A shot of the moon taken by a telescope created by 3-D printing. Credit: University of Sheffield
What would Galileo think of this? Here’s a shot of our closest large celestial neighbor, the Moon, taken through a 3-D printed telescope. Better yet — before long, the creators of this telescope promise, the plans will be made available on the Internet for all to use.
“This is all about democratizing technology, making it cheap and readily available to the general public,” stated Mark Wrigley, who-co led the design. He runs a one-person company (Alternative Photonics) and built the telescope with support from the University of Sheffield in the United Kingdom.
“And the PiKon is just the start. It is our aim to not only use the public’s feedback and participation to improve it, but also to launch new products which will be of value to people.”
The mirror size of the telescope was not disclosed in a press release, but its magnification is 160. This makes it able to look at planets, moons, galaxies and star clusters. Stacking images is also possible to look for moving objects such as comets, the university stated.
The creators say it only costs £100 ($165) to make, so we can hardly wait to see what the plans contain. More information on the telescope is available on the PiKon website.
The control room at Lockheed Martin shortly before MAVEN successfully entered Mars orbit tonight September 21, 2014. Credit: NASA-TV
138 million miles and 10 months journey from planet Earth, MAVEN moved into its new home around the planet Mars this evening. Flight controllers at Lockheed Martin Space Systems in Littleton, Colorado anxiously monitored the spacecraft’s progress as onboard computers successfully eased the Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft into Mars orbit at 10:24 p.m. Eastern Daylight Time.
Shortly before orbital insertion, six small thrusters were fired to steady the spacecraft so it would enter orbit in the correct orientation. This was followed by a 33-minute burn to slow it down enough for Mars’ gravity to capture the craft into an elliptical orbit with a period of 35 hours. Because it takes radio signals traveling at the speed of light 12 minutes to cross the gap between Mars and Earth, the entire orbital sequence was executed by onboard computers. There’s no chance to change course or make corrections, so the software has to work flawlessly. It did. The burn, as they said was “nominal”, science-speak for came off without a hitch.
Simulation of MAVEN in orbit around Mars. The craft’s unique aerodynamically curved solar panels allow it to dive more deeply into the Martian atmosphere. Credit: NASA
“This was a very big day for MAVEN,” said David Mitchell, MAVEN project manager from NASA’s Goddard Space Flight Center, Greenbelt, Maryland. “We’re very excited to join the constellation of spacecraft in orbit at Mars and on the surface of the Red Planet. Congratulations to the team for a job well done today.”
Over the next six weeks, controllers will test MAVEN’s instruments and shape its orbit into a long ellipse with a period of 4.5 hours and a low point of just 93 miles (150 km), close enough to get a taste of the planet’s upper atmosphere. MAVEN’s one-Earth-year long primary mission will study the composition and structure of Mars’ atmosphere and how it’s affected by the sun and solar wind. At least 2,000 Astronomers want to determine how the planet evolved from a more temperate climate to the current dry, frigid desert.
Evidence for ancient water flows on Mars – a delta in Eberswalde Crater. Credit: NASA
Vast quantities of water once flowed over the dusty red rocks of Mars as evidenced by ancient riverbeds, outflow channels carved by powerful floods, and rocks rounded by the action of water. For liquid water to flow on its surface without vaporizing straight into space, the planet must have had a much denser atmosphere at one time.
Three to four billion years ago, Mars may have been much more like Earth with a thicker atmosphere and water flowing across its surface (left). Over time, it evolved into a dry, cold planet with an atmosphere too thin to support liquid water. Credit: NASA
Mars’ atmospheric pressure is now less than 1% that of Earth’s. As for the water, what’s left today appears locked up as ice in the polar caps and subsurface ice. So where did it go all the air go? Not into making rocks apparently. On Earth, much of the carbon dioxide from volcanic outgassing in the planet’s youth dissolved in water and combined with rocks to form carbon-bearing rocks called carbonates. So far, carbonates appear to be rare on Mars. Little has been seen from orbit and in situ with the rovers.
Illustration of electrons and protons in the solar wind slamming into and ionizing atoms in Mars upper atmosphere. Once ionized, the atoms may be carried away by the wind. Credit: NASA
During the year-long mission, MAVEN will dip in and out of the atmosphere some 2,000 times or more to measure what and how much Mars is losing to space. Without the protection of a global magnetic field like the Earth’s, it’s thought that the solar wind eats away at the Martian atmosphere by ionizing (knocking off electrons) its atoms and molecules. Once ionized, the atoms swirl up the magnetic field embedded in the wind and are carried away from the planet.
MAVEN’s suite of instruments will provide the measurements essential to understanding the evolution of the Martian atmosphere. Courtesy LASP/MAVEN
Scientists will coordinate with the Curiosity rover, which can determine the atmospheric makeup at ground level. Although MAVEN won’t be taking pictures, its three packages of instruments will be working daily to fill gaps in the story of how Mars became the Red Planet and we the Blue.
For more on the ongoing progress of MAVEN later tonight and tomorrow, stop by NASA TV online. You can also stay in touch by following the hashtags #MAVEN and #JourneytoMars on social media channels including Twitter, Instagram and Facebook. Twitter updates will be posted throughout on the agency’s official accounts @NASA, @MAVEN2Mars and @NASASocial.
Some of the many thousands of merging galaxies identified within the GAMA survey. Credit: Professor Simon Driver and Dr Aaron Robotham, ICRAR.
The Anglo-Australian Telescope in New South Wales has been watching how lazy giant galaxies gain size – and it isn’t because they create their own stars. In a research project known as the Galaxy And Mass Assembly (GAMA) survey, a group of Australian scientists led by Professor Simon Driver at the International Centre for Radio Astronomy Research (ICRAR) have found the Universe’s most massive galaxies prefer “eating” their neighbors.
According to findings published in the journal “Monthly Notices of the Royal Astronomical Society”, astronomers studied more than 22,000 individual galaxies to see how they grew. Apparently smaller galaxies are exceptional star producers, forming their stellar members from their own gases. However, larger galaxies are lazy. They aren’t very good at stellar creation. These massive monsters rarely produce new stars on their own. So how do they grow? They cannibalize their companions. Dr. Aaron Robotham, who is based at the University of Western Australia node of the International Centre for Radio Astronomy Research (ICRAR), explains that smaller ‘dwarf’ galaxies were being consumed by their heavyweight peers.
“All galaxies start off small and grow by collecting gas and quite efficiently turning it into stars,” he said. “Then every now and then they get completely cannibalized by some much larger galaxy.”
So how does our home galaxy stack up to these findings? Dr. Robotham, who led the research, said the Milky Way is at a tipping point and is expected to now grow mainly by eating smaller galaxies, rather than by collecting gas.
“The Milky Way hasn’t merged with another large galaxy for a long time but you can still see remnants of all the old galaxies we’ve cannibalized,” he said. “We’re also going to eat two nearby dwarf galaxies, the Large and Small Magellanic Clouds, in about four billion years.” Robotham also added the Milky Way wouldn’t escape unscathed. Eventually, in about five billion years, we’ll encounter the nearby Andromeda Galaxy and the tables will be turned. “Technically, Andromeda will eat us because it’s the more massive one,” he said.
This simulation shows what will happen when the Milky Way and Andromeda get closer together and then collide, and then finally come together once more to merge into an even bigger galaxy.
Simulation Credit: Prof Chris Power (ICRAR-UWA), Dr Alex Hobbs (ETH Zurich), Prof Justin Reid (University of Surrey), Dr Dave Cole (University of Central Lancashire) and the Theoretical Astrophysics Group at the University of Leicester. Video Production Credit: Pete Wheeler, ICRAR.
What exactly is going on here? Is it a case of mutual attraction? According to Dr. Robotham when galaxies grow, they acquire a heavy-duty gravitational field allowing them to suck in neighboring galaxies with ease. But why do they stop producing their own stars? Is it because they have exhausted their fuel? Robotham said star formation slow downs in really massive galaxies might be “because of extreme feedback events in a very bright region at the center of a galaxy known as an active galactic nucleus.”
“The topic is much debated, but a popular mechanism is where the active galactic nucleus basically cooks the gas and prevents it from cooling down to form stars,” Dr. Robotham said.
Will the entire Universe one day become just a single, large galaxy? In reality, gravity may very well cause galaxies groups and clusters to congeal into a limited number of super-giant galaxies, but that will take many billions of years to occur.
“If you waited a really, really, really long time that would eventually happen, but by really long I mean many times the age of the Universe so far,” Dr. Robotham said.
While the GAMA survey findings didn’t take billions of years, it didn’t happen overnight either. It took seven years and more than 90 scientists to complete – and it wasn’t a single revelation. From this work there have been over 60 publications and there are still another 180 in progress!
A density map of part of the Milky Way disk, constructed from IPHAS data. The axes show galactic latitude and longitude, coordinates that relate to the position of the centre of the galaxy. The mapped data are the counts of stars detected in i, the longer (redder) wavelength broad band of the survey, down to a faint limit of 19th magnitude. Although this is just a small section of the full map, it portrays in exquisite detail the complex patterns of obscuration due to interstellar dust. Credit: Hywel Farnhill, University of Hertfordshire.
On the darkest of nights, thousands of stars are sprinkled across the celestial sphere above us. Or, to be exact, there are 9,096 stars observable across the entire sky. Divide that number in half, and there are 4,548 stars (give or take a few) visible from horizon to horizon.
But this number excludes the glowing band stretching across the night sky, the Milky Way. It’s the disk of our own galaxy, a system stretching 100,000 light-years across. The naked eye is unable to distinguish individual specks of light, but the Isaac Newton Telescope (INT) on La Palma in the Canary Islands has recently charted 219 million separate stars in this disk alone.
For the last 10 years a team of astronomers led by Geert Barentsen from the University of Hertfordshire has been collecting and compiling light from all stars brighter than 20th magnitude, or one million times fainter than the human eye can see (at 6th magnitude).
They created a beautiful density map of the Milky Way, giving them new insight into the structure of this vast system. The black, fog-like regions are galactic dust, which blocks more distant light. The brighter regions are densely packed stars.
The INT took measurements in two broad filters, which captured light at the red end of the visible spectrum, and in one narrow filter, which captured light only from the hydrogen emission line, H-alpha. The inclusion of H-alpha enables exquisite mapping of nebulae, glowing clouds of hydrogen gas.
The production of the catalogue is an example of modern astronomy’s exploitation of “big data.” But it would also grace the walls of any art studio.
An exoplanet about ten times Jupiter's mass located some 330 light years from Earth. X-ray: NASA/CXC/SAO/I.Pillitteri et al; Optical: DSS; Illustration: NASA/CXC/M.Weiss
Hot young stars are wildly active, emitting huge eruptions of charged particles form their surfaces. But as they age they naturally become less active, their X-ray emission weakens and their rotation slows.
Astronomers have theorized that a hot Jupiter — a sizzling gas giant circling close to its host star — might be able to sustain a young star’s activity, ultimately prolonging its youth. Earlier this year, two astronomers from the Harvard-Smithsonian Center for Astrophysics tested this hypothesis and found it true.
But now, observations of a different system show the opposite effect: a planet that’s causing its star to age much more quickly.
The planet, WASP-18b has a mass roughly 10 times Jupiter’s and circles its host star in less than 23 hours. So it’s not exactly a classic hot Jupiter — a sizzling gas giant whipping around its host star — because it’s characteristics are a little more drastic.
“WASP-18b is an extreme exoplanet,” said lead author Ignazio Pillitteri of the National Institute for Astrophysics in Italy, in a news release. “It is one of the most massive hot Jupiters known and one of the closest to its host star, and these characteristics lead to unexpected behavior.”
The team thinks WASP-18 is 600 million years old, relatively young compared to our 5-billion-year-old Sun. But when Pillitteri and colleagues took a long look with NASA’s Chandra X-ray Observatory at the star, they didn’t see any X-rays — a telltale sign the star is youthful. In fact, the observations show the star is 100 times less active than it should be.
“We think the planet is aging the star by wreaking havoc on its innards,” said co-author Scott Wolk (who also worked on the previous study showing the opposite effect) from the Harvard-Smithsonian Center for Astrophysics.
The researchers argue that tidal forces created by the gravitational pull of the massive planet might have disrupted the star’s magnetic field generated by the motion of conductive plasma deep inside the star. It’s possible the exoplanet significantly interfered with the upper layers of the convective zone, reduced any mixing of stellar material, and effectively canceled out the magnetic activity.
The effect of tidal forces from the planet may also explain an unusually high amount of lithium seen in the star. Lithium is usually abundant in younger stars, but disappears over time as convection carries it further toward the star’s center, where it’s destroyed by nuclear reactions. So if there’s less convection — as seems to be the case for WASP 18 — then the lithium won’t circulate toward the center of the star and instead will survive.
The findings have been published in the July issue of Astronomy and Astrophysics and are available online.
Artist's conception of a supermassive black hole in a galaxy's center. Credit: NASA/JPL-Caltech
In a finding that could turn supermassive black hole formation theories upside-down, astronomers have spotted one of these beasts inside a tiny galaxy just 157 light-years across — about 500 times smaller than the Milky Way.
The clincher will be if the team can find more black holes like it, and that’s something they’re already starting to work on after the discovery inside of galaxy M60-UCD1. The ultracompact galaxy is one of only about 50 known to astronomers in the nearest galaxy clusters.
“It’s very much like a pinprick in the sky,” said lead researcher Anil Seth, an astrophysicist at the University of Utah, of M60-UCD1 during an online press briefing Tuesday (Sept. 16).
Seth said he realized something special was happening when he saw the plot for stellar motions inside of M60-UCD1, based on data from the Gemini North Telescope in Hawaii. The stars in the center of the galaxy were orbiting much more rapidly than those at the edge. The velocity was unexpected given the kind of stars that are in the galaxy.
“Immediately when I saw the stellar motions map, I knew we were seeing something exciting,” Seth said. “I knew pretty much right away there was an interesting result there.”
Ultracompact dwarf galaxy M60-UCD1 shines in the inset image based on images from the Hubble Space Telescope and Chandra X-Ray Telescope. Chandra data is pink, and Hubble data is red, green and blue. The large galaxy dominating the field of view is M60. At the right edge is NGC 4647. Credit: X-ray: NASA/CXC/MSU/J.Strader et al, Optical: NASA/STScI
In its weight class, M60-UCD1 is a standout. Last year, Seth was second co-author on a group that announced that it was the densest nearby galaxy, with stars jam-packed 25 times closer than in the Milky Way. It’s also one of the brightest they know of, a fact that is helped by the galaxy’s relative closeness to Earth. It’s roughly 54 million light-years away, as is the massive galaxy it orbits: M60. The two galaxies are only 20,000 light-years apart.
Supermassive black holes are known to lurk in the centers of most larger galaxies, including the Milky Way. How they got there in the first place, however, is unclear. The find inside of M60-UCD1 is especially intriguing given the relative size of the black hole to the galaxy itself. The black hole is about 15% of the galaxy’s mass, with an equivalent mass of 21 million Suns. The Milky Way’s black hole, by contrast, takes up less than a percentage of our galaxy’s mass.
Given so few ultracompact galaxies are known to astronomers, some basic properties are a mystery. For example, the mass of these galaxy types tends to be higher than expected based on their starlight.
Some astronomers suggest it’s because they have more massive stars than other galaxy types, but Seth said measurements of stars within M60-UCD1 (based on their orbital motion) show normal masses. The extra mass instead comes from the black hole, he argues, and that will likely be true of other ultracompact galaxies as well.
A Hubble Space Telescope image of ultracompact galaxy M60-UCD1 (inset), which is suspected to host a supermassive black hole at its center. It is orbiting the nearby massive galaxy M60. Within the same field of view is NGC 4647. Credit: NASA/Space Telescope Science Institute/European Space Agency
“It’s a new place to look for black holes that was previously not recognized,” he said, but acknowledged the idea of black holes existing in similar galaxies will not be widely accepted until the team makes more finds. An alternative explanation to a black hole could be a suite of low-mass stars or neutron stars that do not give off a lot of light, but Seth said the number of these required in M60-UCD1 is “unreasonably high.”
His team plans to look at several other ultracompact galaxies such as M60-UCD1, but perhaps only seven to eight others would be bright enough from Earth to perform these measurements, he said. (Further work would likely require an instrument such as the forthcoming Thirty-Meter Telescope, he said.) Additionally, Seth has research interests in globular clusters — vast collections of stars — and plans a visit to Hawaii next month to search for black holes in these objects as well.
Results were published today (Sept. 17) in the journal Nature.
A screenshot from "StarryNights", a video showing several observatories at work. Credit: Jan Hattenbach / Vimeo (screenshot)
We often speak of the discoveries and data flowing from astronomical observatories, which makes it easy to forget the cool factor. Think of it — huge telescopes are probing the universe under crystal-clear skies, because astronomers need the dark skies to get their work done.
That’s what makes this astronomical video by Jan Hattenbach such a treat. He’s spent the past three years catching stunning video shots at observatories all over the world, showing timelapses of the Milky Way galaxy and other celestial objects passing overhead.
“The time-lapses were a byproduct of our visual observing – because obviously, these sites are also the best in the world for visual observing and astrophotography. If you ever have the chance to spend a night at one of these observatories, consider yourself very lucky!” wrote Hattenbach on Vimeo.
And often you don’t even need a telescope to appreciate the beauty of the cosmos. Earlier this summer, we posted another video showing the stunning sky above Desert National Park.
Uranus as seen through the automated eyes of Voyager 2 in 1986. (Credit: NASA/JPL).
It’s no joke… now is the time to begin searching the much-maligned (and mispronounced) planet Uranus as it reaches opposition in early October leading up to a very special celestial event.
Last month, we looked at the challenges of spying the solar system’s outermost ice giant world, Neptune. Currently located in the adjacent constellation Aquarius, Neptune is now 39 degrees from Uranus and widening. The two worlds had a close conjunction of just over one degree of separation in late 1993, and only long time observers of the distant worlds remember a time waaaay back in the early-1970s where the two worlds appeared farther apart than 2014 as seen from our Earthly vantage point.
Uranus rising to the east the evening of October 7th, just prior to the start of the October 8th lunar eclipse later the same evening. Created using Stellarium.
In 2014, opposition occurs at 21:00 Universal Time (UT)/5:00 PM EDT on October 7th. If this date sounds familiar, it’s because Full Moon and the second total lunar eclipse of 2014 and the ongoing lunar tetrad of eclipses occurs less than 24 hours afterwards. This puts Uranus extremely close to the eclipsed Moon, and a remote slice of the high Arctic will actually see the Moon occult (pass in front of) Uranus during totality. Such a coincidence is extremely rare: the last time the Moon occulted a naked eye planet during totality occurred back during Shakespearian times in 1591, when Saturn was covered by the eclipsed Moon. This close conjunction as seen from English soil possibly by the bard himself was mentioned in David Levy’s book and doctoral thesis The Sky in Early Modern English Literature, and a similar event involving Saturn occurs in 2344 AD.
The footprint of the October 8th occultation of Uranus. Credit: Occult 4.1.
We’re also in a cycle of occultations of Uranus in 2014, as the speedy Moon slides in front of the slow moving world every lunation until December 2015. Oppositions of Uranus — actually pronounced “YOOR-un-us” so as not to rhyme with a bodily orifice — currently occur in the month of September and move forward across our calendar by about 4 days a year.
Uranus (lower left) near the limb of the gibbous Moon of September 11th, 2014. Credit: Roger Hutchinson.
This year sees Uranus in the astronomical constellation Pisces just south of the March equinoctial point. Uranus is moving towards and will pass within a degree of the +5.7 magnitude star 96 Piscium in late October through early November. Shining at magnitude +5.7 through the opposition season, Uranus presents a disk 3.7” in size at the telescope. You can get a positive ID on the planet by patiently sweeping the field of view: Uranus is the tiny blue-green “dot” that, unlike a star, refuses to come into a pinpoint focus.
The apparent path of Uranus from September 2014 through January 2015 across the constellation Pisces. The inset shows the tilt and orbit of its major moons across a 2′ field of view. Created by the author using Starry Night Education software.
Uranus also presents us with one of the key mysteries of the solar system. Namely, what’s up with its 97.8 degree rotational tilt? Clearly, the world sustained a major blow sometime in the solar system’s early history. In 2014, we’re viewing the world at about a 28 degree tilt and widening. This will continue until we’re looking straight at the south pole of Uranus in early 2030s. Of course, “south” and “north” are pretty arbitrary when you’re knocked back over 90 degrees on your axis! And while we enjoy the September Equinox next week on September 23rd, the last equinox for any would-be “Uranians” occurred on December 16th, 2007. This put the orbit of its moons edge-on from our point of view from 2006-2009 for only the third time since discovery of the planet in 1781. This won’t occur again until around 2049. Uranus also passed aphelion in 2009, which means it’s still at the farther end of its 19.1 to 17.3 astronomical unit (A.U.) range from the Sun in its 84 year orbit.
The moons of Uranus and Neptune as imaged during the 2011 opposition season. Credit: Rolf Wahl Olsen, used with permission.
And as often as Uranus ends up as the butt (bad pun) of many a scatological punch line, we can at least be glad that the world didn’t get named Georgium Sidus (Latin for “George’s Star”) after William Herschel’s benefactor, King George the III. Yes, this was a serious proposal (!). Herschel initially thought he’d found a comet upon spying Uranus, until he realized its slow motion implied a large object orbiting far out in the solar system.
A replica of the reflecting telescope that Herschel used to discover Uranus. Credit: Alun Salt/Wikimedia Commons image under a Creative Commons Attribution Share-Alike 2.0 license.
Spurious sightings of Uranus actually crop up on star maps prior to Herschel’s time, and in theory, it hovers juuusst above naked eye visibility near opposition as seen from a dark sky site… can you pick out Uranus without optical assistance during totality next month? Hershel and Lassell also made claims of spotting early ring systems around both Uranus and Neptune, though the true discovery of a tenuous ring system of Uranus was made by the Kuiper Airborne Observatory (a forerunner of SOFIA) during an occultation of a background star in 1977.
A corkscrew chart for the moons of Uranus through October. Credit: Ed Kotapish/Rings PDS node.
Looking for something more? Owners of large light buckets can capture and even image (see above) 5 of the 27 known moons of Uranus. We charted the orbital elongations for favorable apparitions through October 2014 (to the left). Check out last year’s chart for magnitudes, periods, and maximum separations for each respective moon. An occulting bar eyepiece may help you in your quest to cut down the ‘glare’ of nearby Uranus.
When will we return to Uranus? Thus far, humanity has explored the world up close exactly once, when Voyager 2 passed by in 1986. A possible “Uranus Probe” (perhaps, Uranus Orbiter is a better term) similar to Cassini has been an on- and off- proposal over the years, though it’d be a tough sell in the current era of ever dwindling budgets. Plutonium, a mandatory power source for deep space missions, is also in short supply. Such a mission might take up to a decade to enter orbit around Uranus, and would represent the farthest orbital reconnaissance of a world in our solar system. Speedy New Horizons is just whizzing by Pluto next July.
All great thoughts to ponder as you scour the skies for Uranus in the coming weeks!
A group of amateur photographers set up on a beach on Lake Superior near Duluth to photograph the northern lights. To shoot the aurora you'll need a tripod and middle to high end digital camera. Pocket cameras work well in daylight and can be used to shoot bright northern lights, but the images will be noisy. Credit: Bob King
Everybody loves pictures of the northern lights! If you’ve never tried to shoot the aurora yourself but always wanted to, here are a few tips to get you started.
“T” stands for a terrific aurora seen last winter near Duluth, Minn. U.S. Photo taken with a high-end digital camera (Canon EOS 1-D Mark III) at ISO 800, 30-second exposure. Credit: Bob King
The strong G3 geomagnetic storm expected tonight should kick out a reasonably bright display, perfect for budding astrophotographers. Assuming the forecasters are correct, you’ll need a few things. A location with a nice open view to the north is a good start. The aurora has several different active zones. There are bright, greenish arcs, which loll about the northern horizon, parallel rays midway up in the northern sky and towering rays and diffuse aurora that can surge past the zenith. Often the aurora hovers low and remains covered by trees or buildings, so find a road or field with good exposure.
15-second time exposure of Vega rising taken with a typical digital pocket camera. Notice the grain or noise throughout. Credit: Bob King
Second, a tripod. You can do so much with this three-legged beast. No better astro tool in the universe. Even the brightest auroras will require a time exposure of at least 5 seconds. Since no human can be expected to hold a camera steady that long, a tripod is a necessity. After that, it comes down to a camera. Most “point-and-shoot” models have limited time exposure ability, often just 15 seconds. That may be long enough for brighter auroras, but to compensate, you’ll have to increase your camera’s sensitivity to light by increasing the “speed” or ISO. The higher you push the ISO, the grainier the images appear especially with smaller cameras. But you’ll be able to get an image, and that may be satisfaction enough.
I use a Canon EOS-1 Mark III camera to shoot day and night. While not the latest model, it does a nice job on auroras. The 16-35mm zoom wide-angle lens is my workhorse as the aurora often covers a substantial amount of sky. My usual routine is to monitor the sky. If I see aurora padding across the sky, I toss the my equipment in the car and drive out to one of several sites with a clear exposure to the north. Once the camera meets tripod, here’s what to do:
A bright, active aurora. I used my zoom lens at 16mm at f/2.8 and about a 15-second exposure at ISO 800. Credit: Bob King
* Focus: Put the camera in manual mode and make sure my focus is set to infinity. Focusing is critical or the stars will look like blobs and the aurora green mush. There are a couple options. Use autofocus on a cloud or clouds in the daytime or the moon at night. Both are at “infinity” in the camera’s eye. Once focused at infinity, set the camera to manual and leave it there the rest of the evening to shoot the aurora. OR … note where the little infinity symbol (sideways 8) is on your lens barrel and mark it with a thin sharpie so you can return to it anytime. You can also use your camera in Live View mode, the default viewing option for most point-and-shoot cameras where you compose and frame live. Higher-end cameras use a viewfinder but have a Live View option in their menus. Once in Live View, manually focus on a bright star using the back of the camera. On higher-end cameras you can magnify the view by pressing on the “plus” sign. This allows for more precision focus.
* Aperture: Set the lens to its widest open setting, which for my camera is f/2.8. The lower the f-stop number, the more light allowed in and the shorter the exposure. Like having really big pupils! You want to expose the aurora in as short a time as possible because it moves. Longer exposures soften its appearance and blur exciting details like the crispness of the rays.
A friend takes a night sky shot silhouetted against the glow of the northern lights. Credit: Bob King
* ISO speed: Set the ISO to 800 for brighter auroras or 1600 for fainter ones and set the time to 30-seconds. If the aurora is bright and moving quickly, I’ll decrease exposure times to 10-15 seconds. The current crop of high end cameras now have the capacity to shoot at ISOs of 25,000. While those speeds may not give the smoothest images, dialing back to ISO 3200 and 6400 will make for photos that look like they were shot at ISO 400 on older generation cameras. A bright aurora at ISO 3200 can be captured in 5 seconds or less.
* Framing: Compose the scene in the viewfinder or monitor. If you’re lucky or plan well, you can include something interesting in the foreground like a building, a picturesque tree or lake reflection.
* Press!: OK, ready? Now press the button. When the image pops up on the viewing screen, does the image seem faint, too bright or just right. Make exposure adjustments as needed. If you need to expose beyond the typical maximum of 30 seconds, you can hold the shutter button down manually or purchase a cable release to hold it down for you.
Great example of a well-composed photo with an interesting foreground choice. This intense aurora was shot on September 12, 2014 in central Maine. Credit: Mike Taylor
It’s easy, right? Well then, why did it take me 400 words to explain it??? Of course the magic happens when you look at the monitor. You’ll see these fantastic colorful forms and ask yourself “did I do that?”
A bright arc and pink-topped rays stipple the northern sky and cross the Bowl of the Big Dipper last night around 11:30 p.m. CDT over Caribou Lake north of Duluth, Minn. Credit: Guy Sander
(Scroll down for latest update)
Auroras showed up as forecast last night beginning around nightfall and lasting until about 1 a.m. CDT this morning. Then the action stopped. At peak, the Kp indexdinged the bell at “5” (minor geogmagnetic storm) for about 6 hours as the incoming shock from the arrival of the solar blast rattled Earth’s magnetosphere. It wasn’t a particularly bright aurora and had to compete with moonlight, so many of you may not have seen it. You needn’t worry. A much stronger G3 geomagnetic storm from the second Earth-directed coronal mass ejection (CME) remains in the forecast for tonight.
Plot showing the Kp index of magnetic activity high in the Earth’s magnetic domain called the magnetosphere. The two red bars show the Kp at ‘5’ last night and early this morning (dotted line represents 0 UT or 7 p.m. CDT). Inset is the current detailed forecast in Universal Time (Greenwich Time) in 3-hour increments. Credit: NOAA
Activity should begin right at nightfall and peak between 10 p.m. and 1 a.m. Central Daylight Time. The best place to observe the show is from a location well away from city lights with a good view of the northern sky. Auroras are notoriously fickle, but if the NOAA space forecasting crew is on the money, flickering lights should be visible as far south as Illinois and Kansas. The storm also has the potential to heat and expand the outer limits of Earth’s atmosphere enough to cause additional drag on low-Earth-orbiting (LEO) satellites. High-frequency radio transmissions like shortwave radio may be reduced to static particularly on paths crossing through the polar regions.
Earth’s magnetic bubble, generated by motions within its iron-nickel core and shaped by the solar wind, is called the magnetosphere. It extends some 40,000 miles forward of the planet and more than 3.9 million miles in the tailward direction. Most of the time it sheds particle blasts from the sun called coronal mass ejections, but occasionally one makes it past our defenses and we get an auroral treat. Credit: NASA
If you study the inset box in the illustration above, you can see that from 21-00UT (4 -7 p.m. Central time) the index jumps quickly form “3” to “6” as the blast from that second, stronger X-class flare (September 10) slams into our magnetosphere. Assuming the magnetic field it carries points southward, it should link into our planet’s northward-pointing field and wreak beautiful havoc. A G2 storm continues through 10 p.m. and then elevates to Kp 7 or G3 storm between 10 p.m. and 1 a.m. before subsiding slightly in the wee hours before dawn. The Kp index measures how disturbed Earth’s magnetic field is on a 9-point scale and is compiled every 3 hours by a network of magnetic observatories on the planet.
A lovely rayed arc reflected in Caribou Lake north of Duluth, Minn. on September 11, 2014. Tonight the moon rises around 9:30 p.m. The lower in the sky it is, the brighter the aurora will appear. Hopefully tonight’s lights will outdo what the moon can dish out. Credit: Guy Sander
All the numbers are lined up. Now, will the weather and solar wind cooperate? Stop back this evening as I’ll be updating with news as the storm happens. For tips on taking pictures of the aurora, please see this related story “How to Take Great Pictures of the Northern Lights”.
The auroral oval at 11:15 p.m. CDT tonight September 12 shows a temporary pullback into northern Canada. Where the sky is dark, auroras are typically seen anywhere under or along the edge of the oval. Click for current map. Credit: NOAA
* UPDATE 8:15 a.m. Saturday September 13: Well, well, well. Yes, the effects of the solar blast did arrive and we did experience a G3 storm, only the best part happened before nightfall had settled over the U.S. and southern Canada. The peak was also fairly brief. All those arriving protons and electrons connected for a time with Earth’s magnetic field but then disconnected, leaving us with a weak storm for much of the rest of the night. More activity is expected tonight, but the forecast calls for a lesser G1 level geomagnetic storm.
* UPDATE 11 p.m. CDT: After a big surge late this afternoon and early evening, activity has temporarily dropped off. The ACE plot has “gone north” (see below). Though we’re in a lull, the latest NOAA forecast still calls for strong storms overnight.
Definite aurora seen through breaks in the clouds low in the northern sky here in Duluth, Minn. After a big surge late this afternoon and during early evening, activity’s temporarily dropped off. The ACE plot has “gone north”.
* UPDATE 9 p.m. CDT: Aurora a bright greenish glow low in the northern sky from Duluth, Minn.
* UPDATE 7:45 p.m. CDT September 12: Wow! Kp=7 (G3 storm) at the moment. Auroras should be visible now over the far eastern seaboard of Canada including New Brunswick and the Gaspe Peninsula. I suspect that skywatchers in Maine and upstate New York should be seeing something as well. Still dusk here in the Midwest.
