comet Archives

November 14, 2013December 23, 2015 by Jason Major

Comets Encke and ISON Spotted from Mercury

MESSENGER wide-angle camera images of comets Encke and ISON

Two comets currently on their way toward the Sun have been captured on camera from the innermost planet. The MESSENGER spacecraft in orbit around Mercury has spotted the well-known short-period comet Encke as well as the much-anticipated comet ISON, imaging the progress of each over the course of three days. Both comets will reach perihelion later this month within a week of each other.

While Encke will most likely survive its close encounter to continue along its 3.3-year-long lap around the inner Solar System, the fate of ISON isn’t nearly as certain… but both are making for great photo opportunities!

The figure above shows, on the left, images of comet 2P/Encke on three successive days from Nov. 6 to Nov. 8; on the right, images of C/2012 S1 (ISON) are shown for three successive days from Nov. 9 to Nov. 11. Both appear to brighten a little bit more each day.

MESSENGER image of ISON from Nov. 10 (enlarged detail)

MESSENGER is viewing these comets from a vantage point that is very different from that of observers on Earth. Comet Encke was approximately 0.5 AU from the Sun and 0.2 AU from MESSENGER when these images were taken; the same distances were approximately 0.75 AU and 0.5 AU, respectively, for ISON. More images will be obtained starting on November 16 when the comets should be both brighter and closer to Mercury. (Source: MESSENGER featured image article.)

Encke will reach its perihelion on Nov. 21; ISON on Nov. 28.

“We are thrilled to see that we’ve detected ISON,” said Ron Vervack, of the Johns Hopkins University Applied Physics Laboratory, who is leading MESSENGER’s role in the ISON observation campaign. “The comet hasn’t brightened as quickly as originally predicted, so we wondered how well we would do. Seeing it this early bodes well for our later observations.”

Comet 2P/Encke on October 30, 2013. The coma is partially obscuring the small barred spiral galaxy NGC 4371. Credit and copyright: Damian Peach. — Comet 2P/Encke photographed on October 30 by Damian Peach.

Unlike ISON, Encke has been known for quite a while. It was discovered in 1786 and recognized as a periodic comet in 1819. Its orbital period is 3.3 years — the shortest period of any known comet — and November 21 will mark its 62nd recorded perihelion. (Source)

“Encke has been on our radar for a long time because we’ve realized that it would be crossing MESSENGER’s path in mid-November of this year,” Vervack explained. “And not only crossing it, but coming very close to Mercury.”

These early images of both comets are little more than a few pixels across, Vervack said, but he expects improved images next week when the comets make their closest approaches to MESSENGER and Mercury.

“By next week, we expect Encke to brighten by approximately a factor of 200 as seen from Mercury, and ISON by a factor of 15 or more,” Vervack said. “So we have high hopes for better images and data.”

– Ron Vervack, JHUAPL

Read more about the MESSENGER cometary observation campaign in the full news release here.

Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington/Southwest Research Institute

October 2, 2013December 23, 2015 by Jason Major

This is Comet ISON Seen From Mars

HiRISE image of comet ISON from Mars orbit (NASA/JPL/University of Arizona)

It’s not much to look at, but there it is: the incoming comet ISON (aka C/2012 S1) as seen by the HiRISE camera aboard NASA’s Mars Reconnaissance Orbiter. An enlarged version of one of four just-released images, this represents a 256-by-256-pixel patch of sky imaged by HiRISE on Sunday, September 29. ISON is the fuzzy blob at center, 8.5 million miles (13.8 million km) away.

See all four images below:

HiRISE images of ISON on Sept. 29, 2013 (NASA/JPL/University of Arizona)

HiRISE researchers Alan Delamere and Alfred McEwen explained in a news release:

Based on preliminary analysis of the data, the comet appears to be at the low end of the range of brightness predictions for the observation. As a result, the image isn’t visually pleasing but low coma activity is best for constraining the size of the nucleus. This image has a scale of approximately 8 miles (13.3 km) per pixel, larger than the comet, but the size of the nucleus can be estimated based on the typical brightness of other comet nuclei. The comet, like Mars, is currently 241 million kilometers from the Sun. As the comet gets closer to the sun, its brightness will increase to Earth-based observers and the comet may also become intrinsically brighter as the stronger sunlight volatilizes the comet’s ices.

More images of ISON from HiRISE are expected as the comet came even closer to Mars, approaching within 6.7 million miles (10.8 million km), but the illumination from those angles may not be as good.

NOTE: These are preliminary single (non-stacked) images, and still contain noise and background stars – hence the fuzziness. Plus HiRISE was not really designed for sky imaging! (Thanks to HiRISE team member Kristin Block for the info.)

So even though it’s at the “low end” of brightness predictions in these HiRISE images, ISON certainly hasn’t “fizzled” like some reports claimed earlier this year (although just how bright it will get in our skies remains to be seen.)

Comet ISON will make its closest pass of the Sun (perihelion) on November 28, 2013, coming within 724,000 miles (1.16 million km) before heading back out into the Solar System… if it survives the encounter, that is. Read more about how to view ISON here and here.

Source: University of Arizona HiRISE article by Alan Delamere and Alfred McEwen

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Worried about ISON’s first (and possibly last) visit to the inner Solar System? Don’t be. Recent rumors of comet-caused catastrophe are greatly exaggerated… read more on David Dickinson’s article Debunking Comet ISON Conspiracy Theories (No, ISON is Not Nibiru).

September 20, 2013December 23, 2015 by Jason Major

An Unexpected Ending for Deep Impact

Comet Tempel 1 a minute after being struck by Deep Impact's impactor on July 4, 2005 (NASA/JPL-Caltech/UMD)

After almost 9 years in space that included an unprecedented July 4th impact and subsequent flyby of a comet, an additional comet flyby, and the return of approximately 500,000 images of celestial objects, NASA’s Deep Impact/EPOXI mission has officially been brought to a close.

The project team at NASA’s Jet Propulsion Laboratory has reluctantly pronounced the mission at an end after being unable to communicate with the spacecraft for over a month. The last communication with the probe was Aug. 8. Deep Impact was history’s most traveled comet research mission, having journeyed a total of about 4.7 billion miles (7.58 billion kilometers).

“Deep Impact has been a fantastic, long-lasting spacecraft that has produced far more data than we had planned,” said Mike A’Hearn, the Deep Impact principal investigator at the University of Maryland in College Park. “It has revolutionized our understanding of comets and their activity.”

Artist's rendering of the Deep Impactor flyby spacecraft (NASA) — Artist’s rendering of the Deep Impactor flyby spacecraft (NASA)

Launched in January 2005, the spacecraft first traveled about 268 million miles (431 million kilometers) to the vicinity of comet Tempel 1. On July 3, 2005, the spacecraft deployed an impactor into the path of comet to essentially be run over by its nucleus on July 4. This caused material from below the comet’s surface to be blasted out into space where it could be examined by the telescopes and instrumentation of the flyby spacecraft. Sixteen days after that comet encounter, the Deep Impact team placed the spacecraft on a trajectory to fly back past Earth in late December 2007 to put it on course to encounter another comet, Hartley 2 in November 2010, thus beginning the spacecraft’s new EPOXI mission.

“Six months after launch, this spacecraft had already completed its planned mission to study comet Tempel 1,” said Tim Larson, project manager of Deep Impact at JPL. “But the science team kept finding interesting things to do, and through the ingenuity of our mission team and navigators and support of NASA’s Discovery Program, this spacecraft kept it up for more than eight years, producing amazing results all along the way.”

The spacecraft’s extended mission culminated in the successful flyby of comet Hartley 2 on Nov. 4, 2010. Along the way, it also observed six different stars to confirm the motion of planets orbiting them, and took images and data of the Earth, the Moon and Mars. These data helped to confirm the existence of water on the Moon, and attempted to confirm the methane signature in the atmosphere of Mars. One sequence of images is a breathtaking view of the Moon transiting across the face of Earth.

This image of comet ISON C/2012 S1 from NASA’s Deep Impact/EPOXI spacecraft clearly shows the coma and nucleus on Jan. 17 and 18, 2013 beyond the orbit of Jupiter. Credit: NASA.

The spacecraft’s extended mission culminated in the successful flyby of comet Hartley 2 on Nov. 4, 2010. In January 2012, Deep Impact performed imaging and accessed the composition of distant comet C/2009 P1 (Garradd).

It took images of comet ISON this year and collected early images of comet ISON in June.

After losing contact with the spacecraft last month, mission controllers spent several weeks trying to uplink commands to reactivate its onboard systems. Although the exact cause of the loss is not known, analysis has uncovered a potential problem with computer time tagging that could have led to loss of control for Deep Impact’s orientation. That would then affect the positioning of its radio antennas, making communication difficult, as well as its solar arrays, which would in turn prevent the spacecraft from getting power and allow cold temperatures to ruin onboard equipment, essentially freezing its battery and propulsion systems.

Without battery power, the Deep Impact spacecraft is now adrift and silent, spinning out of control through the solar system.

Launch of Deep Impact aboard a Boeing Delta II from Cape Canaveral AFB on Jan. 12, 2005 (NASA) — Launch of Deep Impact aboard a Boeing Delta II rocket from Cape Canaveral AFS on Jan. 12, 2005 (NASA)

“Despite this unexpected final curtain call, Deep Impact already achieved much more than ever was envisioned. Deep Impact has completely overturned what we thought we knew about comets and also provided a treasure trove of additional planetary science that will be the source data of research for years to come.”

– Lindley Johnson, Program Executive for the Deep Impact mission

It’s a sad end for a hardworking spacecraft, but over the course of its 8 1/2 years in space Deep Impact provided many significant results for the science community. Here are the top five, according to the mission’s principal investigator Michael A’Hearn.

Read more about the Deep Impact mission here.

Source: NASA press release

September 10, 2013December 23, 2015 by Jason Major

“Oddball” Asteroid is Really a Comet

Spitzer image of an asteroid's surprise coma and tail (NASA/JPL-Caltech/DLR/NAU)

It’s a case of mistaken identity: a near-Earth asteroid with a peculiar orbit turns out not to be an asteroid at all, but a comet… and not some Sun-dried burnt-out briquette either but an actual active comet containing rock and dust as well as CO2 and water ice. The discovery not only realizes the true nature of one particular NEO but could also shed new light on the origins of water here on Earth.

JPL Near-Earth Object database map of 3552 Don Quixote's orbit — JPL Near-Earth Object database map of 3552 Don Quixote’s orbit

Designated 3552 Don Quixote, the 19-km-wide object is the third largest near-Earth object — mostly rocky asteroids that orbit the Sun in the vicinity of Earth.

According to the IAU, an asteroid is coined a near-Earth object (NEO) when its trajectory brings it within 1.3 AU from the Sun and within 0.3 AU of Earth’s orbit.

About 5 percent of near-Earth asteroids are thought to actually be dead comets. Today an international team including Joshua Emery, assistant professor of earth and planetary sciences at the University of Tennessee, have announced that Don Quixote is neither.

an asteroid is coined a Near Earth Asteroid (NEA) when its trajectory brings it within 1.3 AU from the Sun and hence within 0.3 AU of the Earth's orbit. — *An asteroid is coined a near-Earth object (NEO) when its trajectory brings it within 1.3 AU from the Sun and within 0.3 AU of Earth’s orbit. (IAU)*

“Don Quixote has always been recognized as an oddball,” said Emery. “Its orbit brings it close to Earth, but also takes it way out past Jupiter. Such a vast orbit is similar to a comet’s, not an asteroid’s, which tend to be more circular — so people thought it was one that had shed all its ice deposits.”

Using the NASA/JPL Spitzer Space Telescope, the team — led by Michael Mommert of Northern Arizona University — reexamined images of Don Quixote from 2009 when it was at perihelion and found it had a coma and a faint tail.

Emery also reexamined images from 2004, when Quixote was at its farthest distance from the Sun, and determined that the surface is composed of silicate dust, which is similar to comet dust. He also determined that Don Quixote did not have a coma or tail at this distance, which is common for comets because they need the sun’s radiation to form the coma and the sun’s charged particles to form the tail.

The researchers also confirmed Don Quixote’s size and the low, comet-like reflectivity of its surface.

“The power of the Spitzer telescope allowed us to spot the coma and tail, which was not possible using optical telescopes on the ground,” said Emery. “We now think this body contains a lot of ice, including carbon dioxide and/or carbon monoxide ice, rather than just being rocky.”

This discovery implies that carbon dioxide and water ice might be present within other near-Earth asteroids and may also have implications for the origins of water on Earth, as comets are thought to be the source of at least some of it.

The amount of water on Don Quixote is estimated to be about 100 billion tons — roughly the same amount in Lake Tahoe.

“Our observations clearly show the presence of a coma and a tail which we identify as molecular line emission from CO2 and thermal emission from dust. Our discovery indicates that more NEOs may harbor volatiles than previously expected.”

– Mommert et al., “Cometary Activity in Near–Earth Asteroid (3552) Don Quixote “

The findings were presented Sept. 10 at the European Planetary Science Congress 2013 in London.

Source: University of Tennessee press release

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3552 Quixote isn’t the only asteroid found to exhibit comet-like behavior either — check out Elizabeth Howell’s recent article, “Asteroid vs. Comet: What the Heck is 3200 Phaethon?” for a look at another NEA with cometary aspirations.

July 16, 2013December 23, 2015 by Jason Major

Stars, Galaxies, and Comet ISON Grace a New Image from Hubble

Comet ISON seen against a background of stars and galaxies (Source: /hubblesite.org)

This image of the steadily-approaching Comet ISON, made from observations with the Hubble Space Telescope on April 30, show not only the comet itself but also a rich background of stars located within our own galaxy and even the distant spirals of entire galaxies much, much farther away — as Josh Sokol describes it on HubbleSite.org’s ISONblog it’s like the astronomy stickers you’d get for your kid’s bedroom, except you’d never get to see such a scene in real life “unless, of course, you had Hubble.”

Comet C/2012 S1 (ISON) is currently on its way into the inner Solar System on course for a close encounter with the Sun, zooming along at 77,250 km/h (48,000 miles per hour). It will make its closest pass by the Sun on November 28 (coming within just .012 AU) and will hopefully put on a pretty spectacular show in the night sky — especially if it survives the trip.

The track of Comet ISON through the constellations Gemini, Cancer and Leo prior to perihelion. (Credit: NASA/GSFC/Axel Mellinger). — Comet ISON’s projected path through the night sky prior to perihelion. (Credit: NASA/GSFC/Axel Mellinger)

Watch: Comet ISON Timelapse Hubble Movie

The image above was created from multiple Hubble observations earlier this year, some geared toward capturing ISON and others calibrated more for distant, dimmer objects like galaxies and far-flung stars. By combining the results we get a view of a comet speeding through space with an almost too-perfect hyperrealism, courtesy of NASA’s hardest-working space telescope.

“The result is part science, part art. It’s a simulation of what our eyes, with their ability to dynamically adjust to brighter and fainter objects, would see if we could look up at the heavens with the resolution of Hubble. The result is a hodepodge of almost all the meat-and-potatoes subjects of astronomy – no glow-in-the-dark stickers required.”

– Josh Sokol, HubbleSite ISONblog

Learn about other ways NASA will be observing Comet ISON here.

Source: HubbleSite.org

May 7, 2013December 23, 2015 by Jason Major

Claims of Tunguska Meteorite Fragments “Ridiculous,” Scientist Says

A few of the many trees felled by the 1908 Tunguska explosion, photographed in 1929 (Wikipedia Commons)

Last week, Russian researcher Andrei Zlobin announced that stony fragments collected from a riverbed in 1988 are “probably Tunguska meteorites,” and are likely the remains of whatever cosmic object — thought to be either a comet or an asteroid — entered Earth’s atmosphere over the boggy region of Siberia on June 30, 1908, detonating with an estimated force of 5 megatons and leveling over 800 square miles of forest.

So far, definitive pieces of the original object have yet to be found despite numerous expeditions to the remote impact site. In a paper submitted on April 29, Zlobin cites the melted appearance of several stones found at the bottom of the Khushmo River as a good argument to “confirm the discovery” of Tunguska meteorite fragments.

According to Natalya Artemyeva of the Russian Academy of Sciences’ Geosphere Dynamics Institute, however, Zlobin’s claim is “ridiculous.”

In an article published May 4 on RIA Novosti, Artemyeva stated “There are many meteorites on Earth. For 100 plus years since the fall of the Tunguska space body, the weight of meteoric dust and small meteorites that have fallen out in that region has exceeded the mass of Tunguska.”

Stones found by Andrei Zlobin in the Khushmo River (A. Zlobin)

An estimated 100 tons of space debris enters Earth’s atmosphere on a daily basis.

Although Zlobin admits in his submitted paper that “strict confirmation of discovered melted stones as Tunguska meteorites is possible only after attentive chemical analysis of substance,” it seems that he is making rather bold claims based on appearance alone — especially considering the enigmatic and iconic nature of this particular impact event.

Read more: Tunguska Mystery Solved?

“It’s ridiculous,” Artemyeva said. “You can’t say by the appearance of a stone that it’s a meteorite. I don’t think there is ground for scientific discussion here.”

And, according to Artemyeva, even if the stones are found to be actual meteorites, connecting them to the 1908 event will still be a challenge.

Zlobin’s samples, which were in storage until 2008, are still awaiting full chemical analysis.

Read more on RIA Novosti here and on the MIT Technology Review here.

April 29, 2013December 23, 2015 by Bob King

Catch Comet Lemmon While You Can

On May 6 a beautiful thin moon will be near Comet Lemmon at dawn. This map shows the sky about 1 1/4 hours before sunrise. Stellarium

If you honed your observing chops on Comet PANSTARRS this spring, consider dropping in on Comet Lemmon, now returning to the dawn sky. Southern hemisphere observers saw this comet at its brightest in March when it briefly became dimly visible with the naked eye. It’s now faded to around magnitude 6, the same as the faintest stars you can see under a rural sky.

Because it’s been “vacationing” in the southern constellations, northerners have had to wait until now to see it.

Comet Lemmon with gas (left) and dust tails on April 24. Click to see a short movie showing rapid changes in the comet's tail in 25 minutes. Credit: Gerald Rhemann — Comet Lemmon with gas (left) and dust tails on April 24. Click to see a short movie showing rapid changes in the comet’s tail in 25 minutes. Credit: Gerald Rhemann

Like PANSTARRS, C/2012 F6 Lemmon is visible in modest-sized binoculars (7x35s, 10x50s) as a small, fuzzy ball of light with perhaps a faint tail. Watch for it to slowly track along the eastern side of the Great Square of Pegasus for the remainder of April and May. It competes with twilight low in the eastern sky this week but gradually becomes better placed for viewing as May unfolds. The best time to look is about an hour and a half before sunrise now and 2 hours before sunrise by mid-May.

The waning moon interferes some until around May 5. On the 6th, watch for the thin lunar crescent moon to pass 8 degrees below the comet. Around that time, we’ll finally get a good view of Lemmon in a dark, moonles sky just before the start of dawn.

Comet Lemmon will fade from naked eye limit to a dim binocular smudge of 7.5 magnitude by mid-May. If you have a telescope, look for a pair of tails – a short, diffuse one of dust particles and the straight, streak-like gas tail fluorescing in the sun’s ultraviolet light. The tails point approximately to the south-southwest. Catch this comet while you can!

April 17, 2013January 22, 2021 by Bob King

This Weekend’s Lyrid Meteor Shower: How to See It

Lyrid meteors will appear to radiate (red circle) from a point near the bright star Vega in the constellation Lyra. This map shows the sky facing southeast around 3:30 a.m. April 22 - around the time of maximum. Stellarium

Feeling a little meteor-starved lately? Me too. It’s been a meteor shower desert since the Quadrantids of early January. That’s about to change. This weekend brings the celestial version of April showers with the annual appearance of the Lyrids.

The Lyrids ding the bell at maximum strength this weekend April 21-22 (Sunday night-Monday morning in the Americas) hurtling meteors at the modest rate of 10-20 per hour from a point in the sky not far from bright Vega in the constellation Lyra. While some showers spread their meteor crumbs over several days, the Lyrids’ peak activity lasts less than a day. The western hemisphere – particularly the western half of North America – is favored this year.

A Lyrid meteor captured by NASA astronaut Don Pettit out the window of the International Space Station on April 21, 2012. The lights of Florida are visible to the right of the meteor. Credit: NASA — A Lyrid meteor captured by NASA astronaut Don Pettit out the window of the International Space Station on April 21, 2012. The lights of Florida are visible to the right of the meteor. Click to enlarge. Credit: NASA

There will be a small price to pay for the show. The Lyrid radiant, the point in the sky from which the showers members radiate, rises in the east rather late – around 10:30 p.m. local time. Then there’s the bright gibbous moon, which has a habit of drowning out fainter stars and meteors alike. That makes the best time for viewing the shower after moonset or around 4 a.m. Monday morning. Since dawn begins about 5, you’ll have one good hour. That’s plenty of time to snag at least a few flaming motes of Comet Thatcher.

A bright fireball meteor in twilight. The Lyrids, like all meteor showers, offer up the occasional fireball among a mix of fainter meteors. Credit: John Chumack

Like most meteor showers, the Lyrids have a parent and single parents are the rule. For the Lyrids, it’s Comet Thatcher, discovered on April 5, 1861, a week before the start of the Civil War, by amateur astronomer A.E. Thatcher observing from New York City. Later it was found to be linked to the Lyrid meteor shower.

Each year in late April, Earth passes through centuries of dust shed by the comet’s tail. When bits of Thatcher flotsam strike the air some 60-70 miles high, they burn up in flashes of meteoric light. Comet tears.

The delicate, rarefied dust tail of Comer C/2012 K5 in Dec. 2012. If Earth happens to intersects a comet's dusty orbit - as we do with Comet Thatcher every April - we witness a meteor shower. Credit: Michael Jaeger — The delicate, rarefied dust tail of Comer C/2012 K5 in Dec. 2012. If Earth happens to intersects a comet’s dusty orbit – as we do with Comet Thatcher every April – we witness a meteor shower. Credit: Michael Jaeger

All meteors are worthy of keeping an eye on, but bear in mind that the Lyrids are no Perseids, the famed summertime shower offering up to 60 meteors per hour under dark skies. But what they lack in numbers, they make up in reliability and surprise.

Records indicate that people have been watching the Lyrids for at least 2,600 years, the longest of any shower. Our oldest descriptions come from the Chinese who penned that “stars fell like rain” on March 16, 687 BC. Apparently the shower was more active in the past and has since evolved into a minor display. But there have been occasional surprises, and that’s what keeps the Lyrids interesting.

Comet Thatcher circles the sun every approxiimately 415 years. Each time it does, the comet leaves dust and small bits of ice and rock in a trail behind it. Sometimes it sheds more dust than others, creating filaments of denser material that can create surprisingly high numbers of Lyrid meteors when the Earth passes through. Not to scale. Illustration: Bob King — Comet Thatcher circles the sun once every approxiimately 415 years. Each time it does, the comet leaves dust and small bits of ice and rock in a trail behind it. Sometimes it sheds more dust than others, creating denser filaments that can make for unexpectedly high numbers of Lyrid meteors when the Earth passes through. Not to scale. Illustration: Bob King

On April 20, 1803 a fire bell roused Richmond, Virginia residents from their beds to witness a similar rain of stars when up to 700 meteors per hour were seen. Other Lyrid outbursts occurred in 1922 (100 per hour), 1945 (100/hr), 1982 (90/hour). Last year’s peak hit 37 per hour from a dark sky site. Now and then, Earth encounters a thicker band of comet debris left behind by Comet Thatcher, suddenly increasing the meteor count by many times and just as suddenly dropping back to the usual 10-20 per hour.

So here’s the bottom line. Don’t expect a big blast, but do avail yourself of the leisurely pleasure of meteor watching and the possibility of seeing pieces of a comet that rounds the sun only every 415 years. Find a spot where artificial lights is at a minimum, dress warmly and head out around 3:30 a.m. Monday. Set up a comfortable lawn chair and have tea or coffee and a blanket at the ready. You’ll do well to face south or east. Now recline back to allow a fulsome view of the sky above and wait for a few well-deserved ooohs and aaahs.

March 20, 2013April 8, 2018 by Bob King

Keeping up with Comet PANSTARRS through the end of March

Multiple exposures of Comet PANSTARRS taken on March 19 were stacked to create this amazing image. The field of view is about 6 by 4 degrees. Details: Leica-Apo180mm lens at f/4. Click to enlarge. Credit: Michael Jaeger

Wow – what an image! Michael Jaeger’s photo of Comet C/2011 L4 PANSTARRS on March 19 resembles those taken by the orbiting Stereo-B spacecraft. Check out this video (and the one below) to see what I mean. Most observers using binoculars and telescopes are seeing the comet’s head, bright false nucleus and a single plume-like tail.

Michael Jaeger of Stixendorf, Austria has been shooting beautiful comet images since 1982. Credit: Michael Jaeger

Careful photography like Jaeger’s reveals so much more – two bright, broad dust tails and three shorter spikes. One of the dust tails peels off to the left of the comet’s head, the other extends upward feather-like before splitting into two separate streamers. There are also several narrow, spike-like tails due to various excited elements and gas emissions from the comet’s icy nucleus.

Video of Comet PANSTARRS made from pictures taken by NASA’s STEREO-B spacecraft on March 13, one of two spacecraft that orbit ahead and behind Earth monitoring solar activity on the sun’s farside.

Michael Jaeger of Austria has been shooting pictures of comets since 1982. His images always reveal details that entice visual observers to go out and look for more than what first meets the eye. Last night I got my first look at the comet through a telescope and was delighted at the sight of its smooth, luminous tail and brilliant yellow false-nucleus. The false nucleus is the bright spot visible in the center of the PANSTARRS’ head; in 10×50 binoculars it looks like a star. Through a telescope it’s a fuzzy, yellow pea. Buried deep within the false nucleus is the icy comet nucleus itself, vaporizing in the sun’s heat and shrouded by its own dust.

Comet PANSTARRS last night March 19, 2013 in a setting with white pines. Details: 300mm lens, f/2.8, ISO 800 and 3-second exposure. Credit: Bob King — Comet PANSTARRS last night March 19, 2013 in the company of white pines. Details: 300mm lens, f/2.8, ISO 800 and 3-second exposure. Credit: Bob King

The comet has faded in the past week or two from 1st magnitude – equal to some of the brightest stars – to about magnitude 2.5 or somewhat fainter than the stars of the Big Dipper. In very clear skies, it was still dimly visible with the naked eye about 40 minutes after sunset low in the northwestern sky. I only knew where to look after first finding the comet in 10×50 binoculars. The tail points straight up and stretches nearly 2 degrees in length once the sky gets dark enough to increase contrast and before PANSTARRS sinks too low. I kept it in view for nearly an hour from a wind-whipped location north of Duluth, Minn.

The comet at 64x through a 15-inch (37cm) telescope on March 19, 2013. The pale yellow false nucleus highlights the smooth, curved tail. Illustration: Bob King

Through the telescope the nucleus blazed yellow from sunlit dust. Set inside the comet’s sleek, smooth head it reminded me of a lighthouse beacon shining through the mist. Gorgeous! The tail trailed bent back to the northeast with a slight arc. I highly recommend setting up your telescope for a look at PANSTARRS, if for no other reason than to see the beauty of the false-nucleus within the finger-like tail.

Use this map to find Comet PANSTARRS now through March 31. It depicts the sky facing west-northwest 30 minutes after sunset. The comet’s height remains fairly steady at about 10-14 degrees but it moves steadily northward (to the right). The yellow circles represent the sun’s position every 3 days. It also moves northward but more slowly. One fist equals about 10 degrees of sky. Created with Chris Marriott’s SkyMap software — Use this map to find Comet PANSTARRS now through March 31. It depicts the sky facing west-northwest 30-40 minutes after sunset. The comet’s height remains fairly steady at about 10-14 degrees but it moves steadily northward (to the right). The yellow circles represent the sun’s position every 3 days. It also moves northward but more slowly. One fist equals about 10 degrees of sky. Created with Chris Marriott’s SkyMap software

You can use the chart to help you find the comet for the remainder of the month. It shows the comet’s position every 3 days now through March 31 from mid-northern latitudes, specially 42 degrees north (Chicago, Ill.). If you live in the northern U.S., the comet will be in approximately the same positions but slightly higher in the sky; in the southern U.S. it will be a little lower. Notice the “15 degree” altitude line. If you set the bottom of your fist flat on the horizon, the 15 degree line is a fist and a half above that level.

Boulder Panstarrs from Patrick Cullis on Vimeo.

Time lapse video made by Patrick Cullis showing Comet PANSTARRS setting behind the Flatirons of Boulder, Col. on March 19. As you watch, notice how the comet appears against the sky background and the direction it moves toward the horizon – both clues to help you find it.

The map compensates for the sun rising later each night and shows the comet’s height above the horizon when the sun is 7.5 degrees below the horizon. 7.5 degrees corresponds to about 30 minutes after sunset. Notice that the sun moves northward (to the right) just like the comet does over the next couple weeks but more slowly.

A compass has two sets of markings. One shows the basic directions N, S, etc. Those directions are subdivided into degrees of azimuth seen in the outer ring. Credit: Wikipedia

See those yellow numbers along the map’s horizon? Those are compass bearings called azimuths. If you have a compass, dig it out and give it a look. Every compass is marked in degrees of azimuth. 270 degrees is due west, 285 degrees is a fist and a half to the right of due west, 315 degrees is exactly halfway between due west and due north. North can be either 360 degrees or 0 degrees. Azimuths are simple way to subdivide directions to make them more precise.

Comet PANSTARRS very low in the northwestern sky shortly before setting last night March 19. Details: 300mm lens, f2.8, ISO 3200 and about 4 seconds. Credit: Bob King — Comet PANSTARRS very low in the northwestern sky shortly before setting last night March 19. Details: 300mm lens, f2.8, ISO 3200 and about 4 seconds exposure. Credit: Bob King

The next time it’s clear, bring your binoculars and a compass (if needed) and find a location with a great view of the western sky preferably down to the horizon. Use the map along with the compass bearings to guide your eyes in the right direction. You can also use the sun’s position below the horizon to point you to the comet by angling up from the lingering glow at the sunset point. Remember to first focus your binoculars on the moon, cloud bank or star before attempting to find PANSTARRS. There’s nothing more frustrating than sweeping for a fuzzy comet with an out-of-focus instrument.

March 8, 2013December 23, 2015 by Bob King

A Guide to Help You See Comet PANSTARRS at its Brightest

Comet L4 PANSTARRS setting over Brindabella Ranges to the west of Canberra, Australia on March 5, 2013. The photo gives a good idea of the naked eye of the comet. Credit: Vello Tabur

This is the big week so many of us in the northern hemisphere have been waiting for. Comet C/2011 L4 PANSTARRS, which has put on a splendid show in the southern hemisphere, now finally comes to a sky near us northerners!

Sky watchers in Australia and southern South America report it looks like a fuzzy star a little brighter than those in the Big Dipper with a short stub of a tail visible to the naked eye. The comet should brighten further as it wings its way sunward. Closest approach to the sun happens on March 10 at a distance of 28 million miles. That’s about 8 million miles closer than the orbit of Mercury.

Though very low in the western sky after sundown, the comet should be visible across much of the U.S., southern Canada and Europe beginning tonight March 8.

Comet PANSTARRS will be visible tonight through about March 19 for sky watchers living near the equator. Map is drawn for Singapore. All maps created with Chris Marriott's SkyMap software — Comet PANSTARRS will be visible through about March 19 for sky watchers living near the equator. Map is drawn for Singapore. All maps created with Chris Marriott’s SkyMap software

PANSTARRS’ low altitude presents a few challenges. Approaching clouds, general haziness and the extra thickness of the atmosphere near the horizon absorbs the comet’s light, causing it to appear fainter than you’d expect. A casual sky watcher may not even notice its presence. That’s why I recommend bringing along a pair of binoculars and using the map that best fits your latitude. Find a place with a wide open view to the west, focus your binoculars on the most distant object you can find (clouds are ideal) and then slowly sweep back and forth across the sky low above the western horizon

Comet PANSTARRS map for the southern U.S. March 6-21. Time shown is about 25 minutes after sunset facing west. Map is drawn for Phoenix, Ariz.

As the nights pass, PANSTARRS rises higher in the sky and becomes easier to spot for northern hemisphere observers while disappearing from view in the south. On the 12th, a thin lunar crescent will shine just to the right of the comet. Not only will it make finding this fuzzy visitor easy-peasy, but you’ll have the opportunity to make a beautiful photograph.

Comet PANSTARRS and thin crescent moon should be a striking site about a half hour to 45 minutes after sunset on March 12. Stellarium — Comet PANSTARRS and the thin crescent Moon should make a striking sight together about a half hour to 45 minutes after sunset on March 12. Stellarium

The maps shows the arc of the comet across the western sky in the coming two weeks for three different latitudes. Along the bottom of each map is the comet’s altitude in degrees for the four labeled dates. The sun, which is below the horizon, but whose bright glow you’ll see above its setting point, will help you determine exactly in what direction to look.

One of your best observing tools and the one closest at hand (pun intended) is your hand. Photo: Bob King

A word about altitude. Astronomers measure it in degrees. One degree is the width of your little finger held at arm’s length against the sky. Believe it or not, this covers two full moon’s worth of sky. Three fingers at arm’s length equals 5 degrees or the separation between the two stars at the end of the bowl of the Big Dipper. A fist is 10 degrees. This weekend PANSTARRS will be 2-3 “fingers” high around 25 minutes after sunset when the sky is dark enough to go for it.

The northern U.S. is favored for this leg of the comet's journey. Notice how the comet arcs up higher in the sky compared to the southern U.S. and especially the equator. Map drawn for Duluth, Minn. The comet will remain visible for many weeks. Earth is closest to PANSTARRS on March 5 at 102 million miles. — The northern U.S. is favored for this leg of the comet’s journey. Notice how the comet arcs up higher in the sky compared to the southern U.S. and especially the equator. Map drawn for Duluth, Minn. The comet will remain visible for many weeks. Earth is closest to PANSTARRS on March 5 at 102 million miles.

To find PANSTARRS, locate it on the map for a particular date, note its approximate altitude and relation to where the sun set and look in that direction. Assuming your sky to the west is wide open and clear, you should see a comet staring back. If you don’t find it one night, don’t give up. Go out the next clear night and try again. While Comet PANSTARRS will fade over the next few weeks, it will also rise higher into a darker sky and become – for a time – easier to see. I also encourage you to take out your telescope for a look. You’ll see more color in the comet’s head, details in its tail and an intensely bright nucleus (center of the comet), a sign of how fiercely sunlight and solar heating are beating up on this tender object.

Sound good? Great – now have at it!