Astrophotos Archives

August 11, 2015December 23, 2015 by David Dickinson

A Thrift Store Find Yields an Astronomical Mystery

A good mystery is often where you find it. Photographer Meagan Abell recently made a discovery during a thrift store expedition that not only set the internet abuzz, but also contains an interesting astronomical dimension as well. This is an instance where observational astronomy may play a key role in pinning down a date, and we’d like to put this story before the Universe Today community for further insight and consideration.

Meagan first discovered the set of four medium format negatives at a thrift store on Hull Street in Richmond, Virginia. Beyond that, they have no provenance. Meagan was amazed at what see saw when she scanned in the negatives: the images of a woman walking into the surf have an ethereal beauty all their own. Obviously the work of a skilled photographer, the photos appear to date from the late 1940s or 1950s.

Meagan turned to social media for help, and cyber-sleuths responded in a big way. #FindTheGirlsOnTheNegatives became a viral hit, but thus far, who the women in the images are and the story behind them remains a mystery.

We do know one tantalizing bit of information: several Facebook users have pinned down the location as Dockweiler Beach, California near Los Angeles International Airport. Keen-eyed observers noted the similarity of the outline of the distant hills seen to the north in one of the images.

A few things caught our eye upon reading the mystery of the girls in the negatives this past weekend. One shot clearly shows the notch of the Sun just below the twilight horizon. A second, even more intriguing image shows a tiny sliver of Moon just to the subject’s upper left.

Could a date, or set of dates, be estimated based on these factors alone?

Let’s slip into astro-detective mode now. A few things are obvious right off the bat. First, the Moon is a waxing crescent, meaning the shots would have to be set in the evening. This also lends credence to the ocean being the Pacific, because the sunset is occurring over water. The similarity in cloud formations across all of the images seen also strongly suggests the photographer took all of the pictures on the same evening, during one session.

Can that crescent Moon tell us anything? It’s tiny and indistinct, but we have a few things to go on. The Moon looks to be a 5-6 day old waxing crescent about 30-40% illuminated. Not all waxing crescent Moons are created equal, as the ‘horns of the Moon’ can point in various directions based on the angle of the ecliptic to the local horizon at different times of the year.

A typical sampling of the orientation of the horns of the waxing crescent Moon throughout the year as seen from latitude 34 degrees north. Image credit: Dave Dickinson

The horns of the Moon appear to be oriented about 35 degrees from horizontal. Assuming the subject in the red dress is elevated slightly and about 20 feet from the observer, the Moon would be about 25-30 degrees above the horizon in the shot.

Now, Dockweiler Beach is located at latitude 33 degrees 55’ 20” north, longitude 118 degrees 26’ 3” west. The beach itself faces a perpendicular azimuth of 240 degrees out to sea, or roughly WSW.

Already, we can rule out winter and spring, because of the unfavorable angle of the dusk ecliptic. We want a time of year with A) a shallow southward ecliptic and B) a sunset roughly due west.

Turns out, late July through early October fit these ideal conditions for the location.

Can we narrow this even further? Well, here’s one possibility. Remember, this next step is what gumshoe PIs call a ‘hunch’…

The motion of the Moon is a wonderfully complicated affair. The path of the Moon is inclined about five degrees relative to the ecliptic, meaning that the Moon can ride anywhere from declination 28 degrees south, to 28 degrees north. From latitude 34 degrees north, this puts the mid-July ecliptic at about 33 degrees elevation across the meridian at sunset.

The nodal points where the path of the Moon crosses the ecliptic also precess slowly around the celestial sphere. This motion completes one revolution every 18.6 years, meaning that the Moon reaches those maximum declination values (sometimes referred to as a ‘long nights’ or the Major Lunar Standstill of the Moon) just under once every 19 years.

This occurred last in 2006, and will occur next in 2025. Incidentally, we’re at a shallow mid-point (known as a Minor Lunar Standstill) between the two dates this coming Fall.

A good fit? A comparison of the Moon in the image (left) with a simulated view in Stellarium from August 19th, 1950 (click to enlarge). Image credit: Dave Dickinson/Meagan Abell

This also puts the late summer 1^st quarter Moon as far south ‘in the weeds’ as possible. Extrapolating back in time, this sort of wide-ranging Moon occurred around 1949. Looking at the celestial scene in Stellarium, three dates nail the horn angle and elevation of the Moon seen in the photograph pretty closely around this time:

-August 11^th, 1948

-August 29^th, 1949

-August 19^th, 1950

Of course, this is just a hunch. Perhaps the subject was standing on a westward facing spit of rocks. Or maybe the photographer was closer or farther away than estimated. Or maybe the negative was inverted left to right along the way… that’s why I’d like to invite, you, the astute sky watcher, to weigh in.

And even if we pinned down the date, the mystery remains. Who are the girls in the negatives? What became of the photo shoot? And how did the negatives end up in a thrift store in Virginia?

Read another astronomical mystery sleuthed out by Dave Dickinson, with The Downing of Spirit ‘03: Did the Moon Play a Role?

Update: an sharp-eyed reader noticed that if you boost the contrast, you can see an additional ‘speck’ in the Moon image (see comment discussion below):

Update: Meagan responds: “The object along the horizon in the crescent Moon image is actually just a transparency defect.” A second image from the same strip does not show the white speck (arrowed above) near the horizon.

August 7, 2015December 23, 2015 by Bob King

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

How To Watch

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

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

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

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

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

July 8, 2015December 23, 2015 by Bob King

Once Around The Sun With Jupiter

Jupiter takes 12 years to make one trip around the Sun. These 12 images were taken between 2003 and 2015. At far left we see Jupiter in 2003, and the years proceed counterclockwise. The 2015 view is immediately above 2003. Credit: Damian Peach

For Jupiterians (Jovians?) a trip around the Sun takes 12 Earth years. If you were born today on the planet or one of its moons, you’d turn one year old in 2027 and reach the ripe old age of 12 in 2111.

In this remarkable montage, astrophotographer Damian Peach divides a year on Jupiter into 12 parts, with images spaced at approximately one-year intervals between February 2003 and April 2015. Like the planet, Peach was on the move; the photos were taken from four different countries with a variety of different telescopes and cameras.

Jupiter is the 5th planet from the Sun and the largest in the solar system with a diameter about 11 times that of Earth. Credit: NASA

On the tilted Earth, one year brings a full change of seasons as our planet completes a solar loop in 365 1/4 days. Jupiter’s axial tilt is just 3° or nearly straight up and down, so seasons don’t exist. One part of the Jovian year is much the same as another. Still, as you can plainly see, the solar system’s biggest planet has plenty of weather.

Just look at the Great Red Spot or GRS. Through about 2008, it’s relatively large and pale but suddenly darkens in 2010 at the same time the South Equatorial Cloud Belt (the wide stripe of clouds above the Spot) disappears. If you look closely at the Spot from year to year, you’ll see another big change — it’s shrinking! The GRS has been dwindling for several decades, but it’s amazing how obvious the difference is in only a dozen years.

What we think Jupiter's interior looks like. Deep inside, pressure's so great that hydrogen is compressed into a "metallic" form that conducts electricity. Heat from the core powers winds and helps create clouds in Jupiter's atmosphere. Credit: NASA — What we think Jupiter’s interior looks like. Deep inside, pressure’s so great that hydrogen is compressed into a “metallic” form that conducts electricity. Heat from the core powers winds and helps create clouds in Jupiter’s atmosphere. Credit: NASA

Lots of other smaller changes can be seen, too. On Earth, the primary heat source driving weather is the Sun, but on Jupiter it’s residual heat left over from the collapse of the primordial solar nebula, the vast cloud of dust and gas from which the Sun and planets were formed.

It’s HOT inside Jupiter. A thermometer stuck in its core would register between 23,500° and 63,000° F. That’s too cool for nuclear fusion, the process that powers the Sun, but plenty hot to heat the atmosphere and create magnificent weather. The planet gives off 1.6 times as much energy as it get from the Sun. While hardly a star, it’s no ball of ice either.

Jupiter and Venus still travel in tandem at dusk. Look about an hour after sunset a fist and a half high in the western sky. Venus is the bright one with Jupiter tagging along to the right. Fun to think that the light we see from Jupiter is reflected sunlight, but if we could view it with heat-sensing, infrared eyes, it would glow like an ember.

May 31, 2015December 23, 2015 by Bob King

Allergies? Must Be Pollen Corona Season Again

A multi-ringed, oval shaped corona around the Sun on May 30, 2015 seen from northern Minnesota. The white spots are aspen seeds better known as "cotton fluff". Credit: Bob King

Don’t be surprised if you look up in the Sun’s direction and squint with itchy, watery eyes. You might be staring into billows of tree pollen wafting through your town. It’s certainly been happening where I live.

When conditions are right, billions of microscopic pollen grains consort to create small, oval-shaped rings around a bright Moon during the peak of the spring and early summer allergy season. With the Full Moon coming up this week, there’s no better time to watch for them.

Pollen grains from a variety of different common plants including sunflower, morning glory, prairie hollyhock and evening primrose. Credit: Dartmouth Electron Microscope Facility, Dartmouth College — Pollen grains from a variety of different common plants including sunflower, morning glory, prairie hollyhock and evening primrose magnified 500x and colorized. The green, bean-shaped grain at lower left is 0.05 mm across. Credit: Dartmouth Electron Microscope Facility

Because they’re often lost in the glare of the Sun or Moon, the key to finding one is to hide the solar or lunar disk behind a thick tree branch, roof or my favorite, the power pole. Look for a telltale oval glow, sometimes tinted with rainbow colors, right up next to the Moon or Sun’s edge. Common halos, those that form when light is refracted by ice crystals, span 44° compared to pollen coronas, which measure just a few degrees in diameter.

To see or photograph coronas, you need plenty of light. The Sun’s ideal, but so is the Moon around full. Fortunately, that happens on June 2, neatly fitting into the sneezing season. Last night, the same grains — most likely pine tree pollen — also stoked a lunar corona. Once my eyes were dark adapted and the Moon hidden by an arboreal occulting instrument (tree branch), it was easy to see.

A lunar pollen corona on May 30, 2015. The Moon was hidden by a utility pole. Like the solar version, this one is elongated too. The shape is caused by pollen grains' elongated shape and the fact that they tend to orient themselves as they drift in the wind. Credit: Bob King — A lunar pollen corona on May 30, 2015. The Moon was hidden by a utility pole. Like the solar version, this one was also oval and measured about 3.5° across. The shape is caused by elongated pollen grains fact that orient themselves as they drift in the wind. Credit: Bob King

One of things you’ll notice right away about these biological bullseyes is that they’re not circular. Pollen coronas are oval because the pollen particles are elongated rather than spherical like water droplets. When light from the moon or sun strikes pollen, the minute grains diffract the light into a series of closely-spaced colored rings. I’ve read that pine and birch produce the best coronas, but spruce, alder and and others will work, too.

And here’s another amazing thing about these coronas. You don’t need a transparent medium to produce them. No ice, no water. All that’s necessary are very small, similarly-shaped objects. Light waves are scattered directly off their surfaces; the waves interfere with one another to create a diffraction pattern of colored rings.

A lunar pollen corona photographed on June 22, 2008 displays “bumps” or extensions at approximately 90° angles around its periphery. Credit: Bob King

Pollen coronas tend to become more elongated when the Sun or Moon is closer to the horizon, so look be on the lookout during those times for more extreme shapes. For some reason I’ve yet to discover, pollen disks sometimes exhibit “bumps” or extensions at their tops, bottoms and sides.

So many of us suffer from allergies, perhaps the glowing presence of what’s causing all the inflammation will serve as partial compensation for our misery.

May 20, 2015December 23, 2015 by Nancy Atkinson

Watch Jupiter Get Blasted by an Iridium Flare

Screenshot of an Iridium satellite flare right next to Jupiter's location in the sky. From video by Thierry Legault.

Cue the “Space Invaders” sound effects! We’ve shared previously how astrophotographer Thierry Legault will travel anywhere to get a unique shot. He took this impressive but fun video of an Iridium 72 satellite flaring and passing in front of Jupiter, traveling to Oostende Beach at the North Sea in Belgium to capture this transit. He took both a wide angle view as well as the telescopic close-up view of Jupiter, and from the vantage point of Earth, it appears as though Jupiter gets blasted by the flare. In the zoomed-in view, even Jupiter’s moons are part of the scene.

You can almost hear the “pew-pew.”

Legault also shared a another recent video he shot of the Chinese Yaogan 6 satellite. “It is probably out of control, quickly tumbling with very bright and short flashes,” Legault said, and it has been tumbling for about a year. Yaogan 6 is a radar reconnaissance satellite launched by China in 2009. Legault said he did the tracking by hand with professional video tripod with a fluid head.

See more of Legault’s extraordinary astrophotography work at his website.

May 13, 2015December 23, 2015 by Bob King

Does the Red Planet Have Green Auroras?

A map of MAVEN's Imaging Ultraviolet Spectrograph (IUVS) auroral detections in December 2014 overlaid on Mars’ surface. The map shows that the aurora was widespread in the northern hemisphere, not tied to any geographic location. The aurora was detected in all observations during a 5-day period. Credits: University of Colorado

Martian auroras will never best the visual splendor of those we see on Earth, but have no doubt. The Red Planet still has what it takes to throw an auroral bash. Witness the latest news from NASA’s MAVEN atmospheric probe.

In December 2014, it detected widespread auroras across Mars’ northern hemisphere dubbed the “Christmas Lights”. If a similar display happened on Earth, northern lights would have been visible from as far south as Florida.

“It really is amazing,” says Nick Schneider who leads MAVEN’s Imaging Ultraviolet Spectrograph (IUVS) instrument team at the University of Colorado. “Auroras on Mars appear to be more wide ranging than we ever imagined.”

A beautiful curtain of rays spread across the northern sky just last night (May 12) as seen from Duluth, Minn. Aurora colors on Earth are caused by the excitation of nitrogen and oxygen atoms from high-speed particles from the solar wind. Oxygen is responsible for most of the aurora's greens and reds. Credit: Bob King — A beautiful curtain of auroral rays spreads across the northern sky last night (May 12) as seen from Duluth, Minn. Aurora colors on Earth are caused by the excitation of nitrogen and oxygen atoms by high-speed particles in the solar wind. Oxygen in particular is responsible for most of the aurora’s greens and reds. Credit: Bob King

Study the map and you’ll see the purple arcs extend to south of 30° north latitude. So what would Martian auroras look like to the human eye? Would we see an arcade of nested arcs if we faced east or west from 30°N? Well, er, yes, if you could see into the ultraviolet end of the spectrum. Mars’ atmosphere is composed mostly of carbon dioxide, so most of the auroral emissions occur when high speed solar wind particles ionize CO2 molecules and carbon monoxide to produce UV light. Perhaps properly suited-up bees, which can see ultraviolet, would be abuzz at the sight.

High-speed particles from the Sun, mostly electrons, strike oxygen and nitrogen atoms in Earth's upper atmosphere. Credit: NASA — High-speed particles from the Sun, mostly electrons, strike oxygen and nitrogen atoms in Earth’s upper atmosphere. As they return to their “relaxed” state, they emit light in characteristic colors. Credit: NASA

That’s not the end of the story however. Martian air does contain 0.13% oxygen, the element that puts the green and red in Earth’s auroras. The “Christmas Lights” penetrated deeply into Mars’ atmosphere, reaching an altitude of just 62 miles (100 km) above its surface. Here, the air is relatively thicker and richer in oxygen than higher up, so maybe, just maybe Christmas came in green wrapping.

Mars has magnetized rocks in its crust that create localized, patchy magnetic fields (left). In the illustration at right, we see how those fields extend into space above the rocks. At their tops, auroras can form. Credit: NASA — Mars has magnetized rocks in its crust that create localized, patchy magnetic fields (left). In the illustration at right, we see how those fields extend into space above the rocks. At their “peaks”, auroras can form. Credit: NASA

Nick Schneider, who leads MAVEN’s Imaging Ultraviolet Spectrograph (IUVS) instrument team, isn’t certain but thinks it’s possible that a diffuse green glow could appear in Mars’ sky during particularly energetic solar storms.

A magnetosphere is that area of space, around a planet, that is controlled by the planet's magnetic field. The shape of the Earth's magnetosphere is the direct result of being blasted by solar wind, compressed on its sunward side and elongated on the night-side, the magnetotail. Credits: NASA — Earth’s magnetosphere, an area of space that’s controlled by the planet’s magnetic field, guides solar wind electrons and protons along magnetic field lines into the atmosphere in the polar regions to create auroras. The planet’s field is created by electric currents generated in its outer nickel-iron core.
Credits: NASA

While the solar wind produces auroras at both Earth and Mars, they originate in radically different ways. At Earth, we’re ensconced in a protective planet-wide magnetic field. Charged particles from the Sun are guided to the Earth’s poles by following a multi-lane freeway of global magnetic field lines. Mars has no such organized, planet-wide field. Instead, there are many locally magnetic regions. Particles arriving from the Sun go where the magnetism takes them.

“The particles seem to precipitate into the atmosphere anywhere they want,” says Schneider. “Magnetic fields in the solar wind drape across Mars, even into the atmosphere, and the charged particles just follow those field lines down into the atmosphere.”

Maybe one day, NASA or one of the other space agencies will send a lander with a camera that can shoot long time exposures at night. We’ll call it the “Go Green” initiative.

May 10, 2015December 23, 2015 by Bob King

Head Held High, Comet Lovejoy Does the Polar Plunge

Comet C/2014 Q2 Lovejoy on May 7 with its emerald coma and faint gas tail. Lovejoy is currently around magnitude +7.5 and slowly fading. Credit: Rolando Ligustri

Lots of towns hold a polar plunge fundraising event in the winter. Duluth, Minnesota’s version, where participants jump in Lake Superior every February, might just be the coldest. Comet Lovejoy’s a season behind, but sure enough, it’s following suit, diving deep into the dark waters of the north celestial pole this month.

I dropped in on our old friend last night, when it glowed only 8° from the North Star. In 8×40 binoculars, the comet was faintly visible as a hazy blob of light with a brighter center. Not a sight to knock you over, but the fact that this comet is still visible in binoculars after so many months makes it worthwhile to seek out. Moonless skies for the next 10-11 nights means lots of opportunities.

Just face the North Star (Polaris) to begin tracking Comet Lovejoy. Stars are shown to magnitude +8. Click for a larger version. Created with Stellarium — Just face the North Star (Polaris) to begin tracking Comet Lovejoy. The map shows the sky facing north around 10:30 p.m. local time in mid-May. Stars are plotted to magnitude +8. Click for a larger version. Source: Chris Marriott’s SkyMap

Unless a new comet is discovered, Lovejoy will continue to remain the only “bright” comet visible from mid-northern latitudes for some time. There’s a tiny chance Comet C/2014 Q1 PanSTARRS will wax bright enough to see in twilight in early July, but it will be very low in the northwestern sky at dusk and visible for a few nights at most. Only C/2013 US10 Catalina offers the chance for a naked eye / binocular appearance, when it re-emerges from the solar glare in the latter half of November in the morning sky.

Southern hemisphere observers have more to smile about with Comet C/2015 G2 MASTER currently flaunting its fluff at magnitude +6.6 or just under the naked eye limit. They’ll also get a far better view of C/2014 Q1 PanSTARRS come this July and August.

Wide view of the sky facing north in mid-May around 10:30 p.m. local time. Use the Pointer stars in the Big Dipper to point you to Polaris and from there to the comet. Source: Chris Marriott's SkyMap — Wide view of the sky facing north in mid-May around 10:30 p.m. local time. Use the Pointer stars in the Big Dipper to point you to Polaris and from there to the comet. Source: Chris Marriott’s SkyMap

Through a telescope, Lovejoy still shows off a round, 6 arc minute diameter coma (one-fifth as wide as a full moon) and a denser, brighter core highlighted by a starlike false nucleus. We call it false because the true comet nucleus, probably no more than a few kilometers across, hides within a dusty cocoon of its own making. Only spacecraft have been able to get close enough for a clear view of comet nuclei. Each shows a unique and usually non-spherical shape because comets aren’t massive enough for their own self-gravity to crush them into spheres the way larger moons and planets do. If you’re a single object and big, being spherical comes naturally.

Comet Lovejoy will be closest to the imaginary point in the sky called the north celestial pole on May 29. Polaris lies 0.75° from the pole and describes a small circle 1.5° in diameter around it each day. Source: Stellarium

In my 15-inch (37-cm) telescope a faint wisp of a tail poked from the coma to the north. Looking at the map, you can see the comet’s headed due north through Cepheus toward Polaris, the North Star. Each passing night, it draws closer to the sky’s celestial pivot point, missing it by just 1° on the evenings of May 27 and 28. Closest approach to the north celestial pole, which marks the spot in the sky toward which Earth’s north polar axis currently points, occurs on May 29 with a separation of 54 arc minutes or just under a degree.

Finding Polaris is easy. Just draw a line through the two stars at the end of of the Big Dipper’s Bowl toward the horizon. The first similarly bright star you run into is the North Star. Using the map, you can navigate from Polaris to the fuzzy comet with either binoculars or telescope.

April 29, 2015December 23, 2015 by Tim Reyes

New Horizons, Approaching Pluto, Detects Signs of Polar Caps

The overview of the New Horizon journey to the binary system of Pluto and Charon. The NASA probe is now surpassing Hubble imagery. (Photo Credit: NASA/New Horizons)

New Horizons’ LORRI April 28, 2015 Posting

The latest set of images from the long range imager, LORRI, on New Horizons now reveals surface features. At a press conference today, exhilarated NASA scientists discussed what the images are now suggesting. (Photo Credit: NASA/New Horizons)

Today, a trio of NASA scientists expressed their exhilaration with the set of new Pluto images released by the New Horizons team. “Land Ho” exclaimed Dr. Alan Stern as he first tried to explain where they are on their long journey. Nearly 500 years ago, not even Magellan on a three year journey to circumnavigate the Earth waited so long. A ten year journey is beginning to reveal fascinating new details of the dwarf planet Pluto, once the ninth planet of our Solar System. The latest images show surface features on Pluto suggesting polar caps.

A team effort that Dr. Weaver said called upon leading experts to resolve these newest details of Pluto’s surface. The inset at left shows schematically the geographic relationship of the two bodies as they orbit each other. The inset at right shows surface details at 3x maximum resolution. (Photo Credit: NASA/New Horizons)

The NASA press conference took place this afternoon, anchored by Dr. John Grunsfeld, Associate Administrator for the Science Mission Directorate who quickly turned over the discussion to the project scientist of the New Horizons mission, Dr. Alan Stern from the Southwest Research Institute of San Antonio, Texas. Grunsfeld began by stating NASA’s mission – “to explore, discover and inspire” and added that New Horizons is certainly executing these prime objectives.

Alan Stern started off by expressing his excitement with the latest results from the long range telescope on board New Horizons, LORRI, but emphasized he represents a team effort, the culmination of decades of work.

With just 11 weeks remaining and now 98% of the way to Pluto, the latest set of images from LORRI have now revealed details better than the best that was previously attainable – from the Hubble Space Telescope. Most incredible are indications of polar caps on the dwarf planet Pluto.

Dr. Stern, stated that the 25th Anniversay of the Hubble mission has also functioned as a segue to what is about to unfold from New Horizons. Until now, the best images of Pluto’s surface had been wrestled out of images from Hubble with computer processing. Yet, at the present distance New Horizons remains, his team is still relying on image processing to reveal these first surface details.

The gravitational tug of war of the unique binary system has forced both small bodies to forever face each other, similar to how our Moon always faces the Earth. (Photo Credit: NASA/New Horizons)

Dr. Stern stated how remarkable the Pluto-Charon system is. The earlier set of LORRI images from 2014 had shown the gravitational dance of the two small bodies. He stated that they are truly a binary system and a type we have never explored before. Pluto-Charon is a dual synchronous, tidally locked system. Dr. Stern explained that the Earth, close-in to the Sun, and their space probe New Horizons, now on its final approach, is viewing the sunlit side of Pluto and Charon.

The system is tipped over relative to its orbital plane around the Sun. Dr. Stern stated, “it is like watching Pluto rotate on a spit.” He said that we are nearly seeing it face on; similar to an observer hovering far above the Earth’s polar cap and looking down upon the Earth-Moon system. The orbits of the two bodies, as seen in the LORRI image sequence (animations, above), appear elliptical (oval), however, due to the extreme and final state of this binary system, the orbits are perfect circles; the eccentricities are zero! New Horizons is just approaching slightly off center.

Images of the New Horion space probe shows its compactness, necessarily to minimize weight, volume, power demands and achieve the high velocity necessary to reach Pluto in nine years. Af left the instruments are shown included the long range imager, LORRI. (Photo Credit: NASA/New Horizons)

Dr. Stern continued and explained how this latest set is now showing surface features on Pluto. The features “are suggesting the presence of polar caps”, however he also emphasized that it remains only suggestive until New Horizons can deliver more details, that is, higher resolution, color imagery from the Ralph imager and spectroscopic data (Ralph and Alice imaging spectrometers) to reveal composition. Dr. Stern turned over the press conference to Dr. Hal Weaver of John Hopkins’ Applied Physics Laboratory, the lead scientist for the LORRI instrument.

LORRI, the Long Range Reconnaissance Imager, in details of a schematic. (Credit: NASA/New Horizons) — LORRI, the Long Range Reconnaissance Imager, shown through details of a schematic. (Credit: NASA/New Horizons)

LORRI as Dr. Weaver explained is a state-of-the-art instrument. A fixed focus telescopic camera, functional from room temp down to 180 degees Fahrenheit below zero and utilizes an 8 inch primary mirror. The optical quality is extraordinary but the light gathering power is the same as one has in an amateur 8 inch telescope such as offered by Meade or Celestron. Still further, Dr. Weaver stated that LORRI is also extremely efficient and ligthweight, using less than 5 watts of power and weighing less than 20 lbs.

New York City's Manhattan is shown as an example of the resolving power the Ralph multi-spectral imager will have at closest approach to Pluto and Charon (Photo Credit: NASA/New Horizons) — New York City’s Manhattan is shown as an example of the resolving power the Ralph multi-spectral imager will have at closest approach to Pluto and Charon (Photo Credit: NASA/New Horizons)

Dr. Weaver explained how the raw images from LORRI are presently little more than blotches of light, unspectacular at first glance, but with image processing, the details discussed today are revealed. The New Horizons team employed world-class experts in the technique of Image Deconvolution. It was again Hubble that spawned “a cottage industry”, over 20 years ago, including one expert – Todd Lauer of the National Optical Astronomy Observatory. Lauer and others took on the challenge of extracting quality imagery from the Hubble space telescope as it struggled with the astigmatism accidentally built into its optical system. A NASA Space Shuttle mission delivered and inserted a corrective lens into Hubble which has made its 25 years of service possible.

Without the imaging processing technique of deconvolution, the latest images of Pluto are mere blotches. Dr. Weaver credited experts born from the Hubble astigmatism from 20 years ago. (Photo Credit: NASA/New Horizons)

And the New Horizons’ processed images are now slightly better than Hubble and will just get much better. From the Q&A with the press. Weaver explained that while the images show more detail, Earth-based and Hubble images remain more light sensitive. Hubble sets an upper limit to the size of any remaining moons to be discovered. Weaver stated that by June, New Horizons’ LORRI will exceed the light sensitivity limits of Hubble. If there are more moons to be found, June will be the month.

An artist's illustration of Pluto. With a tenuous atmosphere that has so far defied explanations, New Horizons is altogether revealing a light red - peach - colored surface but with large contrasting areas of white and dark red. (Illust. Credit: NASA/New Horizons) — An artist’s illustration of Pluto. With a tenuous atmosphere that has so far defied explanations, New Horizons is altogether revealing a light red – peach – colored surface but with large contrasting areas of white and dark red. (Illust. Credit: NASA/New Horizons)

Through the Q&A, Dr. Stern stated that an extraordinary aspect of Pluto’s atmosphere is that the planet’s atmosphere has continued to expand despite having passed a point in its orbit at which it should be freezing and condensing onto its surface. The atmosphere expanded 200 to 300% in the last decade. With the limited observations, Stern and other Pluto experts surmise that there is a lag in the climate akin to how our hottest months lag the beginning of Summer by a couple of months. Perhaps, a latent heat stored up in the near surface has continued to vaporize frozen gases thus building up the atmosphere more than first expected.

The composition of the dwarf planet’s surface was discussed. Most evident in Earth-based spectroscopy is that there is molecular nitrogen, carbon monoxide and methane. Stern stated they these species of molecules could explain the bright and dark spots of the surface. However, he emphasized that Pluto is composed of 70% rock by mass and the remaining is ice. Charon stands in remarkable contrast to Pluto. Chraon has primarily water and ammonia hydrates on its surface; no detectable atmosphere (so far). Charon’s appearance is much more uniform and bland. Altogether, Stern said that experts call this the Pluto-Charon dichotomy.

The final approach to Pluto is just the beginning of the story of New Horizons' primary targets. The press conference illustration explains near-term plans. (Illust. Credit: NASA/New Horizons) — The present approach at 60 million miles to Pluto is just the beginning of the story of New Horizons’ study of the primary targets. This press conference illustration explains near-term plans. (Illust. Credit: NASA/New Horizons)

Dr. Stern near the end of the press conference restated that this is truly “my meet Pluto moment.” New Horizons is like a plane on its final approach to touchdown but New Horizons cannot slow down. There are no retro-rockets, no propulsion onboard that can slow down the probe on its trek to escape the gravity of the Sun. The probe will join the Pioneer and Voyager space probes as the only Human-made objects to leave the Solar System. With its final approach, with every day, Pluto and Charon closes in as Dr. Stern and Dr. Weaver explained, Pluto’s image will fill the full breadth of the imaging detector. Details on its surface will be equivalent to high resolution images of New York’s Manhattan (figure, above) showing details such as the ponds in Central Park.

To continue following the latest release of images from New Horizons go to http://www.nasa.gov/newhorizons/lorri-gallery.

April 8, 2015December 23, 2015 by Nancy Atkinson

Trail’s End: Beautiful New Night-Sky Timelapse by Randy Halverson

Wyoming Milky Way set. Credit and copyright: Randy Halverson.

Stunning views of the Milky Way, shimmering aurora, spectacular thunderstorms, flashing meteors, zipping satellies, stirring music, and spooky sprites and gravity waves …. they are all part of this wonderful new timelapse by night-sky guru Randy Halverson.

“Trails End is a compilation of some of my favorite timelapse shots from 2014, with a few aurora shots from early this year,” Halverson told us. “It was shot in Wyoming, Utah and South Dakota.”

A few moments to note in the video:

:56 Bolide Meteor
1:01 Aurora at Devils Tower and throughout video
1:33 Two Bolide Meteors
Meteors With Persistent Trains 2:29 very fast and short persistent train to right of the Milky Way, a better one at 3:20
2:43 Final Boost Stage of GSSAP and ANGELS satellites
2:55 Owl sitting in tree
3:00 Pink Aurora in the sand dunes of Wyoming’s Red Desert
3:14 Sprites and Gravity Waves

See more images and details at Randy’s website, dakotalapse.

March 31, 2015December 23, 2015 by Nancy Atkinson

Stunning Photo of Volcanic Lightning at Volcán de Colima in Mexico

The Colima Volcano (Volcán de Colima) pictured on March 29, 2015 with lightning. Credit and copyright: César Cantú.

The Colima volcano in Mexico is active again, and has been spewing out large plumes of ash nearly 3 kilometers into the air. Astrophotographer César Cantú captured this spectacular picture of lightning slicing through the cloud of ash.

How can lightning strike in an ash cloud? Through friction, particles of the ash can charge each other by rubbing against each other during the eruption. When the energy is discharged, it can create lightning bolts.

The Colima volcano is one of the most active volcanoes in Mexico, and is also called ‘Volcán de Fuego’ or ‘Fire volcano.’ It has erupted more than 40 times since the first documented eruption in 1576.

The latest news on this current eruption is that local authorities have put the volcano on a yellow alert, meaning the volcano is showing increased activity, and residents who live nearby should prepare for a possible evacuation.

Stay safe César, and thanks for sharing your image with Universe Today! See a larger version on his website here.