Set the alarm and boil the tea, it’s time for the Orionid meteor shower

The Orionids peak Tuesday and Wednesday mornings Oct. 21-22 next week when an observer might see 20-25 meteors an hour from a dark sky. They’ll appear to radiate above Betelgeuse in northern Orion. Source: Stellarium

The coming week’s menu features a meteoric tossed salad of Taurid fireballs crossing paths with the annual Orionid meteor shower. While the Taurids are a broad, sparse stream coming in dribs and drabs throughout October and November, the Orionids peak on the mornings of October 21-22. Expect to see 20 meteors an hour emanating from a point of sky above the bright star Betelgeuse in the hunter’s shoulder.

Each streak of light you see signals the incineration of a flake of Halley’s Comet, the parent comet of the Orionids. Every year in late October, Earth cuts across Halley’s orbit and bits of dust shed by the comet from previous passes near the sun burn up as they strike the upper atmosphere at speeds of around 148,000 mph.

Composite of a recent Orionid meteor shower taken with an all-sky camera. Credit: NASA

It’s been a couple years since I’ve seen the shower due to clouds or moonlight, but to the patient observer they’re thrilling to watch. Orionids are extremely fast – most tear across the sky in a second or less. Don’t even bother to alert your observing companions if you see one. It’ll be long gone even as the words leave your mouth, though if you’re lucky, some meteors will leave glowing trails of ionized air or even a curl of cosmic smoke (dust) in their wakes.

“The Orionid meteor shower is not the strongest, but it is one of the most beautiful showers of the year,” says Bill Cooke, head of NASA’s Meteoroid Environment Office.

Composite photo of an Orionid meteor shower taken a few years ago. The constellation Orion is seen at lower right center. Credit: SLOOH

This year’s shower won’t be compromised by moonlight either. It may even be enhanced by it. On Tuesday morning, a fingernail crescent will attempt to steal the show as it rises in the east at the start of morning twilight. Which brings us to the best time to view the Orionids.

I’ve drawn the map above for 2 a.m. local time. That’s when the radiant is high enough in the sky for a good show to begin, but the hours just before dawn are a tad better as the radiant point is higher yet. The ideal time would be from 3-6 a.m. Find a place where light pollution is at a minimum and set up facing south-southeast for the best view. A comfy reclining chair and blanket or sleeping bag will help you stay relaxed and warm. It is almost November after all!

Trick or treat – time for the Halloween fireballs!

A Taurid fireball photographed Oct. 28, 2005 by Hiroyuki Lida of Toyama, Japan. At top is the constellation Orion and his three Belt stars. Credit: Hiroyuki Lida

We don’t normally associate October with big meteor showers. That’s reserved for the August Perseids and December Geminids. But just in time for Halloween, this month offers some tasty treats.

October is Taurid fireball season with two separate showers radiating from in and near the constellation Taurus the Bull. Both make for weak displays with counts of 10 or fewer meteors an hour. But what they lack in number they make up in brilliance. While most shower meteors originate from sand to peanut-sized rocks, the Taurids have a large proportion of larger pebble pieces. When the big stuff burns up overhead, it produces bright fireballs.

Both showers are spawned by material left behind by Comet 2P/Encke which orbits the sun once every 3.3 years – one of the shortest known. When Earth intersects the debris stream the rocks strike the atmosphere fast enough to completely vaporize as flashes of light called meteors.

The Taurids are a pair of small showers that trace back to Comet 2P/Encke. They’re active all this month and next and appear to radiate from Taurus the Bull. The radiants slowly travel from west to east across the sky during that time – I’ve marked where they are in early November. Source: Stellarium

The Southern Taurids are active now through late October with the Northern Taurids taking over around Halloween and carrying the ball through November. Because of the unusually large proportion of fireballs from these dual showers, the American Meteor Society (AMS) notes an increase in the number of fireball reports from September through November each year.

Comet Encke and the trail of dust and debris it leaves behind in its orbit photographed by the Spitzer Space Telescope. Some of that material burns up in Earth’s atmosphere as Taurid meteors. Credit: NASA

Taurids travel slower than most meteor streams because Comet Encke’s tight little orbit only reaches into the asteroid belt. Since they don’t have as far to “fall” as they return to Earth’s vicinity, they’re not traveling as fast as some other showers like the Perseids, whose parent comet strays into remote space 51 times Earth’s distance from the sun.

Because of how Earth and the Taurid stream encounter each other, the Taurids play catch-up as they approach Earth somewhat from behind rather than head-on. Combined with their slower-than-usual speeds, they hit the atmosphere at only 61,000 mph (98,000 km/hr). OK, that’s still darn fast but more than twice as slow as the familiar Perseid meteors.

9-hour composite image of the Taurid meteor shower taken on November 4-5, 2008 taken with an all-sky camera in Walker County, Georgia. Credit: NASA

While you probably won’t make a one-night vigil for the Taurids as you would richer showers, be on the lookout for bright meteors this fall.

Taurus rises in the evening hours in the east, so you can start watching from about 10 o’clock all the way to dawn. If you spot a meteor and can trace it backward toward the direction of the Seven Sisters or Pleiades star cluster, chances are you’ve spotted the flaming farewell of a piece of Encke’s Comet.

Next week, we’ll take a closer look at another October meteor shower, this one originating from Halley’s Comet called the Orionids. Stay tuned.

How were the Perseids from your house last night?

Of five Perseids, only one was caught by the camera. It was an unusual meteor that flared twice before burning out. It almost looks like it skipped across the atmosphere like a stone skipping on water. Credit: Bob King

I set the alarm for 2:15 and spent an hour with the Perseids this morning. How many meteors flashed by? Oh, five. But every one was like winning the lottery.

The graph above shows the ZHR (Zenithal Hourly Rate), which is the number of Perseids an observer would see under a very dark sky with the radiant of the shower at the top of the sky. Counts are shown through 9 p.m. CDT Aug. 12. The trend toward maximum is obvious. Times are Universal Time. Subtract 4 hours for EDT, 5 for CDT, 6 for MDT and 7 for PDT. Credit: IMO

The low number was surprising given that magnitude 4 stars were readily visible. On the up side, all of those I saw were bright and moved incredibly fast like sparks from an arc welder. Preliminary data from the International Meteor Organization shows a peak around 55 meteors an hour yesterday evening (Aug. 12, U.S. time). Counts for the early morning hours still aren’t in yet, so final numbers and shower peak time may change.

Self-portrait with Perseids around 3:15 this morning. Perfect weather, friendly moonlight and cricket song made for a pleasant outing. At top you can see Auriga and the Hyades in Taurus. Credit: Bob King

A reminder that the Perseids will continue to fire off meteors through the remainder of the week, although at a declining rate. With the moon rising later each night, viewing conditions will improve, so be on the lookout for more flaming comet flakes.

Don’t wait – go out now to see the Perseid meteor shower

The annual Perseid meteor shower radiates from a point in the constellation Perseus just below the W of Cassiopeia. Rates are usually around 100-120 meteors per hour from a dark, moonless sky at peak. This map shows the sky facing east around midnight Aug. 12-13. Stellarium

The beloved Perseid meteor shower peaks next Tuesday night August 12-13, but it wouldn’t be a bad idea to go out right now for a look. Why? Two good reasons.

First, Earth has already entered the meteor stream formed by dust and grit left in the wake of comet 109P/Swift-Tuttle. I can attest to this. While hardly trying, I spotted a half dozen Perseids after moonset this morning. Second, the nearly full moon will compromise the shower when it’s at its best.

Composite of bright Perseid meteors recorded by NASA all-sky cameras in 2011. Each is a grain rock shed from the tail of comet 109P/Swift-Tuttle. Every year in mid-August, Earth passes through the comet’s debris trail as it orbits around the sun. Any particles we smack into burn up as meteors some 60-70 miles overhead. Credit: NASA

Between now and Friday morning, the moon will set before the start of dawn, leaving skywatchers a dark, moonless window of meteor watching. You might be surprised and see more than you expected. I did.

Come August 12, when the number of meteors peak, a nearly full moon will be up all night compromising the fainter meteors. That doesn’t mean you should abandon viewing that night. Just be aware that you’ll probably see closer to 30 per hour instead of the higher number.

The moon, two days past full, will brighten the sky during the Perseid peak. This view shows the sky facing east around midnight Aug. 12-13. Stellarium

If you’re OK with losing a little sleep sometime in the next few nights, set the alarm for 2-3 a.m., face east or south and relax for an hour under the sky as the Perseids fly by.

Camelopardalid meteor shower targets the moon too – watch for impact flashes

To monitor the moon for possible impacts from the Camelopardalid meteor shower, focus your attention on the speckled area in the darkened upper half of the moon Saturday morning. Impacts may flare to magnitude +8-9. Credit: Bill Cooke

Our favorite orbital partner the moon will join us for the hoped-for Camelopardalid meteor shower Friday night-Saturday morning May 23-24. While any shards of comet debris will flash to incandescence in Earth’s atmosphere, particles striking the airless moon will appear as faint flashes of light when they smack the lunar rocks and vaporize.

Bill Cooke of NASA’s Meteoroid Environment Office suggests that anyone with a telescope should monitor the moon until dawn. The meteor shower is expected to peak in Earth’s skies around 2 a.m. CDT (3 a.m. Eastern, 1 a.m. Mountain and midnight Pacific). On the moon, activity is possible between 9:30 p.m. CDT Friday night through 6 a.m. Saturday morning (2:30-11 a.m. Greenwich Time) with a peak from 1-3 a.m. CDT (6-8 a.m. Greenwich).

The crescent moon and Venus in the eastern sky Saturday morning May 24 around 4 a.m. local time. Stellarium

East Coast skywatchers are favored as the moon is up in the eastern sky around the time of maximum. But the time spread means that anyone from Western Europe across the U.S. could potentially spot a flash. You’ll need a 4-inch or larger telescope magnifying between 40-100x. Higher powers aren’t necessary as they restrict the field of view.

I can’t say how easy it would be to catch one but it will take patience and attention. That’s why the favored method for capturing views of lunar impacts is a video camera hooked up to a telescope set to automatically track the moon. That way you can kick back and examine your results later in the light of day. Seeing a meteor hit live would truly be the experience of a lifetime.

Video frame grab of an earlier meteorite impact on the moon. Impacts look like stars that flash and then quickly disappear. Credit: NASA

As a crescent, much of the moon will be in shadow – perfect for checking for flashes which would otherwise impossible to spot on the brilliant, sunlit crescent. Earthlight will faintly illuminate the remaining 2/3 of the moon, making for a nice dark backdrop against which to see any meteorite strikes.

If you’re into photography and plan to shoot stills or video of the meteor shower and lunar impacts, Brook Brooke Boen ( at NASA’s Marshall Space Flight Center would love to hear from you. Please send any images or video to her e-mail. Your observations will help astronomers better understand the birth and evolution of this brand new meteor shower.

The sky is falling! Surprise meteor shower may strike Saturday morning

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. This map shows the sky facing north around 2 a.m. from the central U.S. Saturday.  Stellarium

Get ready for what could be the most awesome meteor shower of the year. On Saturday morning May 24 between 1 and 4 a.m. skywatchers across much of North America are in prime position to witness the birth of a brand new meteor shower – the Camelopardalids. At least 100 meteors per hour and possibly as many as 400 meteors per hour are expected with a peak viewing time around 2 a.m. Central Daylight Time. Short but sweet!

If predictions by meteor experts Peter Jenniskens of the SETI Institute and Esko Lyyttinen of Finland hold true, that morning, Earth will pass through multiple filaments of sand and pebble-sized debris trails boiled off comet 209P/LINEAR during previous passages near the sun during the 19th and early 20th centuries.

The comet was only discovered in 2004 by the Lincoln Laboratory Near-Earth Asteroid Research (LINEAR) automated sky survey. Unlike Comet Hale-Bopp and the late Comet ISON that swing by the sun once every few thousand years or million years, this one drops by every 5.1 years.

When closest at perihelion, 209P/LINEAR passes some 90 million miles from the sun. At the far end of its orbit it’s about Jupiter’s distance from the sun. In 2012, during a relatively close pass of that planet, Jupiter perturbed its orbit, bringing the comet and its debris trails to within 280,000 miles (450,000 km) of Earth’s orbit, close enough to spark a meteor shower.

When a comet nears the sun, heat vaporizes dust-laden ices from the comet’s nucleus. The solar wind ‘blows’ the dust particles into a tail which spread out along the comet’s orbit. Under the right circumstances, as with returning comet 209P/LINEAR, Earth can pass through the debris stream and we see a meteor shower as comet grit burns up in the atmosphere.

This time around, the comet itself will fly just 5 million miles from Earth on May 29 a little more than 3 weeks after perihelion, making it the 9th closest comet encounter ever observed.

You’d think this close pass would make 209P a bright sight, but it’s only predicted to reach magnitude +11, faint enough to require an 8-inch or larger telescope to see. Most likely the comet is either very small or producing dust at a very low rate or both.

Next week I’ll post maps here on how to find it. For the moment, 209P/LINEAR glows dimly at around magnitude +14 and visible in large amateur telescopes. As it speeds from the Big Dipper south to Crater the Cup over the next couple weeks, we’ll be watching it closely. Check here for updates if the comet experiences any hiccups.

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 a.m. CDT May 24. Click for more details. Credit: Mikhail Maslov

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 (Cam-el-o-PAR-duh-lids) – let’s just call them ‘Cams’ –  contain a significant number of particles larger than 1mm, big enough to flare as fireballs.

Viewers in the northern half of the U.S. and southern Canada have the best seats for watching the potential shower because the radiant is midway up in the northern sky during peak viewing time Saturday morning. For points farther north, all-night twilight will blot out the fainter meteors. For observers in the far southern U.S. the radiant will be low in the northern sky, reducing meteor counts.

There’s always the chance the shower won’t materialize, so prepare yourself for that possibility. At worst we may see zero meteors, but even the most conservative estimates predict a show at least as good as the Perseids and Geminids, two of the strongest showers of the year.

But if you’re an optimist – and what skywatcher can’t afford not to be? – plan to be out before the peak and face north in a comfortable lawn chair. Bring a friend and share a cup of your favorite hot drink while you watch this ultimate wild card event.

Shower observing times across Canada and U.S.:

* Eastern Daylight Time 1:30-5 a.m. with the peak around 3 a.m.

* Central Daylight Time 12:30-4 a.m. with a 2 a.m. peak

* Mountain Daylight Time 11:30-3 a.m. with a 1 a.m. peak

* Pacific Daylight Time 10:30-2 a.m. with a peak at midnight

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. Click for more details. Credit: Dr. Jeremie Vaubaillon

If it’s cloudy or you’re not in the sweet zone for viewing, the SLOOH will cover comet 209P/LINEAR live on the Web with its 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 Follow-up live coverage of the new meteor shower starts at 10 p.m. CDT. The broadcast will feature astronomer Bob Berman of Astronomy Magazine; viewers can ask questions during the comet show by using hashtag #slooh.

Astrophysicist Gianluca Masi will also have 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 24.

No matter what, you’re covered. Later this week I’ll update with a forecast and fresh comet photos and observations. Cross your fingers!

May’s Eta Aquarid meteor shower hails from Halley’s Comet

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

Active right now but peaking on Tuesday and Wednesday mornings May 6-7, the annual Eta Aquarid meteor shower likewise peaks our interest in its origin. Most 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.

Halley’s Comet photographed in May 1986 during its last go-round the sun. Dust particles boiled off the comet when near the sun are left behind in its orbit. Every May, Earth encounters the stream and we see the Eta Aquarid meteor shower. Halley’s next approach to Earth happens in the summer of 2061. Credit: Bob King

The upcoming 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 minute rock particles strewn by Halley during its cyclic 76-year journey from just beyond Uranus to within the orbit of Venus.

Our first pass through Halley’s remains happens this week, the second in late October during  the Orionid meteor shower. Like bugs hitting a windshield, the grains meet their demise when they smack the atmosphere at 42 miles per second (68 km/sec) and fire up for a brief moment as meteors.

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. No moon mars the view, making conditions ideal.

Vintage painting of a fireball meteor flashing across the sky. While the Eta Aquarids aren’t known for their fireballs, the meteors are swift and white.

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.

Expect to see 5-10 meteors per hour during the hour or two before the start of dawn Wednesday May 7. Face east for the best view and relax in a reclining chair. An added bonus this spring season will be hearing the first birdsong as the sky brightens toward the end of your viewing session.

A modern photographic depiction of Eta Aquarid meteors from May 2012. Credit: John Chumack

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. Meteor showers take on the name of the constellation from which they originate.

Aquarius sports at least two showers. This one’s called the Eta Aquarids because it emanates from near the star Eta Aquarii. An unrelated shower, the Delta Aquarids, is active in July and early August.

Happy viewing and clear skies!

Lyrid meteor shower graces the planet on Earth Day

A bright Lyrid meteor streaks across the northwestern sky in this photo taken during the last peak on April 22, 2013. Credit: John Chumack

We celebrate Earth Day this upcoming Tuesday, a time to reflect on how each of us can better our environment. It also happens to be the peak of the annual Lyrid meteor shower.

The Lyrids reliably shoot from the sky every mid to late April, peaking overnight April 21-22 this year. I’ve seen the Lyrids on a couple occasions and can vouch that it’s a reliable though not particularly rich meteor shower. Normal rates are 10 to 20 meteors per hour, but light from the last quarter moon will reduce this year’s count to 5-10 per hour.

This map shows the sky facing east around 12:30 a.m. Tuesday morning April 22 when the radiant will be lower but still up before moonrise. Stellarium

The greatest number of meteors are seen when the radiant, the point in the sky from which they appear to stream, is highest. That occurs just before dawn Tuesday morning. But because the moon doesn’t rise until 2-2:30 a.m., you might do just as well catching the Lyrids from midnight till 2. The radiant will be moderately high in the east and the sky still dark.

The Lyrid radiant is much higher around 4 a.m. when the moon will also be up. Skywatchers take note! The moon will be very close to the third magnitude star Beta Capricorni. Those living in the western half of the U.S. will see it covered up or occulted by the moon around 4:30 a.m. MDT / 3:30 a.m. PDT. The event will be visible in 10x binoculars and small telescopes. Stellarium

While the Lyrids implies an association with the constellation Lyra, home to the brilliant star Vega, the meteors shoot from a location in eastern Hercules 7 degrees southwest of Vega. Each one you see is small bit of dust or rock left behind by Comet Thatcher which last appeared in 1861 and won’t again until 2276.

Voyager 1, which has crossed into interstellar space, is traveling at 38,000 miles an hour or about 1/3 the speed of a Lyrid meteor. Credit: NASA

Each April, Earth passes through Thatcher’s stream of debris and we see the pieces flare as meteors when they strike the air overhead.

Their average speed is 105,000 mph (169,000 km/hr). That’s almost 3 times faster than the current fastest moving spacecraft in the solar system, Voyager 1, at 38,000 mph (61,000 km/hr).

Not a major shower, the Lyrids still occasionally surprise with fireballs and rich outbursts of meteors. Counts were much higher than normal in 1803, 1849, 1850, 1884, 1922, 1945, and 1982. Both Ludwig von Beethoven and famous astronomer William Herschel were around for the 1803 Lyrids which topped out at more than 500 per hour!

NASA’s All Sky Fireball Network detected more than 30 Lyrids as bright as Venus on the nights around the shower’s peak last April 22. Their orbits, shown here in green, neatly intersect the Earth (red splat). “The purple ellipse is the orbit of Comet Thatcher,” adds Bill Cooke, lead scientist for the Office. “The orbits of the comet and the meteoroids match up nicely.” Credit: NASA

To watch the shower, either take the ‘early shift’ from midnight-2:30 a.m. and face east or dare to challenge the moon between 2 and dawn when Hercules and Vega are high in southern sky. I usually spice up my meteor watching with a look through the telescope at the bright planets. Mars shines due south now around midnight with Saturn further off to the southeast.

One final note. The moon will be very close to the star Beta in Capricornus Tuesday morning. Take a look at it in binoculars. If you live in the western half of the U.S., Beta will be occulted by the moon around 4:30 a.m. Mountain time, 3:30 a.m. Pacific. Midwesterners might still see it in bright twilight around 5:30 a.m. with a small telescope. Look immediately to the left of east of the moon’s bright edge.

Invite a friend to join you, boil up some tea and relax under the stars. Every meteor you see is a gift.

Catch some Quadrantids! Year’s first meteor shower peaks tomorrow morning

Watch for the Quads to radiant from a point in northern Bootes below the handle of the Big Dipper tomorrow morning. Stellariu

Tomorrow morning before dawn will be the best time to catch the very first meteor shower of the new year. The Quadrantids, named for the one-time constellation Quadrans Muralis, located below the handle of the Big Dipper, is one the most reliable showers of 2014. While the constellation’s now obsolete and erased from modern sky maps, its name lives on in fiery sparks of meteoric light. Pity the shower rains down at the coldest time of the year.

Ideally, you might see from 60-200 “Quads” per hour, when the shower’s very sharp peak coincides with the radiant being high in the northeastern sky for your location. This year the peak happens around 1:30 p.m. January 3, not exactly ideal for North and South American observers but perfect for folks living in the Middle East and Russia. Numbers will probably be less than half that for western hemisphere skywatchers.

Quadrans Muralis represents the wall quadrant, a instrument once used to measure star positions. Credit: Johann Bode atlas

Don’t let it bring you down. We’ll still see a good show tomorrow morning between the hours of 2 and 6 a.m as meteors emanate from the shower radiant located about a fist below the end of the Big Dipper’s handle in the northeastern sky. No moon will cast its glare to compromise the view. I’d suggest dressing warmly and relaxing in a sleeping bag on a reclining chair. Face to the east or north for the best view. The later you’re up, the more Quads you’ll see as the clock ticks closer to the daytime shower maximum.

A beautiful Quadrantid meteor captured over Duluth near the Big Dipper (partly outlined) a couple years back. Credit: Stephen Bockhold

Quadrantids are slower than other major showers like the August Perseids and December Geminids with speeds around 25 miles per second (41 km/sec). You’ll know you’re seeing a Quad if you can trace its trail back to the northeastern sky below the Dipper.

Peter Jenniskens, senior research scientist at NASA’s SETI Institute, traces the Quads’ origin to the asteroid 2003 EH1, a likely extinct or occasionally active comet. Its orbital characteristics agree well with the paths of our cold weather friends.

Bundle up! Geminid meteor shower peaks this Friday night

The annual Geminid meteor shower will peak Friday night – Saturday morning Dec. 13-14. Geminids can appear anywhere in the sky but if trace their trails backwards they’ll lead back to one point in the sky in Gemini called the radiant. Random meteors not connected with the shower are called sporadics. Stellariumf

This past week we touched on the resurgence of the Andromedid meteor shower and learned that Comet ISON may even gift us with dusty sprinkles next month. These one-off meteor blasts are certainly worth following, but if it’s reliability and numbers you’re looking for, the Geminids are your shower. No speculating here. No maybes. From a dark sky, anywhere from 60-120 Geminids an hour will zip past starting Friday night through dawn Saturday.

Composite photo of many Geminids plus a few sporadic meteors from Dec. 13-14, 2010. Credit: John Chumack

Every year in mid-December, Earth’s orbital path crosses that of 3200 Phaethon (FAY-eh-thon), a 3.2 mile diameter (5.1 km)  asteroid with an orbit takes it only 13 million miles from the sun every 1.4 years – almost three times closer than Mercury. That has consequences as we’ll soon see.

Most meteor showers are the offspring of comets, which drop dust and small rocks along their orbits after getting roasted by the sun. Phaethon’s sometimes referred to as a “rock comet”. Normally a quiet, well-behaved asteroid, Phaethon brightened by a factor of two and was caught spewing jets of dust when nearest the sun in 2009, 2010 and 2012. Apparently the intense heat of the sun either fractured the surface or heated rocks to the point of desiccation, creating enough dust to form temporary tails like a comet.

While it may look like an asteroid most of the time, Phaethon may really be a comet that’s still occasionally active. Either way, this originator of the Geminids produces a reliable meteor shower.

While many will opt to view the Geminids during more convenient evening hours Friday, others will want the darkest skies possible. This map shows the sky facing west around 5 a.m. Saturday Dec. 14 after moonset. Stellarium

This year the Geminids will be at their best overnight Dec. 13-14 with maximum activity forecast for around 8 p.m. CST (2 a.m. Greenwich time Dec. 14) Friday night. At that time, the radiant will be low or will not have risen for western hemisphere skywatchers, but that shouldn’t be a problem – the shower’s active all night. The later it gets, the more meteors you’ll see as the radiant rises ever higher in the sky.

There are two times for viewing the Geminids. You can go out around 9 or 10 Friday evening and face east toward brilliant Jupiter in Gemini, which by good fortune shines close to the shower radiant. Because the bright, waxing gibbous moon will be out, its light will cut the number of meteors you’ll see about in half. That’s why it’s a good idea to hide the moon from view if you can, so its glare isn’t a bother.

If you want to see more Geminids, you can set your alarm for just before 5 a.m. That’s when the moon sets and leaves about an hour of dark sky before the start of morning twilight. Because of the much later hour, the Earth will have “rotated” Gemini and Jupiter into the western sky. Just take that lawn chair and turn it to face the south-southwest for the best view.

Video still of a train or trail left by a bright meteor from the video “Left by a Fireball”. The Big Dipper is seen at left. Credit: Babak Tafreshi

The Geminids are medium-speed meteors, hitting the atmosphere at 70 miles overhead at 35 km/sec and often leave chalky-white “trains” or streaks of what looks like glowing smoke when they burn up. If you get one that lingers a while, consider examining it with binoculars. Sometimes you’ll see swirls and loops in the fading train.

The Geminids are now the richest annual meteor shower, even beating out the August Perseids. Their only drawback? They happen at the coldest time of year. So layer up, heat up the coffee and don’t let the cold rob you of what should be one of 2013′s astronomical highlights.