Tag Archives: meteors

Close but still so far away – the sun at perihelion

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Quadrantid meteor shower Jan. 2-3, 2013

Were you like me and got up this morning only to find the sky still overcast? No meteors for this poor astronomer. I hope some readers fared better.

It always seems to be clear over John Chumack’s home in Dayton, Ohio. Chumack, a long-time amateur astronomer, recorded 52 Quadrantid shower meteors overnight using a low-light video camera. Click the video above to watch it all go by in just 33 seconds.

Earth’s oval or elliptical orbit causes our distance from the sun and orbital speed to vary during a year. This week we’re both closest and moving fastest. Illustration: Bob King

At 10:37 p.m. January 1 this week, Earth passed an annual milestone in its orbit, reaching its closest point to the sun for the year. Astronomers call it perihelion, a Greek-rooted word combining ‘peri’ (close) and ‘helios’ (sun). Earth’s distance from the sun varies over the course of a year because our orbit is not a circle with the sun at the center. Rather it’s an ellipse – like all the other planets’ orbits – with the sun slightly off to one side.

On July 5 this year, Earth will reach its farthest distance from the sun called aphelion (AP-hee-lee-on). The difference from one side of our orbit to the other is only about 3 million miles or 3.3%. While the change in distance affects the amount of heat we receive from the sun, it’s not nearly enough to affect the seasons, which are caused by the 23.5 tilt of our planet’s axis. The tilt of the north pole toward the Sun in June causes summer north of the equator, while summer south of the equator comes six months later when the south pole is facing the Sun.

Difference in the size of the sun when Earth was at aphelion (top) last July and this week at perihelion. It’s very obvious in side-by-side photos but extremely difficult to discern with the naked eye. The difference amounts to just 1.1 minute of arc or 1/30 the diameter of the full moon. Credit: Giorgio Rizzarelli

Because our distance from the sun varies, so does the sun’s size and our planet’s orbital speed. When closest to the sun, Earth moves faster than when farther away, the same way sun-hugging Mercury orbits faster than distant Jupiter. Our average speed is 18.5 miles per second (66,600 mph) through space, but today we’re zipping along 2,160 mph faster than we will come July. I can almost feel the wind in my thinning hair.

The sun is peppered with sunspots in this photo made at  9 a.m. CST today Jan. 3 by the Solar Dynamics Observatory. Sunlight takes 8.2 minutes to arrive at Earth at perihelion and 8.5 minutes at aphelion. Credit: NASA

Giorgio Rizzarelli, a regular reader and commenter on this blog, performed an interesting experiment comparing the size of the sun at aphelion on July 5, 2012 and at perihelion earlier this week. The difference is immediately obvious from his unique perspective.

Giorgio went a step further and measured the difference in diameters to arrive at the Earth’s orbital eccentricity.

Eccentricity or ‘e’ refers to how stretched out a planet’s orbit is compared to a perfect circle. With a circle defined as e = 0, Rizzarelli calculated an ‘e’ of  0.017 (nearly circular but not quite) for Earth’s orbit, in excellent agreement with the published figure of 0.0167. (see calculation below). Amazing what you can do with a camera from your own backyard.

“The disc in lower photo is 3.4% bigger than in the upper, so (dividing by 2) 1.7% bigger than average. Hence Earth today is 1.7% closer to the Sun than average. This defines the approximately eccentricity, (which is) 1.7% or 0.017.” – Giorgio Rizzarelli

Flyby photos show lumps and bumps of far-out asteroid Toutatis

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Composite of 9 pictures showing mulitiple Geminid meteors, including a -6 magnitude fireball, photographed from a mountainside above Coal Creek Canyon, Colorado. Each flash represents a grain or pebble of the asteroid Phaethon burning up in our atmosphere. Credit: Dr. Richard Keen

This morning two small asteroids passed harmlessly by Earth at distances of just 174,000 and 292,000 miles. 2012 XP134, the more distant and measuring 42 feet across, whizzed by at 8 a.m. (CST) and 40-foot -wide 2012 XL134 two hours later. While some may take the sign of so many Earth-approaching asteroids as a bad omen, it’s all good news in my view.

NASA estimates there are a total of about 10 million near-Earth asteroids in the 10-meter (32 feet) range with an expected impact rate of one every 10 years. If you up the size to 30-meters (100 feet), there are 1.3 million objects with an impact rate of one every 200 years. Objects this size are still too small to gouge a crater and cause significant damage on the ground. Most would be expected to fragment in an airburst and possibly drop meteorites along their entry paths.

This chart shows how data from NASA’s Wide-field Infrared Survey Explorer, or WISE, has led to revisions in the estimated population of near-Earth asteroids (NEAs). The infrared-sensing telescope performed the most accurate survey to date of NEAs. Small objects found weekly number in the millions. Click photo to learn more about asteroid numbers. Credit: NASA

With numbers like these, it’s no surprise that Earth-shaving asteroids are discovered routinely. According to Donald Yeomans, manager of NASA’s Near-Earth Object Program Office, asteroid search programs find about 20 every week. In tomorrow’s blog, I’ll be reviewing his brand new book on the topic.

I’m glad all these good people are watching out for flying rocks. Not only does it mean we humans are becoming more knowledgeable about our surroundings, but knowing their orbits allows us to forecast when one of them might pose a danger in the future. This, we hope, will stir us to devise solutions to avoid a potential disaster. In 1990 there were only 134 Earth-approaching asteroids known; as of mid-2012 that number is somewhere around 9,000 and rising every week. Wouldn’t you rather know what’s coming than be in the dark?

Flyby images of the 3-mile long asteroid Toutatis taken by the Chinese Chang ‘e 2 spacecraft earlier this week. Its odd shape might be the result of two separate asteroid fragments that stuck together after a gentle collision. Click for larger version. Credit: SASTIND via Weibo / UMSF

Many of us got to experience first hand this week what happens when minute pieces of an asteroid strike Earth’s atmosphere – a beautiful meteor shower! Thurday night’s Geminids originate from dust and small pebbles released from the 3.1 mile long asteroid 3200 Phaethon. Two nights prior to the Geminid peak, the largest near-Earth asteroid 3179 Toutatis, also about 3 miles long, passed some 3.4 million miles from the planet.


64-frame movie showing Toutatis tumbling through space only 4.3 million miles from Earth on Dec. 12-13. Credit: NASA/Goldstone radar

While Phaethon’s too faint for most amateur telescopes, Toutatis remains bright as it slowly travels through the constellations Cetus and Aries this month. I watched this star-mimic amble through my telescope field of view Thursday night while trying to appreciate exactly what I was looking at. Fortunately the Chinese and NASA’s Goldstone radar provided some help.

A cropped version of picture sequence shows a clearer view of the asteroid’s surface. The bumps could be piles of boulders. Credit: Chinese National Space Agency

As the spacecraft flew by the bizarre-shaped Toutatis at the relative speed of 24,000 mph, it snapped a series of approach pictures. Higher resolution images will soon be released, but these are clear enough to see what appear to be boulder piles strewn about the surface as well as shallow craters. We live in wonderful times.

Farewell DST, hello Orion!

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The two maps show the sky facing east on Nov. 3, when daylight saving time was still in effect, and tonight. Losing an hour makes the stars appear to move an hour westward, raising Orion up in the east at the same time on the clock. Created with Stellarium

Since dropping Daylight Saving Time last weekend you’ve probably noticed how swiftly evening darkness descends. The photojournalist part of me craves daylight, especially if I need to shoot a feature photo for my newspaper’s local news section. It’s not easy to find or photograph people out and about during twilight.

But there are compensations. One of them is the swift kick the stars get once DST is done. You may have noticed last week around 9:30 p.m. local time that Jupiter and his constellation buddies Taurus and Orion grazed the treetops low in the eastern sky.

With our return to standard time, the stars of the eastern sky are up an hour earlier, while those in the west set an hour earlier. If you’re a fan of Orion and Jupiter – and who isn’t? – you don’t have to stay up so late to see them. Meanwhile, you’d better get out early if you want to catch the late summer-early fall stars. They’re all in the western sky and getting the boot an hour sooner.

The secret to this remarkable sleight of hand is simple – 9:30 p.m. daylight time is the same as 8:30 standard time. For our clocks to read 9:30 standard time we have to wait an additional hour, during which time Orion sneaks up from below the horizon and Jupiter vaults higher in the east.

Many of the meteors in this composite photo belong to the Taurid meteor shower, which remains active through the weekend. The bright object at lower right is the moon. Credit: John Chumack

Having Taurus the Bull nosing up earlier is a good thing because the Taurid meteor shower’s putting on a decent show. I wish I could chime in with my own observations, but the sky’s been overcast here. Not so for astrophotographer John Chumack of Dayton, Ohio. He grabbed some great video stills yesterday morning at the start of the shower’s peak activity.

“The meteors were nice and slow … burning up and often leaving small afterglows (trails),” writes Chumack. “Not bad for a minor shower.” The Taurids will continue to fling meteors our way through the weekend. Click HERE for more information on how to view them.

Orionid meteor shower, Iridium flares and chance for auroras tonight

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Map from Heavens Above showing the path of Iridium 96. The satellite will likely be invisible along much of the path but will flare at 5:36 a.m. Credit: Chris Peat / Heavens Above

Don’t forget to watch for flying Orionid meteors tomorrow morning before dawn. This annual shower peaks Sunday Oct. 21 when up to 25 meteors per hour originating from the constellation Orion might be visible from a dark sky site. No moon will mar the view. Head out around 4 a.m. and face south. I encourage you to share your observations in the comment section below.

While you’re out meteor watching, check to see if any of the Iridium satellites are visible from your location. The Iridiums, a group of some 66 satellites orbiting the Earth in a global ‘constellation’ 485 miles high, are used for relaying voice and data communications.

Normally Iridiums are too faint to see except in binoculars, but they have silver-coated Teflon antenna arrays that reflect sunlight like a mirror. When the angle between satellite and observer is right, a brilliant reflection of the sun from the antennas causes an Iridium to suddenly and spectacularly brighten for 5 to 20 seconds. For Duluth, Minn., the city dear to my heart, a -2 magnitude flare (bright as Jupiter) occurs at 5:36 a.m. tomorrow morning just below Orion’s Belt.

Iridium flares start out faint, rapidly brighten to peak light and then quickly fade away. This photo captured Iridium 96 a few years back. Photo: Bob King

Flares range in brightness from equal to the brightest stars all the way up to -8 or about 20 times brighter than Venus. They’re very exciting to see. The new maps at Heavens Above make finding where and when to look a snap. Log in, select your city and then click the Iridium Flares link. You’ll be shown a table of times and brightness. Just click the time to see the map.

The moon will be a thick crescent in the southwestern sky in Sagittarius the Archer tonight. The lunar terminator defines the crescent’s left side. Photo: Bob King

There’s also a chance for a small display of aurora borealis for the northern U.S. tonight through Monday as a high speed stream of solar wind particles buffets Earth’s magnetic field. If auroras show, they’re usually brightest around midnight – 1a.m. Keep an eye out while you’re meteor watching.

And don’t forget the moon, especially if you’re out early this evening.

Binoculars are excellent for bringing out the bigger craters and dark impact basins (lunar seas). Look along the lunar terminator, the arc-shaped border between day and night where shadows are longest and details most clearly defined, for best viewing.

More auroras, less dragon spit and an odd shiny object on Mars

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Last night’s aurora simmers beneath the Big Dipper (left). At right is the Kp index chart showing magnetic activity high in Earth’s atmosphere. When the Kp reaches 5, a minor geomagnetic storm with accompanying auroras is in progress. Last night, it shot up to 6 (moderate storm) and stayed there well into the morning. Credit: Bob King (left) and NOAA

First let’s check in on the aurora. Last night’s display continued well into the morning hours. Our sky clouded after 11:30 p.m. but I’m not complaining. The few openings were enough to relish the lively show.

A large coronal hole (dark spot) that may lead to more northern lights. Photographed on Oct. 6 by the Solar Dynamics Observatory. Credit: NASA

Chances look good again tonight and tomorrow night for at least minor storms. While the effects of the coronal mass ejection (CME) are waning, reinforcements are now coming from an Earth-directed coronal hole. The holes or openings in the sun’s otherwise zippered up magnetic field allow charged particles like electrons and protons to escape and stream outward into space at high speed. When they flow past our planet, they can sometimes stimulate auroras. Yes, Earth’s getting a pounding … and we love it! I’ll update later this evening.

How about those Draconid meteors? I never saw any. Few reports from other observers around the world have come in to confirm visually what the Canadian radar recorded yesterday. Evidently the meteors nabbed by radar were too small to leave trails bright enough for the naked eye to see. According to Bill Cooke of NASA’s Meteoroid Environment Office, a  strand of dust shed by the shower’s parent comet Giacobini-Zinner in 1959 was responsible for the sudden and brief jump in meteors.

A photo of Curiosity’s first scoop of soil yesterday also reveals a shiny, possibly metallic object lower in the frame inside the blue circle. Loaded scoop is above center. Credit: NASA/JPL-Caltech

We won’t have to wait long for the next meteor shower, the reliable Orionids brought to us by Halley’s Comet. That one peaks on the mornings of Oct. 20-22. No moon will mar the view.

A cropped version of the picture above showing the object. Credit: NASA/JPL/Caltech

While the Curiosity Rover jitterbugged its first soil sample to make sure the scoop free of Earth contaminants, its cameras spotted a small, shiny object embedded in the Martian soil. It could be metallic and possibly a piece of hardware or even tape that got loose and dropped to the ground. Mission controllers are suspending soil sampling for the time being as they position the rover’s cameras for a better look. We’ll have an update later today especially if it turns out to be a bolt left behind by an early Martian mechanic.

Tomorrow we’ll have times when you can watch the space station link up with the latest Dragon supply ship launched earlier this week by SpaceX.

Ah, the lovely Quadrantids plus Earth closest to the sun today

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Stephen Bockhold of Duluth took this very nice picture of a Quadrantid shooting away from beneath the curved handle of the Big Dipper this morning. "Took about 30 pictures, only one had a meteor," said Bockhold. I've tried on other meteor shower nights and haven't gotten anything. I consider myself lucky!" Details: Canon T2i, 18-55 mm lens; ISO 3200, 30 sec exposure.

Now I know why the Quadrantid meteor shower doesn’t hit the public radar like the Perseids of August. It’s just too cold. At least it was at my house, but I’m so glad I stepped out the door for an hour to watch. I squished myself into one of those folding lawn chairs and sat looking to the east in the driveway, moon at my back. The wind lashed about, crept up my back and chilled my kneecaps. I stayed put and took it like a stoic. Meteor watchers and amateur astronomers develop a high threshold for pain over time. We stand riveted to the eyepiece or at our watching posts in spite of the mosquitos’ hum and eyelashes sticky with ice.

Honestly, I loved being out. The sense of anticipation during a meteor shower is keen. There’s always that first meteor to get you going and whet the appetite. Once you’ve tasted it, you simply must stay for the whole meal. Most of the 18 Quads I saw were faint and fast, scratching pale paths across the sky that lasted no more than a second. Gaps of five minutes – which seemed like a very long time in the cold – separated sightings of small clusters of meteors. Since I faced east, most of them zipped through the Big Dipper and nearby Canes Venatici. Two were sporadic or random meteors from forgotten comets of long ago. Their paths led back to other points in the sky, not the Quadrantid radiant.

Another Quadrantid meteor over Dayton, Ohio photographed by John Chumack. Details: 8mm lens at f/6, ISO 400 and 30-second exposure.

Two meteors stood out. The first was a yellow-orange, medium-fast blazing bit of dust about as bright as Mars or zero magnitude. The second was a brilliant flash in Leo seen from the corner of my right eye. That one left a trail of glowing ionized gas near Leo’s brightest star Regulus that lasted nearly 10 seconds. At 2:30 a.m. a few clouds crept out of the west and 15 minutes later the sky was mostly cloudy and the meteor window shuttered.

Stiff from sitting with my head cocked skyward for an hour, when I tried to stand up, the chair slid out from under me and my rear end hit the icy ground. Pretty funny at the time. I quickly pulled the scope out for a look at Mars and then reluctantly prepared to go to bed for the second time.

We are fortunate for meteor scientists’ work in identifying the origin of these flying sparks. Knowing we were watching the remains of the splintered comet 2003 EH1 added a deeper dimension to the viewing experience.

According to the International Meteor Organization the Quadrantids peaked at an estimated 94 meteors per hour around 3:30 a.m. CST January 4 with rates as high as 75 per hour several hours earlier around midnight. You can look through the data yourself on their Visual Data Quicklook site. I hope you got a chance to see the shower this morning; our next notable encounter with more cometary remnants will be the Lyrids in April.

Earth's elliptical orbit causes our distance from the sun as well as our orbital speed to change over the course of a year. Illustration: Bob King

This evening around 7 p.m. Central time the Earth will be closest to the sun for the year, an event astronomers call perihelion. The word comes from the Greek ‘peri’ (close) and helios (sun). Earth’s distance from the sun varies over the course of a year because our orbit is not a circle with the sun at the center. Rather it’s an ellipse – like all the other planets’ orbits – with the sun slightly off to one side. On July 4 we’re farthest and today, closest.

The difference from one side of our orbit to the other is only about 3 million miles or 3%. Don’t expect a heat wave, since that’s too small to cause noticeable climate change. The main driver of yearly weather shifts on Earth is the tip of our planet’s axis, which is responsible for the four seasons. Our orbital speed also varies with distance. If your day is dragging, consider that you and the planet are zipping along 2,160 mph faster today compared to aphelion on July 4.

Quadrantid meteor shower sweetens up the week

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Jupiter and the moon couple up tonight high in the southern sky during early evening hours. Maps created with Stellarium

Light years ago, after my wife and I spoke our vows and exchanged rings at our wedding, the singers we’d hired sang the song “Sugar in the Morning”. We walked down the aisle smiling to the tune of “Sugar in the mornin’, sugar in the evenin’, sugar at suppertime. Be my little sugar and love me all the time.”

You can have spoonfuls of astronomical sugar tonight and Wednesday morning starting with a close conjunction of Jupiter and the waxing half moon. As twilight gives way to darkness this evening, face south and look up high. Jupiter will hang directly below the 9-day-old moon. The planet is currently due south around 7 p.m. local time. Through a telescope you’ll see the moons Io, Europa and Ganymede in that order lined up east of the planet. Callisto will be all by itself west of Jupiter’s blazing disk.

A spear-like bright Quadrantid meteor. The meteors are the remains of asteroid 2003 EH3, which astronomers believe is an extinct comet. Credit: Mike Hankey

In the wee hours of Wednesday, conditions are nearly ideal for a great display of the new year’s first meteor shower, the Quadrantids (kwah-DRAN-tids) across much of the U.S. and Canada.

The “Quads” appear to radiate from a point in the sky below the Handle of the Big Dipper, which stands high in the northeastern sky at the time. This area was once home to the now defunct constellation Quadrans Murealis (mural quadrant), the origin of the shower’s name.

Brief but intense, the shower typically peels off around 100 meteors per hour under ideal conditions. What distinguishes the Quadrantids from the likes of the Perseids or Geminids is how brief the period of peak activity is. It typically lasts just an hour or two, so each year only a particular region of the world is favored; for the rest, the radiant either hasn’t risen or it’s daytime.

A good time to view the shower is between about 1 and 3 a.m. CST Thursday Jan. 4 when the radiant is halfway up in the eastern sky around the time of maximum meteor activity.

Shower maximum is expected Wednesday morning Jan. 4 between 1:00 and 2:00 a.m. CST (2-3 a.m. Eastern). At those times, the radiant will be up in the eastern sky and for the Eastern half of the U.S. and Canada – ideal for catching the largest number of meteors. Counts could range from a conservative to more than a 100 per hour. The waxing gibbous moon will put a small dent in festivities, but it’s low in the west and setting around that time, so I don’t expect much interference.

The shower peaks for the West Coast between 11 p.m. and midnight Jan. 3. While the time is easier on the working man and woman, the radiant will not yet have risen, so you won’t see nearly as many meteors. However, you might catch a few Earth-grazing meteors, the ones that climb up from below the horizon and make long trails as they skirt through the upper atmosphere. One of my favorite meteor moments was an Earth-grazing Leonid a few Novembers back. It rose slowly from the northeast horizon and cut a path almost 90 degrees long before finally succumbing to burnout.

For everyone else, except southern hemisphere observers who are too far south for the radiant to rise above the horizon, the American Meteor Society predicts about 25 meteors per hour between moonset and dawn (approx. 4-6 a.m.).

U.S. and Canadian observers should really try to catch the Quadrantids even if it is the coldest time of year. Having maximum coincide with the radiant point being above the horizon is a a rare treat. Observers in the Eastern half of the U.S. can start watching as early as midnight-1 a.m. while those in the West can begin around 11 p.m. on the 3rd.

Put on a few layers of clothing, tuck hand warmers in your boots and gloves, face northeast and have at it! It may even be clear for a change. I observed one Quadrantid shower back in the early1980s and have great memories of several dozen meteors shooting this way and that until the first light of dawn. (UPDATE: Click HERE for a post-meteor shower report.)

Good news again for the GRAIL moon mission – the GRAIL-B probe arrived yesterday and successfully joined its sister GRAIL-A in orbit around the moon. The orbits of both will be refined in the coming weeks with the science mission planned to start in March.

Geminid meteor shower cuts loose Tuesday night

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This map shows the sky around 9 p.m. local time. The radiant, located right next to Castor in Gemini, is the point in the sky from which the Geminid meteors appear to originate. If you see a meteor and can trace its path backwards to this spot, it's a Geminid! Created with Stellarium

They’re back! Another year of your life has passed and the Geminids are here to mark the occasion. This annual and very reliable meteor shower starts ramping tonight with some 40 meteors per hour visible from dark country skies. Unfortunately the moon will spoil the view, cutting that number down to roughly 10 per hour. We were on pins and needles two nights ago hoping to see the moon in eclipse, but now that the best meteor shower of the year is due, we’d sooner see Luna gone. Easy come, easy go.

False color composite of the 2008 Geminid shower taken with an all-sky camera. Credit:NASA/MSFC/B. Cooke, NASA's Meteoroid Environment Office

The shower peaks late Tuesday night through Wednesday morning December 13-14. If you’re out during the evening hours when the radiant is low, you’ll catch about 20 meteors per hour in moonlight. When Gemini reaches its highest elevation in the south around 1-2 a.m. that number could go as high as 30 to 40. Without the 86-percent illuminated moon nearby, an observer under dark skies might spot up to 120 per hour. Either way it’s worth making the effort to see.

Most meteor showers originate in dust and debris left behind by comets during their spin around the sun, but the Geminids are different. Their parent body is the 3-mile-diameter asteroid 3200 Phaethon (FAY-uh-ton). Scientists speculate that when Phaethon passes near the sun, solar heat boils clouds of dust off its surface, which scatter along the asteroid’s orbit. When Earth slices through the orbit every mid-December, some of that dust burns up in our atmosphere to create the Geminid meteor shower.

Geminids are slow compared to meteors in other showers – 79,000 mph compared to the summertime Perseids’ 130,000 mph average speed. They travel in long paths and often take several seconds to fade out. Bright fireballs are not uncommon. Used to be the Perseids were the richest shower of the year, but the Geminids have now moved into first place. They were first recorded in the 1830s, when observers counted about 20 per hour at best. Since then, Earth has been plowing ever deeper into 3200 Phaethon’s debris stream and meteor numbers have climbed steadily.

A brilliant Geminid fireball flares across Orion in this photo from a couple years back. Credit: Wally Pacholka

I always enjoy the Geminids. They’re often bright and it’s easy to catch a few during the hours before midnight. The best way to watch the shower is to dress warmly, relax in a comfortable chair and face away from the moon. I’d suggest looking halfway up in the southern sky with the moon off to your left and out of view. That way you can preserve your night vision and spot more meteors. Start around 9 o’clock when the radiant’s up in the east. Maximum meteor madness will occur Wednesday morning before dawn.

Bring your kids out too or share the shower with a friend. And don’t forget a warm drink! May the weather gods be with you.

Orionid meteor shower could make your wildest dreams come true

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Meteors, nicknamed "falling stars", appear as bright streaks of light against the steady stars. Photo: Bob King

I’ve always enjoyed the scene in the movie Napoleon Dynamite when Pedro, Napoleon’s friend, runs for school president under the slogan “Vote for me, and I’ll make all your wildest dreams come true.”

Since we’ve all wished upon a shooting star at one time or another, the Orionid meteor shower will offer some 20 wishing possibilities per hour when they peak this Friday and Saturday mornings (Oct. 21 and 22) in the hours after midnight. They’re called Orionids because the meteors appear to originate from a spot in the sky to the upper left of the bright pink star Betelegeuse in the constellation Orion the Hunter.

The Orionid meteors will all point back to a spot just above the bright star Betelgeuse in Orion called the meteor radiant. You might also see some stray meteors called sporadics that appear on any given night. Orionids can all be traced back to the radiant. Created with Stellarium

Orionids made their first appearance earlier this month as Earth began entering the dust stream left behind by the one and only Halley’s Comet. We cross its orbital path twice a year, and each time we do, our planet slams into sand-sized bits of debris strewn by the comet during the many times it’s circled the sun. The other Halley-related shower is the Delta Aquarids on April 21.

Each year in late October Earth travels through a stream of dusty debris left behind by Halley's Comet. Illustration: Bob King

Since we encounter these cometary morsels nearly head on, they strike the atmosphere at over 147,000 miles per hour and vaporize in bright streaks of meteoric light. The Orionids have been a very reliable and active shower in recent years. Weather permitting, I always make the effort to get out for a look, since meteors are guaranteed. They’re typically white, modest in brightness and amazingly fast. Expect occasional fireballs from the shower, too.

Meteors appear to radiate from a point in the distance the same way snow striking your car windshield does when driving. Even though the snowflakes and meteors are generally parallel to each other, our eyes see them as converging in the distance. A similar illusion happens when looking down a set of train rails. Photo: Bob King

The best time to see them is now through the end of the week but in particular on Friday and Saturday mornings. While Orion’s up in the southeast by midnight, you’ll do better to set the alarm and step outside around 4-5 a.m. With the constellation and radiant high in the south at that hour, many more meteors will be visible. Find a place without a lot of glaring lights, set up a chair and prepare something warm to drink to ward off the fall chill and keep you alert.

The best direction to face is south with Orion in full view. Since dawn starts around 6 a.m. where I live, my plan is to out at 5 for a nice hour’s worth of darkness. The only ding in an otherwise ideal morning will be the thick crescent moon off to the east near the planet Mars. Its light will hide some of the fainter meteors, but shouldn’t pose a serious threat to your wishing and watching enjoyment.

Perseid meteors meet the moon meet the space station

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The International Space Station cruises across the eastern sky this morning about 3:40 a.m. Watch for it during the Perseid meteor shower over the next few nights. Details: 20mm lens at f/2.8, 2-minute exposure, ISO 800. At right is the planet Jupiter. Photo: Bob King

I can foretell the future. Though the maximum of the Perseid meteor shower is still a night away, I’m certain I’ve seen my personal peak. Two mornings ago, my older daughter came to visit. After our walk, she wanted to watch meteors. When I told her, we’d have to wait until the early morning hours when the moon was near setting, that didn’t phase her a bit. “I’m up until 3 all the time,” she replied.

Poor dad was tired, but I took a nap as she tapped away compiling music on her computer. Then just before 1 o’clock, I awoke and asked if she was ready to go. Pillows in hand, we walked outside and sprawled out on the concrete driveway at my mom’s place. The air was cool, so she wrapped herself in a blanket. We spent the next half hour looking straight up.

If you're out meteor watching in the morning hours, face east to see a panoply of bright winter season stars. Jupiter will be the brightest thing in the sky. From there, work your way to the others. An open eastern horizon provides a glimpse of Orion at dawn. Time shown is about 3:30 a.m. local. Created with Stellarium

One’s sense of anticipation is strong when watching for meteors. You know with certainty that they’ll show, but the first flash seems to take forever. Once the ice is broken however, you get into that easy rhythm of “no expectations” and stop wondering when the next one will arrive. After 15 minutes, they all become pleasant surprises.

Then there’s the matter of a happy conclusion. You don’t want to head back to bed without the sense of completeness that that “one last meteor” provides.  This is true whether you’re alone or sharing the shower with family or friends.

Unfortunately,  you’re now back to where you started with expectations. You’ll stand there for what feels like forever for that final meteor that signals the OK to go to bed. Does this happen to you too?

In the end, we shared seven nice ones altogether – six Perseids and one Aquarid – and at that hour, those seemed enough to satisfy us both. I felt fortunate to share a corner of the cosmos with Katie.

Orion's Belt (below center) rises in a narrow gap in the treeline this morning about 4:15 a.m. At upper left is the bright star Betelgeuse. Rigel is at lower right. Details: 35mm lens, f/2.8, 20 seconds exposure, ISO 1600. Photo: Bob King

You’ll have some extra fun during this year’s Perseid shower watching the space station pass overhead. I was out again this morning watching for and hoping to photograph meteors in a sliver of darkness between moonset and dawn. Although I didn’t succeed in capturing a single one with my camera, I did get a great view of the space station. Not only that, but Orion, my favorite constellation, rose in the east at dawn. After a long (or short) night with the Perseids, Orion’s a wonderful treat to cap off your meteor-viewing session. The cooler temperatures that come with mid-August dawns sync well with the arrival of winter’s mighty hunter. Keep an eye out for the aurora too. Recent large solar flares have upped our chances of seeing them tonight.

With the weather not looking good for the next two nights, my Perseid watching is already winding down. I hope you’ll have better luck. Remember that the later you stay up, the more meteors you’ll see. You’ll know a particular meteor’s a Perseid and not a sporadic or member of other weak showers active this time of year, if you can trace its path back to the northeastern sky in the direction of the W of Cassiopeia, near where the radiant lies.

I usually face east or southeast for the Perseids, but meteors will streak in all directions. Those near the radiant will appear short compared to meteors seen “broadside” well away from the radiant in the southwestern or northwestern sky. As described in a previous blog, moonlight will be a factor, but if you keep the moon out of your field of vision and allow your eyes to adjust to the darkness, you’ll improve your chances of seeing more meteors.

The ISS is backlit by the sun as it orbits Earth. Credit: NASA

The International Space Station (ISS) transitions this week from morning to evening passes. The times below are for the Duluth, Minn. region. To figure out exactly when the station flies over your town, go to Spaceweather Satellite flybys and key in your zip code or log on to Heavens-Above.

* Friday morning Aug. 12 starting at 4:26 a.m. High pass across the southwestern sky – very bright!
* Saturday Aug. 13 — Today the space station makes the transition from morning to evening viewing. The first pass will be at 5:05 a.m. very low in the south-southwest. The evening pass will appear across the south-southeast sky starting at 9:40 p.m.
* Sunday Aug. 14 at 10:17 p.m. Brightest of the week! Flies directly overhead from out of the west. Watch it fade away as it enters Earth’s shadow to the right of Cassiopeia in the northeast about 10:22 p.m.
* Monday Aug. 15 at 9:20 p.m. Fine, bright pass across the south. Second shorter pass in the northwest at 10:56 p.m. Fades out just above the Bowl of the Big Dipper.
* Tuesday Aug. 16 at 9:57 p.m. high across the north.
* Wednesday Aug. 17 at 8:59 p.m. nearly overhead. Brilliant pass! Second short pass at 10:36 p.m. across the north. Fades out below the W of Cassiopeia