Posted on by David Dickinson

Get Ready for the Fireballs of October

A recent fireball captured over the UK on October

On October 31st 2005, trick-or-treaters across the central U.S. eastern seaboard were treated to a brilliant fireball, a celestial spectacle that frequently graces October skies.

Mid- to late October is fireball season, a time when several key meteor showers experience a broad peak. We’re already seeing an uptick in fireball activity as monitored by numerous all-sky cameras this month, including NASA’s system positioned across the United States. Three lesser known but fascinating showers are the chief culprits.

Credit: NASA
A Bay area fireball captured in 2012. Credit: NASA/Robert P. Moreno Jr.

The main meteor shower on tap for the month of October is the Orionids. This shower radiates from the Club of the constellation Orion, and is the product of that most famous comet of them all, 1P Halley. Halley’s Comet is actually the source of two annual meteor showers, the October Orionids and the May Eta Aquarids. We’re seeing the inward stream of Halley debris in October, and Orionid velocities average a swift 66 kilometres a second. The radiant rides highest for northern hemisphere observers at 4 AM local, and 2014 sees an estimated zenithal hourly rate (ZHR) of 20 predicted to arrive on the mornings of October 21st through the 22nd. The Orionids experience a broad peak spanning October 21st through November 7th, and 2014 sees the peak arrive just two days prior to the Moon reaching New phase. The Orionids have exhibited an uptick in activity as high as 50-75 per hour from 2005-2007, and it’s been suggested that a 12 year peak cycle may govern the Orionids, as the path of meteoroid debris stream is modified by the gravitational influence of the giant planet Jupiter.

Orionid
A recent early Orionid meteor. Credit: Sharin Ahmad @Shahgazer.

Two other nearby radiants in the sky also produce an exceptionally large number of fireballs in late October: the Southern Taurids and Northern Taurids. These are complex streams laid down by the periodic comet 2P Encke, which possesses the shortest orbital period of any comet known at 3.3 years. Though the ZHR for both is only slightly above the background sporadic rate for northern hemisphere Fall at about five per hour, the Taurids also produce a high ratio of fireballs. The southern Taurids peak in early October and are already active, and the Northern Taurids peak in late October through early November, earning them the nickname the “Fireballs of Halloween”. Unlike many meteor showers, the Northern Taurids are approaching the Earth from behind in our orbit and have a slow relative atmospheric entry velocity of 28 kilometres per second. This makes for long, stately meteor trains often visible in the evening hours before local midnight.

Taurid
A 2012 Taurid meteor. Credit: Andrei Juralve.

The Taurids also seem to exhibit a seven year periodicity that begs for further study. 2008 was a fine year for Taurid fireballs… could 2015 be next?

Of course, the exact definition of a “fireball” meteor varies by source, though we prefer the definition of a fireball as a meteor brighter than magnitude -3. A fireball reaching -14 (a Full Moon equals magnitude -13, about 2.5 times fainter) is often termed a bolide.

Halley's orbit
Comet 1P/Halley’s orbital path through the inner solar system. (Credit: NASA/JPL).

Observing meteor showers such as the Orionids is as simple as sitting back and patiently watching the skies. Our own personal rule while starting a meteor vigil is to scan the skies for 10 minutes; one or more meteor sightings is a good sign to keep on watching, while no meteors means it’s time to pack it in and instead maybe write about astronomy. Dark, moonless skies are key, and you can report how many meteors you see to the International Meteor Organization. Be sure to keep a pair of binoculars handy to examine any lingering smoke trails post-fireball passage.

Credit: Stellarium
The positions of the radiants of the Orionids and the Taurids, with peak dates. Credit: Stellarium.

Of course, seeing a Taurid fireball is largely a matter of luck and looking at the right place in the sky at the right time. All-sky cameras work great in this regard, and many amateurs now use tripod mounted DLSRs set to take wide-field exposures of the sky automatically throughout the night. Just watch out for dew! Nearly every meteor we’ve caught on camera turned up only in post review, a testament to how much of the sky a lone pair of eyes still misses.

Spot a fireball? The American Meteor Society maintains a great online database of recent sightings and reports. Keep in mind, lots of “meteor-wrongs” inevitably crop up on Facebook and Twitter during any event, posted by folks eager for likes and retweets. Faves of such spoofers are: the Peekskill meteor train, the reentry of Hyabusa, Mir, and scenes (!) from the movie Armageddon. We’ve seen ‘em all passed off as legit, though you’re more than welcome to try and be original… a majority of initial meteor images almost always come from dash cams (remember Chelyabinsk?) and security cameras.

Finally, in addition to fireballs, there’s another astronomical tie-in for Halloween, as it’s one of four cross-quarter tie-in days approximately mid-way between a solstice and an equinox. The other three are: Lammas Day (August 1st), Groundhog’s Day (February 2nd) and May Day (May 1st). We just think that it’s great — if a bit paradoxical — to see modern day suburbanites dress up as ghouls and goblins as they reenact archaic rites and holidays…

Don’t forget to keep an eye out for the fireballs of October this Halloween!

Posted on by Bob King

How to See Comet Siding Spring as it Encounters Mars

Comet C/2013 A1 Siding Spring passes just north of the sparking Butterfly Cluster on October 9. Credit: Rolando Ligustri

With excitement building as Comet Siding Spring rapidly approaches the Red Planet, we’ll soon have the opportunity to spot it through our own telescopes. Dark skies return this week with the moon now past full and rising later each night. Until recently, the comet could only be seen by skywatchers living in southern latitudes. Now it’s popped high enough above the southern horizon to see from mid-northern latitudes, albeit low in the sky. Observers with 8-inch (20 cm) or larger telescopes can follow the comet as it travels from Scorpius north to Ophiuchus and its encounter with Mars on October 19. 

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JPL Horizons light curve for Comet C/2013 A1 Siding Spring shows it brightening as it approaches Earth and then fading after late September. For our purposes we’re interested in the purple squares which are visual magnitude estimates of the whole comet submitted to the Comet Observation Database. Recently, the comet has faded faster than predictions. Click for more details. Credit: CIOC

Until late September, the comet had been brightening as forecast based on the simple principle that the closer an object is to Earth the brighter it appears in the sky. Siding Spring came just shy of 1 A.U. of Earth in early September and has since been slip-sliding away. All through the first weeks of September it glowed at magnitude +9-10 and could be spotted in small telescopes trekking across the south polar constellations. Now on the cusp of its big moment with Mars, Siding Spring has been fading faster than expected.

It could be running low on exposed ice or concluding a long, slow outburst. Maybe it’s as simple as our changing perspective on the comet’s tail – we see it from the side now instead of looking down the tail where reflective dust piles up along our line of sight. No one knows exactly why, but given that comets are famous for their unpredictability due to their fragile nature and the varying rates at which they sputter away ice and dust, we shouldn’t be too surprised.

The paths of Mars and Comet Siding Spring are clearly on a (near) collision course! Watch over the coming nights as they draw ever closer. Source: Chris Marriott's SkyMap
The paths of Mars and Comet Siding Spring are clearly on a (near) collision course! Watch over the coming nights as they draw ever closer. This map shows the sky facing southwest at nightfall from Kansas City, Missouri. From the central U.S. the comet will be about 13-15º high but only ~5-8º altitude in the northern border states. Source: Chris Marriott’s SkyMap

So what does that mean for observers? The most recent observations put the comet at about magnitude +11 with a loosely condensed coma and diameter of about one arc minute or a little larger than Jupiter appears in a telescope. It’s a small, relatively faint object now but should be visible in 8-inch and larger telescopes from a dark sky assuming it doesn’t “drop off the deep end” and fade even faster.  With Mars nearby, finding the general location of Siding Spring is easy. The maps will help you pinpoint it.

Daily positions of Comet Siding Spring October 10-20 from the central U.S. at nightfall. Stars shown to magnitude +11.5. Closest approach to Mars is October 19. Brighter stars like 3 Sagittarii, 44 and 51 Ophiuchi and Theta Ophiuchi are labeled. Source: Chris Marriott's SkyMap
Daily positions of Comet Siding Spring October 10-20 from the central U.S. at nightfall. Stars shown to magnitude +11.5. Closest approach to Mars is October 19. The brighter stars 3 Sagittarii, 44 and 51 Ophiuchi and Theta Ophiuchi are labeled. Click for large version to print and use at the telescope. Source: Chris Marriott’s SkyMap

The good news is that the comet is heading straight north and getting higher in the sky every night. The bad news is that it’s also dropping westward each evening mostly negating its northerly altitude gains. Those in the southern U.S. will have the best viewing window with Siding Spring 20º high at nightfall (14º in the central states and 6º in the north). To ensure success, find a spot with a wide open view as far down to the southwestern horizon as possible. You’ll make best use of your time and see the comet highest if you set up during evening twilight and begin searching as soon as the sky is dark. Given that Mars is 1st magnitude and the comet has faded more than expected, it may be difficult to see against the planet’s glare on the 19th. Not that I want to dissuade you from trying, but the nights leading up to and after the encounter will prove better for comet spotting.

Need to get in closer yet? This map shows Mars and Comet Siding Spring on five nights closer to its flyby with stars to magnitude +12. Time and location are the same as the map above. Click for larger version. Source: Chris Marriott's SkyMap
Need to get in closer? This more detailed map shows Mars and Comet Siding Spring nightly October 15-20 with stars to magnitude +12. Time and location are the same as the map above. Click for larger version. Source: Chris Marriott’s SkyMap

The fluffball passed the glittery Butterfly Cluster (M6) in Scorpius on October 9 displaying an attractive curved tail pointing southeast. Tim Reyes of Universe Today calculated the current tail length at ~621,000 miles (1 million km) with a coma ~19,900 miles across (32,000 km).  Closest approach occurs around 1:28 p.m. Central Daylight Time (18:28 UT) October 19 when the comet will miss Mars by only 88,000 miles (141,600 km). Dust particles leaving the coma will rip by the planet at ~125,000 mph (56 km/sec). Will they pass close enough to set the Martian sky a-sparkle with meteors?

Not only will the Mars orbiters gather information about the comet and its dust before, during and after the encounter, a fleet of additional telescopes will be making the most of the rare opportunity. Credit: NASA
Not only will the Mars orbiters gather information about the comet and its dust before, during and after the encounter, a fleet of additional telescopes will make the most of the rare opportunity. Credit: NASA

According to a recent NASA press release, the period of greatest risk to orbiting spacecraft will start about 90 minutes after the closest approach of the comet’s nucleus and will last about 20 minutes, when Mars will come closest to the center of the widening trail of dust flying from the comet’s nucleus. Since the comet will barely graze the planet, dust impacts on orbiting spacecraft may or may not happen.

Back on Earth we can watch the daredevil pass by telescope or catch it live on the Web here:

* SLOOH:  broadcast begins Sunday Oct. 19 at 9:51 a.m. CDT (14:51 UT)

* Gianluca Masi’s Virtual Telescope:  streaming begins Sunday, Oct. 19 at 11:45 a.m. CDT (16:45 UT)

Posted on 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
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
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
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
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!

Posted on by David Dickinson

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

Photo by author

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 8th. 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 8th. 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 27th, 1996, you caught the last of the series, and if you catch the next eclipse in the saros on October 18th, 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 9th, 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!

Stellarium
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 30th, 1591, involving Saturn and the eclipsed Moon, and another such odd occurrence transpires in 2344 A.D.

2344 eclipse
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 +7.9th 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 1/100th 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 8th. 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.

Orbitron
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 4th, 2015… but in just two weeks time, the western United States and Canada will also witness a fine partial solar eclipse on Oct 23rd…

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.

Posted on 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.

Posted on 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.

Posted on 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 19th 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.

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

On Sunday September 28th, 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 28th. 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 23rd at 4:00 UT, about 2.2 astronomical units from the Sun and 2.6 A.U.s from Earth.

Credit: Andrew Symes
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 24th 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 29th. The ruddy pair sits just three degrees apart on the 28th, 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 19th!

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 28th.

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 23rd 1998, the Moon actually occulted Venus and Jupiter at the same time, although you had to journey to Ascension Island to witness it!

Credit: Stellarium
The waning crescent Moon approaches Jupiter and Venus on April 23rd, 1998. Credit: Stellarium.

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 15th, 2036:

Credit: Starry Night.
Smile: A close pass of the Moon, Saturn, and Regulus in 2036. Credit: Stellarium.

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!

Posted on 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.

Posted on 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.

Posted on 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.

Stellarium
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.

Credit:
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.

Credit:
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.
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.

Credit: Ed Kotapish
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!