brief post to an eclipse-watcher mailing list attests:

"Managed to see annularity through a thin layer of clouds. However it was quite windy up there and taking eclipse pictures was a real challenge, not to mention various camera/lens problems. Came back safely to high camp after an exhausting 21-hour journey and now preparing to descend the headwall before the next storm comes in. The return to the base camp will likely be after the storm."

While many penguins no doubt experienced the event, besides Jubier's small group the only other humans who likely saw the annular Sun were those aboard a Russian vessel, Akademik Fedorov, that happened to be performing maintenance work at the otherwise uninhabited Russkaya Research Station. I'm still trying to determine if the skies there were clear on eclipse day.

Others had success outside the path of annularity. For example, at the South Pole, where the Moon gobbled up 80% of the Sun, Ethan Dicks braved -55°F to record the shots seen at right (his full series is here). "For the photographically curious," he reports, "I used an Olympus E-10 with a 1.4× tele-magnifier, giving an equivalent focal length of 200 mm. I made a double-layer mylar filter, which stopped down the light enough for me to shoot at 1/640 (fastest shutter speed available) and between f/5.6 and f/8."

From the relative comfort of Nelson, New Zealand, Williams College astronomer Jay Pasachoff and his wife, Naomi, watched as the Moon covered and uncovered 53% of the Sun's disk over a 128-minute span. For Pasachoff, who chairs the International Astronomical Union's Working Group on Eclipses, this was his 46th solar eclipse.

This solar eclipse happened at new Moon (as they all do). Two weeks later, on February 20th, the full Moon undergoes a total lunar eclipse that'll be observable throughout Europe and the Americas. It's going to be cold, I'm sure, but nothing near -40°F!

And on August 1st, for the first time in 28 months, the Moon will once again hide the Sun completely. For this total solar eclipse, I'll once again be boarding a chartered jet to intercept the Moon's shadow in midair. Wish me luck!

Sure, it gets cold in February. But how can you stay inside with so many wonderful winter wonders arrayed overhead this month?

The evening sky is now brimming with bright stars: the unmistakable outline of Orion, fiery Aldebaran, the Pleiades, the twins Castor and Pollux, and gleaming white Capella — to name just a few.

Add to that Mars, riding much higher up than usual for northern skygazers, and the ringed wonder, Saturn, rising up in the east. Meanwhile, Venus and Jupiter are dancing together in the predawn twilight.

Introduce yourself to the stars above by downloading this podcast to your MP3 player. Then go outside and let Sky & Telescope's executive editor, Kelly Beatty, show you where to look. Follow along as he leads you to mighty Orion, the Hunter, and many other stellar attractions.

Clear skies, and happy hunting!

If you're an early riser, you probably noticed Venus sparkling high in pre-dawn sky some time during the last few months of 2007. Venus has been getting lower and lower every morning throughout January. But it's still more than 10° (one fist-width) above the eastern horizon a half hour before sunrise if you live at mid-northern latitudes. And the planet is so brilliant that it appears spectacular even after the sky has grown so bright that you can read by its light.

Just a few days ago, I noticed that another bright light had appeared lower-left of Venus. This is Jupiter, the fourth-brightest object in the sky after the Sun, Moon, and Venus. Jupiter is dazzling in any other context, but it appears almost feeble next to Venus's overwhelming brilliance.

Every morning the view changes radically. Venus is getting rapidly lower and Jupiter higher, with the two approaching each other at a rate of 1° per day. It's quite a show!

At their closest approach, on the morning of February 1st, the two planets will be slightly over ½° apart. That's close enough to fit easily in a single telescopic field at 50×. And at that magnification, you can easily see the disks of both planets, together with at least three of Jupiter's four brightest moons. (Io passes in front of the planet at 5:52 a.m. PST, and will probably be invisible after that.)

Make sure that you take a look if the sky is even halfway clear. You don't even have to get up all that early — 6 a.m. should give you plenty of time at most locations.

In a rare bit of meteorological cooperation, metropolitan Boston had clear, albeit cold, skies for last night’s flyby of the asteroid 2007 TU₂₄. And even as an observer experienced in hunting down moving targets, I had to stay on my cold toes to follow this speedy chunk of rock as it crossed nearly 3° of sky per hour.

The image here is a 10-minute exposure centered on 8:00 p.m. EST (1:00 Universal Time on the 29th), during which 2007 TU₂₄ appeared to cross a Moon’s diameter of sky. Estimated to be about 800 feet across, the asteroid was then about 370,000 miles from Earth and closing. Closest approach wasn’t for another 7½ hours, when the distance would narrow to 340,000 miles, about 1.4 times the Moon’s distance.

Visually the asteroid was a little brighter than 12th magnitude and brightening about 0.2 magnitude per hour. Observing with a 7-inch reflector about an hour after this photograph was taken, my S&T colleague Tony Flanders estimated 2007 TU₂₄ to be about magnitude 11½ — fainter than he expected. In fact, Roger Sinnott, another S&T editor, was unable to spot it with a 5-inch scope.

Did you look for this speedy interloper? If so, did you see it? Let me know via the Comments section below.