Don’t miss this Saturday’s Saturn-moon conjunction

The big picture in the southern sky this Saturday morning at dawn shows the moon just a degree below Saturn with Mars at upper right in the south and Venus very low in the southeastern sky. Stellarium

A very nice, close pairing of Saturn and the waning 3rd quarter moon will happen Saturday morning at dawn. With late sunrises still the rule, this should be a very easy event to catch even through a parted window shade.

At closest, the two will be just two moon widths or 1 degree apart. Saturn’s in Libra the Scales, a dim constellation that precedes the brighter, more picturesque Scorpius the Scorpion. You can see part of the scorpion to the lower left of the duo. In particular, look for the bright red supergiant star Antares.

Both Libra and Scorpius are late spring-early summer constellations, visible at nightfall in May when the butterflies fly. It’s thoughts like these that lift our spirits on cold winter nights. I had the same feeling two nights ago when I happened to be out observing around 11:30 p.m. and caught sight of a “new” star flashing in the northeastern sky – Arcturus. If there were ever a vanguard of spring, this star is it. Arcturus creeps higher every frigid night until the snow is gone, the leaves turn out and jackets are shed.

Mobile phone shot of Venus in twilight Monday morning. Credit: Sean Cassidy

While you’re out enjoying Saturday’s conjunction (by the way, Saturday’s named for the Roman god Saturn) stay out a little longer to enjoy the reappearance of Venus low in the southeastern sky about 40 minutes before sunrise. Sean’s photo will help you know what to expect.

The Unsolved Mystery of the Star of Bethlehem

The three Magi depicted in the Hortus Deliciarum by Herrad of Landsberg in 1185 AD. 

We’ll never know for sure what “star” the Magi saw when they set off from Babylon to Jerusalem seeking their newborn king, but that doesn’t stop us from wondering whether it might have had a natural cause. There are many possible explanations, a few of which we’ll explore here.

“For we have seen His star in the East (upon rising) and have come to worship him” reads the biblical account of the Three Wise Men. After meeting with King Herod, they rode south to Bethlehem:

“… and the star they had seen when it rose went ahead of them until it stopped over the place where the child was. When they saw the star, they were overjoyed.”

Precious little more was written about the star. If the Three Kings’ account had only mentioned a constellation or nearby star for reference, we could have narrowed down the possibilities. We do know the Magi’s general direction of travel and the accepted time frame of Christ’s birth between the years 7 and 2 B.C.

Bethlehem is 5.5 miles south of Jerusalem, where the Three Kings met with King Herod sometime around his death in 4 B.C.

We also know that whatever they saw moved from east to south. First visible in the east, the “star” next appeared over Bethlehem, located 5.5 miles (9 km) south of Jerusalem. As the Magi rode from Jerusalem they would have seen the apparition in the southern sky. Let’s now explore the possibilities:

* Meteors
I think we can rule out meteors or their brilliant cousins, fireballs, because they’re too brief a phenomenon, and the Kings saw the apparition on at least two occasions. Meteors also don’t “rise” but streak across the sky from any direction.

* Comets:

Woodcut showing destructive influence of a fourth century comet from Stanilaus Lubienietski’s Theatrum Cometicum (Amsterdam, 1668). Comets in the past were often described as “hanging” over a location much like the ”star” of Bethlehem, but were typically seen as augurs of doom.

Halley’s Comet would have been a bright naked eye sight in Gemini in the east before dawn in late August 12 B.C. and again in the northwestern evening sky in September. A tempting possibility but the time frame is wrong – too early for Christ’s birth.

But another comet recorded in the Book of Han was observed within the correct time frame by Chinese astronomers in 5 B.C.:

“Second year of the Chien-p’ing reign period, second month (5 B.C., March 9-April 6), a suibsing (tailed comet) appeared at Ch’ien-niu for over 70 days.”

The comet first appeared in the constellation Capricornus, which would have been visible in the eastern sky before dawn from the Middle East in early spring. Assuming it came into view just after perihelion (closest approach to the sun), it would have traveled to the west and into the southern sky roughly within the time frame required for the Wise Men to travel from the Babylon to Jerusalem and finally to Bethlehem.

Or the comet could have been seen in the east before perihelion and then crossed over into the west-southwestern evening sky as a brilliant post-perihelion sight. The Bible also mentions “shepherds abiding in the field, keeping watch over their flock by night” at the time of the birth. This points to spring as being the likely season, the same as the comet’s period of visibility.

This almost sounds like an open and shut case except for a niggling detail. Comets were generally seen in ancient cultures as omens of doom and gloom, not bringers of good news like the birth of a new king. Comets scared people because they came out of nowhere and crossed the sky in unpredictable ways. To this day a bright comet’s appearance still stirs fears of impending catastrophe in some.

* Nova or supernova

A bright nova (temporary brightening of a white dwarf in a binary star system as it “feeds” on gas from its companion) or supernova would attract the attention of many. Most remain bright for weeks or months. Credit:

Exploding stars are great candidates because they fit the description of a star, and in the case of a supernova, can appear as brilliant as Jupiter or Venus. That would certainly get the attention of the oriental astrologers, who kept a vigilant eye on the heavens waiting for the ancient prophecy of a “star” in Israel to be fulfilled.

Because of Earth’s revolution around the sun it’s even possible for a “new star” to appear first in one direction and then be visible a couple months later in another, especially if you factor in time of night. Unfortunately there are no records of novas or supernovas by the super-observant Chinese or anyone else occurring during the time frame.

* Conjunctions of bright planets

The western sky at the end of evening twilight on Feb. 25, 6 B.C. would have displayed a striking gathering of the planets Jupiter, Mars and Saturn. All three were within 7 degrees of each other. Created with Chris Marriott’s SkyMap software

Conjunctions occur when two or more bright celestial objects line up closely in the sky. A conjunction of two planets is not that unusual, but a gathering of three is and may have held great symbolic value in ancient times. One such triple conjunction involving Mars, Jupiter and Saturn took place in at dusk in the constellation Pisces on February 25, 6 B.C. Could this have inspired the Magi to begin their westward journey?

On Feb. 20, five days before the symmetrical gathering of planets , a very young evening crescent moon passed through the group. Created with Chris Marriott’s SkyMap software

Five days earlier the three were nearly as close and joined by a young crescent moon, an even more auspicious sight.

Of course there are problems with this scenario. The planets appeared in the western sky and the arrangement and number of planets visible would have changed months later when the kings rode to Bethlehem.

An amazing three conjunctions of Jupiter and Saturn from late May to early December 7 B.C. Created with Chris Marriott’s SkyMap software

A recurring conjunction of Jupiter and Saturn played out between May and December in 7 B.C. when the two planets were separated by just one degree (two full moon diameters) on three occasions in the constellation Pisces. The first close pass took place in the eastern morning sky on May 29; the second on Sept. 30 (southern evening sky) and the final pairing on Dec. 5, also in the southern evening sky.

A bright planet duo over so many months rates as an eye-catcher and the directions fit the bill, but the Magi described the object as a brilliant star, not a pair of stars. Even though a degree is a relatively small distance, it would have been easy to see them as two separate objects.

Venus and Jupiter just 0.6 arc minute apart – merged into one – on June 17, 2 B.C. Created with Chris Marriott’s SkyMap software

That brings us to the dual conjunctions of the two brightest planets of all – Jupiter and Venus – in the eastern sky at dawn from the Middle East on August 12, 3 B.C. and again 10 months later on Jun 17, 2 B.C. On both occasions astrologers would have watched the two planets come so close together they would have briefly merged into one before separating again.

OK, a keen eye might have separated the pair on August 12 when they were 2/5 of a moon diameter (12 arc minutes) apart, but they would have been far too tight on June 17 – just 0.6 arc minutes – for anything but a good pair of binoculars or telescope to split them.

During the first conjunction, the Magi would have seen this brilliant pairing in the eastern sky; on June 17 the following year, they lit up the western sky.

Despite appearing as a solitary brilliant “star”, this conjunction would not have been seen in the southern sky on a journey to Bethlehem but in the west, unless we interpret the direction implied in the Bible passage more broadly.

So what’s your pleasure? My best guesses for the Bethlehem Star are the Chinese comet of 4 B.C. or the pair of Jupiter-Venus conjunctions in 3 and 2 B.C. Or it could have been a succession of events – multiple conjunctions and a comet – that led the Magi to conclude that the prophecy of Christ’s birth would soon be fulfilled.

There’s another possibility – the supernatural. But that takes us outside the realm of science. Either way, the star remains a mystery, since we’ll never know for sure what caught the eye of the Three Wise Men as they scanned the heavens looking for signs of what would come.

For more on the topic, click HERE and HERE.

Jupiter and moon team up for a light show tonight

About 5 degrees will separate Jupiter and moon tonight. The map shows the sky facing east around 10 p.m. local time. Stellarium

Everything’s been Comet ISON lately. Since some of you may not care about comets I appreciate your indulgence. Tonight we have a totally non-comet event that everyone can see – a conjunction of the waning gibbous moon and brilliant Jupiter. No getting up at dawn to look. Just peel the shade back around 10 o’clock and gaze into the eastern sky.

Jupiter on Nov. 16, 2013 with its Great Red Spot. Tonight between 11 p.m. and midnight CST, the spot will be well-placed for viewing in Europe (morning hours) and much of the U.S. and Canada. Add one hour for Eastern time; subtract an hour for Mountain and 2 hours for Pacific. Credit: Damian Peach

BUT … if you do have a telescope, tonight is also ideal for spying Jupiter’s Great Red Spot across much of the U.S. and Canada. The Red Spot, a large high-pressure weather disturbance in the planet’s southern hemisphere, will be nicely-placed for viewing between about 11 p.m. and midnight CST. This year it’s distinctly redder than in previous years and therefore more obvious. Sometimes it’s pale brown or salmon and tricky to see.

Use a magnification of 75x or higher and look for a red oval in the planet’s southern hemisphere. The photo shows the planet the way it looks in a typical telescope with south up and east to the right.

Comet Lovejoy buzzes the Beehive Cluster / Moon, Venus “Christmas” conjunction

Comet Lovejoy, glowing green from fluorescing gases, passes below the Beehive star cluster early this morning. Notice the comet’s short tail pointing up to the west. Details: 200mm telephoto at f/2.8, ISO 800, 70-second exposure. Credit: Bob King

Clouds ruled most of last night but not at 1 a.m. this morning when Comet Lovejoy came up over the trees next to the Beehive Cluster in the constellation Cancer. The comet was very easy to see in 10×50 binoculars as a small, glowing patch alongside the larger spray of stars that make up the cluster.

The moon and Venus in a “triple conjunction” with the big ball on the Christmas tree at Bentleyville Christmas display in downtown Duluth last night. Credit: Bob King

Presently at magnitude 6-6.5, Lovejoy will soon become a naked eye comet for observers with dark skies as it sails northward toward the Big Dipper. I can’t wait. It’s been many months since we’ve had a comet that didn’t require a set of glass eyes to see.

The crescent moon hovers of the LED ball atop the Christmas tree. Credit: Bob King

Do you remember the last bright comet? That would have been L4 PANSTARRS last spring. Many struggled to find it because it was only visible for a short time in bright twilight before setting. Though Lovejoy won’t get nearly as bright, skywatchers can follow it into winter with binoculars and small telescopes.

Did you happen to see Venus and moon at dusk yesterday evening? I caught them shining together over our city’s big Christmas lighting display and couldn’t resist a few photos of this rare “triple conjunction”.

If you’re interested in photographing the moon in twilight, you can do it so long as you can hand-hold your camera at 1/30 – not too tough a task. Compose a scene that includes the moon and start shooting about 30 minutes after sunset, when the twilight glow and moonlight are in balance. Let the camera figure the exposure and check the back replay to see if you’re on the money.

Venus and red supergiant Antares meet at dusk

Brilliant Venus (top) slips by Antares in Scorpius this week. Closest approach occurs tonight Oct. 16. Created with Stellarium

There are only four bright stars that lie near the ecliptic, the path the planets, sun and moon take through the sky – Regulus (Leo), Spica (Virgo), Aldebaran (Taurus) and Antares in Scorpius. This week Venus passes the red star Antares in the evening sky. Closest approach of 1.5 degrees happens tonight.

Twilight may be too bright for skywatchers at mid-northern latitudes to spot Antares with the naked eye. Then again, it may be visible if your sky is very clear. Either way the close conjunction will be easy to see in binoculars. Aim them at Venus between 30 minutes and an hour after sunset and look for a spark of pink light to its lower left.

Venus through a telescope looks a little wider than a half moon this week. This is how it looks in a typical astronomical telescope with south up.

Observers in the tropics and southern hemisphere, where Venus is much higher in the sky, will have the naked eye advantage.

On very rare occasions, Venus can occult or pass directly in front of Antares. This last happened on September 17, 525 B.C. and will happen again November 17, 2400. I’ll take tonight’s pass as the next best thing and imagine the rest.

If you have a small telescope, take a minute and point it at Venus. The planet has been steadily approaching Earth, growing in size and changing its phase (like the moon) over the past few months. This week it looks like a waxing moon a couple days past half.


Comet ISON triple conjunction a thing of beauty

A grand alignment! From left: Comet ISON, Mars and Regulus on Oct. 14. The image has been tipped a quarter turn to the left from the naked eye view. Click to enlarge. Credit: Chris Schur

Chris Schur of Payson, Arizona got up at 4 a.m. Monday to capture a special moment. His photo of Comet ISON in a triple conjunction with the star Regulus and planet Mars is stunning – one of the coolest ISON photos I’ve seen yet.

Let’s take a closer look at what’s going on in the image. Mars is in conjunction with Regulus and also with the comet, the comet’s in conjunction with Mars and Regulus and if you look closely, you’ll notice a little blurry spot immediately to the left of Regulus. That’s the dwarf galaxy Leo I located some 820,000 light years from Earth. We’ll throw that in too and call it a quadruple conjunction. Like a good stew, the alignment contains a diverse assortment of deep space ingredients: comet, planet, star and galaxy.

All three are still bunched up tomorrow morning. This map shows the sky around 5:30 – 6 a.m. local time Oct. 16 or about 1 1/2 to 2 hours before sunrise when they’ll be around 30 degrees high. Regulus and Mars are nearly the same brightness. Created with Stellarium

Chris made the photo shortly before dawn on Oct. 14 using a 3.1-inch (80mm) refracting telescope and Canon XTi set at ISO 800. His exposure time was 10 minutes on a guided mount. The striking color differences between each object are very apparent. ISON glows green from fluorescing cyanogen and diatomic carbon gases; Mars orange from iron oxide in its soil and Regulus, a star 150 times brighter than the sun and a good deal hotter, shines pale blue-white.

Mars and Regulus are now just a day past conjunction and still only about a degree apart. I’ve included a map to help you find them at the start of dawn. See if you can tell their colors apart with the naked eye.

A heads-up for amateurs with telescopes. Tomorrow morning is the last dark, moon-free time to observe Comet ISON from mid-northern latitudes for the next couple weeks. The comet is now about mag. 10-10.5 and should be visible in 6-inch and larger scopes under good conditions.

Venus and the moon – they’re at it again tonight

Venus (upper left) and the crescent moon last night Oct. 7 from downtown Duluth, Minn. Credit: Bob King

Happen to catch the moon and Venus last night? They’re out again tonight in the western sky just after sunset and even closer together. I managed a quick view and photo before work assignments. All the time I had, but it was enough.

We talked about these close moon-Venus pairings called conjunctions yesterday. Last night the two were further apart and nearly parallel to the horizon. Tonight they’ll be closer.

Watch for the moon to line up with Venus this evening Oct. 8. This map shows the sky facing southwest about 20-30 minutes after sunset. Stellarium

I’ve also included the star Antares in the diagram. It’s a bright red supergiant star in the constellation Scorpius the scorpion. Antares shines at first magnitude, bright by stellar standards but much dimmer than the moon or Venus. Depending on the clarity of your sky, you might just glimpse it in mid-late twilight without optical aid. To guarantee a view, take along a pair of binoculars.

Sunday Venus moon conjunction will be a beauty

The moon and Venus pair up tomorrow evening low in the western sky. Start looking about 15 minutes after sunset. Stellarium

Have you seen Venus yet? It’s our only easily visible bright planet in the evening sky. Too bad it sets so soon. Once dusk is done, we’re left with dim Uranus and Neptune until after midnight when Jupiter finally joins the clan. While Saturn is technically an evening planet, it hardly counts. By the time it gets dark enough to see from mid-northern latitudes, it’s close to setting.

Venus is visible low in the west-southwest sky during early evening twilight. Credit: Bob King

Venus is about a fist high in the west-southwest 15 minutes after sunset. You can go out tonight and find the planet shining bright and alone above treeline and hilltop. Tomorrow night Sept. 8 the 3-day thin crescent moon will join Venus in a beautiful, close conjunction. As yellow mellows to red on the western horizon the moon will pass only a couple degrees to the left or east of the planet seen from the Americas. Europeans will see the moon just below Venus.

Venus hangs near the horizon for the remainder of the year, taking its sweet time to climb into better view. On the 17th and 18th Saturn glides above Venus in yet another conjunction. For that you’ll need binoculars, but tomorrow night’s show will require only an open view to the west and a pair of eyes.

Mars and Jupiter team up for a sweet dawn conjunction; Venus meets Regulus

Jupiter (bottom) and Mars this morning at 4:30 a.m. Jupiter was easy to see low in the northeastern sky but Mars was very faint to the eye. Binoculars showed it much better. Details: 130mm telephoto, f/2.8, ISO 400, 1-second. Credit: Bob King

If you like the TV show Dancing with the Stars you can watch a planetary version of the same this week in the dawn sky. While most of us have been sleeping, Mars and Jupiter have been busy climbing from the horizon haze; they’re finally in view again about the time the first birds sing. Watch this week as the two draw ever closer.

Jupiter and Mars will be close tomorrow morning but their separation will shrink to minimum (0.8 degrees) next Monday morning July 22. Both maps show the sky facing northeast at dawn. Maps created with Stellarium

Come July 21-22 the two planets will be in conjunction less than one degree apart, the width of your little finger held up to the sky. Watch for them beginning 90 minutes to an hour before sunrise. I was pleasantly surprised this morning how easy Jupiter was to see with the naked eye. It cleared my local treeline around 4:15 a.m. Mars was considerably fainter than old Jove and took a determined effort to spot. Binoculars gave a great view of both.

European Space Agency astronaut Luca Parmitano uses a digitalcamera during a session of extravehicular activity (EVA) on July 16 as work continues on the space station. Credit: NASA

If you need additional motivation to get up a dawn, the International Space Station is back in a pass-making mood, zipping across the sky from west to east and occasionally cruising by Mars and Jupiter before disappearing over the eastern horizon.

Below are times when it will be visible in Duluth, Minn. and region. For times for your city, click over to Heavens Above or Spaceweather’s Satellite Flybys page and enter your zip code. The ISS looks like a brilliant, unblinking yellow-tinted “star” as it slides from west to east:

* Friday July 19 starting at 4:54 a.m. across the southern sky in morning twilight. Max. altitude: 43 degrees.
* Sat. July 20 at 4:07 a.m. in the south-southeast 28 degrees
* Sun. July 21 at 4:54 a.m. straight across the top of sky 85 deg. Brilliant!
* Mon. July 22 at 4:07 a.m. high in the south 65 deg. Brilliant!
* Tues. July 23 at 3:20 a.m. in the southeast. 41 deg. Second pass at 4:54 a.m. across the north 48 deg.

Watch for Venus and Regulus in conjunction on July 21. The two will be near one another for several evenings around that time. This map shows the sky facing west about and hour after sunset.

Mornings not your thing? Venus and Regulus, the brightest star in Leo the Lion, will pair up for an evening conjunction also on July 21-22. At closest, the planet and star will be a hair more than one degree apart.

All these alignments occur because the planets, which orbit the sun in the flat plane of the solar system, occasionally lie along the same line of sight and appear to almost touch. Sure it’s just a parlor game, but many of us, myself included, look forward to these special shows every time.

How to get to Mars in 1 minute and 7 seconds

Mars photographed with the C2 coronagraph on SOHO (Solar and Heliospheric Observatory) earlier this morning. SOHO uses a disk to block the sun’s light so astronomers can study its atmosphere called the corona. Mars appears next to the sun only because it’s in the same line of sight. The planet’s actually in the distant background. Credit: NASA/ESA

On April 17 the Red Planet and Earth will line up on opposite sides of the sun, an event called solar conjunction. Other than not being able to see Mars because it’s hidden in the solar glare, the event has one real consequence for earthlings. We’ll explore that in a minute. Let’s just say that since the two planets now sit at opposite ends of the seesaw, Mars is about as far away as it gets, winking at Earth across a distance of 225.7 million miles. Compare that to 35 million when we’re closest.

That’s OUT THERE. Even light, traveling at 186,000 miles per second, takes 20 minutes to cross the gulf separating Earth from Mars. That means a 40 minute round trip for radio communications between the Curiosity and Opportunity rovers and mission control.

Screen grab from the “How Far is it to Mars?” site that give you a taste for how far the moon and Mars are from Earth. Click to go there. Credit: David Paliwoda and Jesse Williams

How would you like to get a feel for that distance? Understanding that time is precious, we’ll go easy on you by making the journey when Mars is closest to Earth. Normally it would take about 150 days to travel to the Red Planet using current technology. We’ll arrive quicker by accelerating to 3 times the speed of light. Even at that pace, you might be surprised how long it takes to arrive. Click HERE or on the image above to take the free journey. Bon voyage!

Curiosity drilled two holes in the “John Klein” rock in early February and gathered the powdered tailings to analyze its composition. The holes are each 2/3″ or 16mm across. On March 26, the rover used its powerful ChemCam laser to repeatedly zap the drilled powder, creating a row of tiny pits. The vaporized rock emitted light that was analyzed by Curiosity to determine its makeup. Click to enlarge. Credit: NASA/JPL-Caltech

Let’s return to the consequences of a Mars solar conjunction. As described in this earlier blog, Mars’ close alignment with the sun does affect our ability to communicate with the Opportunity and Curiosity rovers. Signals sent from Earth pass directly along the sun’s line of sight en route to Mars where they could be corrupted by solar radiation storms and electrified particles in the sun’s corona.

Interesting white rocks scattered about where Curiosity is stationed in Yellowknife Bay in Gale Crater. Notice how rounded some of the other pebbles are – possibly from water erosion. Click to enlarge. Credit: NASA/JPL-Caltech

It’s no big deal if bits of information go missing in a transmission from Curiosity, but if a bad command were sent from Earth, it might cause the robot to seize up or do damage to itself. To avoid potential problems, NASA has suspended communications for the remainder of April. Each day, Curiosity sends daily beeps to Earth telling mission control “I’m still here.”

Cool “aerial” view of Mt. Sharp inside Gale Crater (where Curiosity landed) taken by the orbiting Mars Odyssey satellite. The layering in the mountain at upper left may have been made when sediments were deposited by flowing waters. Click to enlarge. Credit: NASA/JPL/ASU