How to find and follow asteroid 2012 DA14 during Friday’s flyby

Get ready for Friday’s flyby of the 150-long rocky asteroid 2012 DA14. Credit: NASA/JPL-Caltech

Near-Earth asteroid 2012 DA14 has become a sizzling topic online and on the TV news. Not a week goes by lately when I don’t hear about “the asteroid that’s going to fly by Earth”. Yesterday John, my mailman, asked me about it.

“Supposed to be half as long as a football field,” he offered. John was right. It’s a good-sized rock – the largest we know of to approach Earth this closely.

It’s fun that folks are excited about this 150-foot long solar system vagabond. I only wish we’d all have a chance to see it. Using the charts and tips below, it’s my hope that many of you will.

2012 DA14 was discovered by astronomers in the La Sagra Sky Survey program in Spain in February 2012. With an orbital period (time it takes to go around the sun) of about 368 days it makes annual spins by Earth. Friday’s flyby will be the closest the asteroid has been for many years and the closest it will come for at least the next 30.

And we do mean close. On Feb. 15 at about 1:24 p.m. (CST), 2012 DA14 will zoom 17,200 miles above the Earth’s surface traveling at 17,400 mph. While this is a record approach for a known object of this size, other smaller asteroids have skimmed nearer yet.

We only have to look back to June 27, 2011 when 2011 MD, about 20-50 feet wide, passed just 7,500 miles overhead. No harm came to Earth’s nail-biting residents then and none will during Friday’s pass. The record by the way for the closest-known shave goes to the petite, 3-foot-long 2011 CQ1 at 3,400 miles on Feb. 4, 2011.

2012 DA14 will briefly fly between the geostationary belt of communications satellites (white dots) and the Earth during closest approach Friday Feb. 15. Notice how it comes from under the Earth, moving from south to north. Credit: Simone Corbellini

On average, we’d expect an object of 2012 DA 14′s size to get this close to the Earth about once every 40 years. An actual collision by something this big is far rarer – about once every 1200 years.

On its inbound leg, 2012 DA14 will buzz between the constellation of GPS satellites, which orbit at about 12,600 miles, and the ring of geostationary satellites located about 22,200 miles above Earth’s equator. None will be in danger because the asteroid will come up from below and pass through the empty zone between the two.

Some 300 active weather and communications satellites are parked in orbit in the ring and relay communications around the globe. When your favorite TV weatherperson flashes pictures of storms and hurricanes taken from space, you can bet it was photographed and transmitted back to Earth by a geostationary satellite. There are presently about 32 GPS satellites used by government and consumers alike to pinpoint precise locations on the ground.

Simulation of the original constellation of 24 GPS satellites orbiting Earth. Credit: Wikipedia

As the asteroid zips by, Earth’s gravity will bend its orbit, changing its orbital period from 368 to 317 days and making close approaches like this one less likely. As for 2012 DA14 striking any satellite at all, Donald Yeomans, head of NASA’s Near Earth Object Program Office at the Jet Propulsion Laboratory, says it’s “extremely remote.” Given the huge volume of space the asteroid must pass through as it swings by Earth and the tiny number of potential targets, we might liken it to a gnat in a mansion.

Despite its proximity, 2012 DA14′s tiny size means not even the largest telescopes will show it as more than a star-like point of light. If you live in eastern Europe, Asia or Australia, you’ll see the asteroid at its closest, when it not only be brightest but moving fastest. I’ve seen a few Earth-approaching asteroids, and they really can book across the sky, but few travel as fast as this one will. In just three hours centered on closest approach, 2012 DA14 will zip from the Southern Cross all the way to the Bowl of the Big Dipper!

World map with time zones. The area inside the red circle shows very approximately where the asteroid will be visible in a dark sky when it’s closest and brightest. Map credit: Wikipedia

It reaches peak brightness around 1:24 p.m. (CST) or 7:30 p.m. in London, England. While the sky will be dark there at that time, the asteroid will still not have risen in the east. We have to go travel farther east and south to catch it at its brightest. Let’s pick Athens, Greece. There the the sky will be dark early enough to spot the asteroid at its brightest (magnitude 7.4) low in Virgo around 10 p.m. local time using standard 40-50mm binoculars. Observers should look for a dim “star” slowly moving from south to north in the field of view.

A map from Heavens Above showing the entire sky from Jakarta, Indonesia. The labeled arc is the asteroid’s path during the night. Credit: Chris Peat

As we continue moving east across the globe, 2012 DA14 gets higher and higher in a dark sky. If you sense the eastern hemisphere has the best seats in the house, you’re right.

Residents of Jakarta, Indonesia for example will see the whole show from beginning to end. Fortunate sky watchers there can spot 2012 DA14 with a telescope around 1 a.m. Saturday morning Feb. 16 (local time) near the Southern Cross.

By 3 a.m. they can switch over to binoculars to catch it at maximum brightness.  At dawn, the asteroid will have made a complete south-to-north beeline from Cross to Dipper and once again require a telescope to see. What a way to spend a night out, eh?

Did I say it was moving quickly? When nearest Earth, 2012 DA14 will hurry along at 1 degree or two full moon diameters per minute. Not only will you need binoculars, you’ll also need to know exactly where to look. By the time the sky is dark across the U.S., South America and Canada Friday night, the asteroid will have slowed considerably and faded to around magnitude 11.5 -12.

Sadly, U.S. sky watchers will need a 6-inch or larger telescope to find and follow it. The good news is that the asteroid will be conveniently placed in the northern sky near the Little Dipper.

The asteroid is shown at three times for an observer in Athens, Greece Friday evening facing east around 9:45 p.m. local time. 1 = 9:45 p.m., 2 = 10 p.m. and 3 = 10:15 p.m. Stars are plotted to about magnitude 7.5, the asteroid’s brightness at the time. Credit: Chris Marriott’s SkyMap software

I’ve given much thought on how to prepare charts for viewing 2012 DA14. When brightest, it’s not only crossing a great deal of sky in a hurry, but it’s so close to Earth that viewers in say, Vienna, will see it in a somewhat different part of the sky than those in Greece. You can’t make a one-size-fits-all chart for this bugger.

What I did instead was to create two charts – one for Athens, Greece and another for the central U.S. The Greek chart shows the asteroid when closest and brightest; the U.S. chart is centered on Duluth but is useful for a larger region, because the asteroid will be far enough away at that time for the path shift to be much smaller.

Just remember that you’ll need a telescope and good knowledge of the sky to find and follow our friend from the U.S. Use the charts to locate where the asteroid will be at a particular time and then wait for it to arrive as you gaze through the eyepiece.

2012DA14 will have faded to 11.5-12.0 magnitude when it gets dark enough to see it in the U.S., so you’ll need this more detailed chart to find it. Times are Central Standard for Friday Feb. 15, 2013. North is up and stars plotted to mag. 13. Brighter stars labeled with magnitudes. Right-click, save and print out for use at the telescope. Credit: Created with Emil Bonnano’s MegaStar atlas.

I highly recommend two websites that will show you a map of 2012 DA14′s path in your local sky as well as two other options for creating your own map:

Heavens Above - Webmaster Chris Peat has prepared a special 2012 DA14 page on this well-known satellite prediction site. Head over, log in with your location and then click the 2012 DA14 link at the top of the page for a map with times. If you select a spot on the asteroid’s path and click again, you’ll be shown a detailed map with stars to 8th magnitude European, Asian and Down Under sky watchers will find these maps most useful.

* Visual SAT-Flare Tracker 3D - Select your location and click on the 2012 DA14 asteroid header. Then click on the “Best opportunity to see the asteroid from your location” link to see a star map and asteroid path. Be aware that the faintest stars shown here are only about 6th magnitude (naked eye limit), but they’ll still be quite useful for tracking; webmaster Simone Corbellini uses the very accurate JPL Horizons data (see below) for path-making.

* Do-it-yourself – If you have your own star-charting program that allows you to add new asteroids to the database, go to the Minor Planet Center and grab 2012 DA14′s orbital elements. Enter these into your program and print your own star chart. Again, because of how close the asteroid will be, its path might be somewhat different than what your program will show, but at least you’ll be in the neighborhood.

* Tedious but foolproof method – Head over to the JPL Horizon site, type 2012 DA14 into the search box, select your city, time interval (whether you want an asteroid position every 15 minutes, hour or whatever) and then click “Generate ephemeris”. You can hand-plot the positions listed onto a star chart you’ve made with your software program. Be aware that all the times are Universal Time or Greenwich Mean Time (GMT). Subtract 5 hours for Eastern time, 6 for Central and so on. This method has worked very well for me during previous close flybys.

Good luck and I hope a few of you get to see this running rock!

Long twilights coax out shy satellites

Faint auroral rays streak the bottom of the northern sky this past Wednesday morning. Photo: Bob King

A reminder tonight to watch for possible northern lights. The current space weather forecast calls for a good chance of minor storming and an isolated major auroral storm at high latitudes. That means we might see some “green glow” toward the north from the northern U.S. and southern Canada.  The activity stems from a combination of a coronal hole and coronal mass ejection (CME) observed on June 2.

Illustration of what a supernova might look like closeup. Credit: ESO

The sky cleared late last night, giving me the opportunity to view the new supernova in the Whirlpool Galaxy (scroll back to yesterday’s blog for details). It’s classification has been further refined to a Type IIp supernova. This has all the characteristics we discussed yesterday – the collapse and explosion of an evolved supergiant star – but instead of fading at the regular rate, the supernova slows or “plateaus” (hence the ‘p’) for many days before resuming its normal decline in brightness.  You can learn more about the numerous categories of supernova types HERE.

The supernova appeared as a tiny star embedded in a hazy patch in the galaxy’s outer spiral arm. I estimated its brightness at 14.4 magnitude, though some others call it a bit brighter than that. We’ll keep a close watch to see if it intensifies. Most do within a week or two after discovery. The Whirlpool has been host to three previously observed supernovae – 1945A, 1994I and 2005CS.

A time exposure of the International Space Station taken last June. Photo: Bob King

Lots of satellites crisscrossed the sky last night. That’s one way you can tell summer is almost here – no matter how late you’re out, you’ll always see one, especially the farther north you live. That’s because Earth’s shadow covers less of the sky when the northern hemisphere is oriented toward the sun in summer compared to winter.  It’s also the same reason why twilight is so long this time of year.

Here in Duluth, evening twilight finally wraps up at around 11:15 p.m. but then has the audacity to start again just before 3 a.m. The further north you travel, the closer you approach the high Arctic and 24-hour sunlight. In northern Minnesota around the time of the summer solstice a vestige of twilight lingers in the northern sky all night long.

Satellites either disappear from view or aren’t visible in the middle of the night because they’re within the planet’s shadow and cut off from sunlight. If they were decorated with electric lights, we’d see them no matter when, but their source of illumination is sunlight reflecting off their shiny surfaces. With less of the planet’s shadow covering the sky, more satellites are visible late into the night. You can read more about the best times to observe satellites HERE.

The space station has the morning sky to itself since the Endeavour mission ended. Below you’ll find a list of passes through the middle of next week. The times are accurate for the Duluth, Minn. region. For times for your city, go to Spaceweather flybys and enter your zip code or log in to Heavens-Above.

And don’t forget about NASA’s first space sail, NanoSail-D. It cruises across the sky nearly every night and is currently visible during the 10:30-midnight time span for my region. Once you log in to the Heavens-Above site, click on the NanoSail-D link to take you to list of times. Clicking on any date brings up a map of its path across your sky.

Want to see more shiny birds? Under the satellites heading, click on Daily Predictions for Satellites Brighter Than Magnitude 3.5. In the case of Duluth, Minn. I get a list of 47 satellites potentially visible with the naked eye from suburban and rural sites. Wow!

Space station viewing times:
* Sunday June 5 starting at 3 a.m. A brilliant pass across the top of the sky. A second pass at 4:34 across the northern sky in bright twilight.
* Monday June 6 at 3:23 a.m. Look to the north again as the station slices through the Handle of the Big Dipper at 3:25.
* Tuesday June 7 at 2:14 a.m. when the space station will suddenly appear out of Earth’s shadow high in the northern sky moving to the east. Second pass in the north at 3:47 a.m.
* Wednesday June 8 at 2:37 a.m. and again at 4:12 a.m. Both times across the northern sky.

More satellites than you can shake a laser pointer at

The Seven Sisters cluster clears the trees around 11 p.m. earlier this week. The brightest members form a small dipper shape. The other stars you see crowded around the dipper also belong to the cluster and are easily visible in binoculars. Details: 200mm lens, f/2.8, 15-second exposure at ISO 6400. Photo: Bob King

I’ve been enjoying watching the Pleiades star cluster come up in the east these evenings. As far as I’m concerned, it’s first in the roll call of winter stars. You can see the cluster yourself low above the horizon starting around 10 o’clock. By 11, it’s up high enough for easy viewing.

Venus and the moon this evening in twilight about 20-30 minutes after sunset. Created with Stellarium

Earlier tonight, just after sunset, find a location with a clear view toward the southwestern horizon. You’ll find Venus there accompanied by a thin crescent moon. Through a small telescope, Venus now has a distinct crescent shape similar to but thicker than tonight’s moon. It’s an interesting juxtaposition of two very different worlds – one blisteringly hot with a dense carbon dioxide atmosphere and perpetual cloud cover, the other airless and subject to the extremes of both heat and cold. They do share several features in common. Both have craters and volcanic features like lava channels and domes of extruded magma. Volcanism is likely still going on on Venus, but the moon appears to have quieted down volcanically at least 100 million years ago.

The X-37B is a reusable, robotic spacecraft launched into orbit last April. Credit: NASA/Boeing Phantom Works

In an earlier blog, we visited the U.S. Air Force’s new military surveillance satellite the X-37B, which resembles a miniature space shuttle. The reusable, unmanned craft orbits some 250 miles above the Earth and is visible as a faint star crossing the southern sky. The craft is making evening passes during the next week and a half. Like the space station, it will look like a steady, moving “star” traveling from west to east. Unlike the station, it’s much fainter at only 4th magnitude, similar to the stars in the Little Dipper or those in the Pleiades Cluster. Its nightly path cuts through or just above (north) of the constellation Sagittarius the Archer, better known as the Teapot. You can use yesterday’s map of the Teapot to help you look in the right direction. For Duluth, Minn. and region, X-37B will first appear in the southwest, cross the southern sky near Sagittarius and then move toward the southeast and fade. For times for you city as well as very helpful maps, login to Heavens Above, select your city and then click on the X-37B link.

* Tonight starting at 8:39 p.m. Passes typically take about 3-4 minutes
* Monday Sept. 13 at 8:51 p.m.
* Tuesday Sept. 14 at 8:08 p.m.
* Weds. Sept. 15 at 9:02 p.m. Briefer pass in southwest only
* Thurs. Sept. 16 at 8:19 p.m.

Heavens Above is a wonderful tool for finding additional bright satellites, including quite a few brighter than X-37B. Once you’re logged in, go under the Satellites heading and click on Daily predictions for all satellites brighter than magnitude: 3.5. This will call up a list that for my town contains almost 40 satellites easily visible from my home during morning and evening hours. Brighter ones include the Titan 4B rocket booster, the Lacrosse 2 surveillance satellite and UARS, the Upper Atmosphere Research Satellite. Each is comparable in brightness to a star in the Big Dipper. Clicking on the name of each satellite will take you to an information page where you can click the Passes (visible) link to get a list of times for viewing. Such an embarrassment of riches. Have at it!