Viewing Guide to the 2015 Geminid Meteor Shower

A brilliant Geminid flashes below Sirius and Orion over Mount Balang in China. Credit: NASA/Alvin Wu
A brilliant Geminid flashes below Sirius and Orion over Mount Balang in China. Credit: NASA/Alvin Wu

2015 looks like a fantastic year for the Geminids. With the Moon just 3 days past new and setting at the end of evening twilight, conditions couldn’t be more ideal. Provided the weather cooperates! But even there we get a break. With a maximum of 120 meteors per hour, the shower is expected to peak around 18:00 UT (1 p.m. EST, 10 a.m. PST) December 14th, making for two nights of approximately equal activity: Sunday night Dec. 13-14 and Monday night Dec. 14-15.  Continue reading “Viewing Guide to the 2015 Geminid Meteor Shower”

Hunting Unicorns: Is an Alpha Monocerotid Outburst Due in 2015?

Image Credit: Kenneth Brandon

What’s rarer than a unicorn? Perhaps, its spying a a elusive meteor outburst from the heart of one…

Ready for more meteor shower action? Thus far this season, we’ve covered the Orionids, Taurid fireballs, and the Leonid meteors… 

Up for one more? Well, this week’s offering is a bit chancy, but we ‘may’ be in for a minor outburst from a usually quiescent shower. On any given year, the Alpha Monocerotid meteors wouldn’t rate a second look.

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A confirmed 2014 Alpha Monocerotid. Image credit: The United Kingdom Meteor Observation Network (UKMON)

First, however, a caveat is in order. Meteor showers never read prognostications and often prove to be fickle, and wild card meteor storms doubly so.

Not to be confused with the straight up Monocerotids which peak in early December, the Alpha Monocerotids are moderately active from November 15th through the 25th, with a soft peak on the 22nd. And though the radiant derives its name from the brightest star in the rambling constellation of Monoceros the Unicorn, the radiant is actually located at its peak at right ascension 7 hours 46 minutes and declination +00 degrees 24 minutes, just across the border in the constellation Canis Minor.

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Another bright Alpha Moncerotid meteor under a bright Moon. Image credit: UKMON

The Alpha Monocerotids have a curious history. They first caught the keen eye of observers in 1925, when F.T. Bradley watching from rural Virginia noted 37 meteors over a 13 minute span. In the 20th century, small outbursts seemed to ply the skies around November 22nd on the fifth year of each decade, with brief outbursts seen in 1935 and 1985. NASA astronomer and SETI Institute research scientist Peter Jenniskens predicted a 1995 outburst, and as predicted, a brief 30 minute display greeted members of the Dutch Meteor Society based under dark skies in southern Spain. The shower had a brief 5-minute climax in 1995, with an extrapolated zenithal hourly rate of 420.

6AM local radiant. image credit
The location of the Alpha Monocerotid meteor shower radiant at 6AM local from about 30 degrees latitude north. Image credit: Stellarium

Prospects for the shower in 2015

As of this writing, a major outburst from the Alpha Monocerotids isn’t predicted for 2015… but you just never know. It’s always worth watching for an outburst on the night of November 21/22nd, especially in years ending in five.

In 2015, the Moon phase for the night of Saturday/Sunday November 21st/22nd is waxing gibbous and about 79% illuminated and setting at around 1:00 AM local, putting it safely out of view.

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The orientation of the Earth’s shadow, Moon, Sun and shower radiant at 4:00 UT, November 22nd. Image credit: Orbitron

The predicted peak for the 2015 Alpha Monocerotids is centered on 4:25 UT/11:25 PM EST as per the International Meteor Organization (IMO), favoring western European longitudes in a similar fashion as 1995 at dawn on Sunday, November 22nd.

Thus far, the source comet for the Alpha Monocerotids remains a mystery, though a prime contender is Comet C/1943 W1 van Gent-Peltier-Daimaca. Discovered during the Second World War, this comet has an undefined long period orbit, and reached perihelion 0.87 AU from the Sun on January 12th, 1944.

Jenniskens notes that orbital configurations of Jupiter and Saturn may play a role in the long term modification of meteor streams such as the Alpha Monocerotids. A fascinating discussion on predicting meteor outbursts and the evolution of meteor streams by Mr Jenniskens can be read here.

The stream seems to have a very brief burst of activity of less than an hour, reminiscent of the elusive January Quadrantids. The Alpha Monocerotid radiant sits highest in the sky at around 4 AM local, and the incoming speed of the meteors is a very respectable 65 kilometers a second, making for brief swift trails.

Meteor Watching and Reporting

But beyond just observing, many sky watchers choose to log what they see and report it. Meteor shower streams—especially obscure ones such as the Alpha Monocerotids—are often poorly understood, and observers provide a valuable service by counting and reporting the number of meteors seen over a particular period of time.

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NASA’s All-sky meteor network captures a fireball. Image credit: NASA’s All-Sky Fireball Network

Imaging meteors is as simple as setting up a DSLR on a tripod for wide angle shots, and taking repeated exposures of the sky. We generally take a few test shots to get the ISO/f-stop mix just right for the current sky conditions, then set our intervalometer to take repeated 30-second exposures while we visually observe. Aim about 45 degrees away from the radiant to catch meteors in profile, and check the camera lens periodically for morning dew. We generally keep a hair dryer handy to combat condensation under moisture-laden Florida skies.

Maybe a vigil for an Alpha Monocerotid outburst is an exercise in hunting unicorns… but watching an outburst would be an unforgettable sight. Perhaps, the Alpha Monocerotid stream is on the wane in the 21st century… or a new outburst is still in the wings, waiting to greet dawn residents of the Earth.

‘Explody’ Taurid Meteors Produce Persistent Trains

A bright Taurid meteor falls over Deadfall Basin, near the base of Mount Eddy in California. Credit and copyright: Brad Goldpaint.

“The landscape was just at the verge of trying to silently explode with vibrant colors of red, gold and oranges,” said photographer Brad Goldpaint as he described the autumn view during his hike to Deadfall Basin in California to set up his cameras to try and capture a few Taurid meteors.

But the landscape wasn’t the only thing about to explode.

Later that night Brad captured a few “exploding” meteors that produced what are called persistent trains: what remains of a meteor fireball in the upper atmosphere as winds twist and swirl the expanding debris.

Brad created a time-lapse video from the event and slowed down the footage to highlight the trains.

Persistent trains have been difficult to study because they are rather elusive. But lately, with the widespread availability of ultra-fast lenses and highly sensitive cameras, capturing these trains is becoming more common.

Phil Plait still has the best description out there of what happens when persistent trains are produced:

As a meteoroid (the actual solid chunk of material) blasts through the air, it ionizes the gases, stripping electrons from their parent atoms. As the electrons slowly recombine with the atoms, they emit light — this is how neon signs glow, as well as giant star-forming nebulae in space. The upper-level winds blowing that high (upwards of 100 km/60 miles) create the twisting, fantastic shapes in the train.

The consensus among our Universe Today Flickr pool photographers who posted images of the Taurids this year is that the 2015 Taurids weren’t entirely remarkable. Most astrophotgraphers reported they saw one or two per hour. Here are a few more Taurid meteor shower images from our photographer friends:

A bright Taurid fireball on November 9, 2015. Credit and copyright: Mark Sansom.
A bright Taurid fireball on November 9, 2015. Credit and copyright: Mark Sansom.
Two Taurid meteors from the November 2015 shower, on November 10, 2015. Credit and copyright: Alan Dyer.
Two Taurid meteors from the November 2015 shower, on November 10, 2015. Credit and copyright: Alan Dyer.
A bright Taurid meteor is reflected in a lake in Illinois. Credit and copyright: Kevin Palmer.
A bright Taurid meteor is reflected in a lake in Illinois. Credit and copyright: Kevin Palmer.

MESSENGER Spies a Meteor Shower… on Mercury

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Leonid meteor storms. Taurid meteor swarms. Earth is no stranger to meteor showers, that’s for sure. Now, it turns out that the planet Mercury may experience periodic meteor showers as well.

The news of extraterrestrial meteor showers on Mercury came out of the annual Meeting of the Division of Planetary Sciences of the American Astronomical Society currently underway this week in National Harbor, Maryland. The study was carried out by Rosemary Killen of NASA’s Goddard Spaceflight Center, working with Matthew Burger of Morgan State University in Baltimore, Maryland and Apostolos Christou from the Armagh Observatory in Northern Ireland.  The study looked at data from the MErcury Surface Space Environment Geochemistry and Ranging (MESSENGER) spacecraft, which orbited Mercury until late April of this year. Astronomers published the results in the September 28th issue of Geophysical Research Letters.

Micrometeoroid debris litters the ecliptic plane, the result of millions of years of passages of comets through the inner solar system. You can see evidence of this in the band of the zodiacal light visible at dawn or dusk from a dark sky site, and the elusive counter-glow of the gegenschein.

The orbit of comet 2P Encke. Image credit: NASA/JPL
The orbit of comet 2P Encke. Image credit: NASA/JPL

Researchers have tagged meteoroid impacts as a previous source of the tenuous exosphere tails exhibited by otherwise airless worlds such as Mercury. The impacts kick up a detectable wind of calcium particles as Mercury plows through the zodiacal cloud of debris.

“We already knew that impacts were important in producing exospheres,” says Killen in a recent NASA Goddard press release. “What we did not know was the relative importance of comet streams over zodiacal dust.”

This calcium peak, however, posed a mystery to researchers. Namely, the peak was occurring just after perihelion—Mercury orbits the Sun once every 88 Earth days, and travels from 0.31 AU from the Sun at perihelion to 0.47 AU at aphelion—versus an expected calcium peak predicted by researchers just before perihelion.

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STEREO A catches sight of comet 2P Encke. Image credit: NASA/STEREO

A key suspect in the calcium meteor spike dilemma came in the way of periodic Comet 2P Encke. Orbiting the Sun every 3.3 years—the shortest orbit of any known periodic comet—2P Encke has made many passages through the inner solar system, more than enough to lay down a dense and stable meteoroid debris stream over the millennia.

With an orbit ranging from a perihelion at 0.3 AU interior to Mercury’s to 4 AU, debris from Encke visits Earth as well in the form of the November Taurid Fireballs currently gracing the night skies of the Earth.

The Encke connection still presented a problem: the cometary stream is closest to the orbit of Mercury about a week later than the observed calcium peak. It was as if the stream had drifted over time…

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Comet 2P Encke, captured by NASA’s MESSENGER spacecraft. Image credit: NASA/Johns Hopkins/APL/SW Research Institute

Enter the Poynting-Robertson effect. This is a drag created by solar radiation pressure over time. The push on cometary dust grains thanks to the Poynting-Robertson effect is tiny, but it does add up over time, modifying and moving meteor streams. We see this happening in our own local meteor stream environment, as once great showers such as the late 19th century Andromedids fade into obscurity. The gravitational influence of the planets also plays a role in the evolution of meteor shower streams as well.

Researchers in the study re-ran the model, using MESSENGER data and accounting for the Poynting-Robertson effect. They found the peak of the calcium emissions seen today are consistent with millimeter-sized grains ejected from Comet Encke about 10,000 to 20,000 years ago. That grain size and distribution is important, as bigger, more massive grains result in a smaller drag force.

Image credit: Kevin Palmer
A 2015 Taurid meteor. Image credit: Kevin Palmer

This finding shows the role and mechanism that cometary debris plays in exosphere production on worlds like Mercury.

“Finding that we can move the location of stream to match MESSENGER’s observations is gratifying, but the fact that the shift agrees with what we know about Encke and its stream from independent source makes us confident that the cause-and-effect relationship is real, says Christou in this week’s NASA Goddard press release.

Launched in 2004, MESSENGER arrived at Mercury in March 2011 and orbited the world for over four years, the first spacecraft to do so. MESSENGER mapped the entire surface of Mercury for the first time, and became the first human-made artifact to impact Mercury on April 30th, 2015.

The joint JAXA/ESA mission BepiColombo is the next Mercury mission in the pipeline, set to leave Earth on 2017 for insertion into orbit around Mercury on 2024.

An interesting find on the innermost world, and a fascinating connection between Earth and Mercury via comet 2P Encke and the Taurid Fireballs.

From a Roar to a Purr: Prospects for the 2015 November Leonid Meteors

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A November rain hails from the Sickle of the Lion.

Hot on the heels of the October Orionids and the Halloween fireballs of the Taurid meteors comes the Leonid meteor shower. On most years, the Leonids are a moderate shower, with hourly local rates reaching around 20. Once every 33 years, however, the Leonids are responsible for putting on one of the greatest astronomical shows ever witnessed, producing a grand storm with a zenithal hourly rate topping thousands per hour.

Image credit: Stellarium
The orientation of the Earth and the relative positions of the Sun, Moon and the Leonid meteor radiant on November 17th at 4:00 UT. Image credit: Stellarium

Prospects for 2015

First, the bad news. 2015 isn’t forecast to be a ‘storm year’ for the Leonids, though that shouldn’t stop a vigilant observer from watching.  The good news is, we’re just about midway betwixt the storm years of 1998-99 and 2031-32. The Leonids intensify once every 33 years, and if the increased activity seen in the late 1990s was any indication, we’d bet we’ll start seeing a pickup in rates from the Leonids in the late 2020’s or so. The good news for 2015, however, is that the peak for the Leonids occur on November 18th at around 4:00 Universal Time (UT)/ (11:00 PM EST on November 17th). This places the waxing crescent Moon out of the picture, just a day before reaching First Quarter phase. New Moon for November 2015 occurs on November 11th at 17:47 UT/12:47 PM EST.

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A composite of the 2014 Leonids. Image credit: Alan Dyer/Amazing Sky Photography

Fun fact: the August Perseids, November Leonids and the December Geminid meteor showers are spaced out on the calendar in such a way that, when the Moon phase is favorable for one shower on a particular year, it is nearly always favorable across all of them.

The Leonids are mildly active from November 6th through November 30th, and though the above prediction for activity in 2015 favors European longitudes at dawn, some predictions have the peak arriving up to seven hours early this year.

Image credit: Stellarium
A simulated ‘Leonid storm.’ Note the true position of the radiant in the center of the backwards ‘?’ asterism is slightly offset.  Image credit: Stellarium

The Leonids are the dusty remnants laid down by periodic comet 55P Tempel-Tuttle on its 33-year path through the inner solar system. The Leonids are fast-movers, hitting the Earth nearly head-on in the dawn. You can see this in the relative position of the radiant, which rises in mid-November around 11PM local, and reaches the zenith around 6AM local time.

A late season Leonid meteor from 2014. Image credit: The UK Monitoring network (UKMON)
A late season Leonid meteor from 2014. Image credit: The UK Monitoring network (UKMON)

Often bluish in color, the Leonids hit the Earth’s atmosphere at over 70 km/sec… almost the fastest theoretical speed possible. For best results, watch for Leonids to spike in activity close to local dawn.

A 1799 woodcut depicting the Leonids at sea. Image credit: Public Domain
A 1799 woodcut depicting the Leonids at sea. Image credit: Public Domain

The Leonids have a storied history, going back 902 AD report from Arabic annals of the ‘Year of Stars.’ The Great Meteor Storm of 1833 dazzled (and terrified) residents of the eastern seaboard of the United States, and the spectacle not only inspired astronomer Denison Olmsted to pioneer studies into the fledgling field of meteor shower science, but has been attributed to adding fervor to many of the religious revivalist movements that sprang up in the 1830s in the United States as well.

The last outburst from the Leonids that reached such an apocalyptic scale was in 1966, when observers across the southwestern United States reported hourly rates approaching an amazing ZHR=144,000. Witnesses that remember this spectacle say it produced an illusion reminiscent of the Star Trek ‘warp speed’ effect, as Earth rammed headlong into the dense Leonid meteor stream.

Our own personal encounter with a Leonid meteor storm in 1998 from the dark desert skies of Kuwait wasn’t quite that intense, but thrilling to see nonetheless. Rates neared one every few seconds towards sunrise, with several fireballs punctuating the action, lighting up the desert floor. Here, as US coalition forces were on the verge of unleashing what would become Operation: Desert Fox over Iraq, the Universe was putting on a fireworks show of its own.

The Leonid meteor storms are the stuff of astronomical legend, a once in a lifetime event. Ever since we witnessed just what the Leonids are capable of, we never miss this annual shower, as we remember one night back in 1998, and look forward to the storms of 2032.

Here’s what the Leonids have been doing on previous recent years:

ZHR=15 +/-4 (2014)

Mostly washed out by the near-Full Moon (2013)

ZHR=47 +/-11 (2012)

ZHR=22 +/-3 (2011)

ZHR=32+/-4 (2010)

  • Report those Leonid sightings to the International Meteor Organization, and also be sure to Tweet em to #Meteorwatch
  • Got an image of a Leonid meteor? Send ‘em in to Universe Today at our Flickr Forum… we just might feature it in an after-action round up!

A Halloween Season ‘Taurid Meteor Swarm’ on Tap for 2015?

Image credit: NASA

Asteroid 2015 TB145 isn’t the only cosmic visitor paying our planet a trick-or-treat visit over the coming week. With any luck, the Northern Taurid meteor shower may put on a fine once a decade show heading into early November.

About once a decade, the Northern Taurid meteor stream puts on a good showing. Along with its related shower the Southern Taurids, both are active though late October into early November.

The motion of the radiant of the Northern Taurid meteors from mid-October through mid-November. Image credit: Stellarium
The motion of the radiant of the Northern Taurid meteors from mid-October through mid-November. The shower typically peaks around November 12th annually. Image credit: Stellarium

Specifics for 2015

This year sees the Moon reaching Full on Tuesday October 27th, just a few days before Halloween. The Taurid fireballs, however, have a few things going for them that most other showers don’t. First is implied in the name: the Northern Taurids, though typically exhibiting a low zenithal hourly rate of around 5 to 10, are, well, fireballs, and thus the light-polluting Moon won’t pose much of a problem. Secondly, the Taurid meteor stream is approaching the Earth almost directly from behind, meaning that unlike a majority of meteor showers, the Taurids are just as strong in the early evening as the post midnight early morning hours.  As a matter of fact, we saw a brilliant Taurid just last night from light-polluted West Palm Beach in Florida, just opposite to the Full Moon and a partially cloudy sky.

A 2014 Taurid. Image credit and copyright: Brian who is called Brian
A 2014 Taurid. Image credit and copyright: Brian who is called Brian

In stark contrast to the swift-moving Orionids from earlier this month, expect the Taurid fireballs to trace a brilliant and leisurely slow path across the night sky, moving at a stately 28 kilometre per second (we say stately, as the October Orionids smash into our atmosphere at over twice that speed!)

Ever since the 2005 event, the Northern Taurids seemed to have earned the name as “The Halloween Fireballs” in the meme factory that is the internet. It’s certainly fitting that Halloween should have its very own pseudo-apocalyptic shower. The last good return for the Northern Taurids was 2005-2008, and 2015 may see an upswing in activity as well.

Obviously, something interesting has to be occurring on Comet 2P Encke—the source of the two Taurid meteor streams—to shed the pea-sized versus dust-sized material seen in the Southern and Northern Taurids. With the shortest orbital period 3.3 years of all periodic comets known, the Taurid meteor stream—like Encke itself—follows a shallow path nearly parallel to the ecliptic plane.

Discovered in 1822 by astronomer Johann Encke, Comet 2P Encke has been observed through many perihelion passages over the last few centuries, and passes close to Earth once 33 years, as it last did in 2013.

What constitutes a ‘meteor swarm?’ As with many terms in meteoritics, no hard-and-fast definition of a true ‘meteor swarm’ exists. A meteor storm is generally quoted as having a zenithal hourly rate greater than 1000. Expect activity to be broad over the next few weeks, and the Taurid fireballs always have the capacity to produce the kind of brilliant events captured by security cams and dashboard video cameras that go viral across ye ole Internet.

Watching for fireballs is a thrilling pursuit. These may often leave persistent glowing meteor trails in their wake.  We caught the 1998 Leonids from the dark sky deserts of Kuwait, and can attest to the persistence of glowing fireball trails from this intense storm, sometimes for minutes. Again, the 2015 Taurids aren’t expected to reach that level of intensity, though the ratio of fireballs to faint meteors will be enhanced.

The path of the stream isn’t fully understood, and that is where volunteer observations can come in handy. The International Meteor Organization is always looking for reports from skilled observers, as is the American Meteor Society (AMS).

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The light curve of the suspected Taurid that hit the Moon on Nov 7th. Image Credit: NASA

There’s even been evidence for a recorded meteorite strike related to the northern Taurid fireballs back in 2015 on the dark limb of the Moon as well, a rare event indeed.

After a slow summer, Fall meteor shower activity is definitely heating up. And though 2015 is an off year for the November Leonids, we’re now almost midway between the 1998-99 outbursts, and the possibility of another grand meteor storm in the early 2030s. And another obscure wildcard shower known as the Alpha Monocerotids may put on a surprise showing in November 2015 as well…

Bright Meteor 4th November 2013 from Richard Fleet on Vimeo.

More to come on that. Keep watching the skies, and don’t forget to tweet those Northern Taurid fireball sightings and images to #Meteorwatch!

-Got an image of a Northern Taurid fireball? Send ‘em in to Universe Today for our Flickr forum… we may just feature your pic in an after action round up!

Gallery: 2015 Perseids Are Putting on a Show

Perseid Meteor Shower over the East Point Light House in New Jersey, USA. Credit and copyright: Jeff Berkes.

Have you been looking up the past few nights, trying to see the Perseid Meteor Shower? Many of our readers have been turning their eyes — and cameras — to the skies, with spectacular results. This year’s Perseids were predicted to be one of the best ever, since there has been little to no moonlight to upstage the shower. As you can see from the images here, many astrophotographers were able to capture fast and bright meteors, and even some that left persistent trains.

Remember, tonight (Wednesday, August 12, 2015) is projected to be the peak, so if you’ve got clear skies, take advantage of this opportunity to see a great meteor shower. You can find out how and when to see them in our previous detailed articles by our in-house observing experts David Dickinson and Bob King.

And enjoy the view from our readers in this gallery of 2015 Perseids:

A Perseid Meteor, the Milky Way and the photographer on August 11, 2015 near Bamburgh, Northumberland, England. Credit and copyright:  Peter Greig.
A Perseid Meteor, the Milky Way and the photographer on August 11, 2015 near Bamburgh, Northumberland, England. Credit and copyright:
Peter Greig.
An 'exploding' Perseid meteor as seen on August 11, 2015. Credit and copyright: Chris Lyons.
An ‘exploding’ Perseid meteor as seen on August 11, 2015. Credit and copyright: Chris Lyons.
Bright Perseid and Perseus. Credit and copyright: Chris Lyons.
Bright Perseid and Perseus. Credit and copyright: Chris Lyons.
A green Perseid meteor, along with 2 satellites show up in this image taken on August 11, 2015. Credit and copyright: eos-001 on Flickr.
A green Perseid meteor, along with 2 satellites show up in this image taken on August 11, 2015. Credit and copyright: eos-001 on Flickr.
Perseid meteor from early morning, August 12, 2015 in Weatherly, Pennsylvania. Taken with a Canon 6D and Samyang 14mm lens, 40 second exposure at ISO 3200, unguided. Credit and copyright: Tom Wildoner.
Perseid meteor from early morning, August 12, 2015 in Weatherly, Pennsylvania. Taken with a Canon 6D and Samyang 14mm lens, 40 second exposure at ISO 3200, unguided. Credit and copyright: Tom Wildoner.
Perseid Meteor near Cassiopeia along with the Andromeda Galaxy, as seen from France on August 10, 2015. Credit and copyright: VegaStar Carpentier/ VegaStar Carpentier Photography.
Perseid Meteor near Cassiopeia along with the Andromeda Galaxy, as seen from France on August 10, 2015. Credit and copyright: VegaStar Carpentier/ VegaStar Carpentier Photography.
A Perseid Meteor as seen on August 8, 2015, taken from Oxfordshire with a Canon 1100D + 18-55mm lens, ISO-1600 for 30 seconds. Credit and copyright: Mary Spicer.
A Perseid Meteor as seen on August 8, 2015, taken from Oxfordshire with a Canon 1100D + 18-55mm lens, ISO-1600 for 30 seconds. Credit and copyright: Mary Spicer.

Prolific night sky photographer John Chumack near Dayton, Ohio put together this video of 81 Perseid meteors he captured on August 12, 2015 with his Automated low light -Meteor Video Camera Network:

If you are clouded out, you can still enjoy the shower. NASA TV will be tracking the Perseids live on Wednesday, August 12 starting at 10PM EDT/02:00 UT:

The 2015 Perseids: Weather Prospects, Prognostications and More

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The venerable ‘old faithful of meteor showers’ is on tap for this week, as the August Perseids gear up for their yearly performance. Observers are already reporting enhanced rates from this past weekend, and the next few mornings are crucial for catching this sure-fire meteor shower.

First, here’s a quick rundown on prospects for 2015. The peak of the shower as per theoretical modeling conducted by Jérémie Vaubaillon projects a broad early maximum starting around Wednesday, August 12th at 18:39 UT/2:39 PM EDT. This favors northeastern Asia in the early morning hours, as the 1862 dust trail laid down by Comet 109P Swift-Tuttle — the source of the Perseids — passes 80,000 km (20% of the Earth-Moon distance, or about twice the distance to geostationary orbit) from the Earth. This is worth noting, as the last time we encountered this same stream was 2004, when the Perseids treated observers to enhanced rates up towards 200 per hour. Typically, the Perseids exhibit a Zenithal Hourly Rate (ZHR) of 80-100 per hour on most years.

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The terrestrial situation at the projected peak of the 2015 Perseids. Image credit: NOAA/Dave Dickinson

This translates into a local peak for observers worldwide on the mornings of August 12th and 13th. Comet 109P Swift-Tuttle orbits the Sun once every 120 years, and last reached perihelion in 1992, enhancing the rates of the Perseids throughout the 1990s.

Don’t live in northeast Asia? Don’t despair, as meteor showers such as the Perseids can exhibit broad multiple peaks which may arrive early or late. Mornings pre-dawn are the best time to spy meteors, as the Earth has turned forward into the meteor stream past local midnight, and rushes headlong into the oncoming stream of meteor debris. It’s a metaphor that us Floridians know all too well: the front windshield of the car gets all the bugs!

Perseid radiant
The flight of the Perseid radiant through August. Image credit: Dave Dickinson/Stellarium

Weather prospects — particularly cloud cover, or hopefully, the lack of it — is a factor on every observer’s mind leading up to a successful meteor hunting expedition. Fortunately here in the United States southeast, August mornings are typically clear, until daytime heating gives way to afternoon thunder storms. About 48 hours out, we’re seeing favorable cloud cover prospects for everyone in the CONUS except perhaps the U.S. northeast.

Weather and cloud cover prospects for the mornings of August 12th and August 13th. Image credit: NOAA
Weather and cloud cover prospects for the mornings of August 12th and August 13th. Image credit: NOAA

The Moon is also under 48 hours from New on Wednesday, allowing for dark skies. This is the closest New Moon to the peak of the Perseids we’ve had since 2007, and it won’t be this close again until 2018.

Fun fact: the August Perseids, October Orionids, November Leonids AND the December Geminids are roughly spaced on the calendar in such a way that if the Moon phase is favorable for one shower on a particular year, it’ll nearly always be favorable (and vice versa) on the others as well.

Sky watchers have observed the annual Perseid meteors since antiquity, and the shower is often referred to as ‘The Tears of Saint Lawrence.’ The Romans martyred Saint Lawrence on a hot grid iron on August 10th, 258 AD. The radiant crosses from the constellation Perseus in early August, and sits right on the border of Cassiopeia and Camelopardalis on August 12th at right ascension 3 hours 10’ and declination +50N 50.’ Technically, the shower should have the tongue-twisting moniker of the ‘Camelopardalids’ or perhaps the ‘Cassiopeiaids!’

The last few years have seen respectable activity from the Perseids:

2014- ZHR = 68 (Full Moon year)

2013- ZHR = 110

2012- ZHR = 120

2011- ZHR = 60 (Full Moon year)

2010- ZHR = 90

You can see the light-polluting impact of the nearly Full Moon on the previous years listed above. Light pollution has a drastic effect on the number of Perseids you’ll see. Keep in mind, a ZHR is an ideal rate, assuming the radiant is directly overhead and skies are perfectly dark. Most observers will see significantly less. We like to watch at an angle about 45 degrees from the radiant, to catch meteors in sidelong profile.

Imaging the Perseids is as simple as setting up a DSLR on a tripod as taking long exposures of the sky with a wide angle lens. Be sure to take several test shots to get the combination of f-stop/ISO/and exposure just right for current sky conditions. This year, we’ll be testing a new intervalometer to take automated exposures while we count meteors.

Clouded out? NASA TV will be tracking the Perseids live on Wednesday, August 12th starting at 10PM EDT/02:00 UT:

Remember, you don’t need sophisticated gear to watch the Perseids… just a working set of ‘Mark-1 eyeballs.’ You can even ‘hear’ meteor pings on an FM radio on occasion similar to lightning static if you simply tune to an unused spot on the dial. Sometimes, you’ll even hear a distant radio station come into focus as it’s reflected off of an ionized meteor trail:

And if you’re counting meteors, don’t forget to report ‘em to the International Meteor Organization and tweet ‘em out under hashtag #Meteorwatch.

Good luck and good meteor hunting!

Kick Back, Look Up, We’re In For a GREAT Perseid Meteor Shower

Multi-photo composite showing Perseid meteors shooting from their radiant point in the constellation Perseus. Earth crosses the orbit of comet 109P/Swift-Tuttle every year in mid-August. Debris left behind by the comet burns up as meteors when it strikes our upper atmosphere at 130,000 mph. Credit: NASA

Every year in mid-August, Earth plows headlong into the debris left behind by Comet 109P/Swift-Tuttle. Slamming into our atmosphere at 130,000 mph, the crumbles flash to light as the Perseid meteor shower. One of the world’s most beloved cosmic spectacles, this year’s show promises to be a real crowd pleaser.

The author tries his best to enjoys this year's moon-drenched Perseids from the "astro recliner". Credit: Bob King
The author takes in last year’s moon-drenched Perseids from a recliner. Credit: Bob King

Not only will the Moon be absent, but the shower maximum happens around 3 a.m. CDT (8 UT) August 13 — early morning hours across North America when the Perseid radiant is highest. How many meteors will you see? Somewhere in the neighborhood of 50-100 meteors per hour. As always, the darker and less light polluted your observing site, the more zips and zaps you’ll see.

Find a place where there’s as few stray lights as possible, the better to allow your eyes to dark-adapt. Comfort is also key. Meteor showers are best enjoyed in a reclining position with as little neck craning as possible. Lie back on a folding lawn chair with your favorite pillow and bring a blanket to stay warm. August nights can bring chill and dew; a light coat and hat will make your that much more comfortable especially if you’re out for an hour or more.

The Perseids appear to radiate from spot below the W of Cassiopeia in the constellation Perseus, hence the name "Perseids". Source: Stellarium
The Perseids appear to radiate from spot below the W of Cassiopeia in the constellation Perseus, hence the shower’s name. This map shows the sky facing northeast around 12:30 a.m. local time August 13. Source: Stellarium

I’m always asked what’s the best direction to face. Shower meteors will show up in every corner of the sky, but can all be traced backwards to a point in Perseus called the radiant. That’s the direction from which they all appear to stream out of like bats flying out of a cave.

Another way to picture the radiant it is to imagine driving through a snowstorm at night. As you accelerate, you’ll notice that the flakes appear to radiate from a point directly in front of you, while the snow off to the sides streams away in long trails. If you’re driving at a moderate rate of speed, the snow flies past on nearly parallel paths that appear to focus in the distance the same way parallel railroad tracks converge.

At some personal peril, I grabbed a photo of snow in the headlights while driving home in a recent storm. Meteors in a meteor shower appear to radiate from a point in the distance in identical fashion. Photo: Bob King
Meteors in a meteor shower appear to radiate from a point in the distance in identical fashion to driving a car in a snowstorm. The motion of the car (Earth) creates the illusion of  meteors radiating from a point in the sky ahead of the observer. Credit: Bob King

Now replace your car with the moving Earth and comet debris for snow and you’ve got a radiant and a meteor shower. With two caveats. We’re traveling at 18 1/2 miles per second and our “windshield”, the atmosphere, is more porous. Snow bounces off a car windshield, but when a bit of cosmic debris strikes the atmosphere, it vaporizes in a flash. We often think friction causes the glow of meteors, but they’re heated more by ram pressure.

A bright fireball breaking to pieces near Yellow Springs, Ohio. Meteors are really tubes of ionized air energized by the passage of comet bits. Credit: John Chumack
A bright fireball breaking to pieces near Yellow Springs, Ohio. Meteors are really tubes of ionized air energized by the passage of comet bits. Credit: John Chumack

The incoming bit of ice or rock rapidly compresses and heats the air in front of it, which causes the particle to vaporize around 3,000°F (1,650°C). The meteor or bright streak we see is really a hollow “tube” of glowing or ionized air molecules created by the tiny rock as its energy of motion is transferred to the surrounding air molecules. Just as quickly, the molecules return to their rest state and release that energy as a spear of light we call a meteor.

Imagine. All it takes is something the size of a grain of sand to make us look up and yell “Wow!”

Speaking of size, most meteor shower particles range in size from a small pebble to beach sand and generally weigh less than 1-2 grams or about what a paperclip weighs. Larger chunks light up as fireballs that shine as bright as Venus or better. Because of their swiftness, Perseids are generally white and often leave chalk-like trails called trains in their wakes.

Comet 109P/Swift-Tuttle captured during its last pass by Earth on Nov. 1, 1992. A filament of dust deposited by the comet in 1862 may cause a temporary spike in activity on Aug. 12 around 18:39 UT. Credit: Gerald Rhemann
Comet 109P/Swift-Tuttle seen during its last pass by Earth on Nov. 1, 1992. A filament of dust deposited by the comet in 1862 may cause a temporary spike in activity around 18:39 UT on August 12. Credit: Gerald Rhemann

This year’s shower is special in another way. According to Sky and Telescope magazine, meteor stream modeler Jeremie Vaubaillon predicts a bump in the number of Perseids around 1:39 p.m. (18:39 UT) as Earth encounters a debris trail shed by the Comet Swift-Tuttle back in 1862. The time favors observers in Asia where the sky will be dark. It should be interesting to see if the prediction holds.

How To Watch

Already the shower’s active. Go out any night through about the 15th and you’ll see at least at least a handful of Perseids an hour. At nightfall on the peak night of August 12-13, you may see only 20-30 meteors an hour because the radiant is still low in the sky. But these early hours give us the opportunity to catch an earthgrazer — a long, very slow-moving meteor that skims the atmosphere at a shallow angle, crossing half the sky or more before finally fading out.

I’ve only seen one good earthgrazer in my earthly tenure, but I’ll never forget the sight. Ambling from low in the northeastern sky all the way past the southern meridian, it remained visible long enough to catch it in my telescope AND set up a camera and capture at least part of its trail!

A Perseid meteor streaks across the northeastern sky two Augusts ago. This year's shower will peak on the night of August 12-13 with up to 100 meteors per hour visible from a dark sky. Credit: Bob King
A Perseid meteor streaks across the northeastern sky two Augusts ago. Give the shower an hour’s worth of your time – you won’t be disappointed. Credit: Bob King

The later you stay up, the higher the radiant rises and the more meteors  you’ll see. Peak activity of 50-100 meteors per hour will occur between about 2-4 a.m. No need to stare at the radiant to see meteors. You can look directly up at the darkest part of the sky or face east or southeast and look halfway up if you like. You’re going to see meteors everywhere. Some will arrive as singles, others in short burst of 2, 3, 4 or more. I like to face southeast with the radiant off to one side. That way I can see a mix of short-trailed meteors from near the radiant and longer, graceful streaks further away just like the snow photo shows.

If there’s a lull in activity, don’t think it’s over. Meteor showers have strange rhythms of their own. Five minutes of nothing can be followed by multiple hits or even a fireball. Get into the feel of the shower as you sense spaceship Earth speeding through the comet’s dusty orbit. Embrace the chill of the August night under the starry vacuum.

The 2015 Lyrid Meteors Peak Tomorrow Night!

A lucky capture of a 2013 Lyrid meteor. Image credit and copyright: John Chumack

April showers bring May flowers, and this month also brings a shower of the celestial variety, as the Lyrid meteors peak this week.

And the good news is, 2015 should be a favorable year for the first major meteor shower of the Spring season for the northern hemisphere.  The peak for the shower in 2015 is predicted to arrive just after midnight Universal Time on Thursday April 23rd, which is 8:00 PM EDT on the evening of Wednesday April 22nd. This favors European longitudes right around the key time, though North America could be in for a decent show as well. Remember, meteor showers don’t read forecasts, and the actual peak can always arrive early or late. We plan to start watching tonight and into Wednesday and Thursday morning as well. April also sees a extremely variable level of cloud cover over the northern hemisphere, another reason to start your meteor vigil early on if skies are clear.

The radiant for the 2015 Lyrids as seen from 40 degrees north latitude at local midnight. Credit: Stellarium.
The radiant for the 2015 Lyrids as seen from 40 degrees north latitude at local midnight. Credit: Stellarium.

Another favorable factor this year is the phase of the Moon, which is only a slender 20% illuminated waxing crescent on Wednesday night. This means that it will have set well before local midnight when the action begins.

The source of the Lyrid meteors is Comet C/1861 G1 Thatcher, which is on a 415 year orbit and is expected to come back around again in 2276 A.D. 1861 actually sported two great comets, the other being C/1861 J1, also known as the Great Comet of 1861.

The orientation of the Sun, Moon, and the Lyrid radiant at the expected peak of the shower at 24UT/20EDT April 22nd. credit: Stellarium
The orientation of the Sun, Moon, and the Lyrid radiant at the expected peak of the shower at 24UT/20EDT April 22nd. credit: Stellarium

The Lyrids typically exhibit an ideal Zenithal Hourly Rate (ZHR) of 15-20 per hour, though this shower has been known to produce moderate outbursts from time to time. In 1803 and 1922, the Lyrids produced a ZHR of 100 per hour, and in recent times, we had an outburst of 250 per hour back in 1982. Researchers have tried over the years to tease out a periodicity for Lyrid outbursts, which seem erratic at best. In recent years, the Lyrids hit a ZHR of 20 (2011), 25 (2012), 22 (2013), and 16 last year in 2014.

Keep in mind, we say that the ZHR is an ideal rate, or what you could expect from the meteor shower with the radiant directly overhead under dark skies: expect the actual number of meteors observed during any shower to be significantly less.

A 2014 Lyrid fireball. Credit: The UK Meteor Network
A 2014 Lyrid fireball. Credit: The UK Meteor Network

The radiant for the Lyrids actually sits a few degrees east of the bright star Vega across the Lyra border in the constellation Hercules. They should, in fact, be named the Herculids! In mid-April, the radiant for the April Lyrids has already risen well above the northeastern horizon as seen from latitude 40 degrees north at 10 PM local, and is roughly overhead by 4 AM local. Several other minor showers are also active around late April, including the Pi Puppids (April 24th), the Eta Aquarids (May 6th), and the Eta Lyrids (May 9th). The constellation of the Lyre also lends its name to the June Lyrids peaking around June 6th.

The April Lyrids are intersecting the Earth’s orbit at a high 80 degree angle at a swift velocity of 49 kilometres per second. About a quarter of the Lyrid meteors are fireballs, leaving bright, persistent smoke trains. It’s a good idea to keep a set of binoculars handy to study these lingering smoke trails post-passage.

The Lyrids also have the distinction of having the longest recorded history of any known meteor shower.  Chinese chronicles indicate that “stars dropped down like rain,” on a late Spring night in 687 BC.

Observing a meteor shower requires nothing more than a set of working ‘Mark-1 eyeballs’ and patience. The International Meteor Organization always welcomes reports of meteor counts from observers worldwide to build an accurate picture of evolving meteor debris streams. You can even hear meteor ‘pings’ via FM radio.

Expect the rate to pick up past local midnight, as the Earth plows headlong into the oncoming meteor stream. Remember, the front of the car gets the love bugs, an apt analogy for any Florida resident in mid-April.

A composite view of the 2012 Lyrids plus sporadic meteors. Credit: NASA/MSFC/Danielle Moser
A composite view of the 2012 Lyrids plus sporadic meteors. Credit: NASA/MSFC/Danielle Moser

Catching a photograph of a Lyrid or any meteor is as simple as plopping a DSLR down on a tripod and doing a series of 30 second to several minute long time exposures. Use the widest field of view possible, and aim the camera off at about a 45 degree angle from the radiant to catch the meteors sidelong in profile. Be sure to take a series of test shots to get the ISO/f-stop combination set for the local sky conditions.

Don’t miss the 2015 Lyrids, possibly the first good meteor shower of the year!