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.
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!
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
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.
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 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 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.
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
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 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. 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.
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.
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 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
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
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!
Don't fear the moonlight... Credit and copyright: John Chumack.
Quick… what’s the only major meteor shower named after a defunct constellation? If you said the January Quadrantids, you’d be correct, as this often elusive but abrupt meteor shower is set to peak this coming weekend early in 2015.
And we do mean early, as in the night of January 3rd going into the morning of January 4th. This is a bonus, as early January means long dark nights for northern hemisphere observers. But the 2015 Quadrantids also has two strikes going against them however: first, the Moon reaches Full just a day later on January 5th, and second, January also means higher than average prospects for cloud cover (and of course, frigid temps!) for North American observers.
The rising radiant of the Quads on the morning of January 4th at 3AM local. Note that the Moon and Jupiter are on the scene as well. Created using Starry Night Education software.
Don’t despair, however. In meteor shower observing as in hockey, you miss 100% of the shots that you don’t take.
Sorry for the sports analogy. The radiant for the Quadrantids is located in the modern day constellation of Draco near the Hercules-Boötes border at a right ascension 15 hours, 18 minutes and declination +49.5 degrees north. This puts it very near the +3.3 magnitude star Iota Draconis (Edasich).
The orientation of the Earth’s shadow at the predicted peak of the Quads on January 4th, 2:00 UT. Credit: Orbitron.
In 2015, bets are on for the Quadrantids to peak centered on 2:00 UT January 4th (9:00 PM EST on the 3rd), favoring northern Europe pre-dawn. The duration for the Quadrantids is short lived, with an elevated rate approaching 100 per hour lasting only six hours in duration. Keep in mind, of course, that it’ll be worth starting your vigil on Saturday morning January 3rd in the event that the “Quads” kick off early! I definitely wouldn’t pass up on an early clear morning on the 3rd, just in case skies are overcast on the morning of the 4th…
Due to their high northern radiant, the Quadrantids are best from high northern latitudes and virtually invisible down south of the equator. Keep in mind that several other meteor showers are active in early January, and you may just spy a lingering late season Geminid or Ursid ‘photobomber’ as well among the background sporadics.
Moonset on the morning of the 4th occurs around 6 AM local, giving observers a slim one hour moonless window as dawn approaches. Blocking the Moon out behind a building or hill when selecting your observing site will aid you in your Quadrantid quest.
The approximate realm of the “Mural Quadrant” overlaid on modern day constellations. Credit Stellarium.
Antonio Brucalassi made the first historical reference to the Quadrantids, noting that “the atmosphere was traversed by… falling stars” on the morning of January 2nd, 1825. It’s interesting to note that the modern day peak for the Quads has now drifted a few days to the fourth, due mostly to the leap year-induced vagaries of our Gregorian calendar. The early January meteor shower was noted throughout the 19th century, and managed to grab its name from the trendy 19th century constellation of Quadrans Muralis, or the Mural Quadrant. Hey, we’re lucky that other also-rans, such as Lumbricus the ‘Earthworm’ and Officina Typograhica the ‘Printing Office’ fell to the wayside when the International Astronomical Union formalized the modern 88 constellations in 1922. Today, we know that the Quadrantids come from 2003 EH1, which is thought to be an extinct comet now trapped in the inner solar system on a high inclination, 5.5 year orbit. Could 2003 EH1 be related to the Great Comet of 1490, as some suggest? The enigmatic object reached perihelion in March of 2014, another plus in the positive column for the 2015 Quads.
What the heck is a Mural Quadrant? Like everything he did, Tycho Brahe super-sized his quadrant, depicted here. Credit: Wikimedia Commons.
Previous years for the Quadrantids have yielded the following Zenithal Hourly Rate (ZHR) maximums as per the International Meteor Organization:
2011= 90
2012= 83
2013= 137
2014= +200
The Quadrantid meteor stream has certainly undergone alterations over the years as a result of encounters with the planet Jupiter, and researchers have suggested that the shower may go the way of the 19th century Andromedids and become extinct entirely in the centuries to come.
Don’t let cold weather deter you, though be sure to bundle up, pour a hot toddy (or tea or coffee, as alcohol impacts the night vision) and keep a spare set of batteries in a warm pocket for that DSLR camera, as cold temps can kill battery packs quicker than you can say Custos Messium, the Harvest Keeper.
And though it may be teeth-chatteringly cold where you live this weekend, we actually reach our closest point to the Sun this Sunday, as Earth reaches perihelion on January 4th at around 8:00 UT, just 5 hours after the Quads are expected to peak. We’re just over 147 million kilometres from the Sun at perihelion, a 5 million kilometre difference from aphelion in July. Be thankful we live on a planet with a relatively circular orbit. Only Venus and Neptune beat us out in the true roundness department!
…and no, you CAN’T defy gravity around perihelion, despite the current ill conceived rumor going ‘round ye ole net…
And as a consolation prize to southern hemisphere observers, the International Space Station reaches a period of full illumination and makes multiple visible passes starting December 30th until January 3rd. This happens near every solstice, with the December season favoring the southern hemisphere, and June favoring the northern.
A 2003 south bound Quad nabbed from Cabo Rojo, Puerto Rico (Yes, that’s the Southern Cross!) Credit and Copyright: Frankie Lucena.
So don’t let the relatively bad prospects for the 2015 Quadrantids deter you: be vigilant, report those meteor counts to the IMO, send those meteor pics in to Universe Today and tweet those Quads to #Meteorwatch. Let’s “party like it’s 1899,” and get the namesake of an archaic and antiquated constellation trending!
Now in its seventh year of compilation and the second year running on Universe Today, we’re proud to feature our list of astronomical happenings for the coming year. Print it, bookmark it, hang it on your fridge or observatory wall. Not only is this the yearly article that we jokingly refer to as the “blog post it takes us six months to write,” but we like to think of it as unique, a mix of the mandatory, the predictable and the bizarre. It’s not a 10 ten listicle, and not a full-fledged almanac, but something in between.
A rundown of astronomy for 2015: There’s lots of astronomical action to look forward to in the coming year. 2015 features the minimum number of eclipses that can occur, two lunars and two solars. The Moon also reaches its minimum standstill this coming year, as its orbit runs shallow relative to the celestial equator. The Moon will also occult all naked eye planets except Saturn in 2015, and will occult the bright star Aldebaran 13 times — once during every lunation in 2015. And speaking of Saturn, the rings of the distant planet are tilted an average of 24 degrees and opening to our line of sight in 2015 as they head towards their widest in 2018.
Finally, solar activity is trending downwards in 2015 after passing the sputtering 2014 maximum for solar cycle #24 as we now head towards a solar minimum around 2020.
Our best bets: Don’t miss these fine celestial spectacles coming to a sky near YOU next year:
– The two final total lunar eclipses in the ongoing tetrad, one on April 4th and September 28th.
– The only total solar eclipse of 2015 on March 20th, crossing the high Arctic.
– A fine dusk pairing of the bright planets Jupiter and Venus on July 1st.
– Possible wildcard outbursts from the Alpha Monocerotid and Taurid meteors, and a favorable New Moon near the peak of the August Perseids.
– Possible naked eye appearances by comet Q2 Lovejoy opening 2015 and comet US10 Catalina later in the year.
– The occultation of a naked eye star for Miami by an asteroid on September 3rd.
– A series of fine occultations by the Moon of bright star Aldebaran worldwide.
The rules: The comprehensive list that follows has been lovingly distilled down to the top 101 astronomical events for 2015 worldwide. Some, such as lunar eclipses, are visible to a wide swath of humanity, while others, such as many of the asteroid occultations or the sole total solar eclipse of 2015 happen over remote locales. We whittled the list down to a “Top 101” using the following criterion:
Meteor showers: Must have a predicted ZHR greater than 10.
Conjunctions: Must be closer than one degree.
Asteroid occultations: Must have a probability ranking better than 90 and occult a star brighter than magnitude +8.
Comets: Must reach a predicted brightness greater than magnitude +10. But remember: comets don’t always read prognostications such as this, and may over or under perform at whim… and the next big one could come by at any time!
Times quoted are geocentric unless otherwise noted, and are quoted in Universal Time in a 24- hour clock format.
These events are meant to merely whet the appetite. Expect ‘em to be expounded on fully by Universe Today as they approach. We linked to the events listed where possible, and provided a handy list of resources that we routinely consult at the end of the article.
Got it? Good… then without further fanfare, here’s the top 101 astronomical events for 2015 in chronological order:
The path of Comet Q2 Lovejoy from January 1st to January 31st. Created using Starry Night Education software.
29- The Moon occults Aldebaran at ~17:31 UT for the Arctic, marking the first of 13 occultations of the star by the Moon in 2015.
The view at 6:40 UT on January 24th, as 3 of Jupiter’s moons cast shadows on to the Jovian cloud tops simultaneously. Created using Starry Night Education software.
February
01- Venus passes 0.8 degrees south of Neptune at ~17:00 UT.
05- Earth crosses through Jupiter’s equatorial plane, marking the middle of occultation and eclipse season for the Galilean moons.
06- Jupiter reaches opposition at ~18:00 UT.
18- A “Black Moon” occurs, in the sense of the third New Moon in a season with four.
22- Venus passes 0.4 degrees south of Mars at 5:00 UT.
24- Mercury reaches greatest morning elongation at 26.7 degrees west of the Sun at 19:00 UT.
21- Io and Ganymede both cast shadows on Jupiter from 00:04 to 00:33 UT.
21- Callisto and Europa both cast shadows on Jupiter from 13:26 to 13:59 UT.
23- Saturn reaches opposition at ~1:00 UT.
24- Asteroid 1669 Dagmar occults the +1st magnitude star Regulus at ~16:47 UT for the Arabian peninsula,
the brightest star occulted by an asteroid for 2015.
28- Ganymede and Io both cast shadows on Jupiter from 02:01 to 04:18 UT.
30- Comet 19P/Borrelly may reach binocular visibility.
June
01- The International Space Station reaches full illumination as the June solstice nears, resulting in multiple nightly passes favoring northern hemisphere observers.
04- Io and Ganymede both cast shadows on Jupiter from 4:54 to 6:13 UT.
05- Venus reaches greatest eastern (dusk) elongation for 2015, 45 degrees from the Sun at 16:00 UT.
10- Asteroid 424 Gratia occults a +6.1 magnitude star at ~15:10 UT for northwestern Australia.
13- The Perseid meteors peak from 06:30 to 09:00 UT, with a maximum predicted ZHR of 100 favoring North America.
19- Mars crosses the Beehive Cluster M44.
28- Asteroid 16 Psyche occults a +6.4 magnitude star at ~9:49 UT for Bolivia and Peru.
29- Supermoon 1 of 3 for 2015: The Moon reaches Full at 18:38 UT, 20 hours from perigee.
The path of the Moon through the Earth’s shadow on September 28th. Credit: Fred Espenak/NASA/GSFC
September
01- Neptune reaches opposition at ~3:00 UT.
03- Asteroid 112 Iphigenia occults a +3rd magnitude star for Mexico and Miami at ~9:20 UT. This is the brightest star occulted by an asteroid in 2015 for North America.
02- Geostationary satellite and SDO eclipse season begins as we approach the September equinox.
04- Mercury reaches its greatest elongation for 2015, at 27 degrees east of the Sun at 8:00 UT in the dusk skies.
05- The Moon occults Aldebaran for northeastern North America at ~5:38 UT.
13- “Shallow point” (also known as the minor lunar standstill) occurs over the next lunation, as the Moon’s orbit reaches a shallow minimum of 18.1 degrees inclination with respect to the celestial equator… the path of the Moon now begins to widen towards 2025.
13- A partial solar eclipse occurs, centered on 6:55 UT crossing Africa and the Indian Ocean.
25- Mars passes 0.8 degrees from Regulus at ~4:00 UT.
28- A total lunar eclipse occurs centered on 2:48 UT, visible from the Pacific, the Americas and eastern Europe.
28- Supermoon 2 of 3 for 2015: The Moon reaches Full at 2:52 UT, approximately an hour from perigee. This marks the closest Full Moon of the year.
The path of the September 3rd occultation of a +3rd magnitude star by an asteroid over central Mexico and the Florida Keys. Credit: IOTA/Steve Preston.
The Moon occults Aldebaran: the visibility footprint for North America. The dashed line denotes the area in which the event occurs during the daytime. Credit: Occult 4.1.0.11.
November
01- Io and Ganymede both cast shadows on Jupiter from 17:36 to 17:47 UT.
02- Venus passes 0.7 degrees south of Mars at 00:30 UT.
12- Will the 7 year “Taurid fireball meteor shower” produce?
18- The Leonid meteor shower peaks at 04:00 UT, with an estimated ZHR of 15 favoring Europe.
22- Are we in for a once per decade Alpha Monocerotids outburst? The 2015 peak arrives at 4:25 UT, favoring Europe… with a max ZHR = 400+ possible.
The daytime occultation of Venus by the Moon over North America on December 7th.Credit: Occult 4.1.0.11.
December
01- The International Space Station reaches full illumination as the December solstice nears, resulting in multiple nightly passes favoring the southern hemisphere.
04- Mercury occults the +3.3 magnitude star Theta Ophiuchi for South Africa at 16:16 UT prior to dusk.
06- The Moon occults Mars for central Africa at ~2:42 UT.
07- The Moon occults Venus in the daytime for North America at ~16:55 UT.
14- The Geminid meteor shower peaks at 18:00 UT, with a ZHR=120 favoring NE Asia.
A stunning moment captured as a Geminid meteor over Mt. Fuji is reflected in Lake Saiko on December 14, 2014. Credit and copyright: Yuga Kurita.
It’s nice to know that not everyone around the world was plagued by clouds, dense fog, driving rain and snowstorms like we had in Minnesota during this year’s Geminid Meteor Shower (and all that weather was within one 24-hour period!) In fact, some astrophotographers were able to capture some stunning views of the Geminids, like this absolutely gorgeous shot of a meteor over Mt. Fuji in Japan.
“I’ve captured Fuji with meteors many times in the past,” said photographer Yuga Kurita. “So I went ambitious this time. I tried to capture Fuji and a meteor reflected in Lake Saiko with a standard focal length lens. When I saw this meteor, I was absolutely stunned.”
See more Geminids from around the world, below:
Geminid meteors over Beijing, China. A stacked image of more than 20 meteors, taken in just 140 minutes. Credit and copyright: Steed Yu.Geminid Meteor on 12-15-2014 .Captured cutting through the winter Milkyway in the constellation of Auriga, you can see the very colorful trail of the meteor in this image, the trail stretched more than 15 degrees of sky. Taken near Warrenton, Virginia. Credit and copyright: John Chumack.Four different Geminid meteors as seen from Oxfordshire, England with a Canon 1100D with standard lens. The time of the meteor is marked on the photo. Credit and copyright: Mary Spicer.
Astrophotographer Mary Spicer shared these four meteor shots, and added, “Over about 90 minutes we saw a total of 61 meteors, 57 of which were Geminids and 6 were fireballs.”
In a 3.5 hour period on Dec. 13/14, 2014, the photographer managed to capture 38 Geminid meteors. This composite contains just 11 of those meteors. Credit and copyright: Paul Andrew.
A timelapse movie taken by Michael Mauldin of the clouds and stars over Liberty Hill, Texas on Saturday, December 13, 2014. Two Geminid meteors are captured (each frame is frozen for a few seconds so you can see them):
Geminid meteors caught over Connaught Dome, at the Norman Lockyer Observatory in Devon, England. Credit and copyright: David Strange.Two Geminid meteors — one especially bright — streak through the sky on Sunday, December 14, 2014. This photo is a composite of two separate frames, taken a few minutes apart, to capture both meteors. Credit and copyright: David Murr.A Geminid fireball captured on Dec. 13, 2014 near Cabo Rojo, Puerto Rico. Credit and copyright: Frankie Lucena.A faint green Geminid meteor joined in the sky scene with On display are : M44, Jupiter , the Moon, and Procyon in Canis Minor. Credit and copyright: Carsten Pauer.A unique view of the 2014 Geminid Meteor Shower, taken on Dec. 14. 5 images stacked. Credit and copyright: Jason Asplin.A Geminid Meteor taken on Dec. 14, 2014 from a garden in the middle of Worthing, West Sussex England. Credit and copyright: BiteYourBum.com Photography. A bright Geminid meteor on Dec. 14, 2014. Credit and copyright: Slave Stojanoski.Waiting for Geminids: a self portrait of the photographer waiting for the meteor shower to peak. Credit and copyright: Sergio Garcia Rill.
While the above photo doesn’t have any meteors, it still garners a place in this post because astrophotographer Sergio Garcia Rill was waiting and hoping to capture some. Alas, writes Rill on Flickr, “While I had good enough luck to get some relatively clear skies for the Geminids meteor shower I think I wasn’t fortunate enough to catch any meteors on camera. I saw about a dozen meteors with my eyes, and a couple in the direction my cameras were pointing, but they probably weren’t strong enough to get captured with the settings I had.”
Artist's concept of the planet Mercury orbiting through a debris trail from Comet Encke that may cause a meteor shower. Credit: NASA's Goddard Space Flight Center
We’re sure going to miss the MESSENGER spacecraft at Mercury when it concludes its mission in 2015, because it keeps bringing us really unexpected news about the Sun’s closest planet. Here’s the latest: Mercury may get a periodic meteor shower when it passes through the debris trail of Comet Encke.
Why do scientists suspect this? It’s not from patiently watching for shooting stars. Instead, they believe the signature of calcium in Mercury’s tenuous atmosphere may be pointing to a pattern.
MESSENGER (which stands for MErcury Surface, Space ENvironment, GEochemistry, and Ranging) has been orbiting the planet for three Earth years and sees regular “surges” in calcium abundance on a predictable schedule. The researchers suspect it’s because of bits of dust colliding with Mercury and ricocheting bits of calcium up from the surface.
Mercury also picks up bits of dust from interplanetary debris, but the scientists say it’s not enough to account for the amounts of calcium they see. Extrapolating, the researchers suspect it must occur as the planet passes through debris left behind from a comet or asteroid. There are a small number of such small bodies that do this, and the scientists narrowed it down to Encke.
Illustration of MESSENGER in orbit around Mercury (NASA/JPL/APL)
Computer simulations of the comet’s debris showed a slight difference from what researchers predicted, but they believe it’s because of variations in Mercury’s orbit as it gets tugged by larger planets, particularly Jupiter. Encke itself takes about 3.3 years to do one lap around the Sun, and has been photographed by MESSENGER in the past.
“The possible discovery of a meteor shower at Mercury is really exciting and especially important because the plasma and dust environment around Mercury is relatively unexplored,” stated lead author Rosemary Killen, a planetary scientist at NASA’s Goddard Space Flight Center in Maryland.
MESSENGER, meanwhile, is burning off the last of its fuel to stay in orbit; the final engine maneuver is expected for Jan. 21. Once that’s finished, the spacecraft will slowly spiral down towards the planet for an expected impact in March, ending the mission.
UPDATE: Tune in this Sunday as the good folks over at the Virtual Telescope Project feature a live webcast covering the Geminid meteor shower this Sunday on December 14th at 2:00 UT.
This weekend presents a good reason to brave the cold, as the Geminid meteor shower peaks on the morning of Sunday, December 14th. The Geminids are dependable, with a broad peak spanning several days, and would be as well known as their summer cousins the Perseids, were it not for the fact that they transpire in the dead of northern hemisphere winter.
But do not despair. While some meteor showers are so ephemeral as to be considered all but mythical in the minds of most meteor shower observers, the Geminids always deliver. We most recently caught a memorable display of the Geminids in 2012 from a dark sky locale in western North Carolina. Several meteors per minute pierced the Appalachian night, offering up one of the most memorable displays by this or any meteor shower in recent years.
The Geminids are worth courting frostbite for, that’s for sure. But there’s a curious history behind this shower and our understanding of meteor showers in general, one that demonstrates the refusal of some bodies in our solar system to “act right” and fit into neat scientific paradigms.
A composite of the 2013 Geminids. Credit: the UK Meteor Observation Network
It wasn’t all that long ago that meteor showers — let alone meteorites — were not considered to be astronomical in origin at all. Indeed, the term meteor and meteorology have the same Greek root meaning “of the sky,” suggesting ideas of an atmospheric origin. Lightning, hail, meteors, you can kind of see how they got there.
In fact, you could actually face ridicule for suggesting that meteors had an extraterrestrial source back in the day. President Thomas Jefferson was said to have done just that concerning an opinion espoused by Benjamin Silliman of a December 14th, 1807, meteorite fall in Connecticut, leading to the apocryphal and politically-tinged response attributed to the president that, “I would more easily believe that two Yankee professors would lie, than that stones would fall from heaven.”
Indeed, no sooner than The French Academy of Sciences considered the matter settled earlier in the same decade, then a famous meteorite fall occurred in Normandy on April 26th, 1803,… right on their doorstep. The universe, it seemed, was thumbing its nose at scientific enlightenment.
Things really heated up with the spectacular display known as the Leonid meteor storm in 1833. On that November morning, stars seemed to fall like snowflakes from the sky. You can imagine the sight, as the Earth plowed headlong into the meteor stream. The visual effect of such a storm looks like the starship Enterprise plunging ahead at warp speed with stars streaming by, as if imploring humanity to get hip to the fact that meteor showers and their radiants are indeed a reality.
Still, a key problem persisted that gave ammunition to the naysayers: no new “space rocks” were found littering the ground at sunrise after a meteor shower. We now know that this is because meteor showers hail from wispy cometary debris left along intersections of the Earth’s orbit. Meteorite Man Geoff Notkin once mentioned to us that no meteorite fall has ever been linked to a meteor shower, though he does get lots of calls around Geminid season.
The name of the game in the 19th century soon became identifying new meteor showers. Streams evolve over time as they interact with planets (mostly Jupiter), and the 19th century played host to some epic meteor storms such as the Andromedids that have since been reduced to a trickle.
The Geminids are, however, the black sheep of the periodic meteor shower family. The shower was first noticed by US and UK observers in 1862, and by the 1870s astronomers realized that a new minor shower with a Zenithal Hourly Rate (ZHR) hovering around 15 was occurring near the middle of December from the constellation Gemini.
The source of the Geminids, however, was to remain a mystery right up until the late 20th century.
In the late 1940s, astronomer Fred Whipple completed the Harvard Meteor Project, which utilized a photographic survey that piqued the interest of astronomers worldwide: debris in the Geminid stream appeared to have an orbital period of just 1.65 years, coupled with a high orbital inclination. Modeling suggested that the parent body was most likely a short period comet, and that the stream had undergone repeated perturbations courtesy of Earth and Jupiter.
In 1983, the culprit was found, only to result in a deeper mystery. The Infrared Astronomical Satellite (IRAS) discovered an asteroid fitting the bill crossing the constellation Draco. Backup observations from the Palomar observatory the next evening cinched the discovery, and today, we recognize the source of the Geminids as not a comet — as is the case with every other major meteor shower — but asteroid 3200 Phaethon, a 5 kilometre diameter rock in a 524 day orbit.
Asteroid 3200 Phaethon (arrowed) imaged by Marco Langbroek from the Winer Observatory in Sonita, Arizona. Credit: Wikimedia Commons.
So why doesn’t this asteroid behave like one? Is 3200 Phaethon a rogue comet that has long since settled down for the quiet space rock life? Obviously, 3200 Phaethon has lots of material shedding off from its surface, as evidenced by the higher than normal ratio of fireballs seen during the Geminid meteors. 3200 Phaethon also passes 0.14 AUs from the Sun — 47% closer than Mercury — and has the closest perihelion of any known asteroid to the Sun, which bakes the asteroid periodically with every close pass.
One thing is for certain: activity linked to the Geminid meteor stream is increasing. The Geminids actually surpassed the Perseids in terms of dependability and output since the 1960s, and have produced an annual peak ZHR of well over 100 in recent years. In 2014, expect a ZHR approaching 130 per hour as seen from a good dark sky site just after midnight local on the morning of December 14th as the radiant rides high in the sky. Remember, this shower has a broad peak, and it’s worth starting your vigil on Saturday or even Friday morning. The Geminid radiant also has a steep enough declination that local activity can start before midnight… also exceptional among meteor showers. This year, the 52% illuminated Moon rises around midnight local on the morning of December 14th.
The Geminid radiant looking to the northeast at 11PM local. Note the radiant of the December 22nd Ursids is also nearby. Credit: Stellarium.
And there’s another reason to keep an eye on the 2014 Geminids. 3200 Phaethon passed 0.12 AU (18 million kilometers) from Earth on December 10th, 2007, which boosted displays in the years after. And just three years from now, the asteroid will pass even closer on December 10th, 2017, at just 0.07 AUs (10.3 million kilometers) from Earth…
Are we due for some enhanced activity from the Geminids in the coming years?
All good reasons to bundle up and watch for the “Tears of the Twins” this coming weekend, and wonder at the bizzaro nature of the shower’s progenitor.
Time lapse-photo showing geminids over Pendleton, OR. Credit: Thomas W. Earle
Wouldn’t it be nice if a meteor shower peaked on a weekend instead of 3 a.m. Monday morning? Maybe even showed good activity in the evening hours, so we could get our fill and still get to bed at a decent hour. Wait a minute – this year’s Geminids will do exactly that!
Before moonrise this Saturday night December 13th, the Geminids should put on a sweet display. The radiant of the shower lies near the bright pair of stars, Castor and Pollux. Source: Stellarium
What’s more, since the return of this rich and reliable annual meteor shower occurs around 6 a.m. (CST) on Sunday December 14th, both Saturday and Sunday nights will be equally good for meteor watching. After the Perseids took a battering from the Moon last August, the Geminids will provide the best meteor display of 2014. They do anyway! The shower’s been strengthening in recent years and now surpasses every major shower of the year.
The official literature touts a rate of 120 meteors per hour visible from a dark sky site, but I’ve found 60-80 per hour a more realistic expectation. Either way, what’s to complain?
The third quarter Moon rises around midnight Saturday and 1 a.m. on Monday morning. Normally, moonlight would be cause for concern, but unlike many meteor showers the Geminids put on a decent show before midnight. The radiant, the location in the sky from which the meteors will appear to stream, will be well up in the east by 9:30 p.m. local time. That’s a good 2-3 hours of meteor awesomeness before moonrise.
The author takes in this year’s moon-drenched Perseids in comfort.
Shower watching is a total blast because it’s so simple. Your only task is to dress warmly and get comfortable in a reclining chair aware from the unholy glare of unshielded lighting. The rest is looking up. Geminid meteors will flash anywhere in the sky, so picking a direction to watch the shower isn’t critical. I usually face east or southeast for the bonus view of Orion lumbering up from the horizon.
Bring your camera, too. I use a moderately wide angle lens (24-35mm) at f/2.8 (widest setting), set my ISO to 800 or 1600 and make 30-second exposures. The more photos you take, the better chance of capturing a meteor. You can also automate the process by hooking up a relatively inexpensive intervalometer to your camera and have it take the pictures for you.
As you ease back and let the night pass, you’ll see other meteors unrelated to the shower, too. Called sporadics, they trickle in at the rate of 2-5 an hour. You can always tell a Geminid from an interloper because its path traces back to the radiant. Sporadics drop down from any direction.
Captured by an all-sky camera, a Geminid fireball brighter than Venus streaks across the sky above New Mexico on Dec. 14, 2011. Before disintegrating in the atmosphere the meteoroid was about 1/2 inch across. Credit: Marshall Space Flight Center, Meteoroid Environments Office, Bill Cooke
Geminid meteors immolate in Earth’s atmosphere at a moderate speed compared to some showers – 22 miles per second (35 km/sec) – and often flare brightly. Green, red, blue, white and yellow colors have been recorded, making the shower one of the more colorful. Most interesting, the meteoroid stream appears to be sorted according to size with faint, telescopic meteors maxing out a day before the naked eye peak. Larger particles continue to produce unusually bright meteors up to a few days after maximum.
Most meteor showers are the offspring of comets. Dust liberated from vaporizing ice gets pushed back by the pressure of sunlight to form a tail and fans out over the comet’s orbital path. When Earth’s orbit intersects a ribbon of this debris, sand and gravel-sized bits of rock crash into our atmosphere at high speed and burn up in multiple flashes of meteoric light.
Phaethon sprouts a tail (points southeast or to lower left) when close to the Sun in this image taken by NASA’s STEREO Sun-observing spacecraft in 2012. Credit: Credit: Jewitt, Li, Agarwal /NASA/STEREO
But the Geminids are a peculiar lot. Every year in mid-December, Earth crosses not a comet’s path but that of 3200 Phaethon (FAY-eh-thon), a 3.2 mile diameter (5.1 km) asteroid. Phaethon’s elongated orbit brings it scorchingly close (13 million miles) to the Sun every 1.4 years. Normally a quiet, well-behaved asteroid, Phaethon brightened by a factor of two and was caught spewing jets of dustwhen nearest the Sun in 2009, 2010 and 2012. Apparently the intense heat solar heating either fractured the surface or heated rocks to the point of desiccation, creating enough dust to form temporary tails like a comet.
While it looks like an asteroid most of the time, Phaethon may really be a comet that’s still occasionally active. Periodic eruptions provide the fuel for the annual December show.
Most of us will head out Saturday or Sunday night and take in the shower for pure enjoyment, but if you’d like to share your observations and contribute a bit of knowledge to our understanding of the Geminids, consider reporting your meteor sightings to the International Meteor Organization. Here’s the link to get started.
And this just in … Italian astronomer Gianluca Masi will webcast the shower starting at 8 p.m. CST December 13th (2 a.m. UT Dec. 14) on his Virtual Telescope Project site.
Observations of Comet Siding Spring Oct. 19 by the Mars Orbiter Mission. Credit: Indian Space Research Organisation
Feeling lucky? Events such as the Comet Siding Spring approach by Mars in October only happen about once every eight million years, according to NASA.
And after we were treated to spectacular views from the agency’s spacecraft (see Curiosity and Opportunity and MAVEN, for example), we now have fresh pictures this month from an Indian mission. Also, NASA has released science results suggesting that the chemistry of Mars’ atmosphere could be changed forever from the close encounter.
“The image in the center shows a streak … radiating out of the comet’s nucleus (out of frame), possibly indicating the jet from [the] comet’s nucleus,” the Indian Science Research Organisation wrote of the above image sequence on its Facebook mission page.
“Usually jets represent outgassing activity from [the] vents of the comet-nucleus, releasing dust and ice crystals. The outgassing activity gradually increases as the comet moves closer to the Sun.”
Artist view of the comet passing closest to Mars this Sunday. At the time, the Mars orbiters from the U.S., Europe and India will be huddled on the opposite side of the planet to avoid possible impacts from comet dust. Credit: NASA
The comet’s dust likely produced a meteor shower or meteor storm when particles from it crashed into the upper atmosphere, which “literally changed the chemistry,” added Jim Green, director of NASA’s planetary science division, in a recent discussion highlighted on an agency blog.
The agency says the dust created vaporized metals, which will eventually transform to dust or “meteoric smoke.” MAVEN (which stands for Mars Atmosphere and Volatile EvolutioN) will be monitoring the long-term effects. Possible results include high-altitude clouds or at the most extreme, maybe permanently altering what the chemistry of the atmosphere is. Not a bad thing for a mission to study shortly after it arrived at Mars.
You can view more science results from NASA’s studies of Siding Spring in this recent Universe Today story from Bob King, which talks in more detail about the meteor shower, new layers in the Mars atmosphere and the omnipresent dust.
