David Dickinson, Author at Universe Today

December 23, 2014December 23, 2015 by David Dickinson

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 4^th and September 28^th.

– 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 1^st.

– 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 3^rd.

– 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:

January

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.

February

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.

March

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.

April

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.

May

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.

June

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.

July

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.

August

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

September

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.

October

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.

November

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.

Occultation — The daytime occultation of Venus by the Moon over North America on December 7th. Credit: Occult 4.1.0.11.

December

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.

Sources:

– Occult 4.0

-Kevin McGill’s outstanding astronomical simulations.

-Greatest Elongations of Mercury and Venus.

–Stellarium

–Starry Night Pro

–Orbitron

-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.

December 22, 2014December 23, 2015 by David Dickinson

Comet Q2 Lovejoy Set to Ring in the New Year: Reader Images and More

Keeping warm? Yesterday marked the start of astronomical winter for the northern hemisphere, meaning long nights and (hopefully) clear, cold skies. But we’ve also got another reason to brave the cold this week, as Comet C/2014 Q2 Lovejoy is set to put on a show for northern hemisphere observers.

Already, Comet Q2 Lovejoy has been providing southern hemisphere observers with a fine celestial showing. Discovered by Australian comet hunter extraordinaire Terry Lovejoy on August 17^th of this year as it glided across the constellation Puppis, Q2 Lovejoy has been brightening through early December ahead of expectations. We’ve already been getting some great images from Universe Today readers down south, and we can expect more in the weeks to come. This is Mr. Lovejoy’s fifth comet discovery, and many will remember how comet C/2011 W3 Lovejoy also survived a perilous perihelion passage just 140,000 kilometres from the surface of the Sun during the 2011 holiday season and went on to produce a brilliant display.

Q2 Lovejoy +negative image taken from New Mexico on December 20th. Credit and copyright: Joseph Brimacombe. — Q2 Lovejoy plus negative image taken from New Mexico on December 20th. Credit and copyright: Joseph Brimacombe.

And although Comet 2012 S1 ISON failed to produce in 2014, we had a string of great binocular comets this year, including C/2014 E2 Jacques, K1 PanSTARRS, and A1 Siding Spring.

Currently shining at magnitude +5.5, Q2 Lovejoy is a fine target for binoculars or a small telescope as it crosses the southern constellation of Columba into Lepus just after Christmas Day. Sirius currently makes a good guidepost, as the comet sits about 19 degrees southeast of the brightest star in the sky. And speaking of Sirius, don’t forget to try your hand at spotting its white dwarf companion in 2015!

A black and white view of Comet Lovejoy, taken on Dec. 21, 2014, highlighting the comet's dramatic tail. Credit and copyright: Damian Peach. — A black and white view of Comet Lovejoy, taken on Dec. 21, 2014, highlighting the comet’s dramatic tail. Credit and copyright: Damian Peach.

Q2 Lovejoy also has a high orbital inclination of 80.3 degrees relative to the ecliptic, which is good news, as it will be plunging rapidly northward as it makes its closest passage by Earth on January 7^th at 70.2 million kilometres or 0.47 A.U.s distant. Note that not only will the comet pass extremely close to the globular cluster M79 (photo op!) on the night of December 29^th, but will also pass within 10 degrees of the Pleiades in January before threading its way northward between the famous Double Cluster in Perseus and the Andromeda Galaxy.

Clouded out? You can catch Comet Q2 Lovejoy courtesy of Gianluca Masi and our good friends over at the Virtual Telescope Project live on January 6th and January 11th at 19:00 Universal Time/2:00 PM EST on both dates:

Note: the photo is of Comet C/2014 E2 Jacques from earlier this year. (Credit: the Virtual Telescope Project).

Expect Q2 Lovejoy to ride highest to the south around local midnight starting on January 1^st, and transit the local meridian at 8-9 PM local by mid-month. Keen eyed observers have already managed to spy Q2 Lovejoy unaided from a dark sky site, and we expect this to be the general case for most observers by New Year’s Day. As of this writing, Q2 Lovejoy displays a fine coma 10’ wide with a 7 degree long, fan-shaped tail.

Here’s our handy blow-by-blow for Comet Q2 Lovejoy in the coming weeks:

December

28- Crosses into the constellation Lepus.

29- Passes less than 10’ — a third of the diameter of the Full Moon — from the 7.7 magnitude globular cluster NGC 1904 (Messier 79).

Dec 23rd through February 1st. Credit: Starry Night Education software. — The path of Comet Q2 Lovejoy from December 23rd through February 1st. Credit: Starry Night Education software.

January

1- May break naked eye visibility at magnitude +6.

2- Passes into the constellation Eridanus and reaches opposition at 0.49 A.U.s from the Earth.

5- The Moon reaches Full, hampering observations.

7- May reach a peak brightness at +4^th magnitude.

7- Passes closest to Earth 0.47 AU, moving at an apparent speed of almost 3 degrees a day.

9- Crosses the celestial equator into the constellation Taurus.

17- Crosses the ecliptic plane and into the constellation Aries.

20- Moon reaches New phase, marking a favorable span for observation.

22- Passes within one degree of the 3.6 magnitude star 41 Arietis.

25- Crosses into the constellation Triangulum.

30- Reaches perihelion at 1.29 A.U.

30- Crosses into the constellation Andromeda.

The position of Q2 Lovejoy on New Year’s Day. Credit: NASA/JPL.

February

3- The Moon reaches Full phase, hampering observations.

4- Passes less than one degree from the 2.1 magnitude star Gamma Andromedae (Almach).

18- The Moon reaches New, marking a favorable span of time for observations.

20- Passes less than a degree from the +4th magnitude star Phi Persei and into the constellation Perseus.

March

1- May drop below naked eye visibility.

2- Crosses into the constellation Cassiopeia.

5- The Moon reaches Full phase, hampering observations.

11- Passes less than one degree from the +5 magnitude Owl Cluster.

16- Passes less than one degree from the 2.6 magnitude star Delta Cassiopeiae (Ruchbah).

20- The Moon reaches New, marking a favorable time for observation.

24- Crosses the galactic equator.

April

1- May drop below binocular visibility.

Light curve — The projected light curve of Q2 Lovejoy, with recent observations (black dots). Credit: Seiichi Yoshida’s *Weekly Information About Bright Comets.*

From there, Comet Q2 Lovejoy drops back below +10th magnitude and passes just a degree from the north celestial pole in late May as it heads back out of the inner solar system. Q2 Lovejoy was on a 13,500 year orbit inbound, and its passage through the inner solar system shortened its orbit by about 5,000 years. Just think, about 13 millennia ago, Mesolithic man was busy domesticating early farm animals. Did they, by chance, look up and catch sight of Comet Q2 Lovejoy? And who will be here to ponder its return passage eight millennia hence?

Comet hunting is fun and easy… we prefer to sweep the target area with our trusty Canon 15×45 image stabilized binoculars, though a common pair of 7x 50’s — often favored by hunters and bird watchers — will do just fine. The passage by +7.7 magnitude globular cluster M79 this week will provide a fine contrast in “fuzz balls…” Remember, in comets as in nebulae, the quoted magnitude is often dispersed over a broad surface area, making the objects fainter than a pinpoint star of the same brightness.

And Comet Q2 Lovejoy is the first of several binocular comets to look forward to in 2015. Right now, we’ve got our money on comets C/2014 Q1 PanSTARRS, 19P/Borrelly, C/2013 US10 Catalina, and C/2013 X1 PanSTARRS as possible contenders in 2015. And don’t miss +9th magnitude Comet 15P/Finlay, currently in outburst and playing tag with the planet Mars low in the dusk sky.

Watch this space (bad pun intended) this coming Friday for the low down on all things astronomical in 2015!

-Got pics of Comet Q2 Lovejoy? Send ’em in to Universe Today.

December 17, 2014December 23, 2015 by David Dickinson

Astro-Challenge: Taming the Pup-Can You Glimpse Sirius B?

White dwarf and companion star resolved.

Astronomy is all about thinking big, both in time and space.

The Earth turns on its axis, the Moon passes through its phases, and the planets come into opposition and solar conjunction on a routine basis.

Of course, on the other end of the spectrum, there are some events which traverse such colossal spans of time that the mere mortal life span of measly homo sapiens such as ourselves can never expect to cover them. Many comets have periods measured in centuries, or thousands of years. The axis of the Earth wobbles like a top, completing one turn every 26,000 years in what’s known as the Precession of the Equinoxes. Our solar system completes one revolution about the galactic center every quarter billion years…

Feeling puny yet? Sure, astronomy is also about humility. But among these stupendous cycles, there are some astronomical events that you just might be able to live through. One such instance is the orbits of double stars. And as 2015 approaches, we challenge you to see of the most famous white dwarf of them all, as it reaches a favorable viewing position over the next few years: Sirius B.

Sirius itself is easy to find, as it’s the brightest star in Earth’s sky shining at magnitude -1.42. In fact, you can spot Sirius in the daytime sky if you know exactly where to look.

But it is one of the ultimate in cosmic ironies that the most conspicuous of stars in our sky also hosts such an elusive companion. The discovery of Sirius B awaited the invention of optics capable of resolving it next to its dazzling host. Alvan Clark Jr. and Sr. first spied the enigmatic companion on January 31^st, 1862 while testing their newly constructed 18.5 inch refractor, which was the largest at the time. The discovery was soon verified from the Harvard College Observatory, adding Sirius A and B to the growing list of multiple stars.

A 19th century refractor similar to the one used to discover Sirius B. Photo by the author.

And what a strange companion it turned out to be. Today, we know that Sirius B is a white dwarf, the cooling dense ember of a main sequence star at the end of its life. We call the matter in such a star degenerate, not as a commentary on its moral stature, but the state the electrons and the closely packed nuclei within under extreme pressure. Our Sun will share the same ultimate fate as Sirius B, about six billion years from now.

The challenge, should you choose to accept it, is to spot Sirius B in the glare of its host. The contrast in brightness between the pair is daunting: shining at magnitude +11, the B companion is more than 63,000 times fainter than -1.46 magnitude Sirius A.

The changing position angle of Sirius B. Note that the graphic is inverted, with north at the bottom. Created by the author.

A feat of visual athletics, indeed. Still, Sirius B breaks 10” in separation from its primary in 2015, as it heads towards apastron — its most distant point from its primary, at just over 11” in separation — in 2019. Sirius B varies from 8.2 and 31.5 AUs from its primary. Sirius B is on a 50.1 year orbit, meaning the time to cross this one off of your life list is over the upcoming decade. Perhaps making an animation showing the motion of Sirius B from 2015-2025 would present a supreme challenge as well.

Sirius culminates at local midnight right around New Year’s Eve, shining at its highest to the south as the “ball drops” ushering in 2015. Of course, this is only a fortuitous circumstance that is possible in our current epoch, and precession and the proper motions of both Sirius and Sol will make this less so millennia hence.

Sirius crossing the meridian at local midnight on New Year’s Eve. Credit: Stellarium.

Newsflash: there’s a very special visual treat in the offing next week, as comet C/2014 Q2 Lovejoy is currently hovering around +6^th magnitude and passes 19 degrees south of Sirius on Christmas Day… more to come!

Magnification and good seeing are your friends in the hunt for Sirius B. Two factors describe the position of a secondary star in a binary pair: its position angle in degrees, and separation in arc seconds. When it comes to stars that are a tough split, I find its better to estimate the position angle first before looking it up. A close match can often confirm the observation. Does a friend see the same thing at the eyepiece? A good star to “warm up” on is the +6.8 magnitude companion to Rigel in the foot of Orion, with a separation of 9”.

Nudging Sirius just out of view might allow the B companion to become apparent. Another nifty star-spliting tool is what’s known as an occulting bar eyepiece. Making an occultation bar eyepiece is easy: we’ve used everything from a small strip of foil to a piece of guitar string (heavy E gauge works nicely) for the central bar. An occulting bar eyepiece is also handy for hunting down the moons of Mars near opposition.

Sirius B also works its way into cultural myths and lore, not the least of which are the curious tales of the Dogon people of Mali. At the outset, it seems that these ancient people have knowledge of a small dense hidden companion star to Sirius, knowledge that requires modern technology to reproduce. Carl Sagan noted, however, that cultural contamination may have resulted in the late 19^th century discovery of Sirius B making its way into the Dogon pantheon. The science of anthropology is rife with anecdotes that have been carefully fed to credulous anthropologists only to be reported later as fact, all in the name of a good story.

All amazing things to ponder as you begin your 2015 quest for Sirius B, a bashful but fascinating star.

– Read more on the curious case of the Dogon and Sirius B.

-Want more white dwarfs? Here’s a handy list of white dwarfs of backyard telescopes.

December 11, 2014December 23, 2015 by David Dickinson

The Curious History of the Geminid Meteors

UPDATE: Tune in this Sunday as the good folks over at the Virtual Telescope Project feature a live webcast covering the Geminid meteor shower this Sunday on December 14th at 2:00 UT.

This weekend presents a good reason to brave the cold, as the Geminid meteor shower peaks on the morning of Sunday, December 14th. The Geminids are dependable, with a broad peak spanning several days, and would be as well known as their summer cousins the Perseids, were it not for the fact that they transpire in the dead of northern hemisphere winter.

But do not despair. While some meteor showers are so ephemeral as to be considered all but mythical in the minds of most meteor shower observers, the Geminids always deliver. We most recently caught a memorable display of the Geminids in 2012 from a dark sky locale in western North Carolina. Several meteors per minute pierced the Appalachian night, offering up one of the most memorable displays by this or any meteor shower in recent years.

The Geminids are worth courting frostbite for, that’s for sure. But there’s a curious history behind this shower and our understanding of meteor showers in general, one that demonstrates the refusal of some bodies in our solar system to “act right” and fit into neat scientific paradigms.

A composite of the 2013 Geminids. Credit: the UK Meteor Observation Network

It wasn’t all that long ago that meteor showers — let alone meteorites — were not considered to be astronomical in origin at all. Indeed, the term meteor and meteorology have the same Greek root meaning “of the sky,” suggesting ideas of an atmospheric origin. Lightning, hail, meteors, you can kind of see how they got there.

In fact, you could actually face ridicule for suggesting that meteors had an extraterrestrial source back in the day. President Thomas Jefferson was said to have done just that concerning an opinion espoused by Benjamin Silliman of a December 14^th, 1807, meteorite fall in Connecticut, leading to the apocryphal and politically-tinged response attributed to the president that, “I would more easily believe that two Yankee professors would lie, than that stones would fall from heaven.”

Indeed, no sooner than The French Academy of Sciences considered the matter settled earlier in the same decade, then a famous meteorite fall occurred in Normandy on April 26^th, 1803,… right on their doorstep. The universe, it seemed, was thumbing its nose at scientific enlightenment.

A fine Geminid — A fine 2004 Geminid as imaged by Frankie Lucena.

Things really heated up with the spectacular display known as the Leonid meteor storm in 1833. On that November morning, stars seemed to fall like snowflakes from the sky. You can imagine the sight, as the Earth plowed headlong into the meteor stream. The visual effect of such a storm looks like the starship Enterprise plunging ahead at warp speed with stars streaming by, as if imploring humanity to get hip to the fact that meteor showers and their radiants are indeed a reality.

Still, a key problem persisted that gave ammunition to the naysayers: no new “space rocks” were found littering the ground at sunrise after a meteor shower. We now know that this is because meteor showers hail from wispy cometary debris left along intersections of the Earth’s orbit. Meteorite Man Geoff Notkin once mentioned to us that no meteorite fall has ever been linked to a meteor shower, though he does get lots of calls around Geminid season.

The name of the game in the 19^th century soon became identifying new meteor showers. Streams evolve over time as they interact with planets (mostly Jupiter), and the 19^th century played host to some epic meteor storms such as the Andromedids that have since been reduced to a trickle.

The Geminids are, however, the black sheep of the periodic meteor shower family. The shower was first noticed by US and UK observers in 1862, and by the 1870s astronomers realized that a new minor shower with a Zenithal Hourly Rate (ZHR) hovering around 15 was occurring near the middle of December from the constellation Gemini.

A possible early 2014 Geminid and the near Full Moon as seen by NASA’s All Sky Fireball Network.

The source of the Geminids, however, was to remain a mystery right up until the late 20^th century.

In the late 1940s, astronomer Fred Whipple completed the Harvard Meteor Project, which utilized a photographic survey that piqued the interest of astronomers worldwide: debris in the Geminid stream appeared to have an orbital period of just 1.65 years, coupled with a high orbital inclination. Modeling suggested that the parent body was most likely a short period comet, and that the stream had undergone repeated perturbations courtesy of Earth and Jupiter.

In 1983, the culprit was found, only to result in a deeper mystery. The Infrared Astronomical Satellite (IRAS) discovered an asteroid fitting the bill crossing the constellation Draco. Backup observations from the Palomar observatory the next evening cinched the discovery, and today, we recognize the source of the Geminids as not a comet — as is the case with every other major meteor shower — but asteroid 3200 Phaethon, a 5 kilometre diameter rock in a 524 day orbit.

So why doesn’t this asteroid behave like one? Is 3200 Phaethon a rogue comet that has long since settled down for the quiet space rock life? Obviously, 3200 Phaethon has lots of material shedding off from its surface, as evidenced by the higher than normal ratio of fireballs seen during the Geminid meteors. 3200 Phaethon also passes 0.14 AUs from the Sun — 47% closer than Mercury — and has the closest perihelion of any known asteroid to the Sun, which bakes the asteroid periodically with every close pass.

One thing is for certain: activity linked to the Geminid meteor stream is increasing. The Geminids actually surpassed the Perseids in terms of dependability and output since the 1960s, and have produced an annual peak ZHR of well over 100 in recent years. In 2014, expect a ZHR approaching 130 per hour as seen from a good dark sky site just after midnight local on the morning of December 14th as the radiant rides high in the sky. Remember, this shower has a broad peak, and it’s worth starting your vigil on Saturday or even Friday morning. The Geminid radiant also has a steep enough declination that local activity can start before midnight… also exceptional among meteor showers. This year, the 52% illuminated Moon rises around midnight local on the morning of December 14^th.

And there’s another reason to keep an eye on the 2014 Geminids. 3200 Phaethon passed 0.12 AU (18 million kilometers) from Earth on December 10^th, 2007, which boosted displays in the years after. And just three years from now, the asteroid will pass even closer on December 10^th, 2017, at just 0.07 AUs (10.3 million kilometers) from Earth…

Are we due for some enhanced activity from the Geminids in the coming years?

All good reasons to bundle up and watch for the “Tears of the Twins” this coming weekend, and wonder at the bizzaro nature of the shower’s progenitor.

December 3, 2014December 23, 2015 by David Dickinson

Rise of the Mega Rockets: Comparing Heavy Lift Launch Systems

An Ariane 5 heads spaceward. Credit: Ariane.tv screenshot.

A new generation of space rockets ready to lift new and exciting payloads spaceward is coming to a sky near you.

Tomorrow, a Delta IV Heavy rocket will boost the Orion space capsule on a two orbit journey around the Earth that will test key systems. And though tomorrow’s launch is uncrewed, the Orion Command Module will one day form the core of NASA’s Orion MPCV Multi-Purpose Crew Vehicle and is slated to care out humanity’s first mission to an asteroid and beyond in the next decade.

But a second, lesser known launch also leaves Earth tomorrow as well, atop a rocket that will soon give way to a new generation of lift boosters as launch services vie for new customers. Just over eight hours after the launch of EFT-1, an Ariane 5 rocket lifts off from French Guiana with GSAT-16.

Credit Jason Major. — The EFT-1 Delta IV Heavy posed for roll out. Credit: Jason Major. @JPMajor

Is the ‘battle of the boosters’ heating up?

This comes after the December 2^nd announcement earlier this week by participating members of the European Space Agency to proceed with the development of the next generation Ariane 6 rocket. Also included in the 5.9 billion Euro (7.3 billion USD) budget proposal is funding for the 2018 ExoMars mission, along with further support of ESA’s International Space Station commitments.

To date, ESA has fielded five of its Automated Transfer cargo Vehicles (ATVs) on missions to the International Space Station. ESA will also design the Service Module segment of the Orion MPCV.

“I can summarize this ministerial council by say it was a success… I’d even go so far as to say that it is a great success,” said Jean-Jacques Dordain, the director-general of the European Space Agency.

The Ariane 6 is expected to be on the launch pad by 2020, and will feature two variants capable of placing 5 to 11 tonnes in a geostationary transfer orbit. The solid fuel booster to be incorporated will be based on the Vega rocket design, while the upper stage Vinci engine is already currently in development.

Ariane 6. Credit Wikimedia Commons, SkywalkerPL. — A look at the Ariane 6 rocket. Credit Wikimedia Commons, SkywalkerPL.

The design has been hotly contested among European Space Agency members, many of whom are in favor of other variants based on the upgraded Ariane 5. Some of the largest rockets of all time included those developed by NPO Energia, capable of lofting 100,000 kilograms into low Earth orbit. An Energia N1 Moon rocket exploded on the pad on July 3^rd 1969, effectively ending the Soviet Union’s bid to put a man on the Moon. In comparison, the massive Saturn V rocket — thus far, the largest and most powerful ever fielded by the United States — could deploy the equivalent of 118,000 kg to low Earth orbit and 47,000 kg to a Trans-Lunar Insertion orbit around the Moon.

But that’s just the beginning. Though the Orion capsule will ride atop a United Launch Services Delta IV Heavy tomorrow — a system usually employed for launching clandestine spy satellites — NASA hopes to have its own Space Launch System (SLS) rocket sitting on the pad by the end of 2018. Boeing was awarded the contract for SLS earlier this year, and the system largely rose re-imagined from the ashes of the cancelled Constellation program. The SLS Block 1 is expected to have a lift capacity of 70,000 kg to LEO, while Boeing’s proposed SLS Block 2 variant would, if fielded, have the largest lift capacity of all time at 130,000 kg to LEO. Only the Long March 9 proposed by China approaches that lofty goal.

An artist’s concept of Orion headed towards deep space. Credit: NASA.

And the wild card is Elon Musk’s SpaceX. Already in the game of sending cargo via its Dragon spacecraft to the ISS, SpaceX is developing a reputation for dependability when it comes to getting satellites into orbit at relatively low cost. SpaceX hopes to field its Falcon 9 Heavy with a lift capacity of 53,000 kg to LEO sometime in 2015, and many proposed missions are banking on the the Falcon 9 Heavy as a future service provider for solar system exploration. Certainly, with the recent failure of the Antares rocket on October 28th, SpaceX may look like the more attractive option to many, and the development of the Ariane 6 is expected to face stiff competition in the brave new world of high tech rocketry.

Ever wonder what all of these launch vehicles and spacecraft past and present look like stacked up against each other? There’s a graphic for that, recently featured on Io9:

Credit: Heaney555 — A breakdown and comparison of spacecraft launch systems. Click to enlarge. Credit: Reddit user Heaney555.

From Almaz to Zarya, this is a fascinating study in scale comparison. Be sure to zoom in and check out the tiny ant-like crew compliment of each, also to scale. Of course, the backyard satellite-tracker in us can’t help be notice the brightness-versus size comparison for many of these. For example, the International Space Station on a good pass can appear as bright as Venus at -4^th magnitude — and even look “TIE Fighter shaped” in binoculars — while the smaller Shenzhou and Soyuz modules are often barely visible as they pass overhead. And how we miss watching the Shuttle paired with the International Space Station as they both glided silently by:

But such orbital drama can still be caught if you know when and where to look for it. And speaking of which, viewers in western Australia and the southwestern United States may be able to see Orion and EFT-1 on its first lap around the Earth tomorrow before it fires its engines over the Atlantic headed for a 5,800 km apogee over southern Africa. Assuming EFT-1 lifts off at the beginning of its 159 minute launch window at 7:05 AM EST/12:05 UT, expect it to see it crossing dusk skies over western Australia at 55 minutes after liftoff, and dawn skies for the southwestern U.S. at 95 minutes post-launch respectively.

An awesome sight to behold indeed, marking the start of a brave new era of space exploration.

So what do you, the astute and space-minded reader of Universe Today think? Are the SLS and its kin the lift vehicle(s) of the future, or ‘rockets to nowhere?’ Will they survive the political winds that are bound to blow over the coming decade? Will the Ariane 6 best the Falcon 9 as the lift platform of choice?

One thing is for sure, expect coverage of space exploration drama and more to continue here at Universe Today!

December 1, 2014December 23, 2015 by David Dickinson

Watch Asteroids Whiz by the Earth-Moon System This Week as First Steps Toward Asteroid Exploration Leave the Launch Pad

It’s a dangerous universe out there, for a budding young space-faring species.

Killer comets, planet sterilizing gamma ray bursts, and death rocks from above are all potential hazards that an adolescent civilization has to watch out for.

This week offers two close shaves, as newly discovered Near Earth Asteroids (NEAs) 2014 WC201 and 2014 WX202 pass by the Earth-Moon system.

The passage of 2014 WC201 is coming right up tonight, as the 27-metre space rock passes about 570,000 kilometres from the Earth. That’s 1.4 times farther than the distance from the Earth to the Moon.

Credit: JPL — The orbit of 2014 WC201. Credit: NASA/JPL.

And the good news is, the Virtual Telescope Project will be bringing the passage of 2014 WC201 live tonight starting at 23:00 Universal Time/6:00 PM EST.

Shining at an absolute magnitude of +26, 2014 WC201 will be visible as a +13 apparent magnitude “star” at closest approach at 4:51 UT (December 2^nd)/11:51 PM EST (December 1^st) moving through the constellation Ursa Major. This puts it within range of a large backyard telescope, though the 80% illuminated waxing gibbous Moon will definitely be a mitigating factor for observation.

The JPL Horizons ephemerides generator is an excellent place to start for crafting accurate coordinates for the asteroid for your location.

At an estimated 27 metres/81 feet in size, 2014 WC201 will no doubt draw “house-sized” or “building-sized” comparisons in the press. Larger than an F-15 jet fighter, asteroids such as WC201 cry out for some fresh new descriptive comparisons. Perhaps, as we near a “Star Wars year” in 2015, we could refer to 2014 WC201 as X-wing sized?

Another Apollo NEO also makes a close pass by the Earth this week, as 6-metre 2014 WX202 passes 400,000 kilometres (about the same average distance as the Earth to the Moon) from us at 19:56 UT/2:56 PM EST on December 7^th. Though closer than WC201, WX202 is much smaller and won’t be a good target for backyard scopes. Gianluca Masi over at the Virtual Telescope Project also notes that WX202 will also be a difficult target due to the nearly Full Moon later this week.

The last Full Moon of 2014 occurs on December 6th at 6:26 AM EST/11:26 Universal Time.

2014 WX202 has also generated some interest in the minor planet community due to its low velocity approach relative to the Earth. This, coupled with its Earth-like orbit, is suggestive of something that may have escaped the Earth-Moon system. Could WX202 be returning space junk or lunar ejecta? It’s happened before, as old Apollo hardware and boosters from China’s Chang’e missions have been initially identified as Near Earth Asteroids.

The Earth also occasionally hosts a temporary “quasi-moon,” as last occurred in 2006 with the capture of RH120. 2014 WX202 makes a series of more distant passes in the 2030s, and perhaps it will make the short list of near Earth asteroids for humans to explore in the coming decades.

And speaking of which, humanity is making two steps in this direction this week, with two high profile space launches.

First up is the launch of JAXA’s Hayabusa 2 from the Tanegashima Space Center on December 3rd at 4:22 UT/11:22 PM EST. The follow up to the Hayabusa asteroid sample return mission, Hayabusa 2 will rendezvous with asteroid 1999 JU₃ in 2018 and return samples to Earth in late 2020. The vidcast for the launch of Hayabusa 2 goes live at 3:00 UT/10:00 PM EST on Tuesday, December 2^nd.

And the next mission paving the way towards first boot prints on an asteroid is the launch of a Delta 4 Heavy rocket with EFT-1 from Cape Canaveral this Thursday morning on December 4^th near sunrise at 7:05 AM EST/12:05 UT. EFT-1 is uncrewed, and will test key technologies including reentry on its two orbit flight. Expect to see crewed missions of Orion to begin around 2020, with a mission to an Earth crossing asteroid sometime in the decade after that.

And there are some decent prospects to catch sight of EFT-1 on its first pass prior to its orbit raising burn over the Atlantic. Assuming EFT-1 lifts off at the beginning of its launch window, western Australia may see a good dusk pass 55 minutes after liftoff, and the southwestern U.S. may see a visible pass at dawn about 95 minutes after EFT-1 leaves the pad.

The footprint of EFT-1 on its first North American pass. Credit: Orbitron.

We’ll be tracking these prospects as the mission evolves on launch day via Twitter, and NASA TV will carry the launch live starting at 4:30 AM EST/9:30 UT.

The Orion capsule will come in hot on reentry at a blistering 32,000 kilometres per hour over four hours after liftoff in a reentry reminiscent of the early Apollo era.

Of course, if an asteroid the size of WC201 was on a collision course with the Earth it could spell a very bad day, at least in local terms. For comparison, the 2013 Chelyabinsk meteor was estimated to be 18 metres in size, and the 1908 Tunguska impactor was estimated to be 60 metres across. And about 50,000 years ago, a 50 metre in diameter space rock came blazing in over the ponderosa pine trees near what would one day be the city of Flagstaff, Arizona to create the 1,200 metre diameter Barringer Meteor Crater you can visit today.

A fragment of the Barringer meteorite on display at the Lowell Observatory. Photo by author.

All the more reason to study hazardous space rocks and the technology needed to reach one in the event that we one day need to move one out of the way!

November 28, 2014December 23, 2015 by David Dickinson

Here’s Your Sign: Are You an Ophiuchian?

It happens to all lovers of astronomy sooner or later.

I once had a friend who was excited about an upcoming conjunction of Saturn and Venus. They were passing closer than the apparent diameter of the Full Moon in the dawn sky, and you could fit ‘em both in the same telescopic field of view. I invited said friend to stop by at 5 AM the next morning to check this out. I was excited to see this conjunction as well, but not for the same reasons.

Said friend was into astrology, and I’m sure that the conjunction held a deep significance in their world view. Sure, I could have easily told them that ‘astrology is bunk,’ and the skies care not for our terrestrial woes… or I could carefully help guide this ‘at risk friend’ towards the true wonders of the cosmos if they were willing to listen.

We bring this up because this weekend, the Sun enters the constellation Ophiuchus, one of 13 modern constellations that it can appear in from our Earthly vantage point.

If you’re born from November 30^th to December 18^th, you could consider yourself an “Ophiuchian,” or being born under the sign of Ophiuchus the Serpent Bearer. But I’ll leave it up to you to decide what they might be like.

You might remember how the “controversy” of the 13^th sign made its news rounds a few years back. Hey, it was cool to at least see an obscure and hard to pronounce constellation trending on Twitter. Of course, this wasn’t news to space enthusiasts, and to modern astronomers, a ‘house’ is merely where you live, and a ‘sign’ is what you follow to get there.

The modern 88 constellations we use were formalized by the International Astronomical Union in 1922. Like political boundaries, they’re imaginary constructs we use to organize reality. Star patterns slowly change with time due to our solar system’s motion — and that of neighboring stars —about the galactic center.

Astrologers will, of course, counter that their craft follows a tropical scheme versus a sidereal cosmology. In the tropical system, ecliptic longitude 0 starts from the equinoctial point marking the beginning of spring in the northern hemisphere, and the zodiac is demarcated by 12 ‘houses’ 30 degrees on a side.

This neatly ignores the reality of our friend, the precession of the equinoxes. The Earth’s poles do a slow wobble like a top, taking about 26,000 years to make one turn. This means that in the sidereal scheme of things, our vantage point of the Sun’s position along the zodiac against the background stars if reference to our Gregorian calendar is slowly changing: live out a 72 year lifespan, and the constellations along the zodiac with respect to the Sun will have shifted about one degree due to precession.

Our changing pole star. Credit: Starry Night Education Software.

Likewise, the direction of the North and South Pole is changing as well. Though Polaris makes a good pole star now, it’ll become increasingly less so as our north rotational pole begins to pull away from it after 2100 A.D. To the ancient Egyptians, Thuban (Alpha Draconis) was the pole star.

Credit: Wikimedia Commons — Precession over time. Credit: Tfr000 under Wikimedia Creative Commons 3.0 license.

Astrology and astronomy also have an intimate and hoary history, as many astronomers up until the time of Kepler financed their astronomical studies by casting royal horoscopes. And we still use terms such as appulse, conjunction and occultation, which have roots in astrology.

But the science of astronomy has matured beyond considering whether Mercury in retrograde has any connection with earthly woes. Perhaps you feel that you’re unlucky in love and have a vast untapped potential… sure, me too. We all do, and that just speaks to the universal state of the human condition. Astrology was an early attempt by humanity to find a coherent narrative, a place in the cosmos.

But the rise of the Ophiuchians isn’t nigh. Astrology relented to astronomy because of the latter’s true predictive power. “Look here, in the sky,” said mathematician Urbain Le Verrier, “and you’ll spy a new planet tugging on Uranus,” and blam, Neptune was discovered. If the planets had any true influence on us, why didn’t astrologers manage to predict the same?

Combating woo such as astrology is never simple. In the internet era, we often find tribes of the like-minded folks polarized around electronic camp fires. For example, writing ‘astrology is woo’ for an esteemed audience of science-minded readers such as Universe Today will no doubt find a largely agreeable reception. We have on occasion, however, written the same for a general audience to a much more hostile reception. Often, it’s just a matter of being that lone but patient voice of rationalism in the woods that ultimately sinks in.

So, what’s the harm? Folks can believe whatever they want, and astrology’s no different, right? Well, the harm comes when people base life decisions on astrology. The harm comes when world leaders make critical decisions after consulting astrologers. Remember, Nancy and President Ronald Reagan conferred with astrologers for world affairs. It’s an irony of the modern age that, while writing a take down on astrology, there will likely be ads promoting astrology running right next to this very page. And while professional astronomers spend years in grad school, you can get a “PhD in Astrology” of dubious value online for a pittance. And nearly every general news site has a astrology page. Think of the space missions that could be launched if we threw as much money at exploration as we do at astrology as a society. Or perhaps astronomers should revert back to the dark side and resume casting horoscopes once again?

But to quote Spiderman, “with great power comes great responsibility,” and we promise to only use our astronomical powers for good.

What astronomers want you to know is that we’re not separate from the universe above us, and that the cosmos does indeed influence our everyday lives. And we’re not talking about finding your car keys or selling your house. We’re thinking big. The Sun energizes and drives the drama of life on Earth. The atoms that make you the unique individual that you are were forged in the hearts of stars. The ice that chills our drink may well have been delivered here via comet. And speaking of which, a comet headed our way could spell a very bad day for the Earth.

P_20130928_083416 — Don’t leave home without one… a travelling “pocket planetarium” circa 16th century seen at the Tampa Bay History Center. Photo by author.

All of these are real things that astronomy tells us about our place in the cosmos, whether you’re an Ophiuchian or a Capricorn. To paraphrase Shakespeare, the heavens may (seem to) blaze forth for the death of princes, but the fault lies not in the heavens, but ourselves. Don’t forget that, as James Randi says, “you’re a member of a proud species,” one loves to look skyward, and ultimately knows when to discard fantasy for reality.

November 20, 2014December 23, 2015 by David Dickinson

A Thousand Days ‘Til Totality: Anticipating the 2017 Solar Eclipse

The total solar eclipse of November 2012 as seen from

Where will YOU be on August 21^st, 2017?

Astronomy is all about humility and thinking big in terms of space and time. It’s routine for astronomers to talk of comets on thousand year orbits, or stars with life spans measured in billions of years…

Yup, the lifespan of your average humanoid is indeed fleeting, and pales in comparison to the universe, that’s for sure. But one astronomical series that you can hope to live through is the cycle of eclipses.

I remember reading about the total solar eclipse of February 26^th, 1979 as a kid. Carter was in the White House, KISS was mounting yet another comeback, and Voyager 1 was wowing us with images of Jupiter. That was also the last total solar eclipse to grace mainland United States in the 20^th century.

But the ongoing “eclipse-drought” is about to be broken.

The path of totality across the United States on August 21st, 2017. Credit: Great American Eclipse.com.

One thousand days from this coming Monday, November 24^th on August 21^st 2017, the shadow of the Moon will touch down off of the Oregon coast and sweep eastward across the U.S. heartland before heading out to the Atlantic off of the coast of South Carolina. Millions live within a days’ drive of the 115 kilometre wide path, and the eclipse has the added plus of occurring at the tail end of summer vacation season. This also means that lots of folks will be camping and otherwise mobile with their RVs and able to journey to the event.

The Great American Eclipse of 2017 from Michael Zeiler on Vimeo.

This is also the last total solar eclipse to pass over any of the 50 United States since July 11^th, 1991, and the first eclipse to cross the contiguous United States from “sea to shining sea” since way back on June 8^th, 1918.

Think it’s too early to prepare? Towns across the path, including Hopkinsville, Kentucky and towns in Kansas and Nebraska are already laying plans for eclipse day. Other major U.S. cities, such as Nashville, Idaho Falls, and Columbia, South Carolina also lie along the path of totality, and the spectacle promises to spawn a whole new generation of “umbraphiles” or eclipse chasers.

A total solar eclipse is an unforgettable sight. But unlike a total lunar eclipse, which can be viewed from the moonward-facing hemisphere of the Earth, one generally has to journey to the narrow path of totality to see a total solar eclipse. Totality rarely comes to you.

Viewing — The Zeilers view the November 2013 eclipse from Africa. Credit: Michael Zeiler.

And don’t settle for a 99% partial eclipse just outside the path. “There’s no comparison between partial and total solar eclipses when it comes to sheer grandeur and beauty,” Michael Zeiler, longtime eclipse chaser and creator of the Great American Eclipse website told Universe Today. We witnessed the 1994 annular solar eclipse of the Sun from the shores of Lake Erie, and can attest that a 99% partial eclipse is still pretty darned bright!

There are two total solar eclipses remaining worldwide up until 2017: One on March 20^th, 2015 crossing the high Arctic, and another on March 9th 2016 over Southeast Asia. The 2017 eclipse offers a maximum of 2 minutes and 41 seconds of totality, and weather prospects for the eclipse in late August favors viewers along the northwestern portion of the track.

And though an armada of cameras will be prepared to capture the eclipse along its trek across the U.S., many veteran eclipse chasers suggest that first time viewers merely sit back and take in the moment. The onset of totality sees a bizarre sort of twilight fall across the landscape, as shadow bands skip across the countryside, temperatures drop, and wildlife is fooled into thinking that nightfall has come early.

And then, all too soon, the second set of blinding diamond rings burst through the lunar valleys, the eclipse glasses go back on, and totality is over. Which always raises the question heard throughout the crowd post-eclipse:

When’s the next one?

Well, the good news is, the United States will host a second total solar eclipse on April 8^th, 2024, just seven years later! This path will run from the U.S. Southwest to New England, and crisscross the 2017 path right around Carbondale, Illinois.

Will the woo that surfaced around the approach of Comet ISON and the lunar tetrad of “blood Moon eclipses” rear its head in 2017? Ah, eclipses and comets seem to bring ‘em out of the woodwork, and 2017 will likely see a spike in the talking-head gloom and doom videos ala YouTube. Some will no doubt cite the “perfection” seen during total solar eclipses as proof of divine inspiration, though this is actually just a product of our vantage point in time and space. In fact, annular eclipses are slightly more common than total solars in our current epoch, and will become more so as the Moon slowly recedes from the Earth. And we recently noted in our post on the mutual phenomena of Jupiter’s moons that solar eclipses very similar to those seen from the Earth can also be spied from Callisto.

Heads up to any future interplanetary eclipse resort developer: Callisto is prime real estate.

Forget Mars... "Get your ass to totality!" — Forget Mars… “Get your ass to totality!” Credit: Great American Eclipse.

The 2017 total solar eclipse across America will be one for the history books, that’s for sure.

So get those eclipse safety glasses now, and be sure to keep ‘em handy through 2017 and onward to 2024!

-Read Dave Dickinson’s eclipse-fueled science fiction tales Shadowfall and Exeligmos.

November 19, 2014December 23, 2015 by David Dickinson

Observing Challenge: Watch Asteroid 3 Juno Occult a +7th Magnitude Star Tonight

One of the better asteroid occultations of 2014 is coming right up tonight, and Canadian and U.S. observers in the northeast have a front row seat.

The event occurs in the early morning hours of Thursday, November 20th, when the asteroid 3 Juno occults the 7.4 magnitude star SAO 117176. The occultation kicks off in the wee hours as the 310 kilometre wide “shadow” of 3 Juno touches down and crosses North America from 6:54 to 6:57 Universal Time (UT), which is 12:54 to 12:57 AM Central, or 1:54 to 1:57 AM Eastern Standard Time.

The path of tomorrow’s occultation along with the circumstances. Credit: Steve Preston’s Asteroid Occultation website.

The maximum predicted length of the occultation for observers based along the centerline is just over 27 seconds. Note that 3 Juno also shines at magnitude +8.5, so both it and the star are binocular objects. The event will sweep across Winnipeg and Lake of the Woods straddling the U.S. Canadian border, just missing Duluth Minnesota before crossing Lake Superior and over Ottawa and Montreal and passing into northern Vermont and New Hampshire. Finally, the path crosses over Portland Maine, and heads out to sea over the Atlantic Ocean.

Don’t live along the path? Observers worldwide will still see a close pass of 3 Juno and the +7^th magnitude star as both do their best to impersonate a close binary pair. If you’ve never crossed spotting 3 Juno off of your astro-“life list,” now is a good time to try.

The position of the target star HIP43357/SAO 117176 is:

Right Ascension: 8 Hours 49’ 54”

Declination: +2° 21’ 44”

A finder chart for 3 Juno and HIP43357. Stars are noted down to +10th magnitude. Created using Starry Night Education software.

Generally, the farther east you are along the track, the higher the pair will be above the horizon when the event occurs, and the better your observing prospects will be in terms of altitude or elevation. From Portland Maine — the last port of call for the shadow of 3 Juno on dry land — the pair will be 35 degrees above the horizon in the constellation of Hydra.

The projected sky cover at the time of the occultation. Credit: NWS/NOAA.

As always, the success in observing any astronomical event is at the whim of the weather, which can be fickle in North America in November. As of 48 hours out from the occultation, weather prospects look dicey, with 70%-90% cloud cover along the track. But remember, you don’t necessarily need a fully clear sky to make a successful observation… just a clear view near the head of Hydra asterism. Remember the much anticipated occultation of Regulus by the asteroid 163 Erigone earlier this year? Alas, it went unrecorded due to pesky but pervasive cloud cover. Perhaps this week’s occultation will fall prey to the same, but it’s always worth a try. In asteroid occultations as in free throws, you miss 100% of the shots that you don’t take!

IOTA — The path of the occcultation across eastern North America. Credit: Google Earth/BREIT IDEAS observatory.

Why study asteroid occultations? Sure, it’s cool to see a star wink out as an asteroid passes in front of it, but there’s real science to be done as well. Expect the star involved in Thursday’s occultation to dip down about two magnitudes (six times) in brightness. The International Occultation Timing Association (IOTA) is always seeking careful measurements of asteroid occultations of bright stars. If enough observations are made along the track, a shape profile of the target asteroid emerges. And the possible discovery of an “asteroid moon” is not unheard of using this method, as the background star winks out multiple times.

UT-Juno Occultation — 3 Juno as imaged by the 100″ Hooker telescope at the Mt. Wilson observatory at different wavelengths using adaptive optics. Credit: NASA/JPL/The Harvard Smithsonian Center for Astrophysics.

3 Juno was discovered crossing Cetus by astronomer Karl Harding on September 1^st, 1804 from the Lilienthal Observatory in Germany. The 3^rd asteroid discovered after 1 Ceres and 2 Pallas, 3 Juno ranks 5^th in size at an estimated 290 kilometres in diameter. In the early 19^th century, 3 Juno was also considered a planet along with these other early discoveries, until the ranks swelled to a point where the category of asteroid was introduced. A denizen of the asteroid belt, 3 Juno roams from 2 A.U.s from the Sun at perigee to 3.4 A.U.s at apogee, and can reach a maximum brightness of +7.4th magnitude as seen from the Earth. No space mission has ever been dispatched to study 3 Juno, although we will get a good look at its cousin 1 Ceres next April when NASA’s Dawn spacecraft enters orbit around the king of the asteroids.

3 Juno reaches opposition and its best observing position on January 29^th, 2015.

3 Juno also has an interesting place in the history of asteroid occultations. The first ever predicted and successfully observed occultation of a star by an asteroid involved 3 Juno on February 19^th, 1958. Another occultation involving the asteroid on December 11^th, 1979 was even more widely observed. Only a handful of such events were caught prior to the 1990s, as it required ultra-precise computation and knowledge of positions and orbits. Today, dozens of asteroid occultations are predicted each month worldwide.

Observing an asteroid occultation can be challenging but rewarding. You can watch Thursday’s event with binoculars, but you’ll want to use a telescope to make a careful analysis. You can either run video during the event, or simply watch and call out when the star dims and brightens as you record audio. Precise timing and pinpointing your observing location via GPS is key, and human reaction time plays a factor as well. Be sure to locate the target star well beforehand. For precise time, you can run WWV radio in the background.

And finally, you also might see… nothing. Asteroid paths have a small amount of uncertainty to them, and although these negative observations aren’t as thrilling to watch, they’re important to the overall scientific effort.

Good luck, and let us know of your observational tales of anguish and achievement!

November 14, 2014December 23, 2015 by David Dickinson

Aurora on Venus Versus Solar Activity

It’s a major mystery posed by our sister world.

Does the atmosphere of Venus possess upper atmospheric phenomena similar to the Earth, such as aurora or nightglow?

Now, a recent announcement out of the American Astronomical Society’s 46^th annual meeting of the Division of Planetary Science being held this week in Tucson, Arizona has shed new light on the dilemma.

The discovery was announced on Wednesday, November 12^th at the 46th AAS meeting and was made as a collaborative effort by researchers from New Mexico State University at Las Cruces, the Stanford Research Institute (SRI) International, the University of Colorado at Boulder, the University of Koln and University of Munich, Germany, the European Space and Technology Center in the Netherlands and the Institut de Recherche en Astrophysique et Planétologie, in France.

For the study, researchers observed Venus from December 2010 to July 2012 using the Astrophysical Research Consortium (ARC)Echelle Spectrograph and the ARC 3.5 metre telescope located at Apache Point near Sunspot, New Mexico.

Timing was crucial, as the Sun was coming off of a profound deep minimum through 2009 and just beginning to become active with the start of solar cycle #24. Observers were looking for activity along the 5577.3 angstrom wavelength known as the “oxygen green line.” Activity had not been seen at this wavelength on the nighttime side of Venus since 2004.

The altitude drop in the Venusian atmosphere measured in the study. Credit : Credit: DPS press release/C. Gray/New Mexico State University.

“These are intriguing results, suggesting that it is possible to have aurora on non-magnetic planets,” said Candace Gray, Astronomer and NASA Earth and Space Science Fellow at Las Cruces and lead researcher in the study. “On Venus, this green line has been seen only intermittently.”

Earth is the oddball among the terrestrial planets in the inner solar system with its robust magnetic field. On Earth, aurorae occur when said field captures charged particles ejected from the Sun and funnels them in towards the poles. Events seen in the study tended to drop 140 to 120 kilometres in altitude in the Venusian atmosphere, highly suggestive of auroral activity seen in the ionosphere of Earth.

Researchers were fortunate during one of the recent runs at Apache Point that the Sun kicked off a coronal mass ejection that headed Venus’s way. During the July 2012 solar storm, the team detected one of the brightest green line emissions that had ever been detected by observers on Earth.

Credit: Wikimedia Commons image. — The 3.5 metre telescope at Apache Point, in this case, being used for lunar ranging experiments. Credit: M3long/Wikimedia Commons image.

This demonstrates that perhaps, a magnetic field is optional when it comes to auroral activity, at least in the case of the planet Venus. Located only 0.7 astronomical units (108.5 million kilometres) from the Sun, our tempestuous star actually wraps the planet with its very own magnetotail.

Researchers are also looking to compare their results with observations from the European Space Agency’s Venus Express orbiter which arrived at the planet on April 2006.

“Currently, we are using observations from VIRTIS on Venus Express to try and detect the green line,” Gray told Universe Today. “We had coordinated ground based observations with them this past February, and we detected the green line from the ground when they were observing the night side limb. Additionally, we are using the Electron Spectrometer and ASPERA-4 to observe how the electron energy and density changes in the atmosphere after coronal mass ejection impacts.”

This also raises the interesting possibility that NASA’s MAVEN spacecraft — which recently arrived in orbit around Mars — might just detect similar activity in the tenuous Martian atmosphere as well. Like Venus, the Red Planet also lacks a global magnetic field.

Could this glow be connected with spurious sightings of the “Ashen Light of Venus” that have cropped up over the centuries?

Of course, ashen light, also known as Earthshine on the dark limb of the Moon, is easily explained as sunlight reflected back from the Earth. Moonless Venus, however, should be ashen light free.

“The green line emission that we see is brightest on the limb (edge) of the planet,” Gray told Universe Today. “We’re sure that there is emission all along the nightside, but because of the optical depth, it appears much brighter on the limb of the planet. I think it would be too faint to detect with the naked eye.”

Nightglow has been a leading suspect for ashen light on the Venusian nightside, and a similar green line emission detection rivaling the 2012 event was made by Tom Slanger using the Keck I telescope 1999.

Other proposed suspects over the centuries for ashen light on Venus include lightning, volcanism, light pollution (!) from Venusian cities, or just plain old observer error.

Certainly, future observations are needed to cinch the solar activity connection.

“We will likely observe Venus again from Apache Point the next time Venus is visible to us in June 2015,” Gray told Universe Today. “We will continue looking at Venus Express observations until the craft dies in the atmosphere.”

Venus turns its night time back towards us during the 2012 transit of the Sun, as seen from NASA's Solar Dynamics Observatory (Credit: NASA/SDO). — Venus turns its night time back towards us during the 2012 transit of the Sun, as seen from NASA’s Solar Dynamics Observatory (Credit: NASA/SDO).

Venus can currently be seen crossing through the field of view of SOHO’s LASCO C3 camera. After spending most of 2014 in the dawn sky, Venus will emerge from behind the Sun low in the dusk to head towards greatest elongation in the evening sky on June 6^th, 2015. And from there, Venus will once again slender towards a crescent, presenting its nightside towards Earth, and just perhaps, continuing to present a lingering mystery of modern astronomy.