The Top 101 Astronomical Events for 2016

Camping out under dark skies. Image credit and copyright: Michelle Nixon/MNixon Photography

Here it is… our year end look at upcoming events in a sky near you. We’ve been doing this “blog post that takes four months to write” now on one platform or another every year since 2009, and every year, it gets bigger and more diverse, thanks to reader input. This is not a top 10 listicle, and not a full-fledged almanac, but hopefully, something special and unique in between. And as always, some of the events listed will be seen by a large swath of humanity, while others grace the hinterlands and may well go unrecorded by human eyes. We’ll explain our reasoning for drilling down each category, and give a handy list of resources at the end.

Click on any of the graphics included for the top events for each month to enlarge.

Continue reading “The Top 101 Astronomical Events for 2016”

Slender Moonspotting, Occultations, Daytime Planets and More

Credit and copyright:

One of nature’s grandest ‘occultations’ of all is coming right up this Friday, as the Moon passes in front of the Sun for viewers in the high Arctic for a total solar eclipse. And although 99.999+% percent of humanity will miss totality, everyone can trace the fascinating path of the Moon as it moves back into the evening sky this weekend.

As of this writing, it looks like the fickle March weather is going to keep us guessing right up to eclipse day. Fear not, as the good folks over at the Virtual Telescope Project promise to bring us views of the eclipse live.  Not only does this eclipse fall on the same day as the start of astronomical spring in the northern hemisphere known as the vernal (northward) equinox, but it also marks the start of lunation 1141.

Ever try hunting for the slender crescent Moon in the dawn or dusk sky? The sport of thin Moon-spotting on the days surrounding the New Moon can push visual skills to the very limit. Binoculars are your friend in this endeavor, as you sweep back and forth attempting to see the slim fingernail of a Moon against the low contrast background sky.  Thursday morning March 19th provides a great chance for North American observers to spy an extremely thin Moon about 24 hours prior to Friday’s eclipse.

Projected locales for the first sightings of the slim crescent Moon on the evening of March 20th. Credit: Created by author.

Unfortunately, most of North America misses the eclipse, though folks on the extreme east coast of Newfoundland might see a partially eclipsed sunrise if the day dawns clear.

The Moon will first be picked up in the evening sky post-eclipse this weekend. On Friday evening, folks in the southern United States might just be able to spy a 15 hour old Moon with optical assistance if skies are clear.

As the Moon fattens, expect to see it at its most photogenic as Ashen light or Earthshine illuminates its nighttime side. What you’re seeing is sunlight from the Earth being reflected back in a reverse (waning gibbous) phase as seen from the earthward side of the Moon. The prominence of Earthshine can vary depending on the amount of cloud and snow cover currently turned moonward, though of course, if it’s cloudy from your location, you won’t see a thing…

The universe smiles back: A skewed emoticon grouping of Venus, Mars and the Moon plus Earthshine on February 20th. Photo by author.

Watch that Moon over the coming weeks, as it has a date with destiny.

The Moon occults (passes in front of) two planets and one bright star in the coming week. First up is an occultation of Uranus on March 21st at around 11:00 UT/7:00 AM EDT. Sure, this one is for the most part purely academic and unobservable, as it occurs over central Africa in the daytime and is only 15 degrees east of the Sun. Still, if you can pick up the Moon on the evenings of March 20th or March 21st, you might just be able to spy nearby Uranus shining at +6th magnitude nearby before it heads towards solar conjunction on April 6th.

The visibility footprint of the March 21st occultation of Mars by the Moon. Credit: Occult 4.1.

Next, the Moon occults Mars on March 21st at 22:00 UT/6:00 PM EDT for the southern Pacific coast of South America. North America will see an extremely close photogenic pairing of Luna and the Red Planet. This is one of seven occultations of a naked eye planet by the Moon for 2015, and the first of two for Mars for the year, the next falling on December 6th.

The Moon pairs with Venus on the evening of March 22nd. Credit: Stellarium.

Next up, the Moon has a tryst with brilliant Venus, passing 2.8 degrees from the Cytherean world on March 22nd. Can you spy -4th magnitude Venus near the two day old Moon before sunset? This is the stuff that has inspired astronomically-themed flags and skewed emoticon ‘smiley face conjunctions’ of yore, including the close pairing of Mars, Venus and the Moon seen worldwide last month.

The occultation of Aldebaran by the Moon on March 25th. Credit: Occult 4.1.

Next up, the 30% illuminated Moon occults the bright star Aldebaran for Alaskan viewers at dusk on March 25th. This is the third occultation of the star by the Moon in the ongoing cycle, and to date, no one has, to our knowledge, successfully caught an occultation of Aldebaran in 2015… could this streak be broken next week?

The daytime Moon paired with Jupiter on March 30th. Credit: Starry Night Education software.

And speaking of daytime planet-spotting, Jupiter will sit only five degrees south of the waxing gibbous Moon on the evening of March 30th. Can you spy the giant planet near the daytime Moon in the afternoon sky using binocs? And finally, watch that Moon, as it heads for the third total lunar eclipse of the last 12 months visible from the Americas and the Pacific region on the morning of April 4th

More to come!

Catch a ‘Conjunction Triple Play’ on February 20th as the Moon Meets Venus & Mars

The Moon passes Mars and Venus last month... this week's pass is much closer! (Photo by Author).

Fear not, the chill of late February. This Friday gives lovers of the sky a reason to brave the cold and look westward for a spectacular close triple conjunction of the planets Mars, Venus and the waxing crescent Moon.

This week’s New Moon is auspicious for several reasons.  We discussed the vagaries of the Black Moon of February 2015 last week, and the lunacy surrounding the proliferation of the perigee supermoon. And Happy ‘Year of the Goat’ as reckoned on the Chinese luni-solar calendar, as this week’s New Moon marks the start of the Chinese New Year on February 19th. Or do you say Ram or Sheep? Technical timing for the New Moon is on Wednesday, February 18th at 23:47 UT/6:47 PM EST, marking the start of lunation 1140. The next New Moon on March 20th sees the start of the first of two eclipse seasons for 2015, with a total solar eclipse for the high Arctic. More on that next month!
Continue reading “Catch a ‘Conjunction Triple Play’ on February 20th as the Moon Meets Venus & Mars”

Rare Triple Transit! There’ll be 3 Moon Shadows on Jupiter on January 24th, 2015


Play the skywatching game long enough, and anything can happen.

Well, nearly anything. One of the more unique clockwork events in our solar system occurs this weekend, when shadows cast by three of Jupiter’s moons can be seen transiting its lofty cloud tops… simultaneously.

How rare is such an event? Well, Jean Meeus calculates 31 triple events involving moons or their shadows occurring over the 60 year span from 1981 to 2040.

But not all are as favorably placed as this weekend’s event. First, Jupiter heads towards opposition just next month. And of the aforementioned 31 events, only 9 are triple shadow transits. Miss this weekend’s event, and you’ll have to wait until March 20th, 2032 for the next triple shadow transit to occur.

Hubble spies a triple shadow transit  on March 28th, 2004 . Credit: NASA/JPL/Arizona.
Hubble spies a triple shadow transit on March 28th, 2004 . Credit: NASA/JPL/Arizona.

Of course, double shadow transits are much more common throughout the year, and we included some of the best for North America and Europe in 2015 in our 2015 roundup.

The key times when all three shadows can be seen crossing Jupiter’s 45” wide disk are on the morning of Saturday, January 24th starting at 6:26 Universal Time (UT) as Europa’s shadow ingresses into view, until 6:54 UT when Io’s shadow egresses out of sight. This converts to 1:26 AM EST to 1:54 AM EST. The span of ‘triplicate shadows’ only covers a period of slightly less than 30 minutes, but the action always unfolds fast in the Jovian system with the planet’s 10 hour rotation period.

The view at 6:41 UT/1:41 AM EST. Credit: Created using Starry Night Education software.
The view on January 24th at 6:41 UT/1:41 AM EST. Credit: Created using Starry Night Education software.

Unfortunately, the Great Red Spot is predicted to be just out of view when the triple transit occurs, as it crosses Jupiter’s central meridian over three hours later at 10:28 UT.

The moons involved in this weekend’s event are Io, Callisto and Europa. Now, I know what you’re thinking. Seeing three shadows at once is pretty neat, but can you ever see four?

The short answer is no, and the reason has to do with orbital resonance.

The orbital resonance of the three innermost Galilean moons. (Credit: Wikimedia Commons).
The orbital resonance of the three innermost Galilean moons. (Credit: Wikimedia Commons).

The three innermost Galilean moons of Jupiter (Io, Europa and Ganymede) are locked in a 4:2:1 resonance. Unfortunately, this resonance assures that you’ll always see two of the innermost three crossing the disk of Jupiter, but never all three at once. Either Europa or Ganymede is nearly always the “odd moon out.”

To complete a ‘triple play,’ outermost Callisto must enter the picture. Trouble is, Callisto is the only Galilean moon that can ‘miss’ Jupiter’s disk from our line of sight. We’re lucky to be in an ongoing season of Callisto transits in 2015, a period that ends in July 2016.

Perhaps, on some far off day, a space tourism agency will offer tours to that imaginary vantage point on the surface of one of Jupiter’s moons such as Callisto to watch a triple transit occur from close up. Sign me up!

Jupiter currently rises in late January around 5:30 PM local, and sets after sunrise. It is also well placed for northern hemisphere observers in Leo at a declination 16 degrees north . This weekend’s event favors Europe towards local sunrise and ‘Jupiter-set,’ and finds the gas giant world well-placed high in the sky for all of North America in the early morning hours of the 24th.

2AM local Credit: Stellarium.
Jupiter rides high to the south at 1:45 AM EST for the US East Coast. Credit: Stellarium.

Look closely. Do the shadows of the individual moons appear different to you at the eyepiece? It’s interesting to note during a multiple transit that not all Jovian moon shadows are ‘created equal’. Distant Callisto casts a shadow that’s broad, with a ragged gray and diffuse rim, while the shadow of innermost Io appears as an inky black punch-hole dot. If you didn’t know better, you’d think those alien monoliths were busy consuming Jupiter in a scene straight out of the movie 2010.  Try sketching multiple shadow transits and you’ll soon find that you can actually identify which moon is casting a shadow just from its appearance alone.

The orientation of Earth's nighttime shadow at mid-triple transit. Credit: Created using Orbitron.
The orientation of Earth’s nighttime shadow at mid-triple transit. Credit: Created using Orbitron.

Other mysteries of the Galilean moons persist as well. Why did late 19th century observers describe them as egg-shaped? Can visual observers tease out such elusive phenomena as eruptions on Io by measuring its anomalous brightening? I still think it’s amazing that webcam imagers can now actually pry out surface detail from the Galilean moons!

Photo by author.
The 2004 triple shadow transit. Photo by author.

Observing and imaging a shadow transit is easy using a homemade planetary webcam. We’d love to see someone produce a high quality animation of the upcoming triple shadow transit. I know that such high tech processing abilities — to include field de-rotation and convolution mapping of the Jovian sphere — are indeed out there… its breathtaking to imagine just how quickly the fledgling field of ad hoc planetary webcam imaging has changed in just 10 years.

The moons and Jupiter itself also cast shadows off to one side of the planet or the other depending on our current vantage point. We call the point when Jupiter sits 90 degrees east or west of the Sun quadrature, and the point when it rises and sets opposite to the Sun is known as opposition.  Opposition for Jupiter is coming right up for 2015 on February 6th. During opposition, Jupiter and its moons cast their respective shadows nearly straight back.

Did you know: the speed of light was first deduced by Danish astronomer Ole Rømer in 1671 using the discrepancy he noted while predicting phenomena of the Galilean moons at quadrature versus opposition. There were also early ideas to use the positions of the Galilean moons to tell time at sea, but it turned out to be hard enough to see the moons and their shadows with a small telescope based on land, let alone from the pitching deck of a ship in the middle of the ocean.

And speaking of mutual events, we’re still in the midst of a season where it’s possible to see the moons of Jupiter eclipse and occult one another. Check out the USNO’s table for a complete list of events, coming to a sky near you.

And let’s not forget that NASA’s Juno spacecraft is headed towards Jupiter as well., Juno is set to enter a wide swooping orbit around the largest planet in the solar system in July 2016.

Now is a great time to get out and explore Jove… don’t miss this weekend’s triple shadow transit!

Read Dave Dickinson’s sci-fi tale of astronomical eclipse tourism through time and space titled Exeligmos.

Challenge Yourself! See an Astronomical Event that Only Happens Once Every 26 Years

This artist’s impression shows an eclipsing binary star system. Credit: ESO/L. Calçada.

Update: It’s off. This past weekend, the AAVSO issued Special Notice #395 calling off the campaign to observe Alpha Comae Berenices this month due to “position measurements published a century ago (which) contained errors that affected the predictions for the time of eclipse…”

And the mystery of Alpha Comae Berenices continues. Oh well. Such is the wiles and whims of the universe, and the exciting field of variable star observing!

A truly fascinating event may be in the offing this month.

Picture two distant burning embers (candles, light bulbs, LEDs, what have you) circling each other in the distance. From our far-flung vantage point, the two points of light are too faint to resolve individually, but as they pass in front of each other, a telltale dip in combined brightness occurs as one blocks out the other.

Welcome to the fascinating world of eclipsing binary stars. This week, we’d like to turn our attention towards a special star in the constellation of Coma Berenices which may — or may not — put on such a dimming act later this month.

Starry Night
An Alpha Comae Berenices (Diadem) finder chart, with comparison stars and magnitudes, decimals omitted. Credit: Starry Night Education Software.

The brightest star in the constellation Coma Berenices, Alpha (sometimes referred to as Diadem, or the ‘crown’ of Queen Berenice) shines at an apparent magnitude of +4.3. Located 63 light years distant, the system consists of two +5th magnitude F-type stars each about 3 times more luminous than our Sun locked in a 26 year orbital embrace. The physical separation of the pair is about 10 astronomical units: place Alpha Comae Berenices in our solar system, and the pair would fit nicely between the Sun and Saturn.

The orbital plane of the pair is inclined nearly along our line of sight as seen from the Earth, and it’s long been thought that catching a grazing or central eclipse of the pair might just be possible. No eclipse was recorded last time ‘round back in February 1989, but times have changed lots in observational astronomy. Today, there are enough backyard observers armed with dedicated observatories and rigs that’d be the envy of a small university that documenting such an eclipse might just be possible. In fact, a central eclipse might just dim the star by 0.8 magnitudes, and should be noticeable to the naked eye.

The binary nature of Alpha Comae Berenices was first noted by F. G. W. Struve in 1827, and the split is a challenging one during the best of years with a maximum angular separation of just 0.7 arc seconds. The pair also has a third faint +10th magnitude companion located about 89 arc seconds away.

A simplified diagram depicting an eclipsing binary event along our line of sight. Created by the author.

The American Association of Variable Star Observers (AAVSO) has an Alert Notice calling for sky watchers worldwide to monitor the star. We also understand the orbit of Alpha Comae Berenices much better in 2015 than back in 1989, and the suspected eclipse should occur somewhere between January 22nd and January 28th and may last anywhere from 28 to 45 hours. This lingering ambiguity means that having a dedicated team of observers worldwide may well be key to nabbing this eclipse.

Alpha Comae Berenices rising. Photo by the author.

The Navy Precision Optical Interferometer (NPOI) has already begun refining measurements of the brightness of the star last month, and professional facilities, to include the Fairborn Observatory atop Mt Hopkins in Arizona and the CHARA (the Center for High Angular Resolution Astronomy) Array at Mount Wilson Observatory in southern California will also be monitoring the event.

Sky and Telescope magazine also has an excellent article in their January 2015 issue on the prospects for catching this eclipse.

Looking eastward past local midnight. Credit: Stellarium.

In late January, the constellation of Coma Berenices rises high to the northeast just after local midnight.  It’s worth noting that, if the eclipsing binary nature of Alpha Comae Berenices is confirmed, it would be the longest period known, beating out 14.6 year Gamma Persei discovered in 1990 by more than a decade. A system with as wide a separation as Alpha Comae Berenices would have about a 1 in 1,200 chance in eclipsing along our line of sight due to random chance.

Note: Epsilon Aurigae does have a comparable 27 year period involving a debris disk surrounding its host star. Thanks to sharp-eyed reader Dr. John Barentine for pointing this out!

Of course, the universe does provide us with lots of near misses, allowing for an ‘occasional Diadem’ to indeed occur. Most famous eclipsing variables, such as Algol or Beta Lyrae have periods measured over the span of days or hours. Incidentally, these also make great ‘practice stars’ to test your skills as a visual athlete leading up to the big event next week. A skilled visual observer can note a change as slight as a 0.1 of a magnitude, and it’s a good idea to begin familiarizing yourself with the environs of the star now. The Coma Cluster of galaxies, the globular cluster M53, and the galactic plane crossing intruder Arcturus all lie nearby.

Credit: NASA/Spitzer.
The Coma Cluster as seen by Spitzer Space Telescope and the Sloan Digital Sky Survey. Credit: NASA/Spitzer.

Why study eclipsing binaries? Well, said fleeting mutual events when coupled with spectroscopic measurements and determinations of parallax can tell us a good deal about the astrophysical nature of the stars involved. Eclipsing binary stars have even been used to back up standard candle measurements over extragalactic distances. And of course, orbiting observatories such as Kepler and TESS (to be launched in 2017) look for transiting exoplanets using virtually the same method.

Credit: Brad Timerson.
Have a scope+DSLR? Then you can make refined measurements of eclipsing variable stars. Credit: Brad Timerson/IOTA.

But beyond its practical application, we just think that it’s plain cool that you can actually see something out beyond our solar system changing in the span of just a few days or hours.

Observers also still carry out visual observations of variable stars, just like those pipe-smoking, pocket watch carrying astronomers of yore. This involves merely comparing the target star to nearby stars of the same brightness. If you have a DSLR or a CCD rig plus a telescope, the AAVSO also has instructions for how to monitor a star’s brightness as well. No pocket watch required.

A homemade interferometer used to measure the separation of close double stars.
A homemade ‘card interferometer’ used to measure the separation of close double stars. Photo by author.

Unless, of course, you want to carry a pocket watch just for good luck. Don’t let the cold January winters keep you from joining the hunt. Let’s make some astrophysical history!



The Top 101 Astronomical Events to Watch for in 2015


Phew! It’s here.

Now in its seventh year of compilation and the second year running on Universe Today, we’re proud to feature our list of astronomical happenings for the coming year. Print it, bookmark it, hang it on your fridge or observatory wall. Not only is this the yearly article that we jokingly refer to as the “blog post it takes us six months to write,” but we like to think of it as unique, a mix of the mandatory, the predictable and the bizarre. It’s not a 10 ten listicle, and not a full-fledged almanac, but something in between.     

A rundown of astronomy for 2015: There’s lots of astronomical action to look forward to in the coming year. 2015 features the minimum number of eclipses that can occur, two lunars and two solars. The Moon also reaches its minimum standstill this coming year, as its orbit runs shallow relative to the celestial equator. The Moon will also occult all naked eye planets except Saturn in 2015, and will occult the bright star Aldebaran 13 times — once during every lunation in 2015. And speaking of Saturn, the rings of the distant planet are tilted an average of 24 degrees and opening to our line of sight in 2015 as they head towards their widest in 2018.

Finally, solar activity is trending downwards in 2015 after passing the sputtering 2014 maximum for solar cycle #24 as we now head towards a solar minimum around 2020.

Our best bets: Don’t miss these fine celestial spectacles coming to a sky near YOU next year:

– The two final total lunar eclipses in the ongoing tetrad, one on April 4th and September 28th.

– The only total solar eclipse of 2015 on March 20th, crossing the high Arctic.

– A fine dusk pairing of the bright planets Jupiter and Venus on July 1st.

– Possible wildcard outbursts from the Alpha Monocerotid and Taurid meteors, and a favorable New Moon near the peak of the August Perseids.

– Possible naked eye appearances by comet Q2 Lovejoy opening 2015 and comet US10 Catalina later in the year.

– The occultation of a naked eye star for Miami by an asteroid on September 3rd.

– A series of fine occultations by the Moon of bright star Aldebaran worldwide.

The rules: The comprehensive list that follows has been lovingly distilled down to the top 101 astronomical events for 2015 worldwide. Some, such as lunar eclipses, are visible to a wide swath of humanity, while others, such as many of the asteroid occultations or the sole total solar eclipse of 2015 happen over remote locales. We whittled the list down to a “Top 101” using the following criterion:

Meteor showers: Must have a predicted ZHR  greater than 10.

Conjunctions: Must be closer than one degree.

Asteroid occultations: Must have a probability ranking better than 90 and occult a star brighter than magnitude +8.

Comets: Must reach a predicted brightness greater than magnitude +10. But remember: comets don’t always read prognostications such as this, and may over or under perform at whim… and the next big one could come by at any time!

Times quoted are geocentric unless otherwise noted, and are quoted in Universal Time in a 24- hour clock format.

These events are meant to merely whet the appetite. Expect ‘em to be expounded on fully by Universe Today as they approach. We linked to the events listed where possible, and provided a handy list of resources that we routinely consult at the end of the article.

Got it? Good… then without further fanfare, here’s the top 101 astronomical events for 2015 in chronological order:

The path of Comet Q2 Lovejoy From January 1st to January 31st.
The path of Comet Q2 Lovejoy from January 1st to January 31st. Created using Starry Night Education software.


01- Comet C/2012 Q2 Lovejoy may reach naked eye visibility.

04- The Quadrantid meteors peak at 02:00 UT, favoring northern Europe with an expected ZHR of 120.

04- The Earth reaches perihelion at ~8:00 UT.

14- Mercury reaches greatest evening elongation 18.9 degrees east of the Sun at ~16:00 UT.

17- The moons Io and Europa cast a double shadow on Jupiter from 3:53 to 4:58 UT.

20- Mars passes 0.2 degrees from Neptune at ~20:00 UT.

24- A triple shadow transit of Jupiter’s moons occurs from 6:26 to 6:54 UT.

29- The Moon occults Aldebaran at ~17:31 UT for the Arctic, marking the first of 13 occultations of the star by the Moon in 2015.

The view at 6:40 UT.
The view at 6:40 UT on January 24th, as 3 of Jupiter’s moons cast shadows on to the Jovian cloud tops simultaneously. Created using Starry Night Education software.


01- Venus passes 0.8 degrees south of Neptune at ~17:00 UT.

05- Earth crosses through Jupiter’s equatorial plane, marking the middle of occultation and eclipse season for the Galilean moons.

06- Jupiter reaches opposition at ~18:00 UT.

18- A “Black Moon” occurs, in the sense of the third New Moon in a season with four.

22- Venus passes 0.4 degrees south of Mars at 5:00 UT.

24- Mercury reaches greatest morning elongation at 26.7 degrees west of the Sun at 19:00 UT.

25- The Moon occults Aldebaran for northern Europe at 23:26 UT.

Credit: Eclipse-Maps
The path of the only total solar eclipse of 2015, occurring on March 20th. Credit: Michael Zeiler/Eclipse-Maps.


01- Geostationary satellite & Solar Dynamics Observatory eclipse season begins on the weeks leading up to the March Equinox.

04- Venus passes 0.1 degrees north of Uranus at ~18:00 UT. This is the closest planet-planet conjunction of 2015.

05- A Minimoon occurs, marking the most distant Full Moon of 2015 at 18:07 UT, just 10 hours from apogee.

11- Mars passes 0.3 degrees north of Uranus at ~16:00 UT.

20- A total solar eclipse occurs over the Arctic centered on 9:47 UT.

20- The March northward equinox occurs at 22:45 UT.

21- The Moon occults Mars for South America at ~22:14 UT.

25- The Moon occults Aldebaran for northwestern North America at ~7:17 UT.

Neith lives… the close passage of Uranus near Venus on March 4th. Credit: Stellarium.


04- A total lunar eclipse occurs, centered on 12:01 UT and visible from eastern Asia, the Pacific and the Americas.

08- Mercury passes 0.5 degrees from Uranus at ~11:00 UT.

21- The Moon occults Aldebaran for northern Asia at ~16:57 UT.

22- The Lyrid meteors peak at 24:00 UT, favoring northern Europe with a ZHR of 18.


05- The Eta Aquarid meteors peak (time variable), with an estimated ZHR of 55.

07- Mercury reaches greatest evening elongation at 21.2 degrees east of the Sun at 4:00 UT.

19- The Moon occults Aldebaran for northern North America at ~2:53 UT .

20- Comet C/2014 Q1 PanSTARRS may reach binocular visibility.

21- Io and Ganymede both cast shadows on Jupiter from 00:04 to 00:33 UT.

21- Callisto and Europa both cast shadows on Jupiter from 13:26 to 13:59 UT.

23- Saturn reaches opposition at ~1:00 UT.

24- Asteroid 1669 Dagmar occults the +1st magnitude star Regulus at ~16:47 UT for the Arabian peninsula,

the brightest star occulted by an asteroid for 2015. 

28- Ganymede and Io both cast shadows on Jupiter from 02:01 to 04:18 UT.

30- Comet 19P/Borrelly may reach binocular visibility.


01- The International Space Station reaches full illumination as the June solstice nears, resulting in multiple nightly passes favoring  northern hemisphere observers.

04- Io and Ganymede both cast shadows on Jupiter from 4:54 to 6:13 UT.

05- Venus reaches greatest eastern (dusk) elongation for 2015, 45 degrees from the Sun at 16:00 UT.

10- Asteroid 424 Gratia occults a +6.1 magnitude star at ~15:10 UT for northwestern Australia.

15- The Moon occults Mercury for the South Indian Ocean at ~2:26 UT.

15- Moon occults Aldebaran in the daytime for the high Arctic at ~11:33 UT.

16- Comet C/2014 Q1 PanSTARRS may reach naked eye visibility.

21- The June northward solstice occurs at 16:38 UT.

24- Mercury reaches greatest (morning) elongation at 22.5 degrees west of the Sun at 17:00 UT.

Venus and Jupiter pair together low in the west on July 1st. Credit: Stellarium.


01- Venus passes 0.4 degrees from Jupiter at 9:00 UT, marking the closest conjunction of two naked eye planets for 2015.

02- Comet C/2013 US10 Catalina may reach binocular visibility.

06- Earth reaches aphelion at 13:00 UT.

06- Pluto reaches opposition at 15:00 UT, just a week prior to New Horizons’ historic flyby of the distant world.

12- The Moon occults Aldebaran for northeastern Asia ~18:17 UT.

19- The Moon occults Venus for the South Pacific at ~1:07 UT.

25- Asteroid 49 Pales occults a +6.6 magnitude star at 10:55 UT for Mexico.

28- The Delta Aquarids peak (time variable) with a predicted ZHR of 16.

31- A “Blue Moon” occurs, in the sense of the second Full Moon in a given month.

The light curve of comet C/2013 US10 Catalina through its peak in 2015. Credit: Seiichi Yoshida’s Weekly Information About Bright Comets.


07- Mercury, Jupiter and Regulus pass within a degree of each other over the next few evenings.

08- The Moon occults Aldebaran for central Asia at ~23:45 UT.

13- The Perseid meteors peak from 06:30 to 09:00 UT, with a maximum predicted ZHR of 100 favoring North America.

19- Mars crosses the Beehive Cluster M44.

28- Asteroid 16 Psyche occults a +6.4 magnitude star at ~9:49 UT for Bolivia and Peru.

29- Supermoon 1 of 3 for 2015: The Moon reaches Full at 18:38 UT, 20 hours from perigee.

Lunar eclipse
The path of the Moon through the Earth’s shadow on September 28th. Credit: Fred Espenak/NASA/GSFC


01- Neptune reaches opposition at ~3:00 UT.

03- Asteroid 112 Iphigenia occults a +3rd magnitude star for Mexico and Miami at ~9:20 UT. This is the brightest star occulted by an asteroid in 2015 for North America.

02- Geostationary satellite and SDO eclipse season begins as we approach the September equinox.

04- Mercury reaches its greatest elongation for 2015, at 27 degrees east of the Sun at 8:00 UT in the dusk skies.

05- The Moon occults Aldebaran for northeastern North America at ~5:38 UT.

13- “Shallow point” (also known as the minor lunar standstill) occurs over the next lunation, as the Moon’s orbit reaches a shallow minimum of 18.1 degrees inclination with respect to the celestial equator… the path of the Moon now begins to widen towards 2025.

13- A partial solar eclipse occurs, centered on 6:55 UT crossing Africa and the Indian Ocean.

23- The September southward equinox occurs at 8:20 UT.

25- Mars passes 0.8 degrees from Regulus at ~4:00 UT.

28- A total lunar eclipse occurs centered on 2:48 UT, visible from the Pacific, the Americas and eastern Europe.

28- Supermoon 2 of 3 for 2015: The Moon reaches Full at 2:52 UT, approximately an hour from perigee. This marks the closest Full Moon of the year.

The path of the September 3rd occultation of a +3rd magnitude star by an asteroid over central Mexico and the Florida Keys. Credit: IOTA/Steve Preston.


01- Comet C/2013 US10 Catalina may reach naked eye visibility.

02- The Moon occults Aldebaran for the northern Pacific at 13:14 UT.

02- Io and Callisto both cast shadows on Jupiter from 12:26 to 13:35 UT.

08- The Moon occults Venus for Australia at ~20:32 UT.

11- The Moon occults Mercury for Chile at ~12:00 UT.

12- Uranus reaches opposition at ~3:00 UT.

16- Mercury reaches greatest elongation (morning) 18.1 degrees west of the Sun at 10:00 UT.

17- Mars passes 0.4 degrees from Jupiter at 22:00 UT.

18- Io and Ganymede both cast shadows on Jupiter from 10:45 to 12:10 UT.

21- The Orionid meteors peak (time variable) with a projected ZHR of 15.

25- Venus passes 1 degree from Jupiter ~19:00 UT.

25- Io and Ganymede both cast shadows on Jupiter from 12:37 to 14:51 UT.

27- Supermoon 3 of 3 for 2015: The Moon reaches Full at 12:06 UT, 23 hours from perigee.

29- The Moon occults Aldebaran for Europe at ~23:07 UT.

The Moon occults Aldebaran: the visibility footprint for North America. The dashed line denotes the area in which the event occurs during the daytime. Credit: Occult


01- Io and Ganymede both cast shadows on Jupiter from 17:36 to 17:47 UT.

02- Venus passes 0.7 degrees south of Mars at 00:30 UT.

12- Will the 7 year “Taurid fireball meteor shower” produce?

18- The Leonid meteor shower peaks at 04:00 UT, with an estimated ZHR of 15 favoring Europe.

22- Are we in for a once per decade Alpha Monocerotids outburst? The 2015 peak arrives at 4:25 UT, favoring Europe… with a max ZHR = 400+ possible.

26- The Moon occults Aldebaran for North America at ~9:56 UT.

29- Comet C/2013 X1 PanSTARRS may reach binocular visibility.

The daytime occultation of Venus by the Moon over North America on December 7th. Credit: Occult


01- The International Space Station reaches full illumination as the December solstice nears, resulting in multiple nightly passes favoring the  southern hemisphere.

04- Mercury occults the +3.3 magnitude star Theta Ophiuchi for South Africa at 16:16 UT prior to dusk.

06- The Moon occults Mars for central Africa at ~2:42 UT.

07- The Moon occults Venus in the daytime for North America at ~16:55 UT.

14- The Geminid meteor shower peaks at 18:00 UT, with a ZHR=120 favoring NE Asia.

22- The December southward solstice occurs at 4:48 UT.

23- The Ursid meteor shower peaks at 2:30 UT with a ZHR variable from 10-50 favoring Europe and the Middle East.

23- The Moon occults Aldebaran for Europe and central Asia at ~19:32 UT.

29- Mercury reaches greatest evening elongation at 19.7 degrees east of the Sun at 00:01 UT.


Didn’t see your favorite event on the list? Let us know, and be sure to send in any images of these fine events to Universe Today’s Flickr forum.

Enjoy another exciting year of space and astronomy… we’ll be expounding on these events and more as 2015 unfolds.


Occult 4.0

-Kevin McGill’s outstanding astronomical simulations.

-Greatest Elongations of Mercury and Venus.


Starry Night Pro


-Steve Preston’s asteroid occultation predictions for 2015.

-The USNO forecast of phenomena for 2015.

-Seiichi Yoshida’s Weekly Information About Bright Comets.

-Fred Espenak’s NASA Eclipse web page.

-The American Meteor Society’s 2015 predictions.

-The International Meteor Organization’s 2015 page.

-Fourmilab’s lunar perigee and apogee calculator.