Skywatching Archives

October 6, 2014December 23, 2015 by Bob King

How to Take Great Photos of the Lunar Eclipse

On Wednesday morning October 8, Earth's shadow will nibble away at the moon for this year's second total lunar eclipse. Credit: Bob King

Ready for Wednesday’s morning lunar eclipse? Some people – and I envy them at times – treat an eclipse more casually. They enjoy the show with no desire to set up a telescope or take a photo. For those of us can’t part with our cameras, here’s a little guide to help you get better pictures.

From Philadelphia and other eastern U.S. cities the partial phases of the eclipse will take place with the moon well up in the western sky. By the start of totality, the moon will have dropped to within about 6º of the horizon as shown here. Source: Stellarium

If you’re also into photography and would like to grab a few shots, here are a few tips on what equipment you’ll need and camera settings. This eclipse offers unique opportunities especially for the eastern half of the country because the eclipsed moon will be low in the western sky near the start of and during morning twilight.

In the Midwest at the start of the hour-long totality, the red moon will be about 20º (two fists) above the western horizon. From the East Coast the moon slips into total eclipse only a half hour before sunrise 6-7º high. So if you live in the eastern half of the country, find a site with a good view to the west.

Seen from Denver, total eclipse begins with the moon 30º high (three fists). All of totality and all partial phases of the eclipse will be visible from western Midwest west to Hawaii and Alaska. Source: Stellarium

A low moon means easier framing with a pleasing foreground like a grove of fall trees, a church or distant line of mountain peaks. And the lower it drops, the longer the telephoto lens you can use to enlarge the moon relative to the foreground. When the moon is high in the sky it’s more difficult to find a suitable foreground.

Sometimes it's nice to have a foreground object to add character to your eclipse photos. Last April's totally eclipsed moon joins the old Central High School clock tower in downtown Duluth, Minn. Mars at upper right. Details: 80mm lens, f/5, 1.6-second exposure at ISO 400 on a tripod. Credit: Bob King — Sometimes it’s nice to have a foreground object to add character to your eclipse photos. Last April’s totally eclipsed moon joins the old Central High School clock tower in downtown Duluth, Minn. Mars at upper right. Details: 80mm lens, f/5, 1.6-second exposure at ISO 400 on a tripod. Credit: Bob King

As the scene brightens during twilight, balancing the light of the dim moon, your photos will get even more interesting. Textures and details in foreground objects will stand out instead of appearing as silhouettes.

Use the table below to plan when to watch depending on your time zone. The blanks mean the moon will have set by the time of the event.

Eclipse Events EDT CDT MDT PDT

Penumbra first visible	4:45 a.m.	3:45 a.m.	2:45 a.m.	1:45 a.m.
Partial eclipse begins	5:15 a.m.	4:15 a.m.	3:15 a.m.	2:15 a.m.
Total eclipse begins	6:25 a.m.	5:25 a.m.	4:25 a.m.	3:25 a.m.
Mid-eclipse	6:55 a.m.	5:55 a.m.	4:55 a.m.	3:55 a.m.
Total eclipse ends	7:24 a.m.	6:24 a.m.	5:24 a.m.	4:24 a.m.
Partial eclipse ends	———	7:34 a.m.	6:34 a.m.	5:34 a.m.
Penumbra last visible	———	———	7:05 a.m.	6:05 a.m.

Exposures and lens settings

Partial phase during the April 14-15 eclipse this year. Details: Telescope (=1300mm telephoto lens) at f/11, 1/250 second at ISO 400. Credit: Bob King

The full moon and even the partially eclipsed moon (up to about half) are so bright you can shoot a handheld photo without resorting to a tripod. Exposures at ISO 400 are in the neighborhood of f/8 at 1/250-1/500 second. Only thing is, all you’ll get is the moon surrounded by blackness. These exposures are so brief almost nothing will show in your foreground except for possibly moonlit clouds. That’s usually fine for the early partial phases.

Once the moon is more than half smothered by shadow, open up your lens to a wider setting – f/2.8 to f/4 – or increase the exposure. Let the back of the camera be your guide. If the images look too bright, dial back. If too dim, increase exposure or open the lens to a wider aperture.

To capture the encroaching shadow during partial phases you'll need to overexpose the sunlit part of the moon. Details: f/11, 2-second exposure at ISO 400. Credit: Bob King — To capture the encroaching shadow during partial phases you’ll need to overexpose the sunlit part of the moon. Details: f/11, 2-second exposure at ISO 400. Credit: Bob King

While you can continue to shoot the partially eclipsed moon at f/8 from 1/30-1/125 second, you’ll miss the best part – the portion filling up with Earth’s red shadow. To capture that, break out the tripod, open the lens all the way up – f/2.8-f/4 – and expose at ISO 400 between 1/4 and 1 second.

You can also shoot at ISO 800 and cut those times in half, important if you’re using a longish telephoto lens. Remember, Earth’s rotation means the moon’s on the move and will show trailing if you expose longer than a few seconds. On the other hand, this won’t be a problem if you’re shooting with a wide angle lens though they have their limits, too.

The moon completely immersed in Earth's umbra during totality. Details: f/11, 6-second exposure, ISO 400. Credit : Bob King — The moon completely immersed in Earth’s umbra during totality. Details: f/11, 6-second exposure, ISO 400. To prevent trailing I used a motorized mount to track the moon. Credit : Bob King

During totality, expose anywhere from 1/2 to 5 seconds at f/2.8-4.5 at ISO 400. Let’s say you want to include both scenic foreground and stars in the picture using a wide angle or standard lens. Dial up the ISO to 800, open your lens wide and expose between 6-10 seconds. On the 6-second end you’ll catch only the brightest stars, but the moon won’t show trailing; on the longer end you’ll get lots more stars with some overexposure of the eclipsed moon.

Of course, you can go to even higher ISOs and shorten exposure times considerably. But in all but the newest, high-end cameras that comes at the price of increased graininess and less color saturation.

Wide scene from April's total eclipse with Spica below the moon and Mars to the right. Details: 24mm lens at f/2.8, 8-second exposure at ISO 800. The moon was deliberately overexposed to show it in a field of stars. You can vary the exposure to your taste but the shorter it is, the fewer stars. Longer exposures will show trailing. Credit: Bob King — Wide scene from April’s total eclipse with Spica below the moon and Mars to the right. Details: 24mm lens at f/2.8, 8-second exposure at ISO 800. The moon was deliberately overexposed to show it in a field of stars. You can vary the exposure to your taste but the shorter it is, the fewer stars. Longer exposures will show trailing. Credit: Bob King

Where parts of the eclipse happen in twilight, even mobile phones may suffice. There should be enough light to capture a pretty scene with the moon just emerging from total eclipse and during the ensuing partial phases.

The partial lunar eclipse of June 4, 2012, pre-dawn at moonset, from home in southern Alberta. This is a single exposure with the Canon 60Da and 18-200mm Sigma lens at 115mm and at f/5.6 for 0.4 sec at ISO 160. Copyright: Alan Dyer

If you’re clouded out or on the wrong side of the planet for the eclipse, you can catch live webcasts from the following sites:

* Gianluca Masi’s Virtual Telescope
* Griffith Observatory in Los Angeles
* SLOOH

Clear skies!

October 2, 2014December 23, 2015 by David Dickinson

Our Complete Guide to the October 8th “Hunter’s Moon” Total Lunar Eclipse

October 2014 means eclipse season 2 of 2 for the year is upon us.

Don’t fear the ‘Blood Moon’ that’s currently infecting the web, but if you find yourself on the correct moonward facing hemisphere of the planet, do get out and observe the total lunar eclipse coming right up on the morning of Wednesday, October 8^th. This is the second and final total lunar eclipse of 2014, and the second of four in a quartet series of lunar eclipses known as a tetrad.

And the good news is, the eclipse once again favors nearly all of North America. From the western U.S. and Canada, the Moon will be high in the western skies when partial phases begin early in the morning on October 8^th. The western U.S., Canada and Alaska will see the entire 61 minute span of totality, just 18 minutes shorter than last April’s lunar eclipse. The Moon will be high in the sky during totality for the Hawaiian Islands, and viewers in Australia and the Pacific Far East will witness the eclipse in the evening hours.

Visibility — The visibility regions for the total lunar eclipse. Credit: NASA/GSFC/Espenak.

This lunar eclipse is part of saros 127, and marks number 42 of a series of 72 for that particular saros. If you witnessed the total lunar eclipse visible from North America and Europe on September 27^th, 1996, you caught the last of the series, and if you catch the next eclipse in the saros on October 18^th, 2032, you’ve earned a veteran lunar eclipse-watchers badge of seeing an exeligmos, or “triple saros” of eclipses.

The path of the Moon through the Earth’s umbra on October 8th. Adapted from NASA/GFSC.

Timings for key phases of the eclipse are as follows:

P1- Penumbral phase begins: 8:14 UT/4:14 EDT/1:14 PDT

U1- Umbral (partial) phase begins: 9:15 UT/5:14 EDT/2:14 PDT

U2- Totality begins: 10:24 UT/6:24 EDT/3:24 PDT

Mid-totality- 10:55 UT/6:55 EDT/3:55 PDT

U3- Totality ends: 11:25 UT/7:25 EDT/4:25 PDT

U4- Umbral phase ends: 12:35 UT/5:35 PDT

P4- Penumbral phase ends: 13:35/6:35 PDT

Not all total lunar eclipses are the same when it comes to color. Totality can appear anywhere from a dark brick color, as happened during the December 9^th, 1992, eclipse following the eruption of Mount Pinatubo, when the Moon nearly disappeared during totality, to a bright coppery red, as seen during the April eclipse earlier this year. The Moon passes to the north of the dark central core of the Earth’ shadow next Wednesday, so expect a brighter than normal eclipse, especially along the Moon’s northeast limb. Grab a painter’s wheel and compare the eclipsed Moon to swatches of orange through red: what colors do you see? What you’re seeing is the combinations of all the world’s sunsets refracted into the cone of the Earth’s shadow, which is about three times the size of the Moon at its average distance as seen from Earth. Remember, the Moon is experiencing a total solar eclipse as we watch the lunar eclipse unfold!

The October 8th total solar eclipse as seen from the Apollo 11 landing site on the nearside of the Moon. Created using Stellarium.

This color can be quantified and described on what is known as the Danjon Scale, with 0 being a very dark eclipse with the Moon barely visible, to a 4, meaning a very bright eclipse.

And yes, each total lunar eclipse is now receiving the “Blood Moon” meme thanks to ye ole Internet. Expect the conspiracy-minded to note that this eclipse occurs on the Jewish holiday of Sukkot starting at sundown on the 8th, which isn’t really all that wondrous as the Jewish calendar is a luni-solar one, and total lunar eclipses have to occur during a Full Moon by definition. Wait long enough, and an occasional “Sukkot total lunar eclipse” does indeed occur.

Uranus occultation — The footprint of the October 8th occultation of Uranus by the Moon during totality. (Credit: Occult 4.1.0).

But a truly rare event does occur during this eclipse, as the Moon actually occults (passes in front of) the planet Uranus during totality for observers in northern Alaska and northeast Asia. The rest of us in the observing zone will see a near miss. Can you spy Uranus with binoculars near the lunar limb during totality? Another such rarity occurred during Shakespeare’s time on December 30^th, 1591, involving Saturn and the eclipsed Moon, and another such odd occurrence transpires in 2344 A.D.

The circumstances of the 2344 eclipse/occultation. Credit: Starry Night, NASA/GSFC & Occult 4.0.1.

The brightest star to be occulted by the total eclipsed Moon as it crosses the constellation Pisces is +7.9^th magnitude HIP 4231 for the northern U.S. and Canada.

And speaking of historical eclipses, there’s a Columbus Day tie-in with the phenomenon as well. Like many mariners of his day, Columbus was well-versed in celestial navigation, and used a total lunar eclipse to get a good one-time fix on his longitude at sea, an experiment that you can easily replicate. Columbus also wasn’t above using prior knowledge of an impending lunar eclipse to get himself and his crew out of a bind with the locals when the need arose.

An outstanding sequence of images taken during the April 15th, 2014 total lunar eclipse. Credit: Michael Zeiler (Eclipse-Maps) Used with permission. — An outstanding sequence of images taken during the April 15th, 2014, total lunar eclipse. Credit: Michael Zeiler (Eclipse-Maps) Used with permission.

Photographing an eclipse with a DSLR is as easy as shooting an image of the Moon. Try this a few evenings before the big event. A minimum focal length of 200mm is needed to render the Moon larger than a white dot in the image, and remember that the Moon is much darker during total eclipse, and you’ll need to step the exposure times rapidly down from 1/100^th of a second to 2 to 4 seconds during totality.

A long-running effort by Sky & Telescope has been looking for amateur observations of precise crater contacts along the rim of the umbra in an effort to measure variations in the diameter of the Earth’s shadow.

starry night — The Moon versus Uranus as seen from Napa, California just past mid-eclipse on the morning of October 8th. Credit: Starry Night Education Software.

As always, weather prospects are the big question mark when it comes to eclipses. Typically, the southwestern U.S. experiences 13-20 clear days in the month of October; prospects worsen to the northwest, with an average of 3-12 days. We’ll be looking at resources such as NOAA, Skippy Sky and ClearSkyChart on the evenings leading up to the 8^th. The great thing about a lunar eclipse is, you don’t need a 100% clear sky to see it: just a clear view of the Moon!

Up for a challenge? We’ve yet to see a capture of a shadow transit of the International Space Station in front of the eclipsed Moon. This time around, such a capture should be possible across southern coastal California and the Baja peninsula just minutes prior to the onset of totality.

A shadow pass of the International Space Station just prior to the onset of totality. Note the position of the Moon. Created using Orbitron.

Another bizarre catch, known as a selenelion — witnessing the end of lunar totality after sunrise — may just be possible across the northeastern U.S. into the Canadian Maritimes as the eclipsed Moon sets during totality. The more elevation you can get the better! This works because the Moon lingers a bit in the large shadow of the Earth, plus atmospheric refraction gives the low altitude Sun and Moon a slight boost.

Clouded out? On the wrong side of the planet? You can watch the eclipse online at the following links:

– Live views courtesy of Gialuca Masi and the Virtual Telescope starting at 10:00 UT on October 8th.

– A live webcast starting at 9:00 UT courtesy of Slooh:

– A Columbia State University broadcast, (time to be determined).

Planning an ad-hoc broadcast? Let us know!

And as the eclipse wraps up, the biggest question is always: When’s the next one? Well, lunar eclipse number three of the four eclipse tetrad occurs next year on April 4^th, 2015… but in just two weeks time, the western United States and Canada will also witness a fine partial solar eclipse on Oct 23^rd…

Stay tuned!

Got images of the total lunar eclipse? Send ‘em in to Universe Today’s Flickr forum!

Interested in eclipse sci-fi? Check out our latest short stories Exeligmos and Shadowfall.

September 29, 2014December 23, 2015 by Bob King

PanSTARRS K1, the Comet that Keeps Going and Going and Going

Comet C/2012 K1 PANSTARRS photographed on September 26, 2014 by Rolando Ligustri. Like most comets, we see two tails. K1's dust tails points off to the left, it's gas or ion tail to the right. Credit: Rolando Ligustri

Thank you K1 PanSTARRS for hanging in there! Some comets crumble and fade away. Others linger a few months and move on. But after looping across the night sky for more than a year, this one is nowhere near quitting. Matter of fact, the best is yet to come.

This new visitor from the Oort Cloud making its first passage through the inner solar system, C/2012 K1 was discovered in May 2012 by the Pan-STARRS 1 survey telescope atop Mt. Haleakala in Hawaii at magnitude 19.7. Faint! On its the inbound journey from the Oort Cloud, C/2012 K1 approached with an orbit estimated in the millions of years. Perturbed by its interactions with the planets, its new orbit has been reduced to a mere ~400,000 years. That makes the many observing opportunities PanSTARRS K1 has provided that much more appreciated. No one alive now will ever see the comet again once this performance is over.

Comet C/2012 K1 PanSTARRS' changing appearance over the past year. Credit upper left clockwise: Carl Hergenrother, Damian Peach, Chris Schur and Rolando Ligustri — Comet C/2012 K1 PanSTARRS’ changing appearance over the past year. Credit upper left clockwise: Carl Hergenrother, Damian Peach, Chris Schur and Rolando Ligustri

Many amateur astronomers first picked up the comet’s trail in the spring of 2013 when it had brightened to around magnitude 13.5. My observing notes from June 2, 2013, read:

“Very small, about 20 arc seconds in diameter. Pretty faint at ~13.5 and moderately condensed but not too difficult at 142x . Well placed in Hercules.” Let’s just say it was a faint, fuzzy blob.

K1 PanSTARRS slowly brightened in Serpens last fall until it was lost in evening twilight. Come January this year it returned to the morning sky a little closer to Earth and Sun and a magnitude brighter. As winter snow gave way to frogs and flowers, the comet rocketed across Corona Borealis, Bootes and Ursa Major. Its fat, well-condensed coma towed a pair of tails and grew bright enough to spot in binoculars at magnitude 8.5 in late May.

Skywatchers can find C/2012 K1 PanSTARRS in the morning just in Hydra-Puppis just before dawn. The map shows its location daily with stars to magnitude 8.5. The numbers next to some stars are standard Flamsteed atllas catalog numbers. Source: Chris Marriott's SkyMap — Skywatchers can find C/2012 K1 PanSTARRS in the morning sky in the Hydra and Puppis just before dawn when it’s highest in the southeastern sky. The map shows its location daily with stars to magnitude 8.5. The numbers next to some stars are standard Flamsteed atlas catalog numbers. Click for a larger version. Source: Chris Marriott’s SkyMap

By July, it hid away in the solar glare a second time only to come back swinging in September’s pre-dawn sky. Now in the constellation Hydra and even closer to Earth, C/2012 K1 has further brightened to magnitude 7.5. Though low in the southeast at dawn, I was pleasantly surprised to see it several mornings ago. Through my 15-inch (37-cm) reflector at 64x I saw a fluffy, bright coma punctuated by a brighter, not-quite-stellar nucleus and a faint tail extending 1/4º to the northeast.

Mid-northern observers can watch the comet’s antics through mid-October. From then on, K1 will only be accessible from the far southern U.S. and points south as it makes the rounds of Pictor, Dorado and Horologium. After all this time you might think the comet is ready to depart Earth’s vicinity. Not even. C/2012 K1 will finally make its closest approach to our planet on Halloween (88.6 million miles – 143 million km) when it could easily shine at magnitude 6.5, making it very nearly a naked-eye comet.

PanSTARRS K1’s not giving up anytime soon. Southern skywatchers will keep it in view through the spring of 2015 before it returns to the deep chill from whence it came. After delighting skywatchers for nearly two years, it’ll be hard to let this one go.

September 24, 2014December 23, 2015 by Dan Majaess

A Splash of Color Across the Supermoon

Color variations observed a day after the supermoon are indicative of compositional differences over the Lunar surface (image credit: Noel Carboni).

A software engineer from Florida recently captured an image of the day-old supermoon in September that clearly conveys color variations across its surface. Such variations are often imperceptible, but the brightness and color differences were digitally enhanced to make them easier to discern. The color variations are indicative of compositional differences across the Lunar surface (e.g., iron content and impact ejecta).

A supermoon is a full Moon that is observed during the satellite’s closest approach to Earth. The Moon’s orbit is described by a marginally elongated ellipse rather than a circle, and hence the Moon’s distance from Earth is not constant. The Moon will achieve its largest apparent diameter in the Sky during that closest approach, which in part gives rise to the supermoon designation.

Noel Carboni, who imaged the supermoon a day after the full phase, told Universe Today that he, “created the image using 17 frames shot with a Canon EOS-40D, which was mounted to a 10-inch Meade telescope.” He added that, “each exposure was 1/40th of a second, and a workstation was used to stitch the image which is more than 17,000 pixels square.”

Carboni noted that, “Ever since the 1980s, I have harbored a growing interest in digital imaging. It is exciting that nowadays affordable and high quality image capture equipment are available to consumers, and that formidable digital image processing tools are available to just plain folks!”

His astrophotography may be well known to readers of Universe Today, as his work has been featured on NASA’s Astronomy Picture of the Day (APOD) and elsewhere. A gallery of Carboni’s astrophotography can be viewed at his webpage.

Readers desiring to learn more about the Moon and its surface can join the Moon Zoo Citizen Science Project, and glance at images from NASA’s Lunar Reconnaissance Orbiter. The Moon Zoo project aims to inspect millions of images captured by that instrument, which will invariably help scientists advance our understanding of the Moon.

September 23, 2014December 23, 2015 by David Dickinson

A Triple Occultation Bonanza: A Challenging Series of Occultations This Weekend and More

The 1st Quarter Moon occults Saturn during the last event in the series on August 5th, 2015. Sequence courtesy of Teale Britstra.

Got clear skies? This week’s equinox means the return of astronomical Fall for northern hemisphere observers and a slow but steady return of longer nights afterwards. And as the Moon returns to the evening skies, all eyes turn to the astronomical action transpiring low to the southwest at dusk.

Three planets and two “occasional” planets lie along the Moon’s apparent path this coming weekend: Mars, Saturn, Mercury and the tiny worldlets of 4 Vesta and 1 Ceres. Discovered in the early 19^th century, Ceres and Vesta enjoyed planetary status initially before being relegated to the realm of the asteroids, only to make a brief comeback in 2006 before once again being purged along with Pluto to dwarf planet status.

The Moon approaches Saturn on the evening of September 28th as seen from latitude 30 degrees north. Credit: Stellarium.

On Sunday September 28^th, the four day old Moon will actually occult (pass in front of) Saturn, Ceres, and Vesta in quick succession. The Saturn occultation is part of a series of 12 in an ongoing cycle. This particular occultation is best for Hawaiian-based observers on the evening of September 28^th. Astute observers will recall that Ceres and Vesta fit in the same 15’ field of view earlier this summer. Both are now over six degrees apart and slowly widening. Unfortunately, there is no location worldwide where it’s possible to see all (or two) of these objects occulted simultaneously. The best spots for catching the occultations of +7.8 magnitude Vesta and +9.0 magnitude Ceres are from the Horn of Africa and just off of the Chilean coast of South America, respectively. The rest of us will see a close but photogenic conjunction of the trio and the Moon. To our knowledge, an occultation of Ceres or Vesta by the dark limb of the Moon has yet to be recorded. Vesta also reaches perihelion this week on September 23^rd at 4:00 UT, about 2.2 astronomical units from the Sun and 2.6 A.U.s from Earth.

4 Vesta and 1 Ceres share the same field of view this past summer. Credit: Andrew Symes @FailedProtostar.

The reappearance of the Moon in the evening skies is also a great time to try your hand (or eyes) at the fine visual athletic sport of waxing crescent moon-spotting. The Moon passes New phase marking the start of lunation 1135 on Wednesday, September 24^th at 6:12 UT/2:12 AM EDT. First sighting opportunities will occur over the South Pacific on the same evening, with worldwide opportunities to spy the razor-thin Moon low to the west the following night. Aim your binoculars at the Moon and sweep about three degrees to the south, and you’ll spy Mercury and the bright star Spica just over a degree apart.

This week’s New Moon is also notable for marking the celebration of Rosh Hashanah, and the beginning of the Jewish year 5775 A.M. at sundown on Wednesday. The Jewish calendar is a hybrid luni-solar one, and inserted an embolismic or intercalculary month earlier this spring to stay in sync with the solar year.

Occult 4.0 — The occultation footprint of Saturn. The dashed line denotes where the event occurs in the daytime, while the solid line marks where it can be seen after sunset. Created using Occult 4.1.0.

The Moon also visits Mars and Antares on September 29^th. The ruddy pair sits just three degrees apart on the 28^th, making an interesting study in contrast. Which one looks “redder” to you? Antares was actually named by the Greeks to refer to it as the “equal to,” “pseudo,” or “anti-Mars…” Mars can take on anything from a yellowish to pumpkin orange appearance, depending on the current amount of dust suspended in its atmosphere. The action around Mars is also heating up, as NASA’s MAVEN spacecraft just arrived in orbit around the Red Planet and India’s Mars Orbiter is set to join it this week… and all as Comet A1 Siding Spring makes a close pass on October 19^th!

And speaking of spacecraft, another news maker is photo-bombing the dusk scene, although of course it’s much too faint to see. NASA’s Dawn mission is en route to enter orbit around Ceres in early 2015, and currently lies near R.A. 15h 02’ and declination -14 37’, just over a degree from Ceres as seen from Earth. The Moon will briefly “occult” the Dawn spacecraft as well on September 28^th.

Credit: Starry Night — Crowded skies: the Moon approaching Saturn, 4 Vesta, 1 Ceres and the Dawn spacecraft on the 28th. The red arrow shows the direction of the Moon. Created using Starry Night Education Software.

Be sure to keep an eye out for Earthshine on the dark limb of the Moon as our natural neighbor in space waxes from crescent to First Quarter. What you’re seeing is the reflection of sunlight from the gibbous Earth illuminating the lunar plains on the nighttime side of the Moon. This effect gives the Moon a dramatic 3D appearance and can vary depending on the amount of cloud and snow cover currently facing the Moon.

Such a close trio of conjunctions raises the question: when was the last time the Moon covered two or more planets at once? Well, on April 23^rd 1998, the Moon actually occulted Venus and Jupiter at the same time, although you had to journey to Ascension Island to witness it!

Such bizarre conjunctions are extremely rare. You need a close pairing of less than half a degree for two bright objects to be covered by the Moon at the same time. And often, such conjunctions occur too close to the Sun for observation. A great consequence of such passages, however, is that it can result in a “smiley-face” conjunction, such as the one that occurs on October 15^th, 2036:

Such an occurrence lends credence to a certain sense of cosmic irony in the universe.

And be sure to keep an eye on the Moon, as eclipse season 2 of 2 for 2014 kicks off next week, with the second total lunar eclipse of the year visible from North America.

More to come!

September 19, 2014December 23, 2015 by Elizabeth Howell

Look Up! The Space Station Must Be The Ultimate Stargazing Location

"I never imagined that flying to space would give me a different view of our entire galaxy," tweeted Expedition 41 astronaut Alexander Gerst from the International Space Station in September 2014. Credit: Alexander Gerst / Twitter

While NASA often speaks about the power of Earth observation from the International Space Station, the picture above from one of the astronauts on board now shows something else — you can get an awesome view of the Milky Way.

With the view unobscured by the atmosphere, the picture from Expedition 41 European astronaut Alexander Gerst shows that his perch on the ISS is pretty amazing. We wonder how it compares to some of the desert or mountaintop observatories here on Earth! And there are astronomical experiments on board, such as this one that may have found dark matter.

Below we’ve handpicked some of the best recent pictures from Gerst and NASA astronaut Reid Wiseman, a crewmate, as they take in the wonder of our planet and the universe.

I love watching #ocean currents. The Bay Bridge Tunnel in #Virginia has noticeable impact. pic.twitter.com/2c7DE3P68k

— Reid Wiseman (@astro_reid) September 17, 2014

This is where they produced the liquid oxygen for our #Soyuz rocket. @astro_reid #Exp41 pic.twitter.com/aC3a0wyxeA

— Alexander Gerst (@Astro_Alex) September 19, 2014

#Edouard – Perhaps the most perfectly shaped #hurricane ever created by nature. pic.twitter.com/PME51rDqkR

— Reid Wiseman (@astro_reid) September 17, 2014

I had no luck in spotting Kilimanjaro, but this view of East #Africa is pretty spectacular, too! #BlueDot pic.twitter.com/EbcBajShrH

— Alexander Gerst (@Astro_Alex) September 18, 2014

Almost all of #Japan at dawn. pic.twitter.com/zqrfEMcEyp

— Reid Wiseman (@astro_reid) September 14, 2014

Sometimes it seems like our planet is a living being itself. If it were, what would it tell us? #BlueDot #aurora pic.twitter.com/SZR1uIipDH

— Alexander Gerst (@Astro_Alex) September 14, 2014

September 16, 2014December 23, 2015 by Elizabeth Howell

Glowing Galaxies Shine Above Trance-Like Telescopic Timelapse

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.

September 15, 2014December 23, 2015 by David Dickinson

Stalking Uranus: A Complete Guide to the 2014 Opposition Season

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.

In 2014, opposition occurs at 21:00 Universal Time (UT)/5:00 PM EDT on October 7^th. 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.

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 23^rd, the last equinox for any would-be “Uranians” occurred on December 16^th, 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... Credit: — 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!

September 12, 2014December 23, 2015 by Bob King

How to Take Great Pictures of the Northern Lights

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 from near Duluth, Minn. US. Photo taken with a high-end digital camera (Canon Eos 1 Mark III) at ISO 800, 30-second exposure. Credit: Bob King — “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 grainy texture. Credit: Bob King — 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, very active aurora. I used my zoom lens at 16mm at f/2.8 and a 15-second exposure at ISO 800. — 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.

My friend Glenn takes a night sky shot silhouetted against the northern lights. Credit: Bob King — 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. An intense aurora on September 12, 2014 in central Maine. Credit: Mike Taylor — 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?”

Have fun and good luck in your photography.

September 12, 2014April 26, 2016 by Bob King

Will Aurora Strike Tonight? Here’s What to Expect

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 index dinged 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 3-hour increments. Credit: NOAA — 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. Credit: NASA — 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. Credit: Guy Sander — 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 around 2:30 p.m. CDT this afternoon September 12 shows a southward expansion into the Scandinavian countries and Russia and Iceland. Where the sky is dark, auroras are typically seen anywhere under or along the edge of the oval. Click for current map. Credit: NOAA — 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". — 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.