Re-awakened NASA probe discovers first new comet

Comet NEOWISE discovered by the re-activated NEOWISE probe on Feb. 14, 2014. The telescope searches for asteroids and comets by examining the heat they give off as infrared light. Credit: NASA

Great bit of news. NASA’s recently re-awakened Near-Earth Object Wide-field Infrared Survey Explorer (NEOWISE) rubbed the sleep from its eyes and promptly discovered a new comet. The Earth-orbiting telescope snagged C/2014 C3 (NEOWISE) on Valentine’s Day when it was about 143 million miles (230 million km) from Earth. Although the comet’s orbit isn’t precisely determined, it appears to originate from the realm of the distant planets Uranus and Neptune.

Originally called the Wide-field Infrared Survey Explorer (WISE), its primary mission wrapped up in 2011 after two very successful years. WISE performed an all-sky survey in infrared light (heat) that uncovered tens of thousands of new asteroids, luminous, star-burst galaxies and dim brown dwarfs. Along the way it also added 21 new comets to its booty.

Our eyes can’t see infrared, but we sense it as heat. The probe’s 15.7-inch (0.4-m) telescope is optimized for just that very slice of the spectrum. Infrared light penetrates dust clouds revealing what’s inside (newborn stars for instance) and can see otherwise faint, dark asteroids by the heat they radiate into space.

Two years later in September 2013 WISE was taken out of hibernation and re-activated as NEOWISE to assist NASA’s efforts to identify the population of potentially hazardous near-Earth objects. It will also study previously known asteroids and comets to better understand their sizes and compositions.

Comet Lovejoy on Feb. 28, 2014. Credit: Rolando Ligustri

Wondering what’s going on with comets you and I might see in our telescopes? Comet ISON has long gone to comet heaven. And three other bright comets – Lovejoy, Encke and C/2012 X1 LINEAR – that kept us from our sleep so many nights have either faded from view or lost their luster. Morning skywatchers using 6-inch or larger telescopes can still follow Lovejoy and  X1 LINEAR, both glowing around magnitude 9, but it’s slim pickings otherwise.

Sit tight. Come late summer we’ll have several nice binocular comets from which to choose.


Jupiter meets the moon / Two comets pass in the night / Space station at dusk

A 22-degree halo, formed by light refracting through the faces of hexagonal ice crystals in cirrostratus clouds, reaches almost to Jupiter (lower left) last night Feb. 8. Credit: Bob King

The moving moon keeps things interesting on a very human time scale, gliding about one outstretched fist to the east every night. Last night ice-crystally clouds made a beautiful lunar halo that nearly but not quite touched Jupiter.

The moon will lie about a bit more than a fist to Jupiter’s right tonight and below it tomorrow night. Stellarium

Tonight the moon will lie to the right of the brilliant planet, while on Monday the two will be in conjunction with the waxing gibbous moon floating just below. It’s fun to watch the moon’s travels across the sky. Because of its 5.1 degree tilted orbit, the moon follows a slightly different track through the zodiac constellations each month in a cycle lasting 18.6 years. Planets move, stars drift westward with the seasons – taken all together, the moon makes repeated visits in ever-different arrangements with the bright stars and planets it passes every month.

This wide view shows much of the sky facing south about 90 minutes before sunrise. In addition to the bright planets, two bright stars – Antares in Scorpius and Spica in Virgo – join the scene. Stellarium

Yesterday morning was clear and I went out to look at comets and planets. How convenient that the morning planets are arrayed across the southern sky, so that one might begin on one end with Mars and finish up with Venus.

Like a kid, I started with the eye-candy planet Saturn first, then jumped over to the Venusian crescent and finally hit Mars as the sky was turning blue. What a lineup – wonderful opportunities to meet our planetary neighbors as long as you’re dressed for the weather.

Comets C/2012 X1 LINEAR (top) and C/2013 R1 Lovejoy appear to be chasing each other in this photo taken with a wide field 4-inch telescope before dawn Feb. 8, 2014. They were about 2.5 degrees apart at the time. Credit: Damian Peach

Comets C/2013 R1 Lovejoy at magnitude 8 and C/2012 X1 LINEAR at 9 still shine brightly enough to show in 6-inch and larger telescopes. Both are in the constellation Ophiuchus and well-placed for observation in the eastern sky just before the start of dawn. On Feb. 6 they were in conjunction only 2 degrees apart – a rare event. Despite appearances, the two comets are unrelated and many millions of miles apart.

Although they’re slowly parting, both are still within 3 degrees of each other, making it fun to drop in on both of them with a telescope. UK astrophotographer Damian Peach captured a wonderful image of the pair on Feb. 8. For finder maps and more information on Lovejoy and XI LINEAR, click HERE.

From aboard the International Space Station, astronaut Rick Mastracchio tweeted this view of Sochi, Russia, the site of the XXII Winter Olympic Games. Credit: NASA

Out at dusk these February evenings? The International Space Station (ISS) is making passes at us just in time for Valentine’s Day. The Expedition 38 crew has been working on biomedical research and performing tests on miniature free-flying robots inside the station called Synchronized Position Hold, Engage, Reorient, Experimental Satellites or simply, SPHERES.

Bowling-ball-sized robot spheres in the space station help with routine monitoring, maintenance and data transfer. Credit: NASA

The volleyball-sized robots has been working on the station since 2006; they take photos and videos, make Wi-Fi connections and fly in formation. They’ll also be used outside the station to make repairs, conduct inspections and assist in de-orbiting malfunctioning spacecraft.

From the ground, the football-field sized space station looks like a brilliant yellow star traveling from west to east across the sky. I’ve listed a few times below when it’s visible from the Duluth, Minn. region. For times and directions for your town, go to Heavens Above or key in your zip code at Spaceweather’s Satellite Flybys link.

* Tonight Feb. 9 starting at 5:57 p.m. Low pass across the south-southeast. Max. brightness at magnitude -1.8. Second brief, brilliant appearance in the west at 7:33 p.m. Disappears into Earth’s shadow 2 minutes later. Magnitude -2.4

* Mon. Feb. 10 at 6:44 p.m. Fabulously bright, high pass across the top of the sky. Mag. -3.4!

* Tues. Feb. 11 at  5:56 p.m. high in the southern sky. Glides very close to Jupiter seconds before 6 p.m. Mag. -3.0

* Weds. Feb. 12 at 6:44 p.m. high in the northern sky. Mag. -2.7

Comet ISON update Dec. 7 – Possible sightings, new map

Comet ISON in the most recent good resolution image taken by NASA’s STEREO-A probe late on Dec. 3. I’ve processed the photo to better show the comet, which has now become a faint, expanding cloud of dust and small rocks. Credit: NASA

Yesterday morning I dressed for subzero chill to look at comets Lovejoy and Nevski, Mars and a faint supernova in the constellation Leo. Although my hour under the stars didn’t lack in astronomical pleasures, I couldn’t help thinking about ISON. This week was supposed to be the start of that comet’s grand entry into the dawn sky after getting fired up by the sun. Instead we’re hoping to catch a glimpse of its final gasp. When I packed away the telescope and returned to the welcome warmth of my home, I felt a tinge of comet blues.

While you might share my disappointment, the good news is that ISON seems to have just enough oomph to re-appear in the sky before dawn. To date, there have been two possible and one positive sightings:

* Piotry Guzik of Poland strongly suspected seeing a faint 1/4-degree-wide smudge with 10×50 and 15×70 binoculars Friday morning Dec. 6 at dawn.

* A possible picture of the comet was taken by David Rankin also on Dec. 6. Rankin’s image is particularly interesting because it shows maybe-ISON in the correct orientation “lying on its side”. (I just heard this morning that the comet’s position in the photo is off by one degree from its predicted position, making it doubtful we’re seeing the comet. Perhaps it’s a cloud?).

* This morning Dec. 7, J. J. Gonzalez of Spain made what appears to be a definitive observation of the comet with an 8-inch (20 cm) telescope at magnitude 7.2 from his dark, mountaintop location. He described it as 10 arc minutes across (30 arc minutes = one full moon diameter), elliptical in shape and nearly smooth with very little brightening toward its center. Gonzalez also spied two faint, tail-like structures extending to the south and northwest.

I suspect the digital imagers will be out in force over the weekend. We’ll know very soon what ISON’s ghost looks like from the ground.

Michael Jaeger of Austria photographed this tail disconnection event in Comet Lovejoy on Dec. 5, 2013. Comets can lose their tails when magnetic fields entwined with the solar wind snap it off. Like some lizards, a new one quickly re-grows to replace the old. Credit: Michael Jaeger

Comet Lovejoy compensated for whatever twang of regret I felt at not seeing ISON leap over the trees. How fortunate we are to have this picturesque and interesting stand-in for the much-hyped ISON. In my dark eastern sky, Lovejoy could still be seen with the naked eye as a small, “soft” star of magnitude 5.5 in the constellation Corona Borealis. Fainter than a week ago, it will soon fade below the naked eye limit.

Fountains or jets of material launching from the Lovejoy’s nucleus are visible in moderate-sized telescope (8-inches and up) at powers of 200x and higher. This photo taken Dec. 5, 2013. Credit: Gianluca Masi

In 10×50 binoculars a streak of a tail shot up northwest of the bright head. I could trace it for 2.5 degrees. Fascinating fountain-like structures similar to the what you see in Gianluca Masi’s photo sprung up south-southeast of Lovejoy’s core when viewed at high magnification.

After 20 minutes of study I balled my hands into fists inside my gloves to warm them back up and then moved on to Mars.

Lovejoy slowly drops lower and lower in the morning sky over the next few weeks. You’ve got another 7-9 days of good viewing before the full moon returns to the morning sky. Use this chart to help you find it. That’s also the same amount of time left to attempt to see Comet ISON. Because it’s so amorphous and dim, moonlight will almost certainly kill it visually, though amateurs may still be able to get images.

New map for finding Comet ISON shows the sky facing east an1 1/2 to 1 3/4 hours before sunrise for mid-northern latitude skywatchers. The comet’s position is shown daily but marked every 3 days. Stars plotted to mag. 6. Guide stars are labeled: Oph = Ophiuchus, Her = Hercules, Ser = Serpens and CrB = Corona Borealis. Click for a large version. Created with Chris Marriott’s SkyMap software

My original ISON charts assumed the comet would be relatively bright in a twilight sky. This freshly baked map reflects the new reality and shows a lot more stars to hopefully help guide you to your target.

Keep in mind that the map shows the constellation positions for Dec. 7. Each night the stars rise 4 minutes earlier  and push up one degree higher in the east. Add that to the comet’s rapid northward motion, and ISON gains altitude quickly in the next week, making a little easier to see each morning … assuming you can see it! On the 7th, for example, the comet is about 6 degrees high at map time; by the 14th, it climbs to 22 degrees.

Finally! Clear skies for Comet ISON – Here’s what I saw

Comet ISON and Mercury over Lake Superior seen from Skyline Parkway in Duluth, Minn. USA this morning Nov. 22, 2013. The photo gives a good impression of how the comet looked in 10×50 binoculars under a very clear, twilit sky. Credit: Bob King

After a week of vigilance and three false-alarm 5 a.m. wakeups, the sky finally cleared this morning for a good view of Comet ISON. Still, nature wasn’t going to let me off easy. 20 mph winds blew the scope around, the mirror was next to impossible to collimate and the temperature got down to 10 F, but yes, the nearly cloudless sky made it all worthwhile.

Another view of the comet taken with a 200mm lens this morning Nov. 22, 2013. Credit: Bob King

Before Comet ISON rose, Comet Lovejoy made for a most impressive sight in the little constellation Canes Venatici just off the Handle of the Big Dipper. To my surprise it was plainly visible with the naked eye once you knew just where to look – even in bright moonlight. I estimated the fuzzball at magnitude 4.5. Through 10×50 binoculars a tail almost 2 degrees long shot straight out back toward the west.

With the temperature cooling to just 10 degrees F (-12 C), the sight of dawn below Spica in the east around 5:45 a.m. make the morning cheerier. Then Mercury appeared. I knew ISON would poke out some 5 degrees to its right, but was a bit taken aback when I picked it up in the 10x50s.

The comet looked weak, not particularly bright, but very comet-y with a star-like head and thin, faint tail pointing back to the northwest. While it was easy to see, I wouldn’t say it was bright – delicate might be the best way to describe it. I estimated ISON’s brightness at about magnitude 3.5.

Comet Lovejoy was bright enough to pick up with a 35mm lens and 30-second exposure in bright moonlight this morning. Credit: Bob King

Through a 15-inch telescope, the comet’s head glowed blue-green and I could just discern the famous “wings” photographed so well by dedicated amateur astronomers recently. For fun I whipped out an inexpensive digital point-and-shoot camera and shot a few frames of ISON through the eyepiece.

Animation of Comet ISON from pictures taken in the higher-resolution HI-1 camera on NASA’s STEREO-A spacecraft this week. White waves coming from the right are denser areas in the solar wind which cause Comet Encke’s tail to ripple. Using comet tails as tracers can provide valuable data about solar wind conditions near the sun. Credit: Karl Battams/NASA/STEREO/CIOC

I was able to hold onto the comet in binoculars until about 6:40 a.m. or 40 minutes before sunrise. Mercury was much easier to see than Comet ISON, and for a special end-of-observing treat, Saturn came up below Mercury. Even though the image flapped and shimmered in the turbulent air, it was my first sight of the planets and its pretty rings this season.

The finest Comet ISON scenic shot I’ve seen to date. It was taken by Juan Carlos Casado from up on a mountaintop on the island of Gran Canaria from the Observatorio del Teide (IAC) Nov. 21, 2013. Mercury is seen through clouds at lower left.

I’ve saved the best for last. This photo was taken yesterday morning Nov. 21 by Juan Carlos Casado of Spain. Nice!

Comet ISON update Nov. 20 – New maps, photos and fresh hope

Delicate striations in Comet ISON’s tail recorded by Joseph Brimacombe of Australia on Nov. 19, 2013. Click to enlarge

We’re in the final stretch! Time for updated maps of Comets ISON and Encke in the remaining days before perihelion or closest approach to the sun. And just for the heck of it, let’s throw in Comet Lovejoy, too. The latest brightness estimate for ISON comes to us from its co-discoverer Vitaly Nevski who estimated its magnitude at 3.7 on Nov. 19, a nice jump from Sunday-Monday. Amateur astronomer Neil Norman reports that southern hemisphere observers in his group report that ISON is a very easy binocular object now.

The first map shows the sky facing southeast an hour before sunrise for the central USA (latitude 39-40 degrees from Virginia through Illinois, Kansas, Nevada and central Cal.). If you live south of this belt, the comets will be slightly higher in the sky; if north, slightly lower. Notice that Mercury travels toward the sun just like Encke and ISON. That’s why you see dates along its path too. Click HERE to find your sunrise time.

What a traffic jam! Comets ISON and Encke viewed from the central U.S. (latitudes 38-41 degrees north) one hour before sunrise CST the next few mornings. Stars shown to magnitude 5.5. Click to enlarge. Created with Chris Marriott’s SkyMap software. Stellarium

Here are ISON altitudes on the following dates 1 hour before sunrise for the central U.S.:

* Nov. 20: 12 degrees
* Nov. 21: 9 degrees
* Nov. 22: 6 degrees
* Nov. 23: 4 degrees

The view from Johannesburg, South Africa (latitude 26 degrees south) of Comet ISON one hour before sunrise in the eastern sky. Comet Encke is now too low to see from this latitude and Mercury is below or just at the horizon. Click to enlarge. Created with Chris Marriott’s SkyMap software

Unless Comet ISON brightens sharply in the next few days, these next few mornings are likely the last time most of us will see it before perihelion. If the comet gets bright enough to attempt in the daytime sky at or near perihelion on Nov. 28, I’ll post another map with directions on how to safely see it without blinding your eyes.

Comet Lovejoy on Nov. 15 still shows a large, pale green coma with fine tail structure visible. Lovejoy will be closest to Earth on the 19th and could reach magnitude 4.5. Click to enlarge. Credit: Damian Peach

Barring that, the best time to enjoy this icy visitor from the Oort Cloud will be during the first three weeks of December. Unfortunately, observers in the southern hemisphere will not have a good look at ISON after perihelion. It quickly leaves the sun behind headed north and sinks below the horizon from far southern locations. For northerners, the comet rapidly moves up and away from the sun into a dark morning sky.

Comet Lovejoy travels between the Big Dipper and the smaller constellation Canes Venatici (the Hunting Dogs) over the next 10 days. Key stars are labeled: UMa = Ursa Major; CVn = Canes Venatici and Boo = Bootes. Stars to magnitude 5.5. Click to enlarge. Created with Christ Marriott’s SkyMap software

I’ve also included a map for spotting Comet Lovejoy – still bright at around magnitude 5 – as it cruises alongside the Big Dipper in the morning sky. Nothing like having the easiest constellation (an asterism actually – the Big Dipper is part of the Great Bear Ursa Major) in the northern hemisphere to help you find a comet. Good fortune indeed!

Fresh maps to help you find Comets ISON and Lovejoy Nov. 10-19

Comet ISON on Nov. 8 from Austria. The bright, long tail is made of dust while the two fainter tails are probably glowing gas called ion tails. Credit: Michael Jaeger

There are now four morning comets visible in 10×50 or larger binoculars from a dark sky site: Lovejoy, ISON, Encke and C/2012X1. The last is the faintest and Encke, while bright at magnitude 7-7.5, is now getting so low, it’s not easy to find for most observers. That leaves us with two reasonably bright targets at comfortable elevations.

What’s this? A comet traffic jam near the Beehive star cluster (top)? Astrophotographer Rolando Ligustri photographed Comet Lovejoy (left) passing the Beehive. At bottom, Comet Lulin made its pass on March 6, 2009. Credit: Rolando Ligustri

A word to the wise – don’t wait too long to see ISON and Lovejoy. The glare of the moon returns to the sky around the 15th and will make both more challenging to find. At the moment Comet Lovejoy is considerably brighter and easier to see then ISON with a magnitude of around 6 versus 8. I even saw it faintly with the naked eye two mornings ago just a finger to the east of the Beehive Cluster.

Updated map showing Comet ISON’s travels through Virgo Nov. 17-21. Map faces southeast and the time is in early twilight about 75 minutes before sunrise. Despite the comet’s low altitude and moonlight, bright Spica and Mercury will help guide you there.  Created with Chris Marriott’s SkyMap program. Click for large version.

So why is Lovejoy so much brighter than ISON the Great right now? Well, it’s much closer to Earth – 42 million miles versus 93 million for ISON. In astronomy, proximity counts. The closer something is, the brighter it looks. There is no better example of this than staring up at the sky on a clear night. Many of the brightest stars achieve that status because they’re closer than the fainter but intrinsically brighter ones.

If you’re not familiar with Virgo’s place in the sky, use this wider-view map that shows bright Mars, Regulus and Arcturus to help point you in Comet ISON’s direction. Stellarium

ISON will hopefully far outshine Lovejoy as we move into late November when the comet get a heavy-duty broiling from the sun. It will pass nearest Earth on Dec. 27 at a distance of 40 million miles. By then Lovejoy will have receded to ISON’s current distance of 93 million miles. Interesting that they they’re moving counter to one another this way.

Comet Lovejoy travels from Cancer across Leo and Leo Minor between now and Nov. 19. The map shows the sky facing south around 5:30 a.m. CST. Stars are labeled for reference. 21 LMi is 21 Leo Minor and 55 UMa is 55 Ursa Major. Stars shown to mag. 6.5 with brilliant Jupiter at upper right as your guide. Created with Chris Mariott’s SkyMap program. Click to enlarge.

While Lovejoy will continue to brighten and could reach 5th magnitude, ISON could become MUCH brighter. The latest estimates have it at the same brightness as Venus (-4 magnitude) for a few hours when it’s closest to the sun on Nov. 28.

The best time to view both comets is right before the start of morning twilight or about 1 3/4 – 2 hours before sunrise. You can click on the charts to get higher-resolution versions of them to print out for use outdoors. Good luck on your comet quest!

Want to see Comets ISON and Lovejoy? Tomorrow morning Nov. 7 is ideal

Comet Lovejoy passes the Beehive Star Cluster in Cancer tomorrow morning Nov. 7. Use Jupiter, the brightest object high in the southern sky, to swing over to the cluster, which looks like a fuzzy spot to the naked eye. The comet and cluster will sit together in the same field of view. Created with Stellarium

Every so often we get help from the stars. Not the fortune-telling kind but real guidance as reference points to help us find cool things in the sky. If you haven’t arisen before dawn to spy Comet ISON and Comet Lovejoy yet, tomorrow morning’s a great time. Both comets are now visible in regular binoculars and near familiar celestial guideposts.

Comet C/2013 R1 Lovejoy has a big, bright coma or head and skinny tail pointing west. This photo was taken on Nov. 3. Through my 15-inch telescope the coma glowed faintly green from fluorescing gases. Credit: Gerald Rhemann

Comet Lovejoy, now easily visible in 50mm and smaller binoculars under a reasonably dark sky, glows at 6th magnitude right next to the pretty Beehive star cluster in the constellation Cancer the Crab. The Beehive, also known as M44, is plainly visible to the naked eye as a small, fuzzy spot. Binoculars resolve into a “beehive” of individual stars. Look just to its lower left to find a softly-glowing patch with a brighter center. That’s Lovejoy.

Longer term chart showing Comet Lovejoy’s position each morning Nov. 1-16 shortly before dawn around 5 a.m. Central Standard Time. Created with Chris Marriott’s SkyMap software

A couple observers have even spotted the comet without any optical aid since it hovers right at the naked eye limit. I saw it Tuesday morning with ease in my 10x50s. Of the two comets, it will appear distinctly brighter.

Comet ISON’s travels take it right next to the star Beta Virginis or Zavijava tomorrow morning. Point your binoculars or scope at the star look a small distance to its lower right or southwest to see the comet. Click to enlarge . Stellarium

The big surprise Tuesday was finding Comet ISON in the same binoculars. It wasn’t much – just a small, fuzzy spot of magnitude 8.5 – but that was bright enough to punch through a thin layer of haze and show in my glass. Tomorrow morning ISON will sit right next to the easy naked eye star Beta Virginis – also called Zavijava – well below Leo’s tail star Denebola. Put Beta in your binoculars and if your sky is dark and clear, you should see it.

Comet ISON on Oct. 31. Binoculars won’t show the tail, but an 8-inch scope will with ease. Credit: Michael Jaeger

By all means, if you have a small telescope, take it out too and make easy work of finding both comets. One more tip. While Lovejoy gets high enough to start observing around 2 a.m. local time, ISON will be low in the southeast at the start of dawn. Be sure you pick a location away from city lights with an open view in that direction. The ideal time to see both comets at their best is 1 1/2 to 2 hours before sunrise. Click HERE to find when the sun rises for your town so you know when to head out for a look.

A bit of news about Comet ISON. Gas production rates in the comet have risen recently, no doubt due to its getting closer to the sun. This could mean a more rapid brightening of the comet in the coming mornings. I hope you’ll be watching.

Morning comets ISON, Encke and Lovejoy heat up, glow green

Comet C/2013 R1 Lovejoy, discovered last month by amateur astronomer Terry Lovejoy, glows green in this photo taken with a 12-inch telescope. The comet is currently visible in 6-inch and larger scopes in the morning sky. It may show in binoculars by month’s end. Click to enlarge. Credit: Gerald Rhemann

The color green represents hope and life. It’s also a sure sign our three morning comets are heating up and becoming more active as they approach the sun. I don’t know anyone who’s noticed the green color with their eyes looking through a telescope – the comets are all still around magnitude 10-11 and too faint to fire up our color vision – but the camera records their limey appearance with ease.

2P/Encke, which orbits the sun every 3.3 years, is a large, soft puff of light in the constellation Lynx visible in the wee hours before dawn. Glowing at magnitude 10, it will show in binoculars next month. Its coma fluoresces green from molecules released from ice vaporizing in the heat of the sun. Photo taken Sept. 30. Click to enlarge. Credit: Damian Peach

In some of the pictures you can clearly see the color difference between the comet’s tail and its fluffy coma – that’s the bulbous glow surrounding the tiny and invisible comet nucleus at the center of all the activity. Comas form tenuous, temporary atmospheres tens of thousands of miles across around the icy comet nucleus.

Comet star of the year ISON shows a beautiful green coma, bright false nucleus and pale yellow tail in the photo taken Oct. 4 from Austria by astrophotographer Gerald Rhemann. Click to enlarge.

Don’t expect to ever see a bare comet nucleus through a telescope. They’re not only very tiny, typically only a few miles across, but cloaked by dust and vapors boiled away by the sun. The closest you’ll get is the bright spot in the center of the comet called the false nucleus – a compact region where the dust and volatiles are densely concentrated around the true nucleus.

Comet ISON again on the morning of Oct. 5. The green coma is approximately spherical with a short dust tail pointing northwest. Comet ISON glows at around magnitude 11 right now. Click to enlarge. Credit: Michael Jaeger

Tails glow pale yellow from sunlight reflecting off cigarette-smoke-sized dust particles released from vaporizing cometary ices. The Caribbean blue-green of the coma, pretty as it is, originates from toxic cyanogen (a compound related to cyanide) and diatomic carbon (two carbon atoms bonded to one another). When energized by ultraviolet light from the sun, the gases fluoresce an eye-appealing green.

Everyone’s got their eyes and cameras glued to Comet ISON. This photo was shot on Oct. 4 with a 12.5-inch (32 cm) telescope from Payson, Arizona. Click to enlarge. Credit: Chris Schur

In my experience, the eye can’t sense the green until the comets become bright enough to show in ordinary binoculars at around 7th magnitude. When viewed through 8-inch or larger telescopes the color is tantalizing, like the green and blue iridescence sometimes seen along the edges of high clouds.

Comets ISON, Encke and Lovejoy are all predicted to brighten into visible green territory come November. That’s only a few weeks today. We’ll take the good news that all three comets are on track and brightening steadily. Stay tuned for more updates. For the latest brightness predictions, check out Seiichi Yoshida’s Weekly Information About Bright Comets.

Touch of comet fatigue? Consider Jupiter and Mars

Jupiter and the moon will be in conjunction in the northeastern sky around 1:30 a.m. tomorrow morning Sept. 28. Stellarijum

As a  passionate comet observer I never tire of these fuzzballs faint or bright, but with every single one of them faint and requiring a telescope to see right now (except maybe C/2012 V2 LINEAR, visible only in the southern hemisphere), you might be weary hearing about all the wonderful views you’re missing.

Have patience. Comet ISON steps it up late next month, waxing bright enough to follow in binoculars and with the naked eye by the third week of November. Comets Encke and Lovejoy will never crack the naked eye limit but should be visible in binoculars under dark sky in late Oct. and Nov. respectively.

Right now we’ve got planets on the menu. Jupiter and Mars are rising a little earlier with each passing night and easily visible with the naked eye. Tonight the thick waning lunar crescent will slide to Jupiter’s lower right. Watch for the pair to clear your skyline around 1-1:30 a.m. local time. Late, I know, but if you’re returning from a Friday night party, it’s worth a minute of your time for some out-of-this-world eye candy before heading in.

Jupiter and moons tomorrow morning around 1:30 a.m. The shadow of Europa is on the far left (west) side of the planet. Created with Chris Marriott’s SkyMap software

Binoculars will show at least two of Jupiter’s four bright moons tomorrow morning. Small telescope users will see all four and may even get a look at the shadow of Europa at magnifications of 80x or higher. Look for a black pinprick way off to the west side of the planet around 1:30 a.m. CDT; the shadow departs the disk around 2.

Icy Europa (far left) casts its shadow on Jupiter’s cloud tops on Sept. 24. The Great Red Spot is at lower left. Click to find other times when the Spot is visible. Credit: John Chumack

The Great Red Spot, which blushes redder this fall than in recent years, will make a great presentation Sunday morning Sept. 29 for much of the Americas. Jupiter’s rotation will turn the Spot to face us square-on around 6 a.m. CDT (7 a.m. Eastern, 5 a.m. Mountain and 4 a.m. Pacific). You’ll still get a good look an hour before and after those times. Look for a ruddy oval in the planet’s southern hemisphere about 1/3 of the way between the equator and south pole.

Mars is visible in the eastern sky at dawn well below and left of brilliant Jupiter. Look for its red color. In the coming week, the planet will approach the bright star Regulus in Leo. Stellarium

Mars hovers in the eastern sky near the star Regulus in Leo; it’s best from around the start of dawn until it disappears in the glare of the impending sunrise. The later you watch, the higher the planet rises and the sharper it will look in a telescope. Thicker, more turbulent near the horizon both blurs and dims celestial objects.

Despite Mars’ teeny disk, astrophotographer Damian Peach shot a couple excellent photos of Mars on Sept. 20. The prominent Africa-shaped feature is a large, low shield volcano called Syrtis Major. Since the photo has south up, the north polar cap is at bottom.

Even in a telescope Mars is very tiny because it’s still so far away – 200.5 million miles (323 million km). The gap between Earth and Mars shrinks a little bit every day until the two planets pull up alongside each other on April 8, 2014. On that day, just 58 million miles (93 million km) will separate them and Mars will shine as brightly as Sirius, the brightest star.

Illustration of Mars tomorrow morning around 6 a.m. CDT. The north polar cap and Syrtis Major present themselves. Created with Meridian

If the air is steady, boost your magnification to 200x or higher and you might see a few of the dark markings in the illustration at left.

The easiest Martian feature to spot right now is the north polar cap. With spring underway in Mars’ northern hemisphere, the cap, composed of both water and carbon dioxide ice, is out in the clear. Look for a tiny, bright, white patch at the planet’s northern limb.

While things like polar caps and moon shadows do require a telescope, finding and following the planets is easy. Throw in a few choice moon alignments (tomorrow for Jupiter, Sept. 30 for Mars) and it’s a show.

Check out these new photos of Comets Encke, ISON and Lovejoy

Beautiful shot of Comet ISON taken with the VATT telescope on Sept 12. The brighter nucleus – source of the comet’s ice and dust – feeds a tail that points to the northwest. Credit: Carl Hergenrother / University of Arizona / Vatican Obs

Carl Hergenrother, a professional astronomer at the University of Arizona’s Lunar and Planetary Lab, recently used the Vatican Advanced Technology Telescope (VATT) 70.8 inch (1.8-m) telescope on Mount Graham to photograph three upcoming bright comets. His images reveal personalities and details not seen in smaller scopes.

Comet 2P/Encke looks like a big powder puff with a faint, pinpoint nucleus (the tiny dot) on Sept. 12. Inset photo shows comet photographed in red light. Credit: Carl Hergenrother / University of Arizona / Vatican Obs

All three are wiggling their way across the morning sky – Comet ISON near Mars in the constellation Cancer; Encke in Auriga and high in the east at dawn and Lovejoy in Monoceros the Unicorn, a dim grouping of stars with a wonderful name east of Orion.

ISON stays within a few degrees of the planet Mars now through late October. Not only is the comet headed toward the sun from the direction of Mars as seen from Earth, it will be physically close to the Red Planet, passing just 6.5 million miles (10.5 million km) away on Oct 1. That’s 6 times closer than its flyby of Earth on Dec. 26. Mars makes a convenient marker for anyone wishing to know where to look for the comet.

Comet C/2013 R1 Lovejoy on Sept. 12 shows a bright nucleus and broader tail than ISON. Credit: Carl Hergenrother / University of Arizona / Vatican Obs

From Martian skies, Comet ISON should be easily visible to the naked eye glowing at around magnitude 2-3. NASA hopes to enlist the electronic eyes of the Mars Reconnaissance Orbiter and two rovers – Opportunity and Curiosity – to take advantage of this unprecedented opportunity.


Comet Encke has the shortest orbit of any known comet. When closest to the sun it swings within the orbit of Mercury then loops out nearly to Jupiter. On Nov. 18, the comet will pass only 2.3 million miles from Mercury.

Comet 2P/Encke has the shortest orbital period of all known comets, cycling around the sun once every 3.3 years. It was first seen by French astronomer Pierre Mechain in 1786 but not recognized as a returning or periodic comet until its orbit was computed by German astronomer Johann Encke in 1819. Like Halley’s Comet, Encke is named after its orbit calculator instead of the original discoverer. The “2P” refers to it being the second periodic comet with a calculated orbit

The sky facing east-southeast just before the start of dawn tomorrow morning Sept. 15. Our three featured comets form a large triangle in the east. All three require at least an 8-inch telescope to see. Created with Stellarium

Although faint and very diffuse now, Comet Encke will brighten to binocular visibility in November. Yesterday morning it was a faint, soft glow through my 15-inch telescope at low magnification. Comet ISON looked great too. It’s “pumped up the volume” compared to a week ago and now burns more brightly at magnitude 12. I noticed that its center was distinctly brighter than a week ago.

Our third morning comet, C/2013 R1 Lovejoy is brand new, discovered by Australian amateur Terry Lovejoy only a week ago. It’s also brighter than several days ago, shining now at around magnitude 12.5-13.0.

The fall is shaping up to be a good one for comet lovers. I want to thank Carl and all the other generous astronomers – amateur and professional – for freely sharing their images with us.