David Dickinson, Author at Universe Today

November 1, 2013December 23, 2015 by David Dickinson

Watch Live: Sunday’s “Hybrid Solar Eclipse”

Totality! As seen during the November 13th, 2012 total solar eclipse. (Image credit: Narayan Mukkavilli, used with permission).

The chase is on. On Sunday, November 3^rd, the shadow of the Moon will cross the Earth for one last time in 2013. We recently wrote about the prospects for viewing this “hybrid” annular-total solar eclipse as it crosses the Atlantic and central Africa. Viewers from northern South America across the U.S. Eastern Seaboard up into the Canadian Maritimes will also be treated to a brilliant rising partial eclipse over the Atlantic at sunrise. Tickets are already in hand for many, as umbraphiles wing their way (cue Indiana Jones music) to dusty and exotic far off locales to stand briefly in the shadow of our Moon…

But what if it’s cloudy?

Once the bane of eclipse-chasers, you can now thwart our sometimes murky atmosphere by catching the solar eclipse online.

I remember our first experience with eclipse-chasing on the internet, trying to catch an eclipse broadcast on ye ole dial up modem from an internet café (remember internet cafes?) way back in the late 90s. This was pre-You Tube, pre-UStream. Needless to say, the tenuous connection afforded nary a frozen glimpse of the partially eclipsed Sun, and crashed all together at the onset of totality.

Fast forward to 2013, when ginormous data packets routinely fly around the globe.

True, this eclipse presents a challenge, as it crosses some pretty wild and unconnected terrain. But one standby that we can expect is the good people at Slooh, who have dispatched a broadcast team to the African nations of Gabon and Kenya:

As of this writing, Slooh looks to be going live at around 11:45 UT on Sunday November 3^rd. This is 6:45 AM EST, which takes into account our “falling back” one hour to UT -5 hours on Sunday morning. Astronomer Brian Cox will be broadcasting live from Kenya, and the broadcast starts just over two hours prior to the first landfall of totality at just before 14:00 UT. From Gabon, Maximum totality will be a brief 1 minute and 5 seconds, and will dwindle to an even briefer 14 seconds over Lake Turkana in Kenya before ending as a brilliant sunset eclipse over Somalia and Ethiopia. A backup broadcast of the partial phases of the eclipse is also planned from Slooh’s home base site in the Canary Islands.

Another fascinating potential broadcast may come our way from the BRCK organization basing their observations of the eclipse from the shores of Lake Turkana in Kenya. Billed as “Your Backup Generator for the Internet,” BRCK’s mission is to bring broadband access internet to people in remote regions of the world. This weekend’s eclipse certainly qualifies. As of writing this on Halloween, October 31^st, the BRCK team had gone into the field to “stress test” their webcasting capability onsite; follow them on Twitter as @brcknet for the latest updates. As of yet, there’s no embed for the broadcast, though we’ll be sure to drop it in if it surfaces!

There’s also some interesting science afoot during this eclipse as well. A recent press release out from Williams College notes that Field Memorial Professor of Astronomy and chair of the International Astronomical Union’s Working Group on Eclipses Jay Pasachoff will observe the eclipse, along with a student and tourist expedition from Gabon. A veteran eclipse chaser, Pasachoff will be working in concert with Dr. Vojtech Rusin of the Astronomical Institute of Slovakia, solar researchers Aris Voulgaris and Robert Lucas and William College students to study the ethereal solar corona. Satellite-based coronagraphs, such as the one employed by SOHO, can create an “artificial eclipse” of the Sun to study the corona, but also face the challenge of scattered light via a phenomenon known as Fresnel-diffraction. Pasachoff and team hope to combine their observations with those being routinely carried out by NASA, the European Space Agency and the Royal Observatory in Belgium to characterize the solar corona and improve our understanding of the space weather environment. Pasachoff’s expedition is being assisted via support from the South African Astronomical Observatory, Nommo Astronomia, the Gabon Astronomy Society and the Gabon Space Agency. Veteran eclipse chaser and historian Michael Zeiler (@EclipseMaps) has also joined up with Pasachoff’s group in Gabon.

In space, the NASA/JAXA joint solar observing Hinode spacecraft and ESA’s Sun watching Proba-2 will also catch several partial eclipses from their respective perches in low Earth orbit. Expect to see these pics in the days following Sunday’s eclipse.

We’ll be dropping in more broadcasts as they come to our attention this weekend here at Universe Today. Planning an ad-hoc webcast of the eclipse? Let us know in the comments below! Even if it’s just a brief view of the rising partially eclipsed Sun from the beach, its worth the effort. Just remember that you’ll need a fairly long focal length (in the range of 200mm or longer) and a proper solar filter for the Sun to appear like anything more than a washed out dot in the broadcast. And always run a test of your rig beforehand!

Good luck, happy eclipse chasing, and don’t forget to send those eclipse pics to Universe Today!

October 28, 2013April 26, 2016 by David Dickinson

Rare ‘Hybrid’ Solar Eclipse on November 3, 2013: How to See It

A partially eclipsed setting Sun as seen from Dallas, Texas on May 20th, 2012. This weekend's eclipse will offer U.S. East Coast residents a similar sunrise view. (Credit: Jason Major/Lights in the Dark).

It’s almost upon us. The final eclipse of 2013 occurs this coming weekend on Sunday, November 3^rd. This will be the fifth eclipse overall, and the second solar eclipse of 2013. This will also be the only eclipse this year that features a glimpse of totality.

This eclipse is of the rare hybrid variety— that is, it will be an annular eclipse along the very first 15 seconds of its track before transitioning to a total as the Moon’s shadow sweeps just close enough to the Earth to cover the disk of the Sun along the remainder of its track.

An animation of the path of the November 3rd hybrid solar eclipse. (Credit: NASA/Goddard Space Flight Center).

How rare are hybrid solar eclipse? Of the 11,898 solar eclipses listed over a 5,000 year span from 1999 BC to 3000 AD in Fred Espenak’s Five Millennium Catalog of Solar Eclipses, only 569, or 4.8% are hybrids.

Who can see this eclipse?

People from northern South America, across the U.S. Eastern Seaboard and up through the Canadian Maritimes will see a brief partial solar eclipse finishing up around 30 minutes after local sunrise. The brief annular “ring of fire” portion of the eclipse begins at sunrise just ~1,000 kilometres east of Jacksonville, Florida, as it races eastward across the Atlantic. See our timeline, below.

Eclipse prospects for the US East Coast. (Courtesy of Michael Zeiler @EclipseMaps)

Nearly all of Africa and the southern Mediterranean region including Spain will see partial phases of the eclipse, while greatest totality occurs just off of the coast of Liberia and heads for first landfall on the African continent over Wonga Wongue Reserve in Gabon. At this point, the duration of totality will already have shrunk back down to 1 minute and 7 seconds. The shadow of the Moon will then cross central Africa, headed for a short but brilliant sunset total eclipse over Uganda, Ethiopia, Kenya and Somalia.

The global path of this weekends eclipse-click to enlarge. (Credit: Michael Zeiler, @EclipseMaps).

This particular eclipse part of saros series 143 and is member 23 of the 72 eclipses in the cycle. The first eclipse in this saros occurred on March 7^th, 1617, and the last one will occur on April 23^rd, 2897.

Saros 143 also has a checkered place in eclipse history. The last eclipse in this series crossed south eastern Asia on October 24^th, 1995.

The first detailed picture of a solar eclipse was also taken of a saros 143 member on July 28, 1851. And one saros later, a total solar eclipse on August 7^th, 1869 may have saved the butt of astronomer and explorer George Davidson while traversing the wilds of Alaska. And one more saros period later, Dmitri Mendeleev (he of the modern periodic table) observed the total solar eclipse of August 19^th, 1887 from a balloon.

A daguerreotype image of the 1851 eclipse captured by Berkowski of the Royal Observatory in Königsberg, Prussia. (Public domain image).

We’ve compiled a brief worldwide timeline for the November 3^rd hybrid eclipse. Keep in mind, the shift back off of Daylight Saving Time occurs on the same morning as the eclipse for North America, putting the U.S. East Coast once again back to -5 hours off of Universal Time (UT):

10:04 UT: The partial phases of the eclipse begin.

11:05:17 UT: annular phases of the eclipse begin.

11:05:36 UT: The eclipse transitions from an annular to a total along its track.

12:46: The point of greatest eclipse, occurring off of the SW coast of Liberia along the coast of Africa. The path will be 57 kilometres wide at this point with a maximum duration for totality at 1 minute & 40 seconds.

14:27 UT: The total phases of the eclipse end.

15:28 UT: Partial phases end.

Remember that solar safety is paramount while observing an eclipse during all partial phases. This is especially critical, as millions of viewers along the U.S. East Coast are poised to catch the eclipse at sunrise over the Atlantic on Sunday. Use only glasses designed specifically for eclipse viewing or welder’s glass #14. One project headed by Astronomers Without Borders is also working to provide eclipse glasses to schools in Africa.

Students in Tanzania demonstrating proper eclipse viewing safety. (Credit: Astronomers Without Borders).

Projecting the Sun onto a wall or a piece of paper is also a safe method to observe the eclipse. Construction of a Sun Gun, a pinhole projector, or even using a spaghetti strainer or colander to project the partially eclipsed sun are all fun projects to try.

Shooting pictures of the rising eclipse is also possible using a DSLR. To capture the disk of the Sun plus an outline of the foreground, you’ll want to use a combination of low ISO 100 and a fast shutter speed (1/4000 or faster) and a zoom lens of at least 200mm or greater. Keep in mind, DO NOT look at the Sun through the camera’s view finder— simply set the focus to infinity and aim via projection. It’s worth practicing your technique a morning or two prior to the main event!

As the partial phase of the eclipse progresses, keep an eye out for “tiny crescents” that may litter the ground. These are caused by gaps in things such as leaves, latticework, etc that may act as natural “pinhole projectors”. Those lucky enough to stand in the path of totality may snare a look at shadow bands sweeping across the landscape as totality approaches, as well as catch a brief glimpse of Baily’s Beads and the pearly white corona of the Sun.

Totality will last less than a minute across most of central Africa, giving viewers a very hurried view before partial phases commence once more. Venus will be easily visible at magnitude -4.4 just 47 degrees east of the Sun. Unfortunately, prospects aren’t great for air or seaborne viewers in the mid-Atlantic to catch sight of comet ISON during the frenzied moments of totality, which will sit 50 degrees from the Sun between magnitude +7 & +8.

The sky over Gabon during mid-eclipse. (Created by the author using Starry Nite).

Weather prospects are an all-important consideration when planning for an eclipse. Jay Anderson maintains an outstanding site with projections tailor-made for each eclipse. For the U.S. East Coast, clear skies right down to the crucial eastern horizon will be key!

A recent surge in piracy off of the West Coast of Africa may also factor into travel considerations for eclipse chasers. You can actually monitor such activities on the high seas now in near real time. Perhaps one could take a page from Mark Twain’s A Connecticut Yankee in King Arthur’s Court, and impress any would-be-brigands with the glory of an impending solar eclipse…

Unfortunately, the International Space Station will have an orbit nearly perpendicular to the Earth-Moon-Sun syzygy, and won’t lend itself to any great prospects of a transit during the partial phases of the eclipse. ESA’s Proba-2 and JAXA’s Hinode will, however, see several partial eclipses from orbit:

Sunspot activity has also been on the upswing as of late, making for a photogenic Sun heading into the partial phases of the eclipse. A well-placed, naked eye Coronal Mass Ejection on the solar limb also isn’t out of the question. Eclipse historian and expert Michael Zeiler notes that a CME last occurred during a total solar eclipse way back in 1860.

Sunspot activity as of October 28th... will it stay active until this weekend's eclipse? (Photo by author). — Sunspot activity as of October 28th… will it stay active until this weekend’s eclipse? (Photo by author).

Totality for this eclipse passes over some wild and largely wifi free areas; few plans to broadcast the eclipse live have surfaced thus far.

Slooh plans a broadcast, as did a proposed Indiegogo project whose current status is unclear. BRCK also plans to broadcast the eclipse live from the shores of Lake Turkana, Kenya. Got plans to webcast even the partial phases of the eclipse? Let us know!

And speaking of eclipse chasing, we plan on heading to the Florida Space Coast Sunday morning at o’dark thirty to nab the partial sunrise eclipse over the Atlantic.

And as always, the question posed immediately after totality is: when’s the next one? Well, the next annular eclipse graces Australia on April 29^th, 2014. The U.S. will also see a partial solar eclipse on October 23^rd next year… but totality will not touch the surface of our fair planet until a high Arctic eclipse on March 20^th, 2015.

Good luck, clear skies, and safe journeys to all who are chasing after this one near and far, and don’t forget to post those pics to Universe Today’s Flickr page!

-See more of Michael Zeiler’s work at Eclipse Maps.

-Simulations were created using Starry Night Education Software.

October 23, 2013December 23, 2015 by David Dickinson

Comet LINEAR Suddenly Brightens with Outburst: How to See It

Comet C/2012 X1 LINEAR as imaged by Howes, Guido & Nicolini on Monday, October 21st. (Credit: remanzacco.blogspot)

It’s swiftly becoming an “all comets, all the time” sort of observing season. The cyber-ink was barely dry on our “How to Spot Comet 2P/Encke” post this past Monday when we were alerted to another comet that is currently in the midst of a bright outburst.

That comet is C/2012 X1 LINEAR. Discovered on December 8^th, 2012 by the ongoing Lincoln Near Earth Asteroid Research (LINEAR) survey based in Socorro, New Mexico, Comet X1 LINEAR was expected to peak out at about +12^th magnitude in early 2014.

That all changed early this week, when amateur observers began to report a swift change in brightness for the otherwise nondescript comet. Japanese observer Hidetaka Sato reported the comet at magnitude +8.5 on October 20^th, a full 5.5 magnitudes above its expected brightness of +14. Remember, the magnitude scale is logarithmic, and the lower the number, the brighter the object. Also, 5 magnitudes represent an increase in brightness of 100-fold.

Astronomers Nick Howes, Martino Nicolini and Ernesto Guido used the remote 0.5 metre iTelescope based in New Mexico on the morning of Monday, October 21^st to confirm the outburst. Other amateurs and professional instruments are just now getting a look at the “new and improved” Comet X1 LINEAR low in the dawn sky. Romanian amateur observer Maximilian Teodorescu noted on yesterday’s Spaceweather that the comet was not visible through his 4.5 inch refractor, though it was easy enough to image.

Comet X1 LINEAR currently sits in the constellation Coma Berenices about mid-way between the stars Diadem, (Alpha Coma Berenices) and Beta Coma Berenices. Shining at +8.5 magnitude, the coma is about 85” across with a 10” bright central region. This gives X1 LINEAR the appearance of an unresolved +8^th magnitude globular cluster. In fact, a classic globular and a star party fave known as M3 lies about 8 degrees away at the junction of the constellations Canes Venatici, Boötes and Coma Berenices. M3 shines at +7^th magnitude and will make a great contrast on the hunt for the comet.

Unfortunately, the window of time to search for the comet is currently short. From latitude 30 degrees north, the comet sits only 15 degrees about the northeast horizon 30 minutes before local sunrise. The situation is a bit better for observers farther to the north, and mid-November sees the comet 20 degrees above the horizon in the dawn sky.

Comet X1 LINEAR is currently covering 40’ (2/3^rdsof a degree, or 1 1/3 the size of a Full Moon) a day, and will spend most of the month of November in the constellation Boötes. Keep in mind, X1 LINEAR is currently still on brightening trend “with a bullet.” Revised light curves now show it on track to reach magnitude +6 near perihelion early next year, but further brightening could still be in the cards for this one. Remember Comet 17P/Holmes a few years back? That one jumped from an uber-faint +17^th magnitude to a naked eye brightness of +2.8 in less than 48 hours.

Comet X1 LINEAR will reach a perihelion of 1.6 Astronomical Units (A.U.s) from the Sun on February 21st, 2014, and pass 1.6 A.U.s from the Earth around June 28^th, 2014. The comet has a high inclination of 44.4° degrees relative to the ecliptic, and is on a respectable 1872 year orbit.

Here are some notable dates for the comet through the end of 2013;

The path of Comet C/2012 X1 LINEAR from October 23 to November 28th. Click to enlarge. (Credit: Created using Starry Night Education Software).

-November 2^nd: Crosses into the constellation Boötes.

-November 6^th: Passes near the +4.9^th magnitude star 6 Boötis.

-November 16^th: Passes near the bright star Arcturus.

-December 6^th: Crosses into the constellation Serpens Caput.

-December 10^th: Passes near the +5 magnitude star Tau1 Serpentis.

-December 14^th: Comet X1 LINEAR sits only 8 degrees from Comet ISON.

-December 26^th: Crosses into the constellation Hercules.

Note: “Passes near” on the above list denotes a pass closer than one degree, except as noted.

Now, we REALLY need the Moon to pass Last Quarter phase this coming Saturday so we can get a good look at all of these dawn comets! As of writing this, the current scorecard of binocular comets— comets with a brightness between magnitude +6 and +10 —sits at:

-2P Encke: +7.9 magnitude in Leo.

-C/2013 R1 Lovejoy: +8.7^th magnitude in Canis Minor.

-C/2013 X1 LINEAR: +8.5^th magnitude in Coma Berenices.

-C/2012 S1 ISON: +9.7^th magnitude in Leo.

-C/2012 V2 LINEAR: +8.9^th magnitude in Centaurus.

Comet X1 LINEAR on the morning of October 25th, as seen from latitude 30 degrees north 45 minutes prior to sunrise. (Created using Stellarium).

It’s also amusing to note how the method of notification for these sorts of outbursts has changed in recent years. I first heard of the outburst of X1 LINEAR on Monday evening via Twitter. Contrast this with Comet Holmes in 2007, which came to our attention via message board RSS feed. And way back in 1983, we all read about of the close passage of Comet IRAS-Araki-Alcock… weeks after it occurred!

Another curious phenomenon may also work its way through the news cycle. When Comet Holmes became a hit back in 2007, spurious reports of comets brightening became fashionable. If you were to believe everything you read on the web, it suddenly seemed like every comet was undergoing an outburst! This sort of psychological trend towards wish fulfillment may come to pass again as interest in comet outbursts mounts.

It’s also worth noting that, contrary to rumors flying around ye’ ole web, Comet X1 LINEAR is not following Comet ISON. The two are on vastly different orbits, and only roughly lie along the same line of sight as seen from our Earthly vantage point.

The orbital path of Comet X1 LINEAR. (Credit: The JPL Solar System Dynamics Small-Body Database Browser). — The orbital path of Comet C/2012 X1 LINEAR. (Credit: The JPL Solar System Dynamics Small-Body Database Browser).

And that’s it for our weekly (daily?) segment of “As the Comets Turn…” don’t forget to “fall back” one hour and plan your morning comet-hunting vigil accordingly this coming Sunday if you live in Europe-UK. North America still has until November 3^rd to follow suit.

Happy comet hunting!

-Got a recent pic of Comet X1 LINEAR? be sure to post it in the Universe Today Flickr forum!

October 21, 2013December 23, 2015 by David Dickinson

How to See This Season’s “Other” Comet: 2P/Encke

Comet 2P/Encke as imaged by Damian Peach on October 12th. (Credit: D. Peach)

2013 may well go down as “The Year of the Comet.” After over a decade punctuated by only sporadic bright comets such as 17P/Holmes, C/2011 W3 Lovejoy and C/2006 P1 McNaught, we’ve already had two naked eye comets visible this year by way of C/2012 F6 Lemmon and C/2011 L4 PanSTARRS. And of course, all eyes are on Comet C/2012 S1 ISON as it plunges towards perihelion on U.S. Thanksgiving Day, November 28^th.

But there’s an “old faithful” of comets that’s currently in our solar neighborhood, and worth checking out as well. Comet 2P/Encke (pronounced EN-key) currently shines at magnitude +7.9 and is crossing from the constellation Leo Minor into Leo this week. In fact, Encke is currently 2 magnitudes— over 6 times brighter than Comet ISON —and is currently the brightest comet in our skies. Encke is expected to top out at magnitude +7 right around perihelion towards the end of November. Encke will be a fine binocular object over the next month, and once the Moon passes Last Quarter phase on October 26^th we’ll once again have a good three week window for pre-dawn comet hunting. Comet Encke made its closest pass of the Earth for this orbit on October 17^th at 0.48 Astronomical Units (A.U.s) distant. This month sees its closest passage to the Earth since 2003, and the comet won’t pass closer until July 11^th, 2030.

The orbital path of Comet 2P/Encke. (Credit: The NASA/JPL Solar System Dynamics Small-Body Database Browser).

This will be Comet Encke’s 62^nd observed perihelion passage since its discovery by Pierre Méchain in 1786. Encke has the shortest orbit of any known periodic comet, at just 3.3 years. About every 33 years we get a favorable close pass of the comet, as last occurred in 1997, and will next occur in 2030.

But this year’s apparition of Comet Encke is especially favorable for northern hemisphere observers. This is due to its relatively high orbital inclination angle of 11.8 degrees and its passage through the morning skies from north of both the ecliptic and the celestial equator. Encke is about half an A.U. ahead of us in our orbit this month, crossing roughly perpendicular to our line of sight.

Note that Encke is also running nearly parallel to Comet ISON from our vantage point as they both make the plunge through the constellation Virgo into next month. Mark your calendars: both ISON and Encke will fit into a telescopic wide field of view around November 24^th in the early dawn. Photo-op!

Here are some key dates to help you in your morning quest for Comet Encke over the next month:

-October 22^nd: Crosses into the constellation Leo.

-October 24^th: Passes near the +5.3 magnitude star 92 Leonis.

-October 25^th: Passes near the +4.5 magnitude star 93 Leonis.

-October 27^th: Passes briefly into the constellation Coma Berenices.

-October 29^th: Passes near the +11^th magnitude galaxy M98, and crosses into the constellation Virgo.

-October 30^th: Passes near the +10^th magnitude galaxy pair of M84 & M86.

2P Encke from 20 Oct to 20 Nov (Created using Starry Night Education Software). — The celestial path of Comet 2P/Encke from October 20th to 20 November 20th. Note that ISON is very near Encke on the final date. Click on the image to enlarge. (Created using Starry Night Education Software).

-November 2^nd: Passes between the two +5^th magnitude stars of 31 and 32 Virginis.

-November 3^rd: A hybrid solar eclipse occurs across the Atlantic and central Africa. It may just be possible to spot comet Encke with binoculars during the brief moments of totality.

-November 4^th: Passes near the +3.4 magnitude star Auva (Delta Virginis).

-November 7^th: Crosses from north to south over the celestial equator.

-November 11^th: Passes near the +5.7^th star 80 Virginis.

-November 17^th: The Moon reaches Full, and enters into the morning sky.

-November 18^th: Passes 0.02 A.U. (just under 3 million kilometers, or 7.8 Earth-Moon distances) from the planet Mercury. A good chance for NASA’s Messenger spacecraft to perhaps snap a pic of the comet?

-November 19^th: Passes 1.5 degrees from Mercury and crosses into the constellation Libra.

-November 20^th: Crosses to the south of the ecliptic plane.

-November 21^st: Reaches perihelion, at 0.33 AU from the Sun.

-November 24^th: Comet Encke passes just 1.25 degrees from Comet ISON. Both will have a western elongation of 15 degrees from the Sun.

-November 26^th: Passes near the +4.5 magnitude star Iota Librae and the +6th magnitude star 25 Librae.

-December 1^st: Crosses into the constellation Scorpius.

-December 5^th: Enters into view of SOHO’s LASCO C3 camera.

Note: “Passes near” on the above list indicates a passage of Comet Encke less than one angular degree (about twice the size of a Full Moon) from an interesting object, except where noted otherwise.

Binoculars are your best bet for catching sight of Comet 2P/Encke. For middle northern latitude observers, Comet Encke reaches an elevation above 20 degrees from the horizon about two hours before local sunrise. Keep in mind, Europe and the U.K. “fall back” an hour to Standard Time this coming weekend on October 27^th, and most of North America follows suit on November 3^rd, pushing the morning comet vigil back an hour as well.

Two other comets are both currently brighter than ISON and also merit searching for: Comet C/2013 R1 Lovejoy, at +8.7^th magnitude in Canis Minor, and Comet C/2012 X1 LINEAR, currently also in Coma Berenices and undergoing a minor outburst at magnitude +8.5.

Be sure to check these celestial wonders out as we prepare for the “Main Event” of Comet ISON in November 2013!

October 16, 2013December 23, 2015 by David Dickinson

On the Road to One Thousand Exoplanets

Planets everywhere. So where are all the aliens? Credit: ESO/M. Kornmesser

A quiet milestone in modern astronomy may soon come to pass. As of today, The Extrasolar Planets Encyclopedia lists a current tally of 998 extrasolar planets across 759 planetary systems. And although various tabulations differ slightly, very soon we should be living in an era where over one thousand exoplanets are known.

The history of exoplanet discovery has paralleled the course of the modern age of astronomy. It’s strange to think that a generation has already grown up over the past two decades in a world where knowledge of extrasolar planets is a given. I remember hearing of the promise of such detections growing up in the 1970’s, as astronomers put the odds at detection of planets beyond our solar system in our lifetime at around 50%.

A "Periodic Table of Exoplanets" Credit: PHL @ UPR Arecibo. — A “Periodic Table of Exoplanets” Credit: PHL @ UPR Arecibo.

Sure, there were plenty of false positives long before the first true discovery was made. 70 Ophiuchi was the site of many claims, starting with that of W.S. Jacob of the Madras Observatory way back in 1855. The high proper motion exhibited by Barnard’s Star at six light years distant was also highly scrutinized throughout the 20^th century for claims of an unseen companion causing it to wobble. Ironically, Barnard’s Star still hasn’t made it into the pantheon of stars boasting planetary worlds.

A portrait of the HR8799 planetary system as imaged by the Hale Telescope. (Credit: NASA/JPL-Caltech/Palomar Observatory).

But the first verified claim of an exoplanetary system came from a bizarre and unexpected source: a pulsar known as PSR B1257+12, which was discovered to host two worlds in 1992. This was followed by the first discovery of a world orbiting a main sequence star, 51 Pegasi in 1994. I still remember getting my hands on the latest issue of Astronomy magazine— we got our news, often months later, from actual paper magazines in those days —announcing “Planet Discovered!” on the cover.

Most methods and techniques used to discover exoplanets rely on either radial velocity or dips in the light output of a star from a transiting world. Both have their utility and drawbacks. Radial velocity looks for shifts in the star’s spectra as an unseen companion tugs it around a common center of mass. Though effective, it can only place a lower limit on the planet’s mass… and it’s biased towards worlds in short orbits. This is one reason that “hot Jupiters” have dominated the early exoplanet catalog: we hadn’t been looking for all that long.

Another method famously employed by surveys such as the Kepler space telescope is the transit detection method. This allows a much more refined estimate of a planet’s mass and orbit, assuming it transits the disk of its host star as seen from our Earthly vantage point in the first place, which most don’t.

A size comparision of exoplanets versus composition. (Credit: Marc Kuchner/NASA/GSFC).

Direct detection via occulting the host star is also coming of age. One of the first exoplanets directly imaged was Fomalhaut b, which can be seen changing positions in its orbit from 2004 to 2006.

Gravitational microlensing has also bared planetary fruit, with surveys such as MOA (Microlensing Observations in Astrophysics) and OGLE (the Optical Gravitational Lensing Experiment) catching brief lensing events as an unseen body passes in front of a background star. Distant free-ranging rogue planets can only be detected via this method.

More exotic techniques also exist, such as relativistic beaming (sounding like something out of Star Trek). Other methods include searches for tiny light variations as an illuminated planet orbits its host star, deformities caused by ellipsoidal variations as massive planets orbit a star, and infrared detections of circumstellar disks. We’re always amazed at the wealth of data that can be teased out of a few dim photons of light.

A scatter plot of exoplanet discoveries as of 2010 mass versus semi-major axis. Select exoplanets are labeled. A majority were detected via radial velocity (blue) and the transiting method (green). The remainder were detected by other methods (click here for a full discription). Graph in the Public Domain. — A scatter plot of exoplanet discoveries as of 2010 displaying mass versus semi-major axis. Select exoplanets are labeled. A majority were detected via radial velocity (blue) and the transiting method (green). The remainder were detected by other methods (click here for a full description). Graph in the Public Domain.

Universe Today has grown up with exoplanet science, from reporting on the hottest, fastest, and other notable “firsts”. A bizarre menagerie of worlds are now known, many of which defy the imagination of science fiction writers of yore. Want a world made of diamond, or one where it rains glass? There’s now an “exoplanet for that”.

Exoplanet news has almost gone from the incredible to the routine, as Tatooine-like worlds orbiting binary stars and systems with worlds in bizarre resonances are announced with increasing frequency.

Exoplanet surveys also have a capacity to peg down that key f_p factor in the famous Drake equation, which asks us “what fraction of stars have planets”. It’s been long suspected that stars with planets are the rule rather than the exception, and we’re just now getting hard data to back that assertion up.

Missions, such as NASA’s Kepler space telescope and CNES/ESA CoRoT space telescope have swollen the ranks of extrasolar worlds. Kepler recently ended its career staring off in the direction of the constellations Cygnus, Hercules and Lyra and still has over 3,200 detections awaiting confirmation.

Exoplanet discoveries by year as of October 2013, color coded by method. Blue=radial velocity, Green=transiting, Yellow=timing, Red=direct imaging, Orange=microlensing

But is a given world Earthlike, or just Earth-sized? That’s the Holy Grail of modern exoplanet detection: an Earth-sized world orbiting in a star’s habitable zone. We’re cautious every time the latest “Earth-twin” makes its way into the headlines. From the perspective of an intergalactic astronomer, Venus in our own solar system might appear to fit the bill, though I wouldn’t bank the construction of an interstellar ark on it and head there just yet.

Exoplanet science has definitely come of age, allowing us to finally begin characterization of solar systems and give us some insight into solar system formation.

But perhaps what will be the most enduring legacy is what the discovery of extrasolar planets tells us about ourselves. How common (or rare) is the Earth? How typical is the story of our solar system? If the “first 1,000” are any indication, we strongly suspect that terrestrial planets come in enough distinct varieties or ”flavors” to make Baskin Robbins envious.

And the future of exoplanet science looks bright indeed. One proposed mission, known as the Fast INfrared Exoplanet Spectroscopy Survey Explorer, or FINESSE, would target exoplanet atmospheres, if given the go ahead for a 2017 launch. Another proposal, known as the Wide Field Infrared Survey Telescope, or WFIRST, would search for microlensing events starting in 2023. A mission that scientists would love to fly that always seems to be shelved is known as the Terrestrial Planet Finder.

But the exoplanet hunting mission that’s closest to launch is the Transiting Exoplanet Survey Satellite, or TESS. Unlike Kepler, which stares at a single patch of sky, TESS will be an all-sky survey looking at a half million stars.

We’re also just approaching an era where spectroscopy may allow us to detect exomoons and the chemistry taking place on these far off exoworlds. An example of an exciting discovery would be the detection of a chemical such as chlorophyll, a chemical that we know on Earth only exists as the result of life. But what a tantalizing discovery a blip on a graph would be, when what we humans really want to see is the vista of those far-flung alien forests!

Such is the exciting era we live in. Congratulations, humanity, on detecting 1,000 exoplanets… here’s to a thousand more!

October 14, 2013December 23, 2015 by David Dickinson

This Week’s Penumbral Lunar Eclipse and the Astronomy of Columbus

You can always count on an eclipse to get you out of a delicate situation. Today is Columbus Day in the United States and Thanksgiving north of the border in Canada. Later this week also marks the start of the second eclipse season for 2013. Today, we thought we’d take a look at the circumstances for the first eclipse of the season kicking off this coming Friday night, October 18, as well as the fascinating role that eclipses played in the life and times of Christopher Columbus.

Friday’s event is a penumbral lunar eclipse, meaning that the Full Moon will only pass through the outer bright rim of the Earth’s shadow. Such events are subtle affairs, as opposed to total and partial lunar eclipses, which occur when the Moon enters the dark inner core, or umbra, of the Earth’s shadow. Still, you may just be able to notice a slight dusky shading on the lower southern limb of the Moon as it flirts with the umbra, barely missing it around the time of central eclipse at 23:51 Universal Time/ 7:51 PM Eastern Daylight Saving Time. Friday night’s penumbral is 3 hours and 59 minutes in duration, and 76.5% of the disk of the Moon will be immersed in the penumbra at maximum eclipse.

Key Events occurring on Friday, October 18^th:

21:50UT/5:50PM EDT: 1^st contact with the Earth’s shadow.

23:51UT/7:51PM EDT: Mid-eclipse.

01:49UT(Oct 19^th)/9:49PM EDT: Last contact. Eclipse ends.

The eclipse will be underway at moonrise for North and South America and occur at moonset for central Asia— Africa and Europe will see the entire eclipse. Standing on Earth’s Moon, an observer on the nearside would see a partial solar eclipse.

A simulation of Friday's lunar eclipse, looking back from Earth Moon at mid-eclipse. (Credit: — A simulation of Friday’s lunar eclipse, looking back from Moon at mid-eclipse. (Wikimedia Commons graphic in the Public Domain).

This eclipse is the 3^rd and final lunar eclipse of 2013, and the 5^th overall. It’s also the first in a series of four descending node eclipses, including the total lunar eclipse of October 8^th next year. It’s also the 52^nd eclipse of 72 in the lunar saros series 117, which started on April 3^rd, 1094 and will end with a final lunar eclipse on May 15^th, 2356. Saros 117 produced its last total lunar eclipse in 1815 and its final partial in 1941.

Though penumbrals are slight events, we’ve been able to notice an appreciable difference before, during and after the eclipse photographically:

Penumbral I — Can you spy the difference? The May 18th, 2002 penumbral lunar eclipse before (left) and during mid-eclipse (right). Photos by Author.

Be sure to use identical exposure settings to catch this effect. Locations where the Moon rides high in the sky also stand the best chance of imaging the faint penumbral shading, as the Moon will be above the discoloring effects of the thicker air mass low to the horizon.

The Moon reaches descending node along the ecliptic about 20 hours after the end of the eclipse, and reaches apogee just over six days later on October 25^th. The October Full Moon is also known as the Hunter’s Moon, providing a bit of extra illumination on the Fall hunt.

And this sets us up for the second eclipse of the season the next time the Moon crosses an ecliptic node, a hybrid (annular-total) solar eclipse spanning the Atlantic and Africa on November 3^rd. More to come on that big ticket event soon!

In Columbus’s day, the Moon was often used to get a rough fix of a ship’s longitude at sea. Columbus was especially intrigued with the idea of using lunar eclipses to determine longitude. If you can note the position of the Moon in the sky from one location versus a known longitude during an event— such as first contact of the Moon with the Earth’s umbra during an eclipse —you can gauge your relative longitude east or west of the point. The sky moves 15 degrees, or one hour of right ascension overhead as we rotate under it. One of the earliest records of this method comes to us from Ptolemy, who deduced Alexander the Great’s position 30 degrees (2 hours) east of Carthage during the lunar eclipse of September 20^th, 331 B.C. Alexander noted that the eclipse began two hours after sunset from his locale, while in Carthage it was recorded that the eclipse began at sunset.

A Jacob's crossstaff, a simple tool for measuring angles in the sky. (Photo by Author). — A Jacob’s cross staff, a simple tool for measuring angles in the sky. (Charles Towne Landing Historic Site Museum, Photo by Author).

Columbus was a student of Ptolemy, and used this method during voyages to and from the New World during the lunar eclipses of September 14^th, 1494 and February 29, 1504. Of course, such a method is only approximate. The umbra of the Earth often appears ragged and indistinct on the edge of the lunar disk at the start of an eclipse, making it tough to judge the actual beginning of an eclipse by more than ten of minutes or so. And remember, you’re often watching from the pitching deck of a ship to boot!

Another problem also plagued Columbus’s navigation efforts: he favored a smaller Earth than we now know is reality. Had he listened to another Greek astronomer by the name of Eratosthenes, he would’ve gotten his measurements pretty darned close.

An eclipse also saved Columbus’s butt on one occasion. The story goes that tensions had come to a head between the locals and Columbus’s crew while stranded on the island of Jamaica in 1504. Noting that a lunar eclipse was about to occur on March 1^st (the evening of February 29th for North America), Columbus told the local leader that the Moon would rise “inflamed with wrath,” as indeed it did that night, right on schedule. Columbus then made a great show of pretending to pray for heavenly intersession, after which the Moon returned to its rightful color. This kept a conniving Columbus and his crew stocked in supplies until a rescue ship arrived in June of that year.

A depiction of the 1504 lunar eclipse from the 1879 text Astronomie Populare by Camille Flammarion. — A depiction of the 1504 lunar eclipse from the 1879 text *Astronomie Populare* by Camille Flammarion.

Be sure to check out this Friday’s penumbral eclipse, and amaze your friends with the prediction of the next total lunar eclipse which occurs on U.S. Tax Day next year on April 15^th, 2014. Can you do a better job of predicting your longitude than Columbus?

October 9, 2013December 23, 2015 by David Dickinson

New Data: Will Comet ISON Survive its Close Perihelion Passage?

An analysis of the dust coma of comet ISON showing the evaporation of ice particles. (Credit: NASA/ESA J.-Y. Li (Planetary Science Institute and the Hubble ISON Imaging Science Team).

It’s the question on every astronomer’s mind this season, both backyard and professional: will Comet C/2012 S1 ISON survive perihelion?

Now, new studies released today at the American Astronomical Society’s 45^th Annual Division for Planetary Sciences meeting being held this week in Denver suggests that ISON may have the “right stuff” to make it through its close perihelion passage near the Sun. This is good news, as Comet ISON is expected to be the most active and put on its best showing post-perihelion… if it survives.

Researchers Matthew Knight of the Lowell Observatory and Research Scientist Jian-Yang Li of the Planetary Science Institute both presented a compelling portrait of the characteristics and unique opportunities presented by the approach of comet ISON to the inner solar system.

Jian-Yang Li studied ISON earlier this year using Hubble before it passed behind the Sun from our Earthly vantage point. Li and researchers were able to infer the position and existence of a jet coming from the nucleus of the comet, which most likely marks the position of one of its rotational poles.

“We measured the rotational pole of the nucleus,” Li noted in a press release from the Planetary Science Institute. The pole indicates that only one side of the comet is being heating by the Sun on its way in until approximately one week before it reaches its closest point to the Sun.”

Could we be in for a “surge” of activity from ISON coming from around November 20^th on?

Comet ISON as imaged from Aguadilla, (sp) Puerto Rico recently on october 6th. (Credit: Efrain Morales Rivera). — Comet ISON as imaged from Aguadilla, Puerto Rico recently on October 6th. (Credit: Efrain Morales Rivera).

Li also noted that the reddish color of the coma of ISON suggests an already active comet sublimating water ice grains as they move away from the nucleus. He also noted that time has been allocated to observe ISON using Hubble this week.

Next up, researcher Mathew Knight presented some encouraging news for ISON when it comes to surviving perihelion.

The findings were a result of numerical simulations carried out by Kevin Walsh and Knight, combined with a historical analysis of previous sun-grazing comets. Both suggest that comet nuclei smaller than 200 metres in diameter, with an average density or lower (for comets, that is) typically do not survive a close passage to the Sun.

Both researchers place the size of ISON’s nucleus in the range of 0.5 to 2 kilometres, comfortably above the 0.2 kilometre “shred limit” for its relative perihelion distance. ISON is not a technically Kreutz group sungrazer, though studies of the over 2,000 known Kreutz comets historically observed provide an interesting guideline for what might be in store for ISON. Four Kreutz comets, including C/2011 W3 Lovejoy and Comet C/1887 B1 partially survived perihelion to become “headless wonders,” while five, including Comet C/1965 S1 Ikeya-Seki — which ISON is often compared to — survived perihelion passage to become one of the great comets of the 20^th century.

ISON will pass inside the Roche limit of the Sun, which is a distance of 2.4 million kilometres (for fluid bodies) and will be subject to temperatures approaching 5,000 degrees Fahrenheit on closest approach.

ISON is a first time visitor to the inner solar system. Discovered on September 21^st, 2012 by Russian researchers Artyom Novichonok and Vitaly Nevsky participating in the International Scientific Optical Network, ISON will pass less than 1.2 million kilometres above the surface of the Sun on November 28^th, 2013.

One interesting but little discussed factor highlighted in today’s press release was the retrograde versus prograde rotation of the cometary nucleus. A fast, prograde spin of an elongated nucleus may spell doom for ISON, as tidal forces will rip it apart. A retrograde rotator, however, is very likely to survive the encounter.

Thus far, there are no solid indications that ISON is indeed a retrograde rotator, although there are tantalizing hints that beg for further observations.

Li notes that it’s tough to infer a bias for comets like ISON to be retrograde over prograde rotators, as we’ve only got five historical comets to go by similar to ISON, and the breakdown is thus about 50/50 for and against.

ISON’s possible survival would validate both studies and their methods and give us more refined predictions for future comets.

“We’ve never discovered a sungrazer this far out,” Knight told Universe Today. “The rotation of ISON depends on the pole position (from Li’s study) and in theory, if we could get enough images, a proper morphology (for ISON) would emerge.”

Comet ISON imaged on October 5th from Long Beach, California. (Credit: Thad Szabo @AstroThad).

The implications of this analysis is certainly good news for observers. If ISON survives perihelion, we would then have a brilliant dawn Christmas comet unfurling its tail off to the northeast in early December.

Of course, these findings are contrary to early cries of its demise, including the paper out of the Institute of Physics that has been circulating touting “The Impending Demise of ISON”. Read Universe Today editor Nancy Atkinson’s excellent synopsis on that, it’s a tale that just won’t seem to die.

And we’ve also done our skeptic’s duty of thoroughly debunking the mounting ISON lunacy, including its status as the harbinger for the “end of the world of the week,” as well as its inability to fulfill prophecy. But if we get a surge in ISON next month as researchers suggest, we fully expect the accompanying hype to crest as well.

The most recent observations put ISON at about +10^th magnitude as it currently crosses the constellation Leo, near Mars and Regulus in the morning sky. We recently did an observing post tracking its plunge to perihelion in late November, and we’ve been diligently hunting for ISON with binoculars every morning pre-dawn.

We’re glad to have some positive science to report on for ISON. Things are looking up for a fine show come early December!

-Read the PSI press release on JianYang Li’s findings as well as the original paper on ISON’s survival prospects by Matthew Knight.

October 8, 2013December 23, 2015 by David Dickinson

A Tale of a Lost Moon: Hubble Spies Neptune’s Moons and Its Rings

Neptune's system of moons and rings visualized. Credit: SETI

“That’s no moon…”

-B. Kenobi

But in this case, it is… a lost moon of Neptune not seen since its discovery in the late 1980’s.

A new announcement from the 45^th Meeting of the Division for Planetary Sciences of the American Astronomical Society being held this week in Denver, Colorado revealed the recovery of a moon of Neptune that was only briefly glimpsed during the 1989 flyby of Voyager 2.

The re-discovery Naiad, the innermost moon of Neptune, was done by applying new processing techniques to archival Hubble images and was announced today by Mark Showalter of the SETI institute.

Collaborators on the project included Robert French, also from the SETI Institute, Dr. Imke de Pater of UC Berkeley, and Dr. Jack Lissauer of the NASA Ames Research Center.

The findings were a tour-de-force of new techniques applied to old imagery, and combined the ground-based 10 meter Keck telescope in Hawaii as well as Hubble imagery stretching back to December 2004.

The chief difficulty in recovering the diminutive moon was its relative faintness and proximity to the “dazzling” disk of Neptune. At roughly 100 kilometres in diameter and an apparent magnitude of +23.9, Naiad is over a million times fainter than +8th magnitude Neptune. It’s also the innermost of Neptune’s 14 known moons, and orbits once every 7 hours just 23,500 kilometres above the planet’s cloud tops. Neptune itself is about 49,000 kilometres in diameter, and only appears 2.3” in size from Earth. From our Earthly vantage point, Naiad only strays about arc second from the disk of Neptune, a tiny separation.

“Naiad has been an elusive target ever since Voyager left the Neptune system,” Showalter said in a recent SETI Institute press release. Voyager 2 has, to date, been the only mission to explore Uranus and Neptune.

To catch sight of the elusive inner moon, Showalter and team applied new analyzing techniques which filtered for glare and image artifacts that tend to “spill over” from behind the artificially occulted disk of Neptune.

Other moons, such as Galatea and Thalassa — which were also discovered during the 1989 Voyager 2 flyby — are also seen in the new images. In fact, the technique was also used to uncover the as of yet unnamed moon of Neptune, S/2004 N1 which was revealed earlier this year.

Naiad is named after the band of nymphs in Greek mythology who inhabited freshwater streams and ponds. The Naiads differed from the saltwater-loving Nereids of mythology fame, after which another moon of Neptune discovered by Gerard Kuiper in 1949 was named.

It’s also intriguing to note that Naiad was discovered in a significantly different position in its orbit than expected. Clearly, its motion is complex due to its interactions with Neptune’s other moons.

“We don’t quite have enough observations to establish a refined orbit,” Mr. Showalter told Universe Today, noting that there may still be some tantalizing clues waiting to be uncovered from the data.

I know the burning question you have, and we had as well during the initial announcement today. Is it REALLY Naiad, or another unknown moon? Showalter notes that this possibility is unlikely, as both objects seen in the Hubble and Voyager data are the same brightness and moving in the same orbit. To invoke Occam’s razor, the simplest solution— that both sightings are one in the same object —is the most likely.

“Naiad is well inside Neptune’s Roche Limit, like many moons in the solar system,” Mr. Showalter also told Universe Today. Naiad is also well below synchronous orbit, and is likely subject to tidal deceleration and may one day become a shiny new ring about the planet.

The labeled ring arcs of Neptune as seen in newly processed data. The image spans 26 exposures combined into a equivalent 95 minute exposure, and the ring trace and an image of the occulted planet Neptune is added for reference. (Credit: M. Showalter/SETI Institute). — The labeled ring arcs of Neptune as seen in newly processed data. The image spans 26 exposures combined into an equivalent 95 minute exposure. The ring trace and an image of the occulted planet Neptune is added for reference. (Credit: M. Showalter/SETI Institute).

And speaking of which, the tenuous rings of Neptune have also evolved noticeably since the 1989 Voyager flyby. First discovered from the ESO La Silla Observatory in 1984, data using the new techniques show that the knotted ring segments named the Adams and Le Verrier have been fading noticeably.

“In a decade or two, we may see an ‘arc-less’ ring,” Showalter noted during today’s Division for Planetary Sciences press conference. The two ring segments observed are named after Urbain Le Verrier and John Couch Adams, who both calculated the position of Neptune due to orbital perturbations of the position of Uranus. Le Verrier beat Adams to the punch, and Neptune was first sighted from the Berlin Observatory on the night of September 23^rd, 1846. Observers of the day were lucky that both planets had undergone a close passage just decades prior, or Neptune may have gone unnoticed for considerably longer.

The rings of Neptune as seen from Voyager 2 during the 1989 flyby. (Credit: NASA/JPL).

Neptune has completed just over one 164.8 year orbit since its discovery. It also just passed opposition this summer, and is currently a fine telescopic object in the constellation Aquarius.

Unfortunately, there aren’t any plans for a dedicated Neptune mission in the future. New Horizons will cross the orbit of Neptune in August 2014, though it’s headed in the direction of Pluto, which is currently in northern Sagittarius. New Horizons was launched in early 2006, which gives you some idea of just how long a “Neptune Orbiter” would take to reach the outermost ice giant, given today’s technology.

This represents the first time that Naiad has been imaged from the vicinity of Earth, and demonstrates a new processing technique capable of revealing new objects in old Hubble data.

“We keep discovering new ways to push the limit of what information can be gleaned from Hubble’s vast collection of planetary images,” Showalter said in the SETI press release.

Congrats to Showalter and team on the exciting recovery… what other moons, both old and new, lurk in the archives waiting to be uncovered?

– Read today’s SETI Institute press release on the recovery of Naiad.

-Be sure to follow all the action at the 45th DPS conference in Denver this week!

October 8, 2013December 23, 2015 by David Dickinson

A Fine Pair of Lunar Occultations for North America This Weekend

Pi Sagittarii moments before it was occulted by the Moon on August 10th, 2011. (Photo by Author).

Heads up, North American residents: our Moon is about to blot out two naked eye stars on Friday and Saturday night.

Such an event is known as an occultation, an astronomical term that has its hoary roots in astronomy’s pseudoscience ancestor of astrology. An occultation is simply when one astronomical body passes in front of another from our line of sight. There’s nothing quite like watching a star disappear on the dark limb of the Moon. In a universe where events often transpire over periods of time longer than a human life span, occultations are abrupt affairs to witness.

Close double stars have also been teased out of occultation data, winking out in a quick, step-wise fashion. If an occultation such as the two this weekend occurs while the Moon is waxing towards Full, we get the added advantage of watching the action on the leading dark limb of the Moon during convenient early evening hours.

Beta Capricorni on the dark limb of the Moon Saturday night. (Created by the author using Starry Night).

First up is the occultation of the +3.9^th magnitude star Rho Sagittarii on Friday night, October 11^th. Central conjunction for this occultation occurs at 00:40 Universal Time (UT) early on the morning of the 12^th. The Moon will be at a 51% illuminated waxing gibbous phase, having passed First Quarter just prior to the start of the occultation at 7:02 PM EDT/23:02 UT on the 11^th. The sunset terminator line at the start of the occultation will bisect the central U.S., and observers east of the Mississippi will get to witness the entire event. The southern graze line will cross Cuba and Guatemala. Note that the Moon will also pass its most southern declination for this lunation just two days prior on October 9^th at 23:00 UT/7:00 PM EDT, at a declination of -19.6 degrees. This is one of the Moon’s most southern journeys for 2013, meaning that it will still ride fairly far to the south in the sky during this weekend’s occultations.

The occultation of Rho Saggitarii by the Moon for the night of October 11th. (rendered using Occult 4.1.02 software). — The occultation of Rho Sagittarii by the Moon for the night of October 11th. the dashed line indicates where the occultation will occur in the daytime; east of this region, the occultation occurs after sunset. (rendered using Occult 4.1.02 software).

Rho Sagittarii is an F-type star 122 light years distant. Stick around until February 23^rd, 2046, and you’ll get to see an even rarer treat, when the planet Venus occults the very same star. Just south of the Rho Sagittarii pair lies the region from which the Wow! Signal was detected in 1977.

The Moon moves at an average speed of just over a kilometre a second in its orbit about the Earth, and traverses roughly the apparent distance of its angular size of 30’ in one hour. The duration of occultations as seen from their center line take about an hour from ingress to egress, though its much tougher to watch a star reappear on the bright limb of the Moon!

And the night of Saturday, October 12^th finds the 62% illuminated waxing gibbous Moon occulting an even brighter star across roughly the same region. The star is +3.1 magnitude Beta Capricorni, which also goes by the Arabic name of Dabih, meaning “the butcher.” Dabih is also an interesting double star with a +6^th magnitude component 3.5’ away from the +3^rd magnitude primary. Dabih is an easy split with binoculars, and it will be fun to watch the two components pass behind the Moon Saturday night. This occultation also occurs the night of October 12^th which is traditionally Fall Astronomy Day. If you’re hosting a star party this coming Saturday night, be sure to catch the well-timed occultation of Beta Capricorni! The central conjunction for this event occurs at 01:27 UT on the morning of the 13^th, and North American observers east of the Rockies will get to see the entire event.

The occultation footprint of Beta Capricorni for the night of October 12th. (Rendered using Occult 4.1.0.2 software).

Beta Capricorni is 328 light years distant, putting the physical separation of the B component at about a third of a light year away from the primary star at 21,000 astronomical units distant. “Beta B” thus takes about 700,000 years to orbit its primary! It’s also amazing to think that those fusion-born photons took over three centuries to get here, only to be rudely “interrupted” by the bulk of our Moon in the very last second of their journey.

And be sure to keep an eye on the primary star as it winks out, as it’s a known spectroscopic triple star with unseen companions in respective 9 and 1374 day orbits. Dabih may just appear to “hang” on the jagged lunar limb as those close companions wink out in a step-wise fashion.

Both occultations are bright enough to watch with the naked eye, although a standard set of 10x 50 binoculars will provide a fine view. The ingress of an occultation is also an excellent event to catch on video, and if you’ve got WWV radio running audio in the background, you can catch the precise time that the star disappears from your locale.

Note: WWV radio is still indeed broadcasting through the ongoing U.S. government shutdown, though they’re operated by NOAA & the NIST.

The International Occultation and Timing Association is always interested in reports of occultations carried out by amateur astronomers. Not only can this reveal or refine knowledge of close double stars, but a series of occultation observations from precisely known locations can map the profile of the lunar limb.

Be sure to catch both events this U.S. Columbus Day/Canadian Thanksgiving Day weekend, and send those pics in to Universe Today!

Precise timings for the ingress and egress of each lunar occultations for major North American cities can be found at the following pages:

– Rho Sagittarii

– Beta Capricorni

October 3, 2013December 23, 2015 by David Dickinson

Is Iran REALLY Planning on Sending a Cat Into Space?

“I’m going where?”

No, this isn’t The Onion… as a concerned consumer of all that is space news, you have indeed arrived at the cyber-doorstep of Universe Today.

I’ll admit though, that we did do a double take about a week back when a peculiar claim came our way via the Iranian Space Agency. Yes, there is an Iranian Space Agency, and it’s kind of frightening that they remain open for business while NASA is largely shutdown.

In mid-September, senior Iranian space program official Mohammad Ebrahimi issued a statement that Iran will attempt another bio-capsule launch “within 45 days”. The unwilling occupant: a Persian cat.

Apparently, a rabbit, a mouse, and another “Space Monkey” were also in the running. Iran’s space program is shrouded in secrecy, and most launches are only announced after they’ve been conducted. This is a convenient political strategy for hiding launch failures that harkens back to the early days of the Cold War. You’re right in guessing that the Iranian Space Agency probably won’t hold a Tweetup for this one. Many western analysts see the Iran’s space effort as a thinly veiled attempt to develop its long range ballistic missile technology. Along with Israel, Iran remains the only Middle Eastern country with the proven technology to conduct indigenous satellite launches.

Iran has stated that it hopes to put an astronaut in orbit by 2019. The Pishgam (or “Pioneer” in Farsi) 2 bio-capsule launch could occur from a mobile launcher at Semnan Space Center as early as October 15^th. Satellite sleuths are also expecting activity at Semnan to pick up this month, with the possible launch of SharifSat atop a Safir 1-B rocket, and Iran’s Toulou satellite aboard a rumored new launch vehicle.

Iran successfully became a space-faring nation with the launch of its 27 kilogram Omid satellite on February 2^nd, 2009. It isn’t immediately clear if the upcoming launch will be an orbital launch or a sub-orbital ballistic shot. If Pisgam-2 achieves orbit, said “Space Cat” would become the first feline to circle the Earth. If recovery is attempted —again, Iran is always nebulous as to their intentions— it would also be the first time they’ve achieved a return from orbit.

But is “Space Cat” even a reality?

Iran has been caught red-handed before playing a shell game with the media in terms of its space program. Earlier this year, “Monkey-gate” erupted, as before-and-after images from the Pisgam-1 bio-capsule suborbital launch clearly showed two different monkeys before and after the flight:

Monkey business? Iran displayed a decidedly different looking monkey before, during, and after launch earlier this year! (Credit: Iran News Agency).

Clearly, Iran and other ‘Axis of Evil’ countries definitely need to sharpen their Photoshop, or at least their monkey-switching skills. Either said monkey launch never actually occurred, or (more likely), the unwilling Iranian space primate never survived the flight.

Perhaps this is why Iran decided on a feline occupant this time around, for possible ease of replacement?

PETA, the People for the Ethical Treatment of Animals, have also issued a statement concerning the impending launch of “Space Cat” by Iran, calling the action an “archaic experiment, a throwback to the primitive techniques of the 1950’s.”

NASA did entertain the idea of "Catronauts" early in the space program. (Credit: NASA). — NASA did entertain the idea of “Catronauts” early in the space program. (Credit: NASA).

The U.S. and the Soviet Union launched animals into space as a prelude to human spaceflight. On November 3^rd, 1957, Laika the dog became the first animal to orbit the Earth. Laika perished is space due to overheating, as did several unfortunate monkeys that were launched on the first US ballistic tests.

Russia still conducts the occasional launch of animals into space, including the Bion-1M “Space Zoo” mission earlier this year. The Bion missions allow for scientists to dissect the specimens afterwards to study the effects of a month in zero-g, something you can’t do with humans.

And the U.S. did once fly cats in zero-g aboard its Convair C-131 “Vomit Comet” aircraft, as can be seen in this bizarre video:

But the first cat in space was actually launched by France atop a Veronique AGI sub-orbital rocket 50 years ago this month on October 18^th, 1963. It would be ironic if Iran conducted it launch this month on the anniversary! The story goes the Felix, the original cat slated for the flight, escaped just prior to launch from the Sahara desert Hammaguir test site in Algeria, and was replaced by the “backup crew,” a female cat named Felicette. Felicette survived the 15 minute flight, reaching an apogee of 217 kilometres. A follow-up launch of a second cat six days later wasn’t so lucky.

Felicette (left) and Felix in publicity shots prior to launch. Note the cranial electrode (!) implants. (Credit: Marjorie-art Voila.net)

As always, Iran’s intentions for the future of its space program remain hidden. Their current launch capabilities remain limited, and are a far cry from being able to hoist a human into orbit anytime soon. If the launch of “Space Cat” does come to pass this month, it’ll be over protests from animal rights groups and the general public. Hey, didn’t the former Iranian president Mahmoud Ahmadinejad say earlier this year after “Monkey-Gate” that he was willing to be “The first Iranian to be sacrificed by the scientists of my country and go into space” as the first Iranian astronaut? Is he really going to let Space Cat upstage him?

Felix and Felicette where also commemorated on several African postage stamps. (Credit: Majorie-art.voila.net).

–Read a great synopsis of the history of felines in space from Heather Archulletta @Pillownaut.