Tracking down February’s mystery supermoon – where is it?

This week’s new moon will be unusually close to Earth. Think of it as a ghostly supermoon. As is true for any new moon, it will be too close to the Sun in the daytime sky to see. This illustration shows the moon’s appearance and location if our eyes could somehow make it out through all the daylight. Source: Stellarium

Here comes the supermoon! But wait, doesn’t that only happen around full moon? Well, not always. Every month the moon swings around Earth in its elliptical (oval) orbit. On one side of the ellipse, it’s closest to Earth and on the opposite side, farthest. When it’s at its closest point, called perigee, at the time of full moon, we call it a supermoon.

During the closest supermoons, our satellite can appear up to 30% brighter and 14% larger. Whether anyone can actually see the difference is open to debate simply because there’s no normal-distance moon nearby with which to make a comparison.

No one pays attention to first quarter or crescent supermoons even though the moon can be closest to us at those phases, too. Thanks to incessant media coverage, only full supermoons get coverage. We like full moons for all sorts of reasons. When an extra close one’s in the offing, as happens on Sept. 27 this year, that’s just one more reason to like them.

The moon’s orbit around Earth is an ellipse with the Earth off-center at one the ellipse’s foci. During its 27-day-long orbit, the moon passes through perigee (closest) and apogee (farthest) points. This week’s new moon will be the second closest perigee of the year after the Sept. 27 full moon. Illustration not to scale. Credit: Bob King

Lest crescents and quarters get short shrift I’m here to hawk this month’s supermoon. Full disclosure. Since it occurs during new moon phase on Feb. 18 you won’t see it. No one sees a new moon except when it happens to be eclipsing the Sun. But northern hemisphere skywatchers can spot the moon two days before new and just one day after new this month, and it’ll be nearly as super as on the18th.

Tomorrow morning Feb. 16 the planet Mercury will lie about 9.5° (about one fist held at arm’s length) to the lower left of the thin crescent two days before new moon phase. This map shows the sky facing southeast about 40 minutes before sunrise. Source: Stellarium

What’s more, if you have a good view of the southeast horizon, tomorrow morning’s skinny crescent will lie near the planet Mercury low in the southeastern sky 40 minutes before sunrise. Be sure to carry along a pair of binoculars as Mercury is near “last quarter” phase and not nearly as bright as it can be.

The moon’s average distance is 240,000 miles, but tomorrow morning at 6 a.m. (CST) it will lie just 226,549 miles from Earth. At 1 a.m. Feb. 18 – the time of the invisible supermoon –  it will be 4,723 miles closer. The following day the moon slides out a bit to 222,092 miles en route to a striking double conjunction with Mars and Venus on Friday the 20th.

Even though we won’t see February’s supermoon, our planet will sense the difference. The additional gravitational force exerted by the close moon will make for unusually high tides. High tides occur when the Sun, moon and Earth are all in a line as they during both new moon phase and at full moon.

The moon, still very close to perigee, pops up in the western sky at dusk on Thurs. Feb. 19 well below Venus and Mars, now in close embrace. This map shows the sky about 35-45 minutes after sunset facing west. Source: Stellarium

So tomorrow morning you can catch the moon near Mercury at dawn, and on Thursday the 19th you’ll have the chance to enjoy the delicate grin of a one-day-old crescent in the west at dusk. Finally, on Friday, don’t miss the close conjunction of the moon with Mars and Venus.

Our satellite has a busy schedule this week!

 

Snake-tongued Comet Lovejoy slithers north, slowly fades

Right now Comet Lovejoy’s faint, double-rayed gas tail extends many degrees to the east of the bright coma. Observers using 10×50 and similar binoculars have traced it out to 10° or more. This photo was taken on Jan. 18th. Credit: Chris Schur

Forked tongues allow snakes to smell in stereo – each fork senses slightly different chemicals in the snake’s vicinity and feeds a separate signal to its brain. When combined, they create a complete “picture” of the reptile’s odiferous world. In much the same way, the two ears on opposite sides of our heard allow us to hear the world in rich stereo sound.

Comet Lovejoy’s nucleus is jetting gas and dust just like Comet 67P/Churyumov-Gerasimenko in this photo taken by the Rosetta spacecraft on November 22, 2014 from a distance of 18.6 miles (30 km). The nucleus is deliberately overexposed in order to reveal the faint jets of activity. Credits: A/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

Lovejoy’s forked tail is hardly an operative organ, but it’s sure amazing sight for stereo eyes. Composed principally of carbon monoxide gas, each of the two primary rays is incredibly well-defined. Gases like water vapor, carbon monoxide and carbon dioxide boil off the nucleus as the Sun warms the comet and help create its big blue-green head or coma. As described here before, the solar wind ionizes or electrifies the gases which allows the magnetic fields embedded in the wind to peel back the gases to form a the glowing gas or ion tail.

Comet Lovejoy arcs up into Triangulum the Triangle later this week and continues into Andromeda into Cassiopeia. Northern hemisphere observers are favored, while those in the southern hemisphere will soon see the comet drop below their horizon. This chart shows Lovejoy’s position every 5 days around 7 p.m. (CST). Stars to magnitude +6. Click to enlarge. Created with Chris Marriott’s SkyMap software

I hope you’ve had the chance to see Comet Lovejoy. While the naked eye view isn’t impressive (though always a pleasure to behold any comet without optical aid), binoculars clearly show the faint, smoky tail extending east of the fuzzy head. In a telescope, even a fairly large one like the 15-inch (37-cm) reflector I use, the fainter rays are indistinct, though the forked tongue shows a little more clearly.

With the moon now returning to the evening sky (see below) and the comet starting to fade, it will gradually become more difficult to see with the naked eye. By mid-February, Lovejoy will probably have dimmed to the naked eye limit of around magnitude +6. But if you use binoculars, you’ll be able to follow our feathery friend through full moon and beyond.

The returning thin crescent moon gathers with brilliant Venus and fading Mercury low in the west-southwest sky during twilight this evening January 21st. This map shows the sky about 40-50 minutes after sunset. Stellarium

Northern skywatchers are fortunate that the comet continues to move north and ever higher in the sky. By late February it will be circumpolar from many locations and remain visible all night.

You can use the map to help you find Lovejoy as it climbs into Triangulum the Triangle this weekend and from there to Andromeda and Cassiopeia.

Venus and Mercury dance cheek-to-cheek as new year begins

Venus and Mercury shine over the Duluth, Minn. city skyline this evening December 31st about 40 minutes after sunset. Venus was very easy to spot but Mercury quite tricky with the naked eye. Binoculars showed it easily. In the coming nights, Mercury rises higher and will get easier to see. Credit: Bob King

Hey, hey, what’s this? Another planet creeping up on Venus? Just in time for the new year, speedy Mercury is quickly catching up to the goddess world.

Surreptitious Mercury climbs toward Venus in the next week. Tonight you’ll find the innermost planet 3.5° below and right of Venus. Look for the pair starting 20 minutes to a half-hour after sunset. Venus is about 6° high. Source: Stellarium

Starting tonight you can see both inner planets low in the southwest at dusk starting about 20 minutes after sunset. All you need is an open horizon in that direction. Just to make sure you spot Mercury, carry along a pair of binoculars. Focus first on Venus, then place it at the top of the field of view and look along the bottom for Mercury. The photo above will serve as a guide.

Facing southwest on January 10th, we’ll see Venus and Mercury at their closest, under a degree apart. This map shows the sky about 25 minutes after sunset when the two planets will be about 10° high or about one balled fist held at arm’s length. Source: Stellarium

As 2015 begins, Mercury is heading into a splendid evening apparition, reaching its greatest distance from the Sun on January 14th. With Venus as helper planet, this will be one of the best times in the new year to find furtive Mercury.

For six nights starting on the 8th, the two planets will dance cheek-to-cheek only 1° or less apart. Their tightest separation, when they’ll be just 2/3° apart, occurs on January 10th. Great sights lie ahead!

 

Wanna name a crater on Mercury? Find out how

Artist’s view of the MESSENGER spacecraft flying over Mercury’s surface displayed in enhanced color. The crater ringed by bright orange is 42-mile-diameter Calvino crater. Click to enter the contest. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington

NASA’s orbiting MESSENGER spacecraft has snapped more than 250,000 photos since plunking into orbit around Mercury in 2011. The solar system’s innermost planet’s ancient surface is Swiss-cheesy with craters of all sizes, all named – according to convention – after deceased artists, musicians, painters, and authors who have made outstanding contributions to their field.

Mercury is a small, crater-rich planet that resembles the Moon. At center is the 129-mile-diameter Copland crater, named after American composer Aaron Copland. Credit: NASA

Hellacious holes bear the names of Beethoven, John Lennon, Anton Chekhov and even the ancient Greek poet Homer. Wouldn’t you like to put your mark on one? The MESSENGER Education and Public Outreach Team is holding a competition to name five impact craters on Mercury. As per International Astronomical Union (IAU) rules, they must be named after named after an artist, composer, or writer who was famous for more than 50 years and has been dead for more than three years. Nor should the name have any political, religious or military significance.

Crater A lies near the center of an area called the “Northern Rise”, a volcanic region that was uplifted long ago. No crater on the Rise has yet to be named. Naming this one would help communicate new findings about the area. Credit: NASA

You have until 5:59 p.m. (23:59 UT) January 15th to complete the entry form and submit it online. You can send in as many entries as you like, but before you go crazy, don’t forget to check your choice against the current, approved list of solar system features. It’s the only way to know whether your proposed name is unique or has already been assigned. Just type it in the search box in the upper right corner.

Not to scare you, but there are presently over 18,000 named craters on Mercury. A tiny number really, compared to all the artists that have stirred our emotions across the history of civilization, so have at it!

Wikipedia’s OK for looking up potential choices but won’t be accepted as a source. For that you’ll need something more definitive like a biography, magazine article, book or encyclopedia. The IAU provides this list of references you’ll find most helpful.

A type of cliff called a scarp cuts through unnamed Crater C. Scarps formed on Mercury as the planet cooled and its crust shrunk and wrinkled like a grape that dries to become a raisin. Yellow-orange volcanic deposits are also seen. By studying this crater scientists can learn about how Mercury formed and the origin of its volcanic landscapes. Credit: NASA

All entries will be reviewed by MESSENGER team representatives and expert panels.15 finalist names will be submitted to the IAU for selection of the five winners. Winning submissions will be announced by the IAU to coincide with MESSENGER’s End of Mission Operations in late March/April 2015.

Naming things is important. As scientists study the tsunami of data returned by MESSENGER, it becomes important to give names to surface features that are of special scientific interest. Having names for landforms like mountains, craters, and cliffs makes it easier for scientists and others to communicate.The MESSENGER science team has selected five craters of particular geological interest, two of which are shown here.

Good luck in your submissions! If you participate, we’d love to know what names you selected. Please share them via the Comments link below.

Who’d a- thunk it? Mercury May Have Meteor Showers Too

Artist’s concept of Mercury crossing the debris trail of Comet Encke, sparking a recurring meteor shower. New evidence from the MESSENGER mission suggests the planet receives regular doses of Mercurial dust. Credit: NASA’s Goddard Space Flight Center

Of course, of course, it only makes sense. We’re so caught up in watching meteor showers on our own planet, who ever thinks about meteors at Mercury? Or Venus for that matter? This week NASA announced that regular spikes in the amount of calcium in Mercury’s upper atmosphere bespeak a cyclical source. The likely culprit? Comet 2P/Encke.

Like breadcrumbs dropped to mark a path, dust and fragile bits of rock are released through vaporization of a comet’s ice and pushed back by the pressure of sunlight to form a tail. The larger pieces are left behind to fan out along the comet’s orbit. If by good fortune Earth’s orbit happens to intersect the debris trail, we see a shower of meteors in the sky.

This photo, made by NASA’s Spitzer Space Telescope in infrared light, shows Comet Encke’s glowing nucleus/nuclear region and a trail of warm dust and pebbly debris shed by the comet along its orbital path. Credit: NASA

Most recently, the Geminids put on a great show, although their origin lies with the peculiar rock-shedding asteroid 3200 Phaethon.

Comet 109P/Swift-Tuttle brings us the familiar Perseid meteor shower, while 2P/Encke gives rise to several meteor streams – the Southern and Northern Taurids, showers that peak in October and November, and the daytime Beta Taurids in June and July.

Measurements taken by MESSENGER’s Mercury Atmospheric and Surface Composition Spectrometer have revealed seasonal surges of calcium that occurred regularly over the first nine Mercury years (1 year = 88 Earth days) since MESSENGER began orbiting the planet in March 2011. Just as we saw huge spikes in the amounts of metals like magnesium and iron in Mars’ upper atmosphere during Comet’s Siding Spring’s brush with the planet last October, MESSENGER’s instrument detected periodic spikes in the amount of calcium – although with a twist.

A color- enhanced view of Mercury, assembled from images taken at various wavelengths by the cameras on board the MESSENGER spacecraft, shows a cratered composed with a surface composed of a variety of minerals. The circular, orange area near the center-top of the disk is the enormous Caloris impact basin. Credit: NASA / Johns Hopkins University Applied Physics Laboratory / Carnegie Institution of Washington

Mercury’s has only a whiff of an atmosphere, what astronomers term an exosphere, the last thing you could call an atmosphere before encountering the vacuum of space. The shower of small dust particles peppering interplanetary space pass right down to the surface and strike the planet’s rocks, knocking calcium-bearing molecules free from the surface, which are then free to rise to greater heights. This process, called impact vaporization, continually renews the gases in Mercury’s exosphere as interplanetary dust and meteoroids rain down on the planet.

These type of impacts happen all the time, but scientists noticed a pattern in the calcium spikes that pointed to a repeating source. Sounds like a perfect time for a comet to step in. Examination of the handful of comets in orbits that would permit their debris to cross Mercury’s orbit indicated that the likely source of the spikes was Encke.

The Jupiter family of comets were all once long-period objects in the Kuiper the orbits of which were changed to short-period by close passes by Jupiter. The green circle is Jupiter’s orbit, the purple is Earth’s. Notice that when farthest from the Sun, the comets about as far as Jupiter is from the Sun. Credit: Wikipedia with additions by the author

“If our scenario is correct, Mercury is a giant dust collector,” said Joseph Hahn, a planetary dynamist in the Austin, Texas, office of the Space Science Institute and coauthor of the study. “The planet is under steady siege from interplanetary dust and then regularly passes through this other dust storm, which we think is from comet Encke.”

To test their hypothesis, Han and crew created detailed computer simulations and discovered that the MESSENGER were offset from the expected results but in a way that made sense due to changes in Encke’s orbit over time from the gravitational pull of Jupiter and other planets.

Pantheon Fossae – The striking troughs of Mercury’s Pantheon Fossae, the feature that MESSENGER scientists first called “The Spider” when they discovered it. Credit: NASA / Johns Hopkins University Applied Physics Laboratory / Carnegie Institution of Washington

Comets get nudged by planets routinely, especially if they pass near Jupiter, the outer Solar System’s gravitational goliath. Jupiter, with the help of Neptune, has re-worked the orbits of countless bodies that once resided in the distant Kuiper Belt into shorter-period comets that swing around the Sun in 20 years or less. Called the Jupiter-family, there are about 400 known and Encke is one of them with an orbital period of just 3.3 years.

Who knows how many other meteor showers might pepper Mercury in a year, but scientists will be looking for potential signs of them in planet’s atmosphere in the months ahead. While they may not leave bold streaks of light as they do on Earth, they create something almost as amazing – a shower of particles that goes up instead of down.

Mercurial delights / Supernova in spiral galaxy M61 / Jupiter spots

Mercury shines brightly in the east-southeast more than an hour before sunrise this morning November 1. The planet remains well-placed for viewing for the coming 10 days. Credit: Bob King

Scattered thin clouds took nothing away from this morning’s otherwise clear sky. With the Moon waxing from quarter to gibbous phase, the slab of darkness between moonset and dawn gets sliced thinner every day. Starting November 4th the Moon will light the sky all night and not give back the darkness till next weekend. I took advantage of a moonless morning to set up the telescope to view two comets, a brand new supernova in the bright Virgo galaxy M61 and the planet Mercury at dawn.

Around 7 a.m. CDT (6 a.m. CDT) in bright twilight, Spica cleared the treetops about 5 degrees to the lower left of Mercury. Watch in the coming mornings as Spica slides up higher in the sky and Mercury slowly drops horizon-ward. Credit: Bob King

Normally I suggest looking for Mercury around 45 minutes before sunrise when it’s high enough for a good view, but if you have an wide open eastern horizon, go for it earlier. The planet is very bright right now at magnitude -0.6 — brighter than it’s nearest rival, Arcturus (0.0) located three outstretched fists to the upper left of Mercury. I was surprised at how bright and easy it was to see it more than an hour before sunrise.

In the next few mornings, Virgo’s brightest star Spica rises near the planet. Watch them do a do-si-do in the coming days as Spica passes Mercury.

Facing east about 50 minutes before sunrise tomorrow and Monday Nov. 2-3. Mercury will be near Spica and about three outstretched fists to the right and below Arcturus. Source: Stellarium

Gianluca Masi captured this view of the supernova 2014dt (tick marks) in the 9th magnitude barred spiral galaxy M61 in Virgo on Halloween. The galaxy is some 55 million light years from Earth. Credit: Gianluca Masi

Virgo brings more than a bright morning planet. Tucked with the broad “Y” or cup-shaped northern half of the constellation, the bright galaxy M61 glows with a brand new supernova visible in amateur telescopes.

Japanese amateur astronomer Koichi Itagaki discovered the new star on October 29 at magnitude +13.6. A little on the faint side, yes, but it has been slowly brightening. This isn’t the first time we’ve witnessed a supernova explosion in the galaxy. At least two others – 2006in and 2008ov – have been observed. Quite the hotbed!

View looking east just before the start of morning twilight. M61 is located in the big Virgo “Y” about three outstretched fists to the right and above brilliant Arcturus. Source: Stellarium

Enlarged view of Virgo to help you better track down M61. When you find it, the supernova will look like a star inside the galaxy east of the core. Click for a large version. Source: Stellarium

Right now, you’ll need an 8-inch or larger telescope and dark sky to see it. The best time is just before dawn when Virgo is highest in the eastern sky. Through the eyepiece of my 15-inch (37-cm) scope this morning the galaxy glowed big and round with a bright core. Supernova 2014dt was a dim “star” 40 arc seconds east and 7 seconds south of the nucleus. Use the maps above to help you find the galaxy.

This morning’s shadow transit of Jupiter’s largest moon Ganymede (left) and a future transit that will occur on November 8 between 3:35 – 7:12 a.m. CST. The Great Red Spot will also be nicely placed for viewing. Add 1 hour for EST, subtract 1 hour for MST and 2 hours for PST. Source: Meridian

I always save the bright planets for last not only because they provide a refreshingly bright treat after hunting comets and supernovae but also because I don’t want to destroy my night vision. But I got a great surprise when pointing the scope at Jupiter. Plain as could be, there was the shadow of the planet’s largest moon Ganymede silhouetted against the white clouds of the equatorial zone and next to it, Ganymede itself. For a minute it looked like two moons casting shadows on the planet. Compared to its shadow, Ganymede was smaller and gray-toned.

You can catch the next Ganymede shadow transit visible in the western hemisphere on the morning of November 8 from 3:35 to 7:12 a.m. CST. A 3-inch or larger telescope is all it takes to view it.

The sun rises just before 8 a.m. over the Wisconsin shoreline of Lake Superior this morning November 1. Credit: Bob King

What better way to top off a morning of sky watching than with a sunrise? Now maybe I’ll take a nap.

Fleet of foot Mercury appears at dawn

Mercury comes into good view the remainder of October and the first week of November low in the eastern sky during morning twilight. This map shows the sky from the central U.S. (Champaign, Ill. in particular) tomorrow morning October 28 about 40 minutes before sunrise. Also shown is the planet’s orbital path in the sky and the bright star Arcturus, which you can use to help you find the planet. Source: Stellarium

Mercury is the solar system’s hot sports car. Not only is it the smallest planet, but it rips around the Sun once every 88 days, faster than any of the others. That’s 4 revolutions for every one the Earth makes. As you read this, Earth’s toting you around the Sun at 66,600 mph. Mercury’s got the pedal to the metal at nearly106,000 mph.

Now through the early November you have a chance to watch this speed demon in morning twilight. Six times a year the fleet planet reaches greatest elongation from the Sun, when it’s highest above the horizon during twilight and easiest to spot. This season that date is November 1st, but you can look for Mercury anytime now through about Nov. 10th.

Mercury has phases like the Moon because of the changing angle it makes to the Sun as viewed from Earth during its 88-day orbit. The dates show inferior conjunction between Earth and Sun (Oct. 16), greatest western elongation (Nov. 1), superior conjunction (Dec. 8) and greatest eastern elongation (Jan 14) when the planet returns to good evening sky viewing. Credit: Bob King

Unlike the outer planets, which orbit beyond the Earth, Mercury orbits between our planet and the Sun. That’s why it never strays far from the Sun in the sky and only puts in an appearance after sunset at dusk or before sunrise at dawn. Because it’s in such an orbital hurry, we usually only get to see the planet for a couple weeks during each favorable elongation.

Mercury shows phases like the Moon. This is approximately how the planet will appear in the next few mornings. Source: Stellarium

To the eye, Mercury looks like a fairly bright star (magnitude 0 and brightening to -0.7 in the next two weeks), but through a small telescope it shows phases just like the Moon and Venus.

Right now it’s a fat croissant but it will fill out and brighten in the days ahead.

Take advantage of the late morning sunrises in the days before we lose Daylight Saving Time to find Mercury at a reasonable hour (around 6:40-7:15 a.m. from many locations).  Look “one fist” above the eastern horizon about 45 minutes before sunrise.

 

Ever seen a lunar eclipse from Mercury? Me neither … till now


Wednesday’s lunar eclipse photographed by NASA’s MESSENGER spacecraft at Mercury

As millions of us awoke at dawn and trundled outside to watch the total lunar eclipse this week another set of eyes was keeping tabs from afar. 66 million miles away, NASA’s MESSENGER spacecraft turned its camera toward Earth to capture several images of the moon disappearing into our planet’s shadow. Laced together, they make for a brief but fascinating glimpse of planetary bodies in motion.

Two of the still images showing Earth and moon before and during Wednesday morning’s total eclipse. Credit: NASA

The animation was constructed from 31 images taken two minutes apart from 5:18 to 6:18 a.m. EDT. The images start just before the Moon entered the umbra, the darkest part of the Earth’s shadow.

“From Mercury, the Earth and Moon normally appear as if they were two very bright stars,” noted Hari Nair, a planetary scientist at the Johns Hopkins University Applied Physics Laboratory, in Laurel, Md. “During a lunar eclipse, the Moon seems to disappear during its passage through the Earth’s shadow, as shown in the movie.”

MESSENGER photographed Earth and moon on May 6, 2010 from 114 million miles (183 million km) away. Credit: NASA

Because the moon is so much darker than Earth its brightness has been increased 25 times to show its disappearance more clearly. I’ve included another picture of the Earth and moon against the starry backdrop of deep space also photographed by MESSENGER. Sure puts things in perspective. While not as breathtaking as photos of Earth taken by the Apollo astronauts, seeing our tiny home floating in the void effectively communicates how improbable our existence is. Thank goodness life got a grip and kept it. After 3.5 billion years of evolution the double helix has proven itself a force with which to be reckoned.

The 133-mile-wide double ringed crater Vivaldi captured at sunrise. The low sun highlights valleys and chains of secondary impact craters radiating away from it. Credit: NASA

MESSENGER has been in orbit around Mercury since March 2011 studying the chemical composition of the surface, measuring planet’s magnetic field, mapping polar ices and of course taking pictures. Enjoy a few recent ones.

Hollows on the floor of an unnamed crater on Mercury. Hollows may be areas “eaten away” by the ceaseless bombardment of particles in the solar wind. Or they may form when heat from volcanic activity melts away softer rocks. No one knows for sure. Credit: NASA

Come fly with me to Mercury


MESSENGER flies over Mercury. The spacecraft blasted off from Cape Canaveral on August 3, 2004.

To commemorate this week’s 10th anniversary of the launch of NASA’s MESSENGER spacecraft to Mercury, NASA released this amazing video of a flight over the planet’s north polar region. The movie was assembled from 214 images taken once per second by the probe’s narrow-angle camera on June 8, 2014. Enjoy the cratery desolation.

As the photos were snapped, MESSENGER orbited at altitudes ranging from 71 to 102 miles (115 to 165 km), traveling at a speed of 2.3 miles per second relative to the surface.

One of the highest resolution pictures ever taken of Mercury’s surface shows a field of craters only 1.8 miles (3 km) wide photographed on June 11, 2014. MESSENGER will drop down much closer to the planet – only 31 miles – starting August 19. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington

“This view is what a traveler on the MESSENGER spacecraft might see during low-altitude operations in the coming year,” said MESSENGER co-investigator Scott Murchie. “During the final phase of its mission, MESSENGER’s science instruments will use low-altitude operations like this to explore the surface and subsurface of Mercury at unprecedented resolution.”

Mercury is presently too close to the sun to see safely, but on August 2 it lined up in conjunction with Jupiter as seen through the coronagraph (sun-blocking device) on the Solar and Heliospheric Observatory. Credit: NASA/ESA

Mercury orbits closest to the sun of the eight planets, completing one revolution every 88 days. It has virtually no atmosphere and measures only about a thousand miles larger than Earth’s moon.

Daytime surface temperatures there can reach 801°F (427°C). Despite the extreme heat, MESSENGER’s instruments detected water ice in permanently shadowed craters in the planet’s polar regions.

Launched in August 2004, MESSENGER traveled 4.9 billion miles (7.9 billion km) to finally settle into orbit around the speedy planet on March 18, 2011. Its convoluted journey included 15 trips around the Sun and flybys of Earth once, Venus twice, and Mercury three times. All of this was done to slow the craft down so it could enter orbit about the planet. It’s returned more than 240,000 pictures so far, many of which you can browse HERE.

Supermoon fun / Mars-Spica conjunction tonight / Venus visits Mercury at dawn

Passing clouds create a colorful corona around last night’s full moon. Credit: Bob King

The moon coaxed many of us out for a look last night. We had clear if hazy skies in my town which made for a striking display of lunar crepuscular rays. Lunar what? If you’ve ever seen sunbeams poking through clouds in the afternoon or evening, you’re looking at crepuscular rays. Crepuscular comes from the Latin word for ‘twilight’ as the beams are often noticed during early evening hours around sunset.

A delicate display of crepuscular rays radiates across the sky above a cloud-shrouded moon. Credit: Bob King

Bright rays shining through gaps in the clouds alternate with shadows cast by other clouds to form a spreading fan of light and dark columns. The dustier or smokier the air, the more vivid the crepuscular display. Notice how they appear to converge on the moon. This is an optical illusion. The rays are perfectly parallel just like endless rows of beans on a farm that appear to merge together in the distance.

Last night’s supermoon shines back from a mobile phone. I took the picture by holding the phone’s camera lens directly over the eyepiece. Credit: Bob King

Many of us like to take pictures of the moon through a telescope using nothing more than a mobile phone. If you’ve tried this, you know how tricky it is to hold the phone camera in the right spot over the telescope eyepiece. It takes a few tries, but the results can be remarkable. Phones do well on bright celestial object like the planets, moon and sun (with a safe filter). Despite what some ads might tout, phones can’t yet record fainter things like galaxies, nebulae and the like.

Orion Telescopes makes an adaptor to hold a phone securely over the telescope. While it gets mixed reviews, you might want to consider it if you don’t want to invest in a separate camera but would still like to create an album of your own astrophotos.

Mars (top) and Spica last night July 12. The difference in color between the rusty planet and blue-white star was very easy to see. Mars will remain near the star the next few nights but change its position like the hour hand on a clock. Credit: Bob King

I know we’ve all been moonstruck the past few nights, but did you happen to notice how close Mars and Virgo’s brightest star Spica have become? Last night they were separated by only 1.5 degrees; tonight they’ll be in conjunction a squinch closer at 1.3 degrees. Watch for the duo in the southwestern sky near the end of evening twilight.

Mars moves eastward and soon departs Spica en route to its next notable appointment, a conjunction with Saturn on August 25. Have you been up at 5 a.m. lately? Me neither. But my crystal ball a.k.a. Stellarium program tells me that Venus and Mercury are playing tag an hour before sunrise in the eastern sky.

Venus and Mercury shine together low in the northeastern sky during morning twilight the next couple weeks. This map shows the view tomorrow morning 45 minutes before sunrise. Venus will be about 10 degrees (one ‘fist’) high, Mercury half as much. Source: Stellarium

Mercury reached greatest elongation (distance) west of the sun yesterday and now appears about five degrees high in the northeast some 45 minutes before sunrise. Look for it about the same distance below brilliant Venus. This is a good apparition of Mercury, and having Venus nearby makes it easy to spot.

The swiftest-moving planet will hang near the goddess planet for the next two weeks, all the while growing in brightness as its phase fills out from crescent to full.