We’ve posted many beautiful aurora photos and videos over the years here at Universe Today, but this one about stopped my heart. Titled “Soaring”, it was all shot in real time by Ole Salomonsen, a landscape photographer based in Tromsø, Norway. Salomonsen has been shooting spectacular stills and videos of the northern lights for years. While not the first aurora video done in real time, it’s probably the most successful, high definition effort to date. Ole used a Sony A7S, which he calls “the best low light camera ever”.
It was shot from late August to mid-November in and around the city of Tromsø, as well as on the island of Senja, Norway’s second largest island and a three-hour drive from the city. But what sets this video apart from many is that it shows the aurora unfolding live as if you’re standing right there. No time lapse.
Coronal aurora scene from “Soaring”. Credit: Ole Salomonsen
Having witnessed the northern lights many times over the years from my home in northern Minnesota, I can vouch for how close to reality this work truly is. There’s a little more color saturation than what the naked eye would pick up, but the aurora’s changing rhythms are beautifully captured. Ole also mixes in dramatic pan shots taken as if you were running to find a clearing to get the best view. Honestly, that blew me away.
“Although auroras mostly move slowly and majestic, they can also move really fast,” wrote Salomonsen. After seeing the slow undulations of curtains and rays early in the film, you’ll really appreciate the aurora’s other side – its dazzling speed.
The human perspective – another scene from “Soaring”. Credit: Ole Salomonsen
“The corona I captured and the lightning fast sequences at the end are some of the most amazing shows I have witnessed in my many years of hunting and filming the lights,” added Ole.
And now for the most amazing part. What you just watched is only a fraction of what Salomonsen has shot during the season. Expect more soon!
A 3-D model of 6 Hebe based on its light curve. The asteroid is about 120 miles in diameter and orbits in the main asteroid belt between Mars and Jupiter. Credit: Charles University_Josef Durech_Vojtech Sidorin
In the reeds that line the banks of the celestial river Eridanus, you’ll find Hebe on the prowl this month. Discovered in 1847 by German amateur astronomer Karl Ludwig Hencke , the asteroid may hold the key to the origin of the H-chondrites, a large class of metal-rich stony meteorites found in numerous amateur and professional collections around the world. You can now see this interesting minor planet with nothing more than a pair of binoculars or small telescope.
Judging by his demeanor, it might have been unwise to tell Karl Hencke he was wasting his time looking for asteroids.
The first four asteroids – Ceres, Pallas, Juno and Vesta – were discovered in quick succession from 1801 to 1807. Then nothing turned up for years. Most astronomers wrongly assumed all the asteroids had been found and moved on to other projects like measuring the orbits of double stars and determining stellar parallaxes. Nothing could have been further from the truth. Hencke, who worked as a postmaster during the day, doggedly persisted in sieving the stars for new asteroids in his free time at night. His systematic search began in 1830. Fifteen years and hundreds of cold nights at the eyepiece later he turned up 5 Astrae (asteroid no. 5) on Dec. 8, 1845, and 6 Hebe on July 1, 1847.
Hebe orbits in the main asteroid belt between Mars and Jupiter with an average distance from the Sun of 225 million miles. It spins on its axis once every 7.3 hours. Credit: Wikipedia
Energized by the finds, astronomers returned to their telescopes with renewed gusto to join in the hunt once again. The rest is history. As of November 2014 there are 415,688 numbered asteroids and a nearly equal number of unnumbered discoveries. Fittingly, asteroid 2005 Hencke honors the man who kept the fire burning.
You’ll find Hebe trucking along in Eridanus this month just north of Delta (left) and Epsilon Eridani, a pair of +3.5 magnitude stars. This map shows stars to magnitude +9.5 with Hebe’s position marked every 5 nights. Click to enlarge. Source: Chris Marriott’s SkyMap software
At 120 miles (190 km) across, Hebe is one of the bigger asteroids (officially 33rd in size in the main belt) and orbits the Sun once every 3.8 years. It will be our guest this final month of the year shining at magnitude +8.2 in early December, +8.5 by mid-month and +8.9 when you don your party hat on New Year’s Eve. All the while, Hebe will loop across the barrens of Eridanus west of Orion. Use the maps here to help track it down. I’ve included a detailed color map above, but also created a “black stars on white” version for those that find reverse charts easier to use.
Use this wide view of the sky to get oriented before zeroing in with the more detailed map above. Hebe lies just a few degrees north of Delta and Epsilon Eridani for much of December. Best viewing time is from 10 p.m. to 2 a.m. local time early in the month. Source: Stellarium
In more recent times, Hebe’s story takes an interesting turn. Through a study of its gravitational nudges on other asteroids, astronomers discovered that Hebe is a very compact, rocky object, not a loosey-goosey pile of rubble like some asteroids. Its high density provides strong evidence for a composition of both rock and iron. Scientists can determine the approximate composition of an asteroid’s surface by studying its reflectance spectrum, or what colors or wavelengths are reflected back from the object after a portion is absorbed by its surface. They use infrared light because different minerals absorb different wavelengths of infrared light. That data is compared to infrared absorptions from rocks and meteorites found on Earth. Turns out, our friend Hebe’s spectrum is a good match to two classes of meteorites – the H-chondrites, which comprise 40% of known meteorites – and the rarer IIE silicated iron meteorites.
Did this slice of meteorite come from Hebe? A 12.9-gram specimen of NWA 2710, an H5 stony chondrite, sparkles in the light. The shiny flecks are iron-nickel metal set in a stony matrix. Credit: Bob King
Because Hebe orbits close to an unstable zone in the asteroid belt, any impacts it suffers are soon perturbed by Jupiter’s gravity and launched into trajectories than can include the Earth. When you spot Hebe in your binoculars the next clear night, you might just be seeing where many of the more common space rocks in our collections originated.
It’s a dangerous universe out there, for a budding young space-faring species.
Killer comets, planet sterilizing gamma ray bursts, and death rocks from above are all potential hazards that an adolescent civilization has to watch out for.
This week offers two close shaves, as newly discovered Near Earth Asteroids (NEAs) 2014 WC201 and 2014 WX202 pass by the Earth-Moon system.
The passage of 2014 WC201 is coming right up tonight, as the 27-metre space rock passes about 570,000 kilometres from the Earth. That’s 1.4 times farther than the distance from the Earth to the Moon.
And the good news is, the Virtual Telescope Project will be bringing the passage of 2014 WC201 live tonight starting at 23:00 Universal Time/6:00 PM EST.
Shining at an absolute magnitude of +26, 2014 WC201 will be visible as a +13 apparent magnitude “star” at closest approach at 4:51 UT (December 2nd)/11:51 PM EST (December 1st) moving through the constellation Ursa Major. This puts it within range of a large backyard telescope, though the 80% illuminated waxing gibbous Moon will definitely be a mitigating factor for observation.
The JPL Horizons ephemerides generator is an excellent place to start for crafting accurate coordinates for the asteroid for your location.
A capture of NEO 2003 DZ15 from 2015. Credit: The Virtual Telescope Project.
At an estimated 27 metres/81 feet in size, 2014 WC201 will no doubt draw “house-sized” or “building-sized” comparisons in the press. Larger than an F-15 jet fighter, asteroids such as WC201 cry out for some fresh new descriptive comparisons. Perhaps, as we near a “Star Wars year” in 2015, we could refer to 2014 WC201 as X-wing sized?
Another Apollo NEO also makes a close pass by the Earth this week, as 6-metre 2014 WX202 passes 400,000 kilometres (about the same average distance as the Earth to the Moon) from us at 19:56 UT/2:56 PM EST on December 7th. Though closer than WC201, WX202 is much smaller and won’t be a good target for backyard scopes. Gianluca Masi over at the Virtual Telescope Project also notes that WX202 will also be a difficult target due to the nearly Full Moon later this week.
The orbital path of NEO asteroid 2014 WX202. Credit: NASA/JPL
The last Full Moon of 2014 occurs on December 6th at 6:26 AM EST/11:26 Universal Time.
2014 WX202 has also generated some interest in the minor planet community due to its low velocity approach relative to the Earth. This, coupled with its Earth-like orbit, is suggestive of something that may have escaped the Earth-Moon system. Could WX202 be returning space junk or lunar ejecta? It’s happened before, as old Apollo hardware and boosters from China’s Chang’e missions have been initially identified as Near Earth Asteroids.
The Earth also occasionally hosts a temporary “quasi-moon,” as last occurred in 2006 with the capture of RH120. 2014 WX202 makes a series of more distant passes in the 2030s, and perhaps it will make the short list of near Earth asteroids for humans to explore in the coming decades.
And speaking of which, humanity is making two steps in this direction this week, with two high profile space launches.
First up is the launch of JAXA’s Hayabusa 2 from the Tanegashima Space Center on December 3rd at 4:22 UT/11:22 PM EST. The follow up to the Hayabusa asteroid sample return mission, Hayabusa 2 will rendezvous with asteroid 1999 JU3 in 2018 and return samples to Earth in late 2020. The vidcast for the launch of Hayabusa 2 goes live at 3:00 UT/10:00 PM EST on Tuesday, December 2nd.
And the next mission paving the way towards first boot prints on an asteroid is the launch of a Delta 4 Heavy rocket with EFT-1 from Cape Canaveral this Thursday morning on December 4th near sunrise at 7:05 AM EST/12:05 UT. EFT-1 is uncrewed, and will test key technologies including reentry on its two orbit flight. Expect to see crewed missions of Orion to begin around 2020, with a mission to an Earth crossing asteroid sometime in the decade after that.
NASA gotchu: An artist’s rendition of a future asteroid capture. Credit: NASA.
And there are some decent prospects to catch sight of EFT-1 on its first pass prior to its orbit raising burn over the Atlantic. Assuming EFT-1 lifts off at the beginning of its launch window, western Australia may see a good dusk pass 55 minutes after liftoff, and the southwestern U.S. may see a visible pass at dawn about 95 minutes after EFT-1 leaves the pad.
The footprint of EFT-1 on its first North American pass. Credit: Orbitron.
We’ll be tracking these prospects as the mission evolves on launch day via Twitter, and NASA TV will carry the launch live starting at 4:30 AM EST/9:30 UT.
The Orion capsule will come in hot on reentry at a blistering 32,000 kilometres per hour over four hours after liftoff in a reentry reminiscent of the early Apollo era.
Of course, if an asteroid the size of WC201 was on a collision course with the Earth it could spell a very bad day, at least in local terms. For comparison, the 2013 Chelyabinsk meteor was estimated to be 18 metres in size, and the 1908 Tunguska impactor was estimated to be 60 metres across. And about 50,000 years ago, a 50 metre in diameter space rock came blazing in over the ponderosa pine trees near what would one day be the city of Flagstaff, Arizona to create the 1,200 metre diameter Barringer Meteor Crater you can visit today.
A fragment of the Barringer meteorite on display at the Lowell Observatory. Photo by author.
All the more reason to study hazardous space rocks and the technology needed to reach one in the event that we one day need to move one out of the way!
Orion (at right), Sirius (bottom) and the pale wintertime Milky Way (center) are well-placed for viewing around 11 o'clock local time in late November. Credit: Bob King
Several nights ago the chill of interstellar space refrigerated the countryside as temperatures fell well below zero. That didn’t discourage the likes of Orion and his seasonal friends Gemini, Perseus and Auriga. They only seemed to grow brighter as the air grew sharper.
Wending between these familiar constellations like a river steaming in the cold was the Milky Way. The name has always been slightly confusing as it refers to both the milky band of starlight and the galaxy itself. Every single star you see at night belongs to our galaxy, a 100,000 light-year-wide flattened disk scintillating with over 400 billion suns.
Face-on (left) and edge-on views of the Milky Way. Our solar system lies in the flat plane of a barred spiral galaxy called the Milky Way. Looking through the plane, the stars pile up to form the Milky Way band. In summer, we face toward the richer, denser core; in winter we look out toward the edge. Credit: NASA with annotations by the author
Earth, Sun and planets huddle together within the mid-plane of the disk, so that when we look straight into it, the density of stars piles up over thousands of light years to form a thick band across the sky. Since most of the stars are very distant and therefore faint, they can’t be seen individually with the naked eye. They blend together to give the Milky Way a milky or hazy look.
During a snowfall, we can see individual flakes nearby but more distant ones increase in number and blend to make a uniform haze similar to what happens when we look across the flat disk of the Milky Way. Credit: Bob King
In a snowstorm, we easily distinguish individual snowflakes falling in front of our face, but looking into the distance, the flakes blend together to create a white, foggy haze. Replace the snowflakes with stars and you have the Milky Way – with a caveat. If we lived in the center of our galaxy, the sky would be milky with stars in all directions just like that snowstorm, but since the Sun occupies the flat plane, they only appear thick when our line of sight is aimed along the galaxy’s equator. Look above and below the disk and the stars quickly thin out as our gaze pierces through the galaxy’s plane and into intergalactic space.
In this view, the ground – Earth – has been removed from the picture and we can see all around us in space. Now we can see that the Milky Way band describes a full circle in the sky. The blue circle represents the galactic equator. The view shows the sky around midnight in early December. The Sun, at lower right, lies in the same direction as the galaxy’s center this month. Source: Stellarium
If you could float in space some distance from the brilliant ball of Earth, you’d see that the Milky Way band passes above, around and below you like a giant hula-hoop. Back on the ground, we can only see about two-thirds of the band over the course of a year. The other third is below the horizon and visible only from the opposite hemisphere, providing yet another good reason to make that trip to Tahiti or Ayers Rock in Australia.
Few know the winter version of the Milky Way that stands above the southeastern horizon around 10:30-11 p.m. local time on moonless nights in early December. No surprise, given it hardly compares to the brightness of the summertime version. This has much to do with where the Sun is located inside the galaxy, some 30,000 light years away from the center or more than halfway to the edge.
Opposite the galaxy’s center lies the anticenter, located near El Nath in the northern horn of Taurus above the constellation Orion. Source: Stellarium
On late fall and winter nights, our planet faces the galaxy’s outer suburbs and countryside where the stars thin out until giving way to relatively starless intergalactic space. Indeed, the anticenter of the Milky Way lies not far from the star El Nath (Beta Tauri) where Taurus meets Auriga. While the hazy band of the Milky Way is still visible through Auriga and Taurus, it’s thin and anemic compared to summer’s billowy star clouds.
The summertime Milky Way from Scorpius to Cygnus is broader and brighter than the winter version because we face toward the galactic center at nightfall. Credit: Stephen Bockhold
At nightfall in July and August, we face toward the galaxy’s center where 30,000 light years worth of stars, star clouds and nebulae stack up to fatten the Milky Way into a bright, chunky arch on summer evenings compared to winter’s thin gruel.
The slanting winter Milky Way touches many of the familiar, bright constellations of December. This map shows the sky facing southeast around 11 o’clock local time in early December or 9 p.m. in late December. Source: Stellarium
The winter Milky Way starts east of brilliant Sirius and grazes the east side of Orion before ascending into Gemini and Auriga and arching over into the western sky to Cassiopeia’s “W”. Binoculars and telescopes resolve it into individual stars and star clusters and help us appreciate what a truly beautiful and rich place our galactic home is.
Few sights that impress us with the scope and scale of where we live than seeing the Milky Way under a dark sky during the silence of a winter night. Picture Earth and yourself as members of that glowing carpet of stars, and when you can’t take the cold anymore, enjoy the delicious pleasure of stepping inside to unwrap and warm up. You’ve been on a long journey.
Just before dawn on Wednesday (Nov. 26), a pilot in Belgrade caught this stunning video of a “huge number of glowing pieces of whatever” breaking up in the atmosphere above.
You know what this is? A rocket, most likely! It’s the upper stage for the Soyuz that launched three people to space on Sunday (Nov. 23), the European Space Agency says.
It happens to all lovers of astronomy sooner or later.
I once had a friend who was excited about an upcoming conjunction of Saturn and Venus. They were passing closer than the apparent diameter of the Full Moon in the dawn sky, and you could fit ‘em both in the same telescopic field of view. I invited said friend to stop by at 5 AM the next morning to check this out. I was excited to see this conjunction as well, but not for the same reasons.
Said friend was into astrology, and I’m sure that the conjunction held a deep significance in their world view. Sure, I could have easily told them that ‘astrology is bunk,’ and the skies care not for our terrestrial woes… or I could carefully help guide this ‘at risk friend’ towards the true wonders of the cosmos if they were willing to listen.
We bring this up because this weekend, the Sun enters the constellation Ophiuchus, one of 13 modern constellations that it can appear in from our Earthly vantage point.
If you’re born from November 30th to December 18th, you could consider yourself an “Ophiuchian,” or being born under the sign of Ophiuchus the Serpent Bearer. But I’ll leave it up to you to decide what they might be like.
Seen at the Albany Park Zoo: Herpetology, or a modern day “serpent bearer?” Photo by author.
You might remember how the “controversy” of the 13th sign made its news rounds a few years back. Hey, it was cool to at least see an obscure and hard to pronounce constellation trending on Twitter. Of course, this wasn’t news to space enthusiasts, and to modern astronomers, a ‘house’ is merely where you live, and a ‘sign’ is what you follow to get there.
The modern 88 constellations we use were formalized by the International Astronomical Union in 1922. Like political boundaries, they’re imaginary constructs we use to organize reality. Star patterns slowly change with time due to our solar system’s motion — and that of neighboring stars —about the galactic center.
Astrologers will, of course, counter that their craft follows a tropical scheme versus a sidereal cosmology. In the tropical system, ecliptic longitude 0 starts from the equinoctial point marking the beginning of spring in the northern hemisphere, and the zodiac is demarcated by 12 ‘houses’ 30 degrees on a side.
This neatly ignores the reality of our friend, the precession of the equinoxes. The Earth’s poles do a slow wobble like a top, taking about 26,000 years to make one turn. This means that in the sidereal scheme of things, our vantage point of the Sun’s position along the zodiac against the background stars if reference to our Gregorian calendar is slowly changing: live out a 72 year lifespan, and the constellations along the zodiac with respect to the Sun will have shifted about one degree due to precession.
Our changing pole star. Credit: Starry Night Education Software.
Likewise, the direction of the North and South Pole is changing as well. Though Polaris makes a good pole star now, it’ll become increasingly less so as our north rotational pole begins to pull away from it after 2100 A.D. To the ancient Egyptians, Thuban (Alpha Draconis) was the pole star.
Precession over time. Credit: Tfr000 under Wikimedia Creative Commons 3.0 license.
Astrology and astronomy also have an intimate and hoary history, as many astronomers up until the time of Kepler financed their astronomical studies by casting royal horoscopes. And we still use terms such as appulse, conjunction and occultation, which have roots in astrology.
But the science of astronomy has matured beyond considering whether Mercury in retrograde has any connection with earthly woes. Perhaps you feel that you’re unlucky in love and have a vast untapped potential… sure, me too. We all do, and that just speaks to the universal state of the human condition. Astrology was an early attempt by humanity to find a coherent narrative, a place in the cosmos.
But the rise of the Ophiuchians isn’t nigh. Astrology relented to astronomy because of the latter’s true predictive power. “Look here, in the sky,” said mathematician Urbain Le Verrier, “and you’ll spy a new planet tugging on Uranus,” and blam, Neptune was discovered. If the planets had any true influence on us, why didn’t astrologers manage to predict the same?
Combating woo such as astrology is never simple. In the internet era, we often find tribes of the like-minded folks polarized around electronic camp fires. For example, writing ‘astrology is woo’ for an esteemed audience of science-minded readers such as Universe Today will no doubt find a largely agreeable reception. We have on occasion, however, written the same for a general audience to a much more hostile reception. Often, it’s just a matter of being that lone but patient voice of rationalism in the woods that ultimately sinks in.
Zodiacal artwork seen at the Yerkes observatory. Photo by author.
So, what’s the harm? Folks can believe whatever they want, and astrology’s no different, right? Well, the harm comes when people base life decisions on astrology. The harm comes when world leaders make critical decisions after consulting astrologers. Remember, Nancy and President Ronald Reagan conferred with astrologers for world affairs. It’s an irony of the modern age that, while writing a take down on astrology, there will likely be ads promoting astrology running right next to this very page. And while professional astronomers spend years in grad school, you can get a “PhD in Astrology” of dubious value online for a pittance. And nearly every general news site has a astrology page. Think of the space missions that could be launched if we threw as much money at exploration as we do at astrology as a society. Or perhaps astronomers should revert back to the dark side and resume casting horoscopes once again?
But to quote Spiderman, “with great power comes great responsibility,” and we promise to only use our astronomical powers for good.
What astronomers want you to know is that we’re not separate from the universe above us, and that the cosmos does indeed influence our everyday lives. And we’re not talking about finding your car keys or selling your house. We’re thinking big. The Sun energizes and drives the drama of life on Earth. The atoms that make you the unique individual that you are were forged in the hearts of stars. The ice that chills our drink may well have been delivered here via comet. And speaking of which, a comet headed our way could spell a very bad day for the Earth.
Don’t leave home without one… a travelling “pocket planetarium” circa 16th century seen at the Tampa Bay History Center. Photo by author.
All of these are real things that astronomy tells us about our place in the cosmos, whether you’re an Ophiuchian or a Capricorn. To paraphrase Shakespeare, the heavens may (seem to) blaze forth for the death of princes, but the fault lies not in the heavens, but ourselves. Don’t forget that, as James Randi says, “you’re a member of a proud species,” one loves to look skyward, and ultimately knows when to discard fantasy for reality.
The total solar eclipse of November 2012 as seen from
Where will YOU be on August 21st, 2017?
Astronomy is all about humility and thinking big in terms of space and time. It’s routine for astronomers to talk of comets on thousand year orbits, or stars with life spans measured in billions of years…
Yup, the lifespan of your average humanoid is indeed fleeting, and pales in comparison to the universe, that’s for sure. But one astronomical series that you can hope to live through is the cycle of eclipses.
I remember reading about the total solar eclipse of February 26th, 1979 as a kid. Carter was in the White House, KISS was mounting yet another comeback, and Voyager 1 was wowing us with images of Jupiter. That was also the last total solar eclipse to grace mainland United States in the 20th century.
But the ongoing “eclipse-drought” is about to be broken.
One thousand days from this coming Monday, November 24th on August 21st 2017, the shadow of the Moon will touch down off of the Oregon coast and sweep eastward across the U.S. heartland before heading out to the Atlantic off of the coast of South Carolina. Millions live within a days’ drive of the 115 kilometre wide path, and the eclipse has the added plus of occurring at the tail end of summer vacation season. This also means that lots of folks will be camping and otherwise mobile with their RVs and able to journey to the event.
This is also the last total solar eclipse to pass over any of the 50 United States since July 11th, 1991, and the first eclipse to cross the contiguous United States from “sea to shining sea” since way back on June 8th, 1918.
Think it’s too early to prepare? Towns across the path, including Hopkinsville, Kentucky and towns in Kansas and Nebraska are already laying plans for eclipse day. Other major U.S. cities, such as Nashville, Idaho Falls, and Columbia, South Carolina also lie along the path of totality, and the spectacle promises to spawn a whole new generation of “umbraphiles” or eclipse chasers.
A total solar eclipse is an unforgettable sight. But unlike a total lunar eclipse, which can be viewed from the moonward-facing hemisphere of the Earth, one generally has to journey to the narrow path of totality to see a total solar eclipse. Totality rarely comes to you.
The Zeilers view the November 2013 eclipse from Africa. Credit: Michael Zeiler.
And don’t settle for a 99% partial eclipse just outside the path. “There’s no comparison between partial and total solar eclipses when it comes to sheer grandeur and beauty,” Michael Zeiler, longtime eclipse chaser and creator of the Great American Eclipse website told Universe Today. We witnessed the 1994 annular solar eclipse of the Sun from the shores of Lake Erie, and can attest that a 99% partial eclipse is still pretty darned bright!
There are two total solar eclipses remaining worldwide up until 2017: One on March 20th, 2015 crossing the high Arctic, and another on March 9th 2016 over Southeast Asia. The 2017 eclipse offers a maximum of 2 minutes and 41 seconds of totality, and weather prospects for the eclipse in late August favors viewers along the northwestern portion of the track.
And though an armada of cameras will be prepared to capture the eclipse along its trek across the U.S., many veteran eclipse chasers suggest that first time viewers merely sit back and take in the moment. The onset of totality sees a bizarre sort of twilight fall across the landscape, as shadow bands skip across the countryside, temperatures drop, and wildlife is fooled into thinking that nightfall has come early.
And then, all too soon, the second set of blinding diamond rings burst through the lunar valleys, the eclipse glasses go back on, and totality is over. Which always raises the question heard throughout the crowd post-eclipse:
When’s the next one?
Well, the good news is, the United States will host a second total solar eclipse on April 8th, 2024, just seven years later! This path will run from the U.S. Southwest to New England, and crisscross the 2017 path right around Carbondale, Illinois.
Will the woo that surfaced around the approach of Comet ISON and the lunar tetrad of “blood Moon eclipses” rear its head in 2017? Ah, eclipses and comets seem to bring ‘em out of the woodwork, and 2017 will likely see a spike in the talking-head gloom and doom videos ala YouTube. Some will no doubt cite the “perfection” seen during total solar eclipses as proof of divine inspiration, though this is actually just a product of our vantage point in time and space. In fact, annular eclipses are slightly more common than total solars in our current epoch, and will become more so as the Moon slowly recedes from the Earth. And we recently noted in our post on the mutual phenomena of Jupiter’s moons that solar eclipses very similar to those seen from the Earth can also be spied from Callisto.
Heads up to any future interplanetary eclipse resort developer: Callisto is prime real estate.
One of the better asteroid occultations of 2014 is coming right up tonight, and Canadian and U.S. observers in the northeast have a front row seat.
The event occurs in the early morning hours of Thursday, November 20th, when the asteroid 3 Juno occults the 7.4 magnitude star SAO 117176. The occultation kicks off in the wee hours as the 310 kilometre wide “shadow” of 3 Juno touches down and crosses North America from 6:54 to 6:57 Universal Time (UT), which is 12:54 to 12:57 AM Central, or 1:54 to 1:57 AM Eastern Standard Time.
The path of tomorrow’s occultation along with the circumstances. Credit: Steve Preston’s Asteroid Occultation website.
The maximum predicted length of the occultation for observers based along the centerline is just over 27 seconds. Note that 3 Juno also shines at magnitude +8.5, so both it and the star are binocular objects. The event will sweep across Winnipeg and Lake of the Woods straddling the U.S. Canadian border, just missing Duluth Minnesota before crossing Lake Superior and over Ottawa and Montreal and passing into northern Vermont and New Hampshire. Finally, the path crosses over Portland Maine, and heads out to sea over the Atlantic Ocean.
Don’t live along the path? Observers worldwide will still see a close pass of 3 Juno and the +7th magnitude star as both do their best to impersonate a close binary pair. If you’ve never crossed spotting 3 Juno off of your astro-“life list,” now is a good time to try.
The position of the target star HIP43357/SAO 117176 is:
Right Ascension: 8 Hours 49’ 54”
Declination: +2° 21’ 44”
A finder chart for 3 Juno and HIP43357. Stars are noted down to +10th magnitude. Created using Starry Night Education software.
Generally, the farther east you are along the track, the higher the pair will be above the horizon when the event occurs, and the better your observing prospects will be in terms of altitude or elevation. From Portland Maine — the last port of call for the shadow of 3 Juno on dry land — the pair will be 35 degrees above the horizon in the constellation of Hydra.
The projected sky cover at the time of the occultation. Credit: NWS/NOAA.
As always, the success in observing any astronomical event is at the whim of the weather, which can be fickle in North America in November. As of 48 hours out from the occultation, weather prospects look dicey, with 70%-90% cloud cover along the track. But remember, you don’t necessarily need a fully clear sky to make a successful observation… just a clear view near the head of Hydra asterism. Remember the much anticipated occultation of Regulus by the asteroid 163 Erigone earlier this year? Alas, it went unrecorded due to pesky but pervasive cloud cover. Perhaps this week’s occultation will fall prey to the same, but it’s always worth a try. In asteroid occultations as in free throws, you miss 100% of the shots that you don’t take!
The path of the occcultation across eastern North America. Credit: Google Earth/BREIT IDEAS observatory.
Why study asteroid occultations? Sure, it’s cool to see a star wink out as an asteroid passes in front of it, but there’s real science to be done as well. Expect the star involved in Thursday’s occultation to dip down about two magnitudes (six times) in brightness. The International Occultation Timing Association (IOTA) is always seeking careful measurements of asteroid occultations of bright stars. If enough observations are made along the track, a shape profile of the target asteroid emerges. And the possible discovery of an “asteroid moon” is not unheard of using this method, as the background star winks out multiple times.
3 Juno as imaged by the 100″ Hooker telescope at the Mt. Wilson observatory at different wavelengths using adaptive optics. Credit: NASA/JPL/The Harvard Smithsonian Center for Astrophysics.
3 Juno was discovered crossing Cetus by astronomer Karl Harding on September 1st, 1804 from the Lilienthal Observatory in Germany. The 3rd asteroid discovered after 1 Ceres and 2 Pallas, 3 Juno ranks 5th in size at an estimated 290 kilometres in diameter. In the early 19th century, 3 Juno was also considered a planet along with these other early discoveries, until the ranks swelled to a point where the category of asteroid was introduced. A denizen of the asteroid belt, 3 Juno roams from 2 A.U.s from the Sun at perigee to 3.4 A.U.s at apogee, and can reach a maximum brightness of +7.4th magnitude as seen from the Earth. No space mission has ever been dispatched to study 3 Juno, although we will get a good look at its cousin 1 Ceres next April when NASA’s Dawn spacecraft enters orbit around the king of the asteroids.
3 Juno reaches opposition and its best observing position on January 29th, 2015.
3 Juno also has an interesting place in the history of asteroid occultations. The first ever predicted and successfully observed occultation of a star by an asteroid involved 3 Juno on February 19th, 1958. Another occultation involving the asteroid on December 11th, 1979 was even more widely observed. Only a handful of such events were caught prior to the 1990s, as it required ultra-precise computation and knowledge of positions and orbits. Today, dozens of asteroid occultations are predicted each month worldwide.
Observing an asteroid occultation can be challenging but rewarding. You can watch Thursday’s event with binoculars, but you’ll want to use a telescope to make a careful analysis. You can either run video during the event, or simply watch and call out when the star dims and brightens as you record audio. Precise timing and pinpointing your observing location via GPS is key, and human reaction time plays a factor as well. Be sure to locate the target star well beforehand. For precise time, you can run WWV radio in the background.
And finally, you also might see… nothing. Asteroid paths have a small amount of uncertainty to them, and although these negative observations aren’t as thrilling to watch, they’re important to the overall scientific effort.
Good luck, and let us know of your observational tales of anguish and achievement!
Does the atmosphere of Venus possess upper atmospheric phenomena similar to the Earth, such as aurora or nightglow?
Now, a recent announcement out of the American Astronomical Society’s 46th annual meeting of the Division of Planetary Science being held this week in Tucson, Arizona has shed new light on the dilemma.
The discovery was announced on Wednesday, November 12th at the 46th AAS meeting and was made as a collaborative effort by researchers from New Mexico State University at Las Cruces, the Stanford Research Institute (SRI) International, the University of Colorado at Boulder, the University of Koln and University of Munich, Germany, the European Space and Technology Center in the Netherlands and the Institut de Recherche en Astrophysique et Planétologie, in France.
For the study, researchers observed Venus from December 2010 to July 2012 using the Astrophysical Research Consortium (ARC)Echelle Spectrograph and the ARC 3.5 metre telescope located at Apache Point near Sunspot, New Mexico.
Timing was crucial, as the Sun was coming off of a profound deep minimum through 2009 and just beginning to become active with the start of solar cycle #24. Observers were looking for activity along the 5577.3 angstrom wavelength known as the “oxygen green line.” Activity had not been seen at this wavelength on the nighttime side of Venus since 2004.
The altitude drop in the Venusian atmosphere measured in the study. Credit : Credit: DPS press release/C. Gray/New Mexico State University.
“These are intriguing results, suggesting that it is possible to have aurora on non-magnetic planets,” said Candace Gray, Astronomer and NASA Earth and Space Science Fellow at Las Cruces and lead researcher in the study. “On Venus, this green line has been seen only intermittently.”
Earth is the oddball among the terrestrial planets in the inner solar system with its robust magnetic field. On Earth, aurorae occur when said field captures charged particles ejected from the Sun and funnels them in towards the poles. Events seen in the study tended to drop 140 to 120 kilometres in altitude in the Venusian atmosphere, highly suggestive of auroral activity seen in the ionosphere of Earth.
Researchers were fortunate during one of the recent runs at Apache Point that the Sun kicked off a coronal mass ejection that headed Venus’s way. During the July 2012 solar storm, the team detected one of the brightest green line emissions that had ever been detected by observers on Earth.
The 3.5 metre telescope at Apache Point, in this case, being used for lunar ranging experiments. Credit: M3long/Wikimedia Commons image.
This demonstrates that perhaps, a magnetic field is optional when it comes to auroral activity, at least in the case of the planet Venus. Located only 0.7 astronomical units (108.5 million kilometres) from the Sun, our tempestuous star actually wraps the planet with its very own magnetotail.
Researchers are also looking to compare their results with observations from the European Space Agency’s Venus Express orbiter which arrived at the planet on April 2006.
“Currently, we are using observations from VIRTIS on Venus Express to try and detect the green line,” Gray told Universe Today. “We had coordinated ground based observations with them this past February, and we detected the green line from the ground when they were observing the night side limb. Additionally, we are using the Electron Spectrometer and ASPERA-4 to observe how the electron energy and density changes in the atmosphere after coronal mass ejection impacts.”
This also raises the interesting possibility that NASA’s MAVEN spacecraft — which recently arrived in orbit around Mars — might just detect similar activity in the tenuous Martian atmosphere as well. Like Venus, the Red Planet also lacks a global magnetic field.
Could this glow be connected with spurious sightings of the “Ashen Light of Venus” that have cropped up over the centuries?
Of course, ashen light, also known as Earthshine on the dark limb of the Moon, is easily explained as sunlight reflected back from the Earth. Moonless Venus, however, should be ashen light free.
“The green line emission that we see is brightest on the limb (edge) of the planet,” Gray told Universe Today. “We’re sure that there is emission all along the nightside, but because of the optical depth, it appears much brighter on the limb of the planet. I think it would be too faint to detect with the naked eye.”
Nightglow has been a leading suspect for ashen light on the Venusian nightside, and a similar green line emission detection rivaling the 2012 event was made by Tom Slanger using the Keck I telescope 1999.
Other proposed suspects over the centuries for ashen light on Venus include lightning, volcanism, light pollution (!) from Venusian cities, or just plain old observer error.
Certainly, future observations are needed to cinch the solar activity connection.
“We will likely observe Venus again from Apache Point the next time Venus is visible to us in June 2015,” Gray told Universe Today. “We will continue looking at Venus Express observations until the craft dies in the atmosphere.”
Venus turns its night time back towards us during the 2012 transit of the Sun, as seen from NASA’s Solar Dynamics Observatory (Credit: NASA/SDO).
Venus can currently be seen crossing through the field of view of SOHO’s LASCO C3 camera. After spending most of 2014 in the dawn sky, Venus will emerge from behind the Sun low in the dusk to head towards greatest elongation in the evening sky on June 6th, 2015. And from there, Venus will once again slender towards a crescent, presenting its nightside towards Earth, and just perhaps, continuing to present a lingering mystery of modern astronomy.
If there’s one meteor shower that has the potential to bring on a storm of epic proportions, it’s the Leonids. Peaking once every 33 years, these fast movers hail from the Comet 55P Temple-Tuttle, and radiate from the Sickle, or backwards “question mark” asterism in the constellation Leo. And although 2014 is an “off year” in terms of storm prospects, it’s always worth taking heed these chilly November mornings as we await the lion’s roar once again.
The prospects: 2014 sees the expected peak of the Leonids arriving around 22:00 Universal Time (UT) which is 5:00 PM EST. Locally speaking, a majority of meteor showers tend to peak in the early AM hours past midnight, as the observer’s location turns forward facing into the oncoming meteor stream. Think of driving in an early November snowstorm, with the car being the Earth and the flakes of snow as the oncoming meteors. And if you’ve (been fortunate enough?) to have never seen snow, remember that it’s the front windshield of the car going down the highway that catches all of the bugs!
This all means that in 2014, the Asian Far East will have an optimal viewing situation for the Leonids, though observers worldwide should still be vigilant. Of course, meteor showers never read online prognostications such as these, and often tend to arrive early or late. The Leonids also have a broad range of activity spanning November 6th through November 30th.
The November path of the radiant of the 2014 Leonids. Credit: Starry Night Education Software.
The predicted ideal Zenithal Hourly Rate for 2014 stands at about 15, which is well above the typical background sporadic rate, but lower than most years. Expect the actual sky position of the radiant and light pollution to lower this hourly number significantly. And speaking of light pollution, the Moon is a 21% illuminated waning crescent on the morning of November 17th, rising at around 2:00 AM local in the adjacent constellation of Virgo.
The Leonids can, once every 33 years, produce a storm of magnificent proportions. The history of Leonid observation may even extend back as far as 902 A.D., which was recorded in Arab annals as the “Year of the Stars.”
But it was the morning of November 13th, 1833 that really gained notoriety for the Leonids, and really kicked the study of meteor showers into high gear.
A depiction of the 1868 Leonids by Étienne Léopold Trouvelot from The Trouvelot Astronomical Drawings, 1881. Image in the Public Domain.
The night was clear over the U.S. Eastern Seaboard, and frightened townsfolk were awakened to moving shadows on bedroom walls. Fire was the first thing on most people’s minds, but they were instead confronted with a stunning and terrifying sight: a sky seeming to rain stars in every direction. Churches quickly filled up, as folks reckoned the Day of Judgment had come. The 1833 Leonid storm actually made later historical lists as one of the 100 great events in the United States for the 19th century. The storm has also been cited as single-handedly contributing to the religious fundamentalist revivals of the 1830s. Poet Walt Whitman witnessed the 1833 storm, and the song The Stars Fell on Alabama by Frank Perkins was inspired by the event as well.
Live in Alabama? Then you may well possess a license plate that commemorates the 1833 Leonid Storm. Wikimedia Commons image in the Public Domain.
But not all were fearful. Astronomer Denison Olmsted was inspired to study the radiants and paths of meteor streams after the 1833 storm, and founded modern meteor science. The Leonids continued to produce storms at 33 year intervals, and there are still many observers that recall the spectacle that the Leonids produced over the southwestern U.S. back 1966, with a zenithal hourly rate topping an estimated 144,000 per hour!
We also have a personal fondness for this shower, as we were fortunate enough to witness the Leonids from the dark desert skies of Kuwait back in 1998. We estimated the shower approached a ZHR of about 900 towards sunrise, as a fireballs seemed to light up the desert once every few seconds.
The situation at 22:00 UT on November 17th, noting the direction of the Earth’s motion with relation to the predicted peak of the 2014 Leonid stream. Created using Stellarium.
The Leonids have subsided in recent years, and have fallen back below enhanced rates since 2002. Here’s the most recent ZHR levels as per the International Meteor Organization:
2009: ZHR=80.
2010: ZHR=32.
2011: ZHR=22.
2012: ZHR=48.
Note: 2013 the shower was, for the most part, washed out by the Full Moon.
But this year is also special for another reason.
Note that the 2014-2015 season marks the approximate halfway mark to an expected Leonid outburst around 2032. Comet 55P Tempel-Tuttle reaches perihelion on May 20th, 2031, and if activity in the late 1990s was any indication, we expect the Leonids to start picking up again around 2030 onward.
A simulated Leonid storm on the morning of November 17th, 2032. Credit: Stellarium.
Observing meteors is as simple as laying back and looking up. Be sure to stay warm, and trace the trail of any suspect meteor back to the Sickle to identify it as a Leonid. The Leonid meteors have one of the fastest approach velocities of any meteor stream at 71 kilometres per second, making for quick, fleeting passages in the pre-dawn sky. Brighter bolides may leave lingering smoke trails, and we like to keep a set of binoculars handy to examine these on occasion.
Looking to do some real science? You can document how many meteors you see per hour from your location and send this in to the International Meteor Organization, which tabulates and uses these volunteer counts to characterize a given meteor stream.
The 1997 Leonids as seen from space by the MSX satellite. Credit: NASA/JPL
And taking images of Leonid meteors is as simple as setting your DSLR camera on a tripod and taking long exposure images of the night sky. Be sure to use the widest field of view possible, and aim the camera about 45 degrees away from the radiant to nab meteors in profile. We generally shoot 30 second to 3 minute exposures in series, and don’t be afraid to experiment with manual F-stop/ISO combinations to get the settings just right for the local sky conditions. And be sure to carefully review those shots on the “big screen” afterwards… nearly every meteor we’ve caught in an image has turned up this way.
Don’t miss the 2014 Leonids. Hey, we’re half way to the start of the 2030 “storm years!”
