Comets Archives

May 20, 2014December 23, 2015 by Bob King

How to See 209P/LINEAR, the Comet Brewing Up Saturday’s Surprise Meteor Shower

Comet 209P/LINEAR may still be faint but it's a beautiful object in this time exposure by Austrian astrophotographer Michael Jaeger. The stars appear as trails because the photographer followed the comet during the exposure.

As we anxiously await the arrival of a potentially rich new meteor shower this weekend, its parent comet, 209P/LINEAR, draws ever closer and brighter. Today it shines feebly at around magnitude +13.7 yet possesses a classic form with bright head and tail. It’s rapidly approaching Earth, picking up speed every night and hopefully will be bright enough to see in your telescope very soon.

As it approaches Earth in the coming nights, comet 209P/LINEAR will appear to move quickly across the sky, traveling from Leo Minor to southern Hydra in little over a week. All maps created with Chris Marriott's SkyMap software — As it approaches Earth in the coming nights, comet 209P/LINEAR will move quickly across the sky, traveling from Ursa Major to southern Hydra in just 10 days. When closest on May 28-29, the comet will cover 10 degrees per day or just shy of 1/2 degree per hour. All maps created with Chris Marriott’s SkyMap software

The comet was discovered in Feb. 2004 by the Lincoln Laboratory Near-Earth Asteroid Research (LINEAR) automated sky survey. Given its stellar appearance at the time of discovery it was first thought to be an asteroid, but photos taken the following month photos by Rob McNaught (Siding Spring Observatory, Australia) revealed a narrow tail. Unlike long period comets Hale-Bopp and the late Comet ISON that swing around the sun once every few thousand years or few million years, this one’s a frequent visitor, dropping by every 5.09 years.

This detailed map shows the comet's path from Leo Minor across the backside of the Sickle of Leo May 23-26. Hopefully it will be bright enough then to spot in an 8-inch or larger telescope. Click to enlarge and then print out for use at the telescope. — This detailed map shows the comet’s path from Leo Minor across the backside of the Sickle of Leo May 23-26. Hopefully it will be bright enough then to spot in an 8-inch or larger telescope. On May 25, it passes close to the colorful double star Gamma Leonis and a pair of NGC galaxies. Stars plotted to magnitude +9. Click to enlarge and then print out for use at the telescope.

209P/LINEAR belongs to the Jupiter family of comets, a group of comets with periods of less than 20 years whose orbits are controlled by Jupiter. When closest at perihelion, 209P/LINEAR coasts some 90 million miles from the sun; the far end of its orbit crosses that of Jupiter. Comets that ply the gravitational domain of the solar system’s largest planet occasionally get their orbits realigned. In 2012, during a relatively close pass of that planet, Jupiter perturbed 209P’s orbit, bringing the comet and its debris trails to within 280,000 miles (450,000 km) of Earth’s orbit, close enough to spark the meteor shower predicted for this Friday night/Saturday morning May 23-24.

Track of the comet through from May 27-29 through the dim constellation Sextans south of Leo. — Track of the comet from May 27-29 through Sextans to the Hydra-Crater border with positions shown every 3 hours. Times are CDT. Click to enlarge.

This time around the sun, the comet itself will fly just 5.15 million miles (21 times the distance to the moon) from Earth around 3 a.m. CDT (8 hours UT) May 29 a little more than 3 weeks after perihelion, making it the 9th closest comet encounter ever observed. Given , you’d think 209P would become a bright object, perhaps even visible with the naked eye, but predictions call for it to reach about magnitude +11 at best. That means you’ll need an 8-inch telescope and dark sky to see it well. Either the comet’s very small or producing dust at a declining rate or both. Research published by Quanzhi Ye and Paul A. Wiegert describes the comet’s current dust production as low, a sign that 209P could be transitioning to a dormant comet or asteroid.

Light curve for comet 209P/LINEAR predicts a maximum magnitude of around 11. Click for more information. Credit: Seiichi Yoshida — Light curve for comet 209P/LINEAR forecasts a maximum magnitude of around 11. Dates are shown along the bottom and magnitude scale along the side. Click for additional information. Credit: Seiichi Yoshida

Fortunately, the moon’s out of the way this week and next when 209P/LINEAR is closest and brightest. Since we enjoy comets in part because of their unpredictability, maybe a few surprises will be in the offing including a brighter than expected appearance. The maps will help you track down 209P during the best part of its apparition. I deliberately chose ‘black stars on a white background’ for clarity in use at the telescope. It also saves on printer ink!

A brand new meteor shower shooting 100 and potentially as many as 400 meteors an hour may radiate from the dim constellation Camelopardalis below the North Star Saturday morning May 24. Each is crumb or pebble of debris lost by 209P/LINEAR during earlier cycles around the sun. This map shows the sky facing north around 2 a.m. from the Saturday May 24 from the central U.S. Stellarium

We’re grateful for the dust 209P/LINEAR carelessly lost during its many passes in the 19th and early 20th centuries. Earth is expected to pass through multiple filaments of debris overnight Friday May 23-24 with the peak of at least 100 meteors per hour – about as good as a typical Perseid or Geminid shower – occurring around 2 a.m. CDT (7 hours UT).

If it’s cloudy or you’re not in the sweet zone for viewing either the comet or the potential shower, astrophysicist Gianluca Masi will offer a live feed of the comet at the Virtual Telescope Project website scheduled to begin at 3 p.m. CDT (8 p.m. Greenwich Time) May 22. A second meteor shower live feed will start at 12:30 a.m. CDT (5:30 a.m. Greenwich Time) Friday night/Saturday morning May 23-24.

SLOOH will also cover 209P/LINEAR live on the Web with telescopes on the Canary Islands starting at 5 p.m. CDT (6 p.m. EDT, 4 p.m. MDT and 3 p.m. PDT) May 23. Live meteor shower coverage featuring astronomer Bob Berman of Astronomy Magazine begins at 10 p.m. CDT. Viewers can ask questions by using hashtag #slooh.

A very exciting weekend lies ahead!

May 19, 2014December 23, 2015 by David Dickinson

Can You Say Camelopardalids? Observing, Weather Prospects and More for the May 24th Meteor Shower

It could be the best of meteor showers, or it could be the…

Well, we’ll delve into the alternatives here in a bit. For now, we’ll call upon our ever present astronomical optimism and say that one of the best meteor showers of 2014 may potentially be on tap for this weekend.

This is a true wild card event. The meteor shower in question hails from a periodic comet 209P LINEAR discovered in 2004 and radiates from the obscure and tongue-twisting constellation of Camelopardalis.

But whether you call ‘em the “209/P-ids,” the “Camelopardalids,” or simply the “Cams,” this weekend’s meteor shower is definitely one worth watching out for. The excitement surrounding this meteor shower came about when researchers Peter Jenniskens and Esko Lyytinen noticed that the Earth would cross debris streams laid down by the comet in 1803 and 1924. Discovered by the LIncoln Near-Earth Asteroid Research (LINEAR) automated all-sky survey located at White Sands, New Mexico, comet 209P LINEAR orbits the Sun once every 5.1 years. 209P LINEAR passed perihelion at 0.97 AUs from the Sun this month on May 6^th.

Looking north from latitude +30N at 7:00 UT on the morning of May 24th. Created using Starry Night.

The meteor shower peaks this coming U.S. Memorial Day weekend on Saturday, May 24^th. The expected peak is projected for right around 7:00 Universal Time (UT) which is the early morning hours of 3:00 AM EDT, giving North America a possible front row seat to the event. Estimates for the Zenithal Hourly Rate (ZHR) of the Camelopardalids run the gamut from a mild 30 to an outstanding 400 per hour. Keep in mind, this is a shower that hasn’t been witnessed, and it’s tough enough to forecast the timing and activity of known showers. It’s really a question of how much debris the 1803 and 1924 streams laid down on those undocumented passages. One possible strike against a “meteor storm” similar to the 1998 Leonids that we witnessed from Kuwait is the fact that the “Cams” have never been recorded before. Still, you won’t see any if you don’t try!

Cams — The orientation of the Earth, the day/night terminator, the Sun, Moon and radiant of the meteor shower on May 24th at 7:00 UT. Created by author.

Comet 209P/LINEAR passes 0.055 AUs — about 8.3 million kilometres — from the Earth on May 29^th, shining at +11^th magnitude and crossing south into the constellation of Leo Minor in late May. Interestingly, it also passes 0.8 degrees from asteroid 2 Pallas on May 26^th. Though tiny, comet 209P/LINEAR’s 2014 passage ranks as the 9^th closest recorded approach of a comet to the Earth.

The Moon is also at an ideal phase for meteor watching this coming weekend as it presents a waning crescent phase just 4 days from New and rises at around 4:00 AM local.

The expected radiant for the Cams sits at Right Ascension 8 hours and declination 78 degrees north in the constellation of Camelopardalis, the “camel leopard…” OK, we’ve never seen such a creature, either. (Read “giraffe”). Unfortunately, this puts the radiant just 20 degrees above the northern horizon as seen from +30 degrees north latitude here in Florida at 7:00 UT. Generally speaking, the farther north you are, the higher the radiant will be in the sky and the better your viewing prospects are. Canada and the northern continental United States could potentially be in for a good show. Keep in mind too, the high northern declination of the radiant means that it transits the meridian (crosses upper culmination) a few hours before sunset Friday night at 6 PM local; this means it’ll have an elevation of about 38 degrees above the horizon as seen from 30 degrees north latitude just after sunset. It may well be worth watching for early activity after dusk!

Weather — A look ahead at the cloud cover prospects for the morning of May 24th. Credit: NOAA.

Clouded out or live on the wrong side of the planet to watch the Camelopardalids? Slooh will be carrying a live broadcast of the event starting at 3:00 PM PDT/ 6:00 PM EDT/ 22:00 UT. Also, the folks at the Virtual Telescope Project will carry two separate webcasts of the event, one featuring the progenitor comet 209P LINEAR starting at 20:00 UT on May 22^nd and another featuring the meteor shower itself starting at 5:30 UT on May 24^th.

Observing meteors is fun and easy and requires nothing more than a good pair of “mark-1 eyeballs” and patience. And although the radiant may be low to the north, meteors can appear anywhere in the sky. We like to keep a pair of binocs handy to examine any lingering smoke trains left by bright fireballs. Counting the number of meteors you see from your location and submitting this estimate to the International Meteor Organization may help in ongoing efforts to understand this first time meteor shower. And capturing an image of a meteor is as simple as setting a DSLR on a tripod with a wide field of view and taking time exposures of the sky… something you can start practicing tonight.

P_20140518_110518 — Our humble meteor observing rig… (Photo by author).

Don’t miss what could well be the astronomical event of the year… I’d love to see a meteor shower named after an obscure constellation such as the #Camelopardalids trending. And we fully expect to start fielding reports of “strange rocks falling from the sky” this week, which the cometary dust that composes a meteor shower isn’t. In fact, Meteorite Man Geoffrey Notkin once noted that no confirmed meteorite fall has ever been linked to a periodic meteor shower.

Don’t miss the celestial show!

-Got pics of the Camelopardalids? Send ‘em to Universe Today. There’s a good chance that we’ll run an after-action photo-round up if the Cams kick it into high gear.

-Read more about the Camelopardalids here in a recent outstanding post by Bob King on Universe Today.

May 15, 2014December 23, 2015 by Elizabeth Howell

It’s Alive! Rosetta’s Comet Flares As It Approaches The Sun

A close-up of comet 67P/Churyumov–Gerasimenko taken from 1.24 million miles (2 million km) away. The image was obtained by the Rosetta spacecraft in April 2014 as it approached the comet for a close-up view. Credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

Wow! This image shows the target comet for the Rosetta mission starting to develop a tail. This bodes well for the European Space Agency spacecraft, which is on its way to study Comet 67P/Churyumov–Gerasimenko later this year to learn more about the origins of the solar system.

“It’s beginning to look like a real comet,” stated Holger Sierks, principal investigator for OSIRIS (Optical, Spectroscopic and Infrared Remote Imaging System.)

“It’s hard to believe that only a few months from now, Rosetta will be deep inside this cloud of dust and en route to the origin of the comet’s activity,” added Sierks, who is with the Max Planck Institute for Solar System Research in Germany.

The picture was one of a series taken over six weeks, between March 27 and May 4, as the spacecraft zoomed to within 1.24 million miles (two million kilometers) of the target. You can see the full animation by clicking on the image below.

Comet 67P/Churyumov–Gerasimenko develops a coma in this sequence of pictures taken by Rosetta, a European Space Agency spacecraft. Credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA — Comet 67P/Churyumov–Gerasimenko develops a coma in this sequence of pictures taken by Rosetta (click the picture to see the animation), a European Space Agency spacecraft. Credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

The comet is now about four times as far from the Sun as the Earth is. Even from afar, the Sun’s heat is warming the comet’s ice, causing dust and vapor to carry out into space — forming the coma. The coma will develop into a long tail when the comet gets even closer to the sun.

Rosetta will be the comet’s companion as it draws closer to the sun; its closest approach will be in August 2015, when it is between the orbits of Earth and Mars. So far, the spacecraft’s 11 instruments appear to be in excellent health, ESA stated, although the agency is remaining cautious as the rendezvous date approaches. The spacecraft will begin orbital insertion activities later this month, and send out its Philae lander in November.

“We have a challenging three months ahead of us as we navigate closer to the comet, but after a 10-year journey it’s great to be able to say that our spacecraft is ready to conduct unique science at comet 67P/C-G,” stated Fred Jansen, ESA’s Rosetta mission manager.

Source: European Space Agency

May 8, 2014December 23, 2015 by David Dickinson

Interesting Prospects for Comet A1 Siding Spring Versus the Martian Atmosphere

Inbound: the Hubble Space Telescope images Comet 2013 A1 Siding Spring with its Wide Field Camera 3. Credit: NASA.

It may be the chance of a lifetime for planetary science.

This October, a comet will brush past a planet, giving scientists a chance to study how it possibly interacts with a planetary atmosphere.

The comet is C/2013 A1 Siding Spring, and the planet in question Mars. And although an impact of the comet on the surface of the Red Planet has long been ruled out, a paper in the May 2014 issue of Icarus raises the interesting possibility of possible interactions of the coma of A1 Siding Spring and the tenuous atmosphere of Mars. The study comes out of the Department of Planetary Sciences at the University of Arizona, the Belgian Institute for Space Aeronomy, the Institut de Planétologie et d’Astrophysique de Grenoble at the Université J. Fourier in France, and the Cooperative Institute for Research in Environmental Sciences at the University of Colorado in Boulder.

For the study, researchers considered how active Comet A1 Siding Spring may be at the time of closest approach on October 19^th, 2014.

Discovered early last year by Robert McNaught from the Siding Spring Observatory in Australia, Comet A1 Siding Spring created a stir in the astronomical community when it was found that it will pass extremely close to Mars later this year. Further measurements of its orbit have since ruled this possibility out, but its passage will still be a close one, with a nominal passage of 138,000 kilometres from Mars. That’s about one third the distance from Earth to the Moon, and 17 times closer than the nearest recorded passage of a comet to the Earth, Comet D/1770 L1 Lexell in 1780. Mars’ outer moon Deimos has an orbital distance of about 23,500 kilometres.

The passage of Comet 2013 A1 Siding Spring through the inner solar system. Credit: NASA.

And although the nucleus will safely pass Mars, the brush with its extended atmosphere might just be detectable by the fleet of spacecraft and rovers in service around Mars. At a distance of 1.4 Astronomical Units (A.U.) from the Sun during the encounter, the vast coma is expected to be comprised primarily of H₂O. At an input angle of about 60 degrees, penetration was calculated in the study to impinge down and altitude of 154 kilometres to the topside of the Martian ionosphere, in the middle of the thermosphere.

Such an effect should linger for just over 4 hours, well over the interaction period of Mars’ atmosphere with the coma of just over an hour, centered on 18:30 UT on October 19^th, 2014.

What kind of views might missions like HiRISE and MSL get of the comet remains to be seen, although NEOWISE and Hubble are already monitoring the comet for enhanced activity. The Opportunity rover is also still functioning, and Mars Odyssey and ESA’s Mars Express are still in orbit around the Red Planet and sending back data. But perhaps the most interesting possibilities for observations of the event are still en route: India’s Mars Orbiter Mission and NASA’s MAVEN orbiter arrive just before the comet. MAVEN was designed to study the upper atmosphere of Mars, and carries an ion-neutral mass spectrometer (NGIMS) which could yield information on the interaction of the coma with the Martian upper atmosphere and ionosphere. The NGIMS cover is slated for release just two days before the comet encounter. All spacecraft orbiting Mars may feel the increased drag effects of the encounter.

A simulation of Mars as seen from Comet A1 Siding Spring on closest approach. Created by the author using Starry Night Software.

Proposals for using Earth-based assets for further observations of the comet prior to the event in October are still pending. Amateur observers will be able to follow the approach telescopically, as Comet A1 Siding Spring is expected to reach +8^th magnitude in October and pass 7’ from Mars in the constellation Ophiuchus as seen from the Earth. Mars just passed opposition last month, but both will be low to the south west at dusk for northern hemisphere observers in October.

It’s also interesting to consider the potential for interactions of the coma with the surfaces of the moons of Mars as well, though the net amount of water vapor expected to be deposited will not be large.

UPDATE: Check out this nifty interactive simulator which includes Comet A1 Siding Springs courtesy of the Solar System Scope:

The H₂O coma of A1 Siding Spring is expected to have a radius of 150,000 kilometres when it passes Mars, just a shade over the nominal flyby distance.

“There is a more extended coma made up of H₂O dissociation products (such as hydrogen and hydroxide) that extends for ~1,000,000 kilometres,” researcher at the Department of Planetary Sciences at the University of Arizona and lead author on the paper Roger Yelle told Universe Today.

“Essentially, Mars is in the outer reaches of the coma. The main ion tail misses Mars but there will be some ions from the comet that do reach Mars. The dust tail just misses Mars, which is fortunate.”

The paper also notes that significant perturbations of the upper atmosphere of Mars will occur if the cometary production rate is 10^28 s-1 or larger, which corresponds to about 300 kilograms per second.

“The MAVEN spacecraft will make very interesting observations,” Roger Yelle also told Universe Today. “The comet will perturb primarily the upper atmosphere of Mars and MAVEN was designed to study the upper atmosphere of Mars. Also, it’s just such an incredible coincidence that the comet arrives at Mars less than one month after MAVEN does. MAVEN is nominally in its checkout phase then, and the main science phase of the mission was not scheduled to start until November 1^st. However, we are reassessing our plans to see what observations we can make. It’s all quite exciting, and we have to balance safety and the desire to make the best science measurements.”

It’s an unprecedented opportunity, that’s for sure… all eyes will be on the planet Mars and Comet A1 Siding Spring on October the 19^th!

May 8, 2014December 23, 2015 by Bob King

Asteroid 2013 UQ4 Suddenly Becomes a Dark Comet with a Bright Future

Comet C/2013 UQ4, once thought to be an asteroid, now shows characteristics of a comet including a coma. This photo was made on May 7, 2014. Credit: Artyom Novichonok and Taras Prystavski

On October 23, 2013, astronomers with the Catalina Sky Survey picked up a very faint asteroid with an unusual orbit more like a that of a comet than an asteroid. At the time 2013 UQ4 was little more than a stellar point with no evidence of a hazy coma or tail that would tag it as a comet. But when it recently reappeared in the morning sky after a late January conjunction with the sun, amateur astronomers got a surprise.

On May 7, Comet ISON co-discoverer Artyom Novichonok, and Taras Prystavski used a remote telescope located in Siding Spring, Australia to take photos of 2013 UQ4 shortly before dawn in the constellation Cetus. Surprise, surprise. The asteroid had grown a little fuzz, making the move to comethood. No longer a starlike object, 2013 UQ4 now displays a substantial coma or atmosphere about 1.5 arc minutes across with a more compact inner coma measuring 25 arc seconds in diameter. No tail is visible yet, and while its overall magnitude of +13.5 won’t make you break out the bottle of champagne, it’s still bright enough to see in a 12-inch telescope under dark skies.

Wide field map showing the comet's movement from Cetus through Pisces and into Cepheus in July when it becomes circumpolar for skywatchers at mid-northern latitudes. It should reach peak brightness of 7th magnitude in early July. Created with Chris Marriott's SkyMap program — Wide field map showing the comet’s movement from Cetus through Pisces and into Cepheus in July when it becomes circumpolar for skywatchers at mid-northern latitudes. It should reach a peak brightness of 7th magnitude in early July. Click to enlarge. Created with Chris Marriott’s SkyMap program

The best is yet to come. Assuming the now renamed C/2013 UQ4 continues to spout dust and water vapor, it should brighten to magnitude +11 by month’s end as it moves northward across Pisces and into a dark morning sky. Perihelion occurs on June 5 with the comet reaching magnitude +8-9 by month’s end. Peak brightness of 7th magnitude is expected during its close approach of Earth on July 10 at 29 million miles (46.7 million km).

This should be a great summer comet, plainly visible in binoculars from a dark sky as it speeds across Cepheus and Draco during convenient viewing hours at the rate of some 7 degrees per night! That’s 1/3 of a degree per hour or fast enough to see movement through a telescope in a matter of minutes when the comet is nearest Earth.

Lightcurve showing the date on the bottom and magnitude along the vertical. Work by Artyom Novichonok and Taras Prystavski — Light curve showing C/2013 UQ4 brightening to a sharp peak in early July and then quickly fading. Created by Artyom Novichonok and Taras Prystavski

Come August, C/2013 UQ4 rapidly fades to magnitude +10 and then goes the way of so many comets – a return to a more sedentary lifestyle in the cold bones of deep space.

C/2013 UQ4 belongs to a special category of asteroids called damocloids (named for asteroid 5335 Damocles) that have orbits resembling the Halley-family comets with long periods, fairly steep inclinations and highly eccentric orbits (elongated shapes). Some, like Comet Halley itself, even travel backwards as they orbit the sun, an orbit astronomers describe as ‘retrograde’.

Evolution of a comet as it orbits the sun. Credit: Laboratory for Atmospheric and Space Sciences/ NASA

Damocloids are thought to be comets that have lost all their fizz. With their volatile ices spent from previous trips around the sun, they stop growing comas and tails and appear identical to asteroids. Occasionally, one comes back to life. It’s happened in at least four other cases and appears to be happening with C/2013 UQ4 as well.

Studies of the comet/asteroid’s light indicate that UQ4 is a very dark but rather large object some 4-9 miles (7-15 km) across. It’s estimated that C/2013 UQ4 takes at least 500 years to make one spin around the sun. Count yourself lucky this damocloid decided to spend its summer vacation in Earth’s skies. We’ll have more detailed maps and updates as the comet becomes more easily visible next month. Stay tuned.

May 5, 2014December 23, 2015 by David Dickinson

Comet Jacques Brightens: How to See it in May

Comet Jacques as imaged on March 18th, shortly after discovery. Credit: Efrain Morales Rivera.

A recently discovered comet is headed northward and is set to put on one of two fine performances for binocular observers in 2014 starting this week.

Comet C/2014 E2 Jacques was discovered on March 13^th 2014 by Cristóvão Jacques, Eduardo Pimentel and João Ribeiro de Barros while observing from the Southern Observatory for Near Earth Asteroids Research (SONEAR) facility located near Oliveira, Brazil.

The comet was just about at +15^th magnitude at the time of discovery as it glided across the southern hemisphere constellation of Centaurus.

While a majority of comet discoveries are destined to remain small and faint, Comet Jacques was immediately shown to be something special. Upon discovery of any new comet, the first task is to gain several observations hours or nights apart to accurately gauge its distance and orbit. Are astronomers looking at a small, garden variety comet close up, or a large, active one far away?

In the case of Comet Jacques, it was something in between: a comet about 1.22 Astronomical Units (A.U.s) distant at time of discovery. Comet Jacques is headed towards perihelion 0.66 A.U. from the Sun in early July and will pass 0.56 A.U. from Earth on August 28th. Follow up observations carried out using the iTelescope at Siding Spring Australia showed a slightly elongated coma about 2 arc minutes across shortly after discovery, and the comet has recently jumped up to magnitude +8 — ahead of the projected light curve — in just the past week.

We caught our first good look at Comet Jacques last night while setting up for the Virtual Star Party. While +10 magnitude or brighter is usually a pretty good rule of thumb for binocular visibility, we found that the comet was only apparent as a fuzzy smudge viewing it with a 8” Schmidt-Cassegrain telescope using averted vision at low power. Remember, the brightness of a comet is spread out over its apparent surface area, similar to viewing a diffuse nebula. Our first telescopic views of the ill-fated comet ISON as it breeched +10^th magnitude were similar. Certainly, a nearby waxing crescent Moon in Gemini last night didn’t help.

How bright will Comet Jacques get? Current projections call for it to perhaps break naked eye visibility around +6^th magnitude after June 1^st and reach as bright as +4^th magnitude in early July near perihelion. After its first evening act in May and June, Comet Jacques will reemerge in the dawn sky for northern hemisphere observers for Act 2 and trace a path northward paralleling the galactic plane through the star rich fields of Perseus, Cassiopeia, Cepheus and Cygnus in August and September of this year. If our luck holds out, Comet Jacques will remain above 6^th magnitude until early September.

Credit JPL — The path of Comet Jacques through the inner solar system. Credit: JPL solar system small body generator.

This comet also created a brief flurry of interest when it was revealed that it will pass just 0.085 AUs or 12,700,000 kilometers from Venus on July 13^th, 2014. Though close, this is still 31 times the distance from Earth to the Moon. The only “eyes” that humanity has currently in operation around Venus is ESA’s Venus Express orbiter. During closest approach Comet Jacques will appear just over 3 degrees away from Venus as seen from our Earthly vantage point.

Another comet is also set to photobomb a planet, as Comet A1 Siding Spring passes a nominal distance of 0.0009 A.U.s or 135,000 kilometers from Mars this Fall on October 19th.

The closest recorded passage of a comet near Earth was Comet D/1770 L1 Lexell in 1770, which passed us 0.015 A.U.s or 233 million kilometres distant.

Now on to Act 1. May finds Comet Jacques spending most of the month in the long rambling constellation of Monoceros. Currently moving just under 2 degrees a day, Comet Jacques crosses the celestial equator northward this week on May 8^th. You’ll note its high orbital inclination of 156.4 degrees as it speeds northward. Comet Jacques has a long orbital period gauged at over 30,000 years — the last time Comet Jacques visited the inner solar system, our ancestors had the Last Glacial Maximum period to look forward to.

Light curve — The projected light curve of comet Jacques with recent observations. Credit: Seiichi Yoshida/aerith.net.

Comet Jacques is currently the brightest comet “with a bullet,” edging out the +9^th magnitude comets C/2012 K1 PanSTARRS gilding through Canes Venatici and comet C/2012 X1 LINEAR, currently residing in the constellation of Aquila the Eagle. A great place to keep up with current observations of comets is the Comet Observation Database. We’re also pinging the IAU Minor Planet Center’s quick look page for new discoveries daily.

Here are some highlights to watch out for as Comet Jacques heads towards perihelion. Passages within one degree — twice the size of the Full Moon — near stars brighter than +5^th magnitude are noted unless mentioned otherwise:

The celestial path of Comet Jacques from May 3rd through June 1st. Credit: Starry Night.

May 8^th: Passes the +4.1 magnitude star Delta Monocerotis and crosses north of the celestial equator.

May 10^th: Passes planetary nebula NGC 2346.

May 11^th: Passes briefly into Canis Minor before reentering the constellation Monoceros.

May 14^th: Full Moon occurs, marking the start of a favorable two week period of moonless evenings soon after.

May 24^th: Passes the +4.8 magnitude star 17 Monocerotis.

May 28^th: New Moon occurs, marking the return of the Moon to early evening skies.

May 29^th: Passes the +4.7 magnitude star 15 Monocerotis.

May 30^th: Passes the Christmas tree cluster. Photo op!

May 31^st: The waxing crescent Moon passes less than 8 degrees from Comet Jacques.

June 1^st: Comet Jacques reaches naked eye visibility?

June 6^th: Crosses into the constellation Gemini.

June 11^th: Crosses into the constellation Taurus.

June 13^th: Full Moon occurs.

June 14^th:Crosses the galactic plane.

June 21^st: Passes into the field of view of SOHO’s LASCO C3 camera.

June 27^th: New Moon occurs.

July 2^nd: Reaches perihelion at 0.6638 A.U. from the Sun.

July 8^th: Crosses north of the ecliptic plane.

July 13^th: Passes 0.085 A.U. from Venus.

August 28^th: Passes 0.56 A.U. from Earth.

And thus, Comet Jacques joins the parade of fine binocular comets in the 2014 night sky, as the stage is set for Act 2 this fall. And keep in mind, the next “big one” could grace our skies at anytime… more to come!

May 4, 2014December 23, 2015 by Bob King

Revisit Halley’s Comet – Stay Up Late for This Week’s Eta Aquarid Meteor Shower

The Eta Aquarid meteor shower is active in early May and peaks before dawn on Tuesday and Wednesday May 6-7 this year. Watch for it before the start of morning twilight in the eastern sky. Created with Stellarium

UPDATE: Watch a live webcast of the meteor shower, below, from NASA’s Marshall Space Flight Center during the night of Monday, May 5 to the early morning of May 6.

Halley’s Comet won’t be back in Earth’s vicinity until the summer of 2061, but that doesn’t mean you have to wait 47 years to see it. The comet’s offspring return this week as the annual Eta Aquarid meteor shower. Most meteor showers trace their parentage to a particular comet. The Perseids of August originate from dust strewn along the orbit of comet 109P/Swift-Tuttle, which drops by the inner solar system every 133 years after “wintering” for decades just beyond the orbit of Pluto, but the Eta Aquarids (AY-tuh ah-QWAR-ids) have the best known and arguably most famous parent of all – Halley’s Comet. Twice each year, Earth’s orbital path intersects dust and rock particles strewn by Halley during its cyclic 76-year journey from just beyond Uranus to within the orbit of Venus. When we do, the grit meets its demise in spectacular fashion as wow-inducing meteors.

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Composite of Aquarid meteors from the 2012 shower. Credit: John Chumack

Meteoroids enter the atmosphere and begin to glow some 70 miles high. The majority of them range from sand to pebble sized but most no more than a gram or two. Speeds range from 25,000-160,000 mph (11-72 km/sec) with the Eta Aquarids right down the middle at 42 miles per second (68 km/sec). Most burn white though ‘burn’ doesn’t quite hit the nail on the head. While friction with the air heats the entering meteoroid, the actual meteor or bright streak is created by the speedy rock exciting atoms along its path. As the atoms return to their neutral state, they emit light. That’s what we see as meteors. Picture them as tubes of glowing gas.

The farther south you live, the higher the shower radiant will appear in the sky and the more meteors you’ll see. For southern hemisphere observers this is one of the better showers of the year with rates around 30-40 meteors per hour. With no moon to brighten the sky, viewing conditions are ideal. Except for maybe the early hour. The shower is best seen in the hour or two before the start of dawn.

The Eta Aquarid shower originates with material left behind by Halley's Comet when the sun boils dust and ice from its nucleus around the time of perihelion. This photo from May 1986 during its last pass by Earth. Credit: Bob King — The Eta Aquarid shower originates with material left behind by Halley’s Comet when the sun boils dust and ice off its nucleus around the time of perihelion. This photo from May 1986 during Halley’s last visit. Credit: Bob King

From mid-northern latitudes the radiant or point in the sky from which the meteors will appear to originate is low in the southeast before dawn. At latitude 50 degrees north the viewing window lasts about 1 1/2 hours; at 40 degrees north, it’s a little more than 2 hours. If you live in the southern U.S. you’ll have nearly 3 hours of viewing time with the radiant 35 degrees high.

A bright, earthgrazer Eta Aquarids streaks across Perseus May 6, 2013. Because the radiant is low for northern hemisphere observers, earthgrazers - long, bright meteors that come up from near the horizon and have long-lasting trails. Credit: Bob King — A bright, earthgrazing Eta Aquarid meteor streaks across Perseus May 6, 2013. Because the radiant is low for northern hemisphere observers, watch for earthgrazers – long, bright meteors that come up from near the horizon and have long-lasting trails. Credit: Bob King

Northerners might spy 5-10 meteors per hour over the next few mornings. Face east for the best view and relax in a reclining chair. One good thing about this event – it won’t be anywhere near as cold as watching the December Geminids or January’s Quadrantids. We must be grateful whenever we can.

Meteor shower members can appear in any part of the sky, but if you trace their paths in reverse, they’ll all point back to the radiant. Other random meteors you might see are called sporadics and not related to the Eta Aquarids. Because Aquarius is home to at least two radiants, we distinguish the Etas, which radiate from near Eta Aquarii, from the Delta Aquarids, an unrelated shower active in July and August.

Wishing you clear skies and plenty of hot coffee at the ready.

April 28, 2014December 23, 2015 by Bob King

May Meteor Storm Alert: All Eyes on the Sky!

Composite photo of Lyrid meteor shower and non-Lyrids taken with a NASA All-sky camera April 21-23, 2012. Credit: NASA/MSFC/Danielle Moser

On Friday night/early Saturday May 23-24 skywatchers across the U.S. and southern Canada may witness the birth of a brand new meteor shower. If predictions hold true, Earth will pass through multiple tendrils of dust and pebbly bits left behind by comet 209P/LINEAR, firing up a celestial display on par with the strongest showers of the year. Or better.

Peter Jenniskens of the SETI Institute, who predicted a possible meteor storm associated with comet 209P/LINEAR. Credit: NASA

Earlier predictions called for a zenithal hourly rate or ZHR of 1,000 per hour, pushing this shower into the ‘storm’ category. ZHR is an idealized number based on the shower radiant located at the zenith under ideal skies. The actual number is lower depending on how far the radiant is removed from the zenith and how much light pollution or moonlight is present. Meteor expert Peter Jenniskens of the SETI Institute and Finland’s Esko Lyytinen first saw the possibility of a comet-spawned meteor storm and presented their results in Jenniskens’ 2006 book Meteor Showers and Their Parent Comets.

Approximate location of the radiant of the 209P/LINEAR shower at the peak of the brief maximum around 2 a.m. CDT May 24. Between 100-400 meteors may radiate from the dim constellation of Camelopardalis near the North Star. This map shows the sky from Des Moines, Iowa. Created with Stellarium — Approximate location of the radiant (blue) of the 209P/LINEAR shower at the peak of the brief maximum around 2 a.m. CDT May 24. Between 100-400 meteors may radiate from the dim constellation of Camelopardalis near the North Star. This map shows the sky from the central U.S. Created with Stellarium

Quanzhi Ye and Paul Wiegert (University of Western Ontario) predict a weaker shower because of a decline in the comet’s dust production rate based on observations made during its last return in 2009. They estimate a rate of ~200 per hour.

On the bright side, their simulations show that the comet sheds larger particles than usual, which could mean a shower rich in fireballs. Other researchers predict rates between 200 and 40o per hour. At the very least, the Camelopardalids – the constellation from which the meteors will appear to originate – promise to rival the Perseids and Geminids, the year’s richest showers. Motivation for setting the alarm clock if there ever was.

Comet 209P/LINEAR on April 14, 2014. It’s currently very faint at around magnitude 17. Material shed by the comet during passes between 1898-1919 may spawn a rich meteor shower overnight May 23-24. Credit: Ernesto Guido, Nick Howes, Martino Nicolini — Comet 209P/LINEAR on April 14, 2014. It’s currently very faint at around magnitude +17. Material shed by the comet during passes from 1898-1919 is expected to contribute to a May 23-24 shower. Credit: Ernesto Guido, Nick Howes, Martino Nicolini

Comet 209P/LINEAR, discovered in Feb. 2004 by the automated Lincoln Laboratory Near-Earth Asteroid Research (LINEAR) sky survey, orbits the sun every 5.04 years with an aphelion (most distant point from the sun) near Jupiter. In 2012, during a relatively close pass of that planet, Jupiter perturbed its orbit, bringing it to within 280,000 miles (450,000 km) of Earth’s orbit.

That set up a remarkably close encounter with our planet on May 29 when 209P will cruise just 5 million miles (8 million km) from Earth to become the 9th closest comet ever observed. Multiple debris trails shed by the comet as long ago as the 18th century will intersect our planet’s path 5 days earlier, providing the material for the upcoming meteor shower/storm.

Shining meekly around magnitude +17 at the moment, 209P/LINEAR could brighten to magnitude +11 as it speeds from the Big Dipper south to Hydra during the latter half of May. Closer to the BIG night, we’ll provide helpful maps for you to track it down in your telescope. Cool to think that both the shower and its parent comet will be on display at the same time.

The shaded area shows where the shower will be visible on May 23-24. North of the red line, the moon (a thick crescent) will be up during shower maximum around 2:10 a.m. CDT. Credit: Mikhail Maslov

The shower’s expected to last only a few hours from about 12:40-3:50 a.m. CDT with the best viewing locations in the U.S. and southern half of Canada. This is where the radiant will be up in a dark sky at peak activity. A thick crescent moon rises around 3-3:30 a.m. but shouldn’t pose a glare problem.

Meteors from 209P/LINEAR are expected to be bright and slow with speeds around 40,000 mph compared to an average of 130,000 mph for the Perseids. Most shower meteoroids are minute specks of rock, but the Camelopardalids contain a significant number of particles larger than 1mm – big enough to spark fireballs.

The dark streak is a series of filaments of dust and grit left behind by 209P/LINEAR mostly between 1803 and 1924 that Earth (shown on path) will pass through on May 23-24, 2014. Credit: — The dark “finger” represents streams of dust and rocks left behind by 209P/LINEAR during passes made from 1803 to 1924. Earth is shown intersecting the debris on May 23-24, 2014. Credit: Dr. Jeremie Vaubaillon

The farther north you live in the shaded area on the map, the higher the radiant stands in the northern sky and the more meteors you’re likely to see. Skywatchers living in the Deep South will see fewer shooting stars, but a greater proportion will be earthgrazers, those special meteors that skim the upper atmosphere and flare for an unusually long time before fading out.

To see the shower at its best, find a dark place with an open view to the north. Plan your viewing between 12:30 and 4 a.m. CDT (May 24), keeping the 2 a.m. forecast peak in mind. Maximum activity occurs around 3 a.m. Eastern, 1 a.m. Mountain and midnight Pacific time.

No one’s really certain how many meteors will show, but I encourage you to make the effort to see what could be a spectacular show.

April 25, 2014December 23, 2015 by Bob King

Take a Look: Comet PANSTARRS K1 Swings by the Big Dipper this Week, Sprouts Second Tail

Comet C/2012 K1 PANSTARRS displays two tails in this excellent image taken with an 8-inch f/2.8 telescope on April 20, 2014 from Austria. The shorter, brighter spike is the dust tail; the longer is the ion tail with distinct kinks caused by interactions with the solar wind.

Comets often play hard to get. That’s why we enjoy those rare opportunities when they pass close to naked eye stars. For a change, they’re easy to find! That’s exactly what happens in the coming nights when the moderately bright comet C/2012 K1 PANSTARRS slides past the end of the Big Dipper’s handle. I hope Rolando Ligustri’s beautiful photo, above, entices you roll out your telescope for a look.

Comet K5 PANSTARRS glides from northern Bootes up the handle of the Big Dipper this coming week not far from the famed Whirlpool Galaxy M51. This map shows the sky facing east (west is at top, east at bottom) with stars to magnitude +11. Created with Chris Marriott's SkyMap software — Comet K1 PANSTARRS glides from northern Bootes up the handle of the Big Dipper this coming week not far from the bright star Alkaid and M51, the Whirlpool Galaxy. This map shows the sky facing east (west is at top, east at bottom) with stars to magnitude +11 and the comet’s position at 10 p.m. CDT daily. Click to enlarge and then print out a copy you can use at the telescope. Created with Chris Marriott’s SkyMap software

If you’ve put off viewing this fuzzball because it’s been lost in the wilds of northern Bootes too long, hesitate no more. I saw it several nights ago through a 15-inch (37-cm) scope and can report a teardrop-shaped coma with a bright, not-quite-stellar nucleus. The comet sports an 8 arc minute long faint tail (1/4 the diameter of the full moon) and glows around magnitude 9-9.5. Granted I observed from dark skies, but K1 PANSTARRS could even be seen faintly in the 10×50 finderscope, putting it within range of ordinary binoculars.

Use this map to get oriented. It shows the sky facing east around 10 o'clock in late April. The comet passes very near Alkaid on April 28-29. Stellarium — Use this map to get oriented. It shows the sky facing east around 10 o’clock in late April. The comet passes very near Alkaid on April 28-29. Stellarium

Ligustri’s photo shows both gas and dust tails, but most observers will probably pick up the dust tail and strain to see the other. The comet has been moving north and slowly waxing in brightness all winter and spring. Right now, it’s ideally placed for viewing in the early evening sky and remains up all night for northern hemisphere observers. On Monday and Tuesday April 28-29 it’s within 1 degree of Alkaid, the bright star at the end of the Dipper’s handle.

C/2012 K1 PANSTARRS, discovered with the Pan-STARRS 1 telescope high up the Haleakala volcano on Maui, Hawaii. Credit: Carl Hergenrother — C/2012 K1 PANSTARRS, discovered in May 2012 with the Pan-STARRS 1 telescope from Hawaii, has been under observation a long time. Here on Sept. 13, 2013 it was a still a small, dim object of magnitude ~+13. Credit: Carl Hergenrother

In a 6-inch (15-cm) scope, expect to see a faint puff with a brighter core; observers with 8-inch and larger telescopes will more easily see the tail. K1 PANSTARRS continues to brighten through the spring and summer as it saunters from the Great Bear into Leo. In late July it will be too near the sun to view but re-emerge a month later in Hydra in the morning sky. Southern hemisphere skywatchers will be favored during the fall and early winter, though the comet will continue to hover very low in the southern morning sky for northerners. Predictions call for the PANSTARRS to reach peak brightness around magnitude +6 to +7 in mid-October.

Sounds like old C/2012 K1 will be around a good, long time. Why not get acquainted?

April 18, 2014December 23, 2015 by David Dickinson

Get Ready for the Lyrid Meteor Shower: Our Complete Guide for 2014

A composite of 33 Lyrid meteors captured by the UK Meteor Network cameras in 2012. Credit: @UKMeteorNetwork

The month of April doesn’t only see showers that bring May flowers: it also brings the first dependable meteor shower of the season. We’re talking about the Lyrid meteors, and although 2014 finds the circumstances for this meteor shower as less than favorable, there’s still good reason to get out this weekend and early next week to watch for this reliable shower.

The Lyrid meteor shower typically produces a maximum rate of 10-20 meteors per hour, although outbursts topping over a hundred per hour have been observed on occasion. The radiant, or the direction that the meteors seem to originate from, lies at right ascension 18 hours and 8 minutes and declination +32.9 degrees north. This is just about eight degrees to the southwest of the bright star Vega, which is the brightest star in the constellation of Lyra the Lyre, which also gives the Lyrids its name.

Fun fact: this radiant actually lies juuusst across the border of Lyra in the constellation of Hercules… technically, the “Lyrids” should be the “Herculids!” This is because the shower was identified and named in the 19th century before the International Astronomical Union officially adopted the modern layout we use for the constellations in 1922.

The rising Lyrid radiant, looking to the north east at 2AM local from latitude 30 degrees north. Created using Stellarium. — The rising Lyrid radiant, looking to the northeast at 2AM local from latitude 30 degrees north. Created using Stellarium.

The source of the Lyrids was tracked down in the late 1860s by mathematician Johann Gottfried Galle to Comet C/1861 G1 Thatcher, the path of which came within 0.02 Astronomical Units (A.U.s) of the Earth’s orbit on April 20^th, 1861, just six weeks before the comet reached perihelion. Comet G1 Thatcher is on a 415 year orbit and won’t return to the inner solar system until the late 23^rd century.

The orbital path of Comet G1 Thatcher during its 1861 passage. Credit: NASA/JPL Ephemeris Generator.

But we can enjoy the dust grains it left in its wake as they greet the Earth to burn up in its atmosphere every April. The activity of the Lyrids typically spans April 16^th to the 25^th, with a short 24 hour peak above a ZHR of 10 on April 22^nd-23^rd. Thus, like the short duration Quadrantids in January, timing is critical; if you happen to observe this shower before or after the peak, you may see nothing at all. This year, the key mornings will be Tuesday, April 22^nd, and Wednesday April 23^rd. The wide disparity of predictions for the exact arrival of the peak of the Lyrids, as quoted in differing sources speaks to just how poorly this meteor shower is understood. Scanning various reliable resources, we see times quoted from April 22^nd at 4:00 Universal Time (UT) from the American Meteor Society, to 17:00 UT on the same date for the Royal Canadian Astronomical Society, to April 23^rd at 17:45 UT from Guy Ottewell’s venerable 2014 Astronomical Calendar!

Definitely, more observations of this curious shower are needed.

The position of the Lyrid meteor shower radiant across the border in the constellation Hercules. (Credit Starry Night Education software).

Now for the bad news. This year finds the light-polluting Moon in nearly its worst location possible for a meteor shower. Remember this week’s total lunar eclipse? Well, the Moon is now waning gibbous and will reach last quarter phase at 7:52 UT/3:52 AM EDT on April 22^nd, and will thus be rising at local midnight and be high in the sky towards dawn. The Lyrid radiant rises at 9:00 PM this week for observers around 40 degrees north and rides highest at 6:00 AM local, about 45 minutes before sunrise.

Looking at the International Meteor Organization’s historical data, here’s what the Lyrids have done over the past few years:

2013- ZHR 22, Moon phase= 88% illuminated, waxing gibbous.

2012– ZHR 25, Moon phase= 2% illuminated, waxing crescent.

2011- ZHR 20, Moon phase= 73% illuminated waning gibbous.

2010- ZHR 32, Moon phase= 62% illuminated waxing gibbous.

2009- ZHR 15, Moon phase= 7% illuminated waning crescent.

A “ZHR” is the Zenithal Hourly Rate, a theoretical maximum number of meteors that an observer could expect to witness under dark skies if the radiant was straight overhead. Note that 2011 had similar circumstances with respect to the Moon as this year, so don’t despair! The Lyrids are approaching the Earth from nearly perpendicular in its orbit and have a head on velocity of about 48 kilometres per second, respectable for a meteor shower. They also present a higher-than-average number of fireballs, with about a quarter leaving persistent trains.

Outbursts have also occurred in 1803, 1849, 1850, 1922, 1945 and 1982. United States observers based in Florida and Colorado noted a brief ZHR approaching 100 per hour back in 1982 under especially favorable New Moon conditions.

The orientation of the Earth on April 22nd at 12UT/08AM EDT. Credit: Stellarium.

Ironically, the Lyrids are also one of the oldest meteor showers identified from historic records. In fact, Galle actually traced the shower back to Chinese records dating all the way back to March 16^th 687 BC, which describes “Stars (that) dropped down like rain…” clearly, the Lyrids were considerably more active in ancient times.

More recently, attempts were made to link the 2012 Sutter’s Mill meteorite fall to the Lyrids, which were underway at the time. This turned out to be a case of “meteor-wrong,” however, as described by Geoff Notkin of the Meteorite Men who noted that no meteorite fall has ever been linked to a meteor shower, though he does get lots of calls whenever news of a big meteor shower hits the press.

A good strategy for beating the Moon includes blocking it behind a hill or building while observing. Early morning is the best time to watch for Lyrids — or most any meteor shower for that matter — as you’re then on the half of the Earth facing forward into the meteor stream. And you don’t have to face toward the radiant to see Lyrid meteors, as they can appear anywhere in the sky.

With the advent of DSLRs, photographing meteors is easier than ever before. All you need to do is use a wide angle lens and take periodic time exposures of the sky. Do a few early test shots to get the combination of f-stop, ISO and shutter speed just right for current sky conditions, and be sure to review those images on a full size monitor afterward: nearly every meteor we’ve captured turned up in post-review only.

Looking to contribute to our understanding of the Lyrid meteors? Simply count the number you see and the location and length of your observation and send your report into the International Meteor Organization. And don’t forget to tweet those Lyrids to #Meteorwatch!

…and there’s more to come. Next month, a true “wildcard outburst” may be in the offing from Comet 209P/LINEAR on May 26^th… can you say “Camelopardalids?”

Stay tuned!