David Dickinson, Author at Universe Today

May 20, 2014December 23, 2015 by David Dickinson

Going Low for Omega Centauri: How to Spot a Southern Hemisphere Jewel from Mid-Northern Latitudes

47 Tucanae… the Coal Sack… Magellanic Clouds large and small… sure, it can be argued that the southern hemisphere sky has got all the “good stuff.” We’ve journeyed below the equator half a dozen times ourselves and we always make it a point to carry our trusty Canon 15x 45 image stabilized binocs – or track someone down with a serious ‘scope – even when astronomy isn’t the main focus of our particular away mission.

But did you know that you can glimpse one of the jewels of the southern hemisphere sky from mid-northern latitudes in May and June?

We’re talking about Omega Centauri in the constellation Centaurus. At a declination of -47 degrees south, it clears 5 degrees above the horizon as seen from around 37 degrees north, which corresponds to the latitudes of Richmond Virginia, Wichita Kansas and Sacramento, California in the United States and Seville Spain, Adana Turkey and Seoul South Korea worldwide.

Omega Centauri as imaged from near Oracle, Arizona at latitude 32 degrees 30′ north. Credit: Mike Weasner/Cassiopeia observatory.

In fact, it would be a fun project to see just how far north you could spot Omega Centauri from… located at right ascension 13 hours 26 minutes and declination -47 29’, Omega Centauri would theoretically juuusst clear the southern horizon at 52 degrees north, well into Canada… but has anyone caught sight of it that far north?

There’s evidence that Ptolemy knew of and recorded Omega Centauri in his Almagest as far back as 150 A.D. It was erroneously misidentified as a star over the centuries, hence the “Omega” designation. It was also too low in the southern sky to be included Charles Messier’s Paris-based catalog of deep sky objects, though it would’ve easily have made the cut had it been located farther north. Omega Centauri was first described by Edmond Halley in 1677 and made its catalog debut in 1746 when astronomer Jean-Philippe de Cheseaux listed it along with 21 other southern sky nebulae.

Shining at magnitude +4, Omega Centauri actually covers a section of sky slightly larger than the apparent size of a Full Moon and is an easy naked eye object from the southern hemisphere. From south of the equator we can easily pick out Omega Centauri from a dark sky site. On a recent trip to the Florida Keys, we could easily detect Omega Centauri riding high to the south over the Straits of Florida at local midnight. In fact, Arthur Upgreen muses in his fantastic book Many Skies just what Florida skies would look like if Omega Centauri were much closer to Earth, filling up the southern horizon scene.

The view from latitude 30 degrees north looking south at 10:30 PM local: click to enlarge. Created using Starry Night software.

Now for the wow factor of what you’re seeing. The largest of the 150-odd known globular clusters associated with our Milky Way Galaxy, Omega Centauri is almost 16,000 light years distant and weighs in at an estimated 4 million solar masses. Globular clusters are ancient structures and Omega Centauri contains millions of Population II stars dating from an age of about 12 billion years ago. The density at the core of the cluster is equal to a star per every 1/10^th of a light year apart, and any planets orbiting said stars would host truly dazzling skies.

The bright star Spica (Alpha Virginis) in the constellation of Virgo the Virgin makes a good guide to find Omega Centauri from the northern hemisphere, as both have nearly the same right ascension to within 10 arc minutes of each other. Both currently transit the southern meridian at around 11:00 AM local in late May, and Omega Centauri lies just 35 degrees — about 3 ½ hand widths held at arm’s length — south of Spica.

Approximate cutoff latitudes for spotting Omega Centauri and Gacrux to the south in May and June. Credit: USGS.

And speaking of Centaurus, the constellation was also recently host to a naked eye nova last year as well. Nova Cen 2013 topped out at magnitude +3.3, though it was placed much farther south than Omega Centauri.

Another unique target in the constellation Centaurus is known as Przybylski’s Star. A seemingly nondescript +8^th magnitude star, Przybylski’s Star has some peculiar spectral properties of rare trace elements. It also sits near the same declination as Omega Centauri at -46 43’ and has a right ascension of 11 hours 38’.

Finally, there’s another southern hemisphere treat peeking just above the southern horizon on late May and June evenings… look about 13 degrees to the lower right of Omega Centauri at around 10:30 PM local in late May, and you might just spy Gacrux (Gamma Crucis), the +1.6 magnitude star that makes up the “head” of the constellation Crux, the Southern Cross. This tough to spot target just tops out at 5 degrees above the southern horizon from here in Tampa Bay, Florida, beckoning northern hemisphere observers on these sultry May and June evenings to the jewels that lie just beyond the horizon to the south.

May 19, 2014December 23, 2015 by David Dickinson

Can You Say Camelopardalids? Observing, Weather Prospects and More for the May 24th Meteor Shower

It could be the best of meteor showers, or it could be the…

Well, we’ll delve into the alternatives here in a bit. For now, we’ll call upon our ever present astronomical optimism and say that one of the best meteor showers of 2014 may potentially be on tap for this weekend.

This is a true wild card event. The meteor shower in question hails from a periodic comet 209P LINEAR discovered in 2004 and radiates from the obscure and tongue-twisting constellation of Camelopardalis.

But whether you call ‘em the “209/P-ids,” the “Camelopardalids,” or simply the “Cams,” this weekend’s meteor shower is definitely one worth watching out for. The excitement surrounding this meteor shower came about when researchers Peter Jenniskens and Esko Lyytinen noticed that the Earth would cross debris streams laid down by the comet in 1803 and 1924. Discovered by the LIncoln Near-Earth Asteroid Research (LINEAR) automated all-sky survey located at White Sands, New Mexico, comet 209P LINEAR orbits the Sun once every 5.1 years. 209P LINEAR passed perihelion at 0.97 AUs from the Sun this month on May 6^th.

The meteor shower peaks this coming U.S. Memorial Day weekend on Saturday, May 24^th. The expected peak is projected for right around 7:00 Universal Time (UT) which is the early morning hours of 3:00 AM EDT, giving North America a possible front row seat to the event. Estimates for the Zenithal Hourly Rate (ZHR) of the Camelopardalids run the gamut from a mild 30 to an outstanding 400 per hour. Keep in mind, this is a shower that hasn’t been witnessed, and it’s tough enough to forecast the timing and activity of known showers. It’s really a question of how much debris the 1803 and 1924 streams laid down on those undocumented passages. One possible strike against a “meteor storm” similar to the 1998 Leonids that we witnessed from Kuwait is the fact that the “Cams” have never been recorded before. Still, you won’t see any if you don’t try!

Cams — The orientation of the Earth, the day/night terminator, the Sun, Moon and radiant of the meteor shower on May 24th at 7:00 UT. Created by author.

Comet 209P/LINEAR passes 0.055 AUs — about 8.3 million kilometres — from the Earth on May 29^th, shining at +11^th magnitude and crossing south into the constellation of Leo Minor in late May. Interestingly, it also passes 0.8 degrees from asteroid 2 Pallas on May 26^th. Though tiny, comet 209P/LINEAR’s 2014 passage ranks as the 9^th closest recorded approach of a comet to the Earth.

The Moon is also at an ideal phase for meteor watching this coming weekend as it presents a waning crescent phase just 4 days from New and rises at around 4:00 AM local.

The expected radiant for the Cams sits at Right Ascension 8 hours and declination 78 degrees north in the constellation of Camelopardalis, the “camel leopard…” OK, we’ve never seen such a creature, either. (Read “giraffe”). Unfortunately, this puts the radiant just 20 degrees above the northern horizon as seen from +30 degrees north latitude here in Florida at 7:00 UT. Generally speaking, the farther north you are, the higher the radiant will be in the sky and the better your viewing prospects are. Canada and the northern continental United States could potentially be in for a good show. Keep in mind too, the high northern declination of the radiant means that it transits the meridian (crosses upper culmination) a few hours before sunset Friday night at 6 PM local; this means it’ll have an elevation of about 38 degrees above the horizon as seen from 30 degrees north latitude just after sunset. It may well be worth watching for early activity after dusk!

Weather — A look ahead at the cloud cover prospects for the morning of May 24th. Credit: NOAA.

Clouded out or live on the wrong side of the planet to watch the Camelopardalids? Slooh will be carrying a live broadcast of the event starting at 3:00 PM PDT/ 6:00 PM EDT/ 22:00 UT. Also, the folks at the Virtual Telescope Project will carry two separate webcasts of the event, one featuring the progenitor comet 209P LINEAR starting at 20:00 UT on May 22^nd and another featuring the meteor shower itself starting at 5:30 UT on May 24^th.

Observing meteors is fun and easy and requires nothing more than a good pair of “mark-1 eyeballs” and patience. And although the radiant may be low to the north, meteors can appear anywhere in the sky. We like to keep a pair of binocs handy to examine any lingering smoke trains left by bright fireballs. Counting the number of meteors you see from your location and submitting this estimate to the International Meteor Organization may help in ongoing efforts to understand this first time meteor shower. And capturing an image of a meteor is as simple as setting a DSLR on a tripod with a wide field of view and taking time exposures of the sky… something you can start practicing tonight.

P_20140518_110518 — Our humble meteor observing rig… (Photo by author).

Don’t miss what could well be the astronomical event of the year… I’d love to see a meteor shower named after an obscure constellation such as the #Camelopardalids trending. And we fully expect to start fielding reports of “strange rocks falling from the sky” this week, which the cometary dust that composes a meteor shower isn’t. In fact, Meteorite Man Geoffrey Notkin once noted that no confirmed meteorite fall has ever been linked to a periodic meteor shower.

Don’t miss the celestial show!

-Got pics of the Camelopardalids? Send ‘em to Universe Today. There’s a good chance that we’ll run an after-action photo-round up if the Cams kick it into high gear.

-Read more about the Camelopardalids here in a recent outstanding post by Bob King on Universe Today.

May 14, 2014December 23, 2015 by David Dickinson

Direct Image of an Exoplanet 155 Light Years Away

Chalk up another benchmark in the fascinating and growing menagerie of extra-solar planets.

This week, an international team of researchers from the Université de Montréal announced the discovery of an exoplanet around the star GU Piscium in the constellation of Pisces the Fishes 155 light years distant. Known as GU Psc b, this world is estimated to be 11 times the mass of Jupiter — placing it just under the lower mass limit for brown dwarf status — and orbits its host star 2,000x farther than the distance from Earth to the Sun once every 80,000 (!) years. In our own solar system, that would put GU Psc b out over twice the distance of the aphelion of 90377 Sedna.

The primary star, GU Psc A, is an M3 red dwarf weighing in at 35% the mass of our Sun and is just 100 million years old, give or take 30 million years. In fact, researchers targeted GU Psc after it was determined to be a member of the AB Doradus moving group of relatively young stars, which are prime candidates for exoplanet detection. Another recent notable discovery, the free-floating “rogue planet” CFBDSIR 2149-0403 is also thought to be a member of the AB Doradus moving group.

The fact that GU Psc B was captured by direct imaging at 155 light years distant is amazing. The international team that made the discovery was led by PhD student at the Department of Physics Université de Montréal Marie-Ève Naud. The team was able to discern this curious planet by utilizing observations from the W.M. Keck observatory, the joint Canada-France-Hawaii Telescope, the Gemini Observatory and the Observatoire Mont-Mégantic in Québec.

Universe Today recently caught up with researcher Marie-Ève Naud and her co-advisor Étienne Artigau about this exciting discovery.

What makes this discovery distinctive? Is this the most distant exoplanet ever imaged?

“Well, first, there are not a lot of exoplanets that were detected ‘directly’ so far. Most were found indirectly through the effect they have on their parent star. The few planets for which we have an actual image are interesting because we can analyze their light directly, and thus learn much more about them. It was also one of the “coolest” planets that have been directly imaged, showing methane absorption. And yes, it is certainly the most distant exoplanet to a main-sequence star that has been found so far.

This distance makes GU Psc b very interesting from a theoretical point of view, because it’s hard to imagine how it could have formed in the protoplanetary disk of its star. The current working definition of an exoplanet is based solely on mass (<13 Jupiter masses), so GU Psc b probably formed in a way that is more similar to how stars formed. It is definitely the kind of object that makes us think about what exactly is an exoplanet.”

At a distance of 2000 A.U.s from its primary, how are astronomers certain that PU Psc b is related to its host and not a foreground or background object?

“As the host star, GU Psc is relatively nearby; it displays a significant apparent proper motion (note: around 100 milliarcseconds a year) relative to distant background stars and galaxies.

On images taken one year apart with WIRCam on the Canada-France-Hawaii Telescope, we observed that the companion displays the same big proper motion, i.e. they move together in the plane of the sky, while the rest of the stars in the field don’t. We also determined the distance of the both the planet and the host star, and they both agree. Also, they both display signs that they are very young.”

Were any groundbreaking techniques used for the discovery, and what does this mean for the future of exoplanet science?

“Quite the opposite… most planet hunting techniques using direct imaging involve state-of-the-art adaptive optics systems, but we used ‘standard’ imaging without any exotic techniques. Planet searches usually attempt to find planets in orbits similar to those of our own solar system giants, and finding these objects, indeed, requires groundbreaking techniques. In a sense, there is an anthropocentric bias in the searches for exoplanets, as people tend to look for systems that are similar to our own solar system. Very distant planets like GU Psc b have been under the radar, even though they are easier to find than their closer-in counterparts. To find this planet, we used very sensitive ‘standard’ imaging, but we chose carefully the wavelengths where planets display colors that are unlike most other astrophysical objects such as stars and galaxies.”

The general field of PU Piscium A & B in the night sky... note that this currently puts it in the dawn sky, near Venus and Uranus! Credit: Starry Night. — The general field of GU Piscium A & B in the night sky… note that this currently puts it in the dawn sky, near Venus and Uranus! Credit: Starry Night.

GU Piscium shines at magnitude +13.6 northeast of the March equinoctial point in the constellation of Pisces. Although its exoplanet companion is too faint to be seen with a backyard telescope, its angular separation is a generous 42,” about the apparent span of Saturn, complete with rings. And it’s shaping up to be a red dwarf sort of week at Universe Today, with our recent list of red dwarf stars for backyard telescopes. And the current tally for extra-solar planets sits at 1,791… hey; didn’t we just pass 1,000 last year?

Congrats to Marie-Ève Naud and her team on this exciting new discovery… and here’s to many more to come!

Read the original paper, Discovery of a Wide Planetary-Mass Companion to the Young M3 Star GU Psc.

May 13, 2014December 23, 2015 by David Dickinson

14 Red Dwarf Stars to View with Backyard Telescopes

An artist's conception of a red dwarf solar system. Credit: NASA/JPL-Caltech.

They’re nearby, they’re common and — at least in the latest exoplanet newsflashes hot off the cyber-press — they’re hot. We’re talking about red dwarf stars, those “salt of the galaxy” stars that litter the Milky Way. And while it’s true that there are more of “them” than there are of “us,” not a single one is bright enough to be seen with the naked eye from the skies of Earth.

A reader recently brought up an engaging discussion of what red dwarfs might be within reach of a backyard telescope, and thus this handy compilation was born.

Of course, red dwarfs are big news as possible hosts for life-bearing planets. Though the habitable zones around these stars would be very close in, these miserly stars will shine for trillions of years, giving evolution plenty of opportunity to do its thing. These stars are, however, tempestuous in nature, throwing out potentially planet sterilizing flares.

Red dwarf stars range from about 7.5% the mass of our Sun up to 50%. Our Sun is very nearly equivalent 1000 Jupiters in mass, thus the range of red dwarf stars runs right about from 75 to 500 Jupiter masses.

For this list, we considered red dwarf stars brighter than +10^th magnitude, with the single exception of 40 Eridani C as noted.

The closest stars within 14 light years of our solar system. Credit: Wikimedia Commons, Public Domain graphic.

I know what you’re thinking… what about the closest? At magnitude +11, Proxima Centauri in the Alpha Centauri triple star system 4.7 light years distant didn’t quite make the cut. Barnard’s Star (see below) is the closest in this regard. Interestingly, the brown dwarf pair Luhman 16 was discovered just last year at 6.6 light years distant.

Also, do not confuse red dwarfs with massive carbon stars. In fact, red dwarfs actually appear to have more of an orange hue visually! Still, with the wealth of artist’s conceptions (see above) out there, we’re probably stuck with the idea of crimson looking red dwarf stars for some time to come.

Star	Magnitude	Constellation	R.A.	Dec
Groombridge 34	+8/11(v)	Andromeda	00h 18’	+44 01’
40 Eridani C	+11	Eridanus	04h 15’	-07 39’
AX Microscopii/Lacaille 8760	+6.7	Microscopium	21h 17’	-38 52’
Barnard’s Star	+9.5	Ophiuchus	17h 58’	+04 42’
Kapteyn’s Star	+8.9	Pictor	05h 12’	-45 01’
Lalande 21185	+7.5	Ursa Major	11h 03’	+35 58’
Lacaille 9352	+7.3	Piscis Austrinus	23h 06’	-35 51’
Struve 2398	+9.0	Draco	18h 43’	+59 37’
Luyten’s Star	+9.9	Canis Minor	07h 27’	+05 14’
Gliese 687	+9.2	Draco	17h 36’	+68 20’
Gliese 674	+9.9	Ara	17h 29’	-46 54’
Gliese 412	+8.7	Ursa Major	11h 05’	+43 32’
AD Leonis	+9.3	Leo	10h 20’	+19 52’
Gliese 832	+8.7	Grus	21h 34’	-49 01’

Notes on each:

Groombridge 34: Located less than a degree from the +6th magnitude star 26 Andromedae in the general region of the famous galaxy M31, Groombridge 34 was discovered back in 1860 and has a large proper motion of 2.9″ arc seconds per year.

Locating Groombridge 34. Created using Stellarium.

40 Eridani C: Our sole exception to the “10^th magnitude or brighter” rule for this list, this multiple system is unique for containing a white dwarf, red dwarf and a main sequence K-type star all within range of a backyard telescope. In sci-fi mythos, 40 Eridani is also the host star for the planet Richese in Dune and the controversial location for Vulcan of Star Trek fame.

Locating 40 Eridani. Created using Stellarium.

AX Microscopii: Also known as Lacaille 8760, AX Microscopii is 12.9 light years distant and is the brightest red dwarf as seen from the Earth at just below naked eye visibility at magnitude +6.7.

A 20 year animation showing the proper motion of Barnard's Star. Credit: Steve Quirk, images in the Public Domain. — A 20 year animation showing the proper motion of Barnard’s Star. Credit: Steve Quirk, images in the Public Domain.

Barnard’s Star: the second closest star system to our solar system next to Alpha Centuari and the closest solitary red dwarf star at six light years distant, Barnard’s Star also exhibits the highest proper motion of any star at 10.3” arc seconds per year. The center of many controversial exoplanet claims in the 20^th century, it’s kind of a cosmic irony that in this era of 1790 exoplanets and counting, planets have yet to be discovered around Barnard’s Star!

Kapteyn’s Star: Discovered by Jacobus Kapteyn in 1898, this red dwarf orbits the galaxy in a retrograde motion and is the closest halo star to us at 12.76 light years distant.

Lalande 21185: currently 8.3 light years away, Lalande 21185 will pass 4.65 light years from Earth and be visible to the naked eye in just under 20,000 years.

Lacaille 9352: 10.7 light years distant, this was the first red dwarf star to have its angular diameter measured by the VLT interferometer in 2001.

Struve 2398: A binary flare star system consisting of two +9^th magnitude red dwarfs orbiting each other 56 astronomical units apart and 11.5 light years distant.

Luyten’s Star: 12.36 light years distant, this star is only 1.2 light years from the bright star Procyon, which would appear brighter than Venus for any planet orbiting Luyten’s Star.

Gliese 687: 15 light years distant, Gliese 687 is known to have a Neptune-mass planet in a 38 day orbit.

Gliese 674: Located 15 light years distant, ESO’s HARPS spectrograph detected a companion 12 times the mass of Jupiter that is either a high mass exoplanet or a low mass brown dwarf.

Gliese 412: 16 light years distant, this system also contains a +15^th magnitude secondary companion 190 Astronomical Units from its primary.

AD Leonis: A variable flare star in the constellation Leo about 16 light years distant.

Gliese 832: Located 16 light years distant, this star is known to have a 0.6x Jupiter mass exoplanet in a 3,416 day orbit.

The closest stars to our solar system over the next 80,000 years. Credit: FrancescoA under a Creative Commons Attribution Share-Alike 3.0 Unported license.

Consider this list a teaser, a telescopic appetizer for a curious class of often overlooked objects. Don’t see you fave on the list? Want to see more on individual objects, or similar lists of quasars, white dwarfs, etc in the range of backyard telescopes in the future? Let us know. And while it’s true that such stars may not have a splashy appearance in the eyepiece, part of the fun comes from knowing what you’re seeing. Some of these stars have a relatively high proper motion, and it would be an interesting challenge for a backyard astrophotographer to build an animation of this over a period of years. Hey, I’m just throwing that out project out there, we’ve got lots more in the files…

May 12, 2014December 23, 2015 by David Dickinson

NASA West Antarctic Ice Sheet Findings: Glacier Loss Appears Unstoppable

It’s a key piece of the climate change puzzle. For years, researchers have been eyeing the stability of the Western Antarctic Ice Sheet as global temperatures rise. Melting of the ice sheet could have dire consequences for sea level rise.

And though not unexpected, news from today’s NASA press conference delivered by Tom Wagner, a cryosphere program scientist with the Earth Science Division of NASA’s Science Mission Directorate in Washington D.C., Sridhar Anandakrishnan, a professor of geosciences at Pennsylvania University, and Eric Rignot, JPL glaciologist and professor of Earth system science at the University of California Irvine was certainly troubling.

The Western Antarctic Ice Sheet is a marine-based ice sheet below sea level that is bounded by the Ronne and Ross Ice Shelf and contains glaciers that drain into the Amundsen Sea. The study announced today incorporates 40 years of data citing multiple lines of observational evidence measuring movement and thickness of Antarctic ice sheets. A key factor to this loss is a thinning along the grounding line of the glaciers from underneath. The grounding line for an ice sheet is the crucial boundary where ice becomes detached from ground underneath and stretches out to become free floating. A slow degradation of the Western Antarctic Ice Sheet has been observed, one that can be attributed to increased stratospheric circulation along with the advection of ocean heat coupled with anthropogenic global warming.

A closeup of the region: red indicates regions where flow speeds have accelerated in the past 40 years. Credit: Eric Rignot

“This sector will be a major contributor to sea level rise in the decades and centuries to come,” Rignot said in today’s press release. “A conservative estimate is it would take several centuries for all of the ice to flow into the sea.”

Thickness contributes to the driving stress of a glacier. Accelerating flow speeds stretch these glaciers out, reducing their weight and lifting them off of the bedrock below in a continuous feedback process.

A key concern for years has been the possible collapse of western Antarctica’s glaciers, leading to a drastic acceleration in sea-level rise worldwide. Such a catastrophic glacial retreat would dump millions of tons of ice into the sea over a relatively short span of time. And while it’s true that ice calves off of the Western Antarctic ice sheet every summer, the annual overall rate is increasing.

The study is backed up by satellite, airborne and ground observations looking at thickness of ice layers over decades.

Researchers stated that the Amundsen Sea Embayment sector alone contains enough ice to increase global sea level by 1.2 metres. A strengthening of wind circulation around the South Pole region since the 1980s has accelerated this process, along with the loss of ozone. This circulation also makes the process more complex than similar types of ice loss seen in Greenland in the Arctic.

The research paper, titled Widespread, rapid grounding line retreat of Pine Island, Thwaites, Smith and Kohler glaciers, West Antarctica from 1992 to 2011 has been accepted for publication in the American Geophysical Union’s journal Geophysical Research Letters. The American Association for the Advancement of Science will also be releasing a related study on the instability of the West Antarctic ice sheet today in the journal Science.

The most spectacular retreat referenced in the study was seen occurring at the Smith/Kohler glaciers, which migrated about 35 kilometres and became ungrounded over a 500 kilometre square region during the span of 1992 to 2011.

Another telling factor cited in the study was the large scale synchronous ungrounding of several glaciers, suggesting a common trigger mechanism — such as ocean heat flux — is at play.

On the ice shelf proper, the key points that anchor or pin the glaciers to the bedrock below are swiftly vanishing, further destabilizing the ice in the region.

Assets that were used in the study included interferometry data from the Earth Remote Sensing (ERS-1/2) satellites’ InSAR (Interferormetry Synthetic Aperture Radar) instruments, ground team observations and data collected from NASA’s Operation IceBridge overflights of the Antarctic. IceBridge uses a converted U.S. Navy P-3 Orion submarine hunting aircraft equipped with radar experiment packages used to take measurements of the thickness of the ice sheet.

Possible follow up studies targeting the region are upcoming, including five Earth science and observation missions scheduled to be launched this year, which include the Soil Moisture and Passive (SMAP) mission, The Orbiting Carbon Observatory (OCO-2) and the Global Precipitation Measurement (GPM) Core Observatory, launched this past February.

Along with these future NASA missions, there are also two missions — RapidScat and the Cloud-Aerosol Transport System or CATS — slated to study climate headed for the International Space Station this year.

This comes as recent United Nations and United States reports have also announced the reality of climate change and anthropogenic global warming.

“The collapse of this sector of West Antarctica appears to be unstoppable,” Rignot said. “The fact that the retreat is happening simultaneously over a large sector suggests it was triggered by a common cause, such as an increase in the amount of ocean heat beneath the floating sections of the glaciers.”

Of course, the solar cycle, volcanic activity, global dimming (via changes in reflectivity, known as albedo) and human activity all play a role in the riddle that is climate change. The bad news is, taking only natural factors into account, we should be in a cooling period right now.

And yes, reflective ice cover also plays a role in the albedo of the Earth, but researchers told Universe Today that no significant overall seasonal variations in the extent of surface layer of ice will change, as the key loss comes from the ungrounding of ice from below. Thus, this ice loss does not present a significant contribution to changes in overall global albedo, though of course, much of this additional moisture will eventually be available for circulation in the atmosphere. And the same was noted in the press conference for those pinning their hopes on the 2014 ice extent being greater than previous years, a season that was a mere blip on the overall trend. The change and retreat in the grounding line below seen in the study was irrespective of the ice extent above.

NASA’s Operation IceBridge will continue to monitor the ice flow when the next Antarctic deployment cycle resumes in October of this year.

And in the meantime, the true discussion is turning to the challenges of living with a warmer planet. Insurance companies, the Department of Defense and residents of low-lying coastal regions such as Miami’s South Beach already know that the reality of global warming and sea level rise is here. Perhaps the very fact that naysayers have at least backed up their positions a bit in recent years from “global warming isn’t happening” to “Its happening, but there are natural cycles” can at least give us a starting point for true intelligent science-based dialogue to begin.

– Social media questions from today’s conference can be reviewed at the #AskNASA hastag.

May 8, 2014December 23, 2015 by David Dickinson

Interesting Prospects for Comet A1 Siding Spring Versus the Martian Atmosphere

Inbound: the Hubble Space Telescope images Comet 2013 A1 Siding Spring with its Wide Field Camera 3. Credit: NASA.

It may be the chance of a lifetime for planetary science.

This October, a comet will brush past a planet, giving scientists a chance to study how it possibly interacts with a planetary atmosphere.

The comet is C/2013 A1 Siding Spring, and the planet in question Mars. And although an impact of the comet on the surface of the Red Planet has long been ruled out, a paper in the May 2014 issue of Icarus raises the interesting possibility of possible interactions of the coma of A1 Siding Spring and the tenuous atmosphere of Mars. The study comes out of the Department of Planetary Sciences at the University of Arizona, the Belgian Institute for Space Aeronomy, the Institut de Planétologie et d’Astrophysique de Grenoble at the Université J. Fourier in France, and the Cooperative Institute for Research in Environmental Sciences at the University of Colorado in Boulder.

For the study, researchers considered how active Comet A1 Siding Spring may be at the time of closest approach on October 19^th, 2014.

Discovered early last year by Robert McNaught from the Siding Spring Observatory in Australia, Comet A1 Siding Spring created a stir in the astronomical community when it was found that it will pass extremely close to Mars later this year. Further measurements of its orbit have since ruled this possibility out, but its passage will still be a close one, with a nominal passage of 138,000 kilometres from Mars. That’s about one third the distance from Earth to the Moon, and 17 times closer than the nearest recorded passage of a comet to the Earth, Comet D/1770 L1 Lexell in 1780. Mars’ outer moon Deimos has an orbital distance of about 23,500 kilometres.

The passage of Comet 2013 A1 Siding Spring through the inner solar system. Credit: NASA.

And although the nucleus will safely pass Mars, the brush with its extended atmosphere might just be detectable by the fleet of spacecraft and rovers in service around Mars. At a distance of 1.4 Astronomical Units (A.U.) from the Sun during the encounter, the vast coma is expected to be comprised primarily of H₂O. At an input angle of about 60 degrees, penetration was calculated in the study to impinge down and altitude of 154 kilometres to the topside of the Martian ionosphere, in the middle of the thermosphere.

Such an effect should linger for just over 4 hours, well over the interaction period of Mars’ atmosphere with the coma of just over an hour, centered on 18:30 UT on October 19^th, 2014.

What kind of views might missions like HiRISE and MSL get of the comet remains to be seen, although NEOWISE and Hubble are already monitoring the comet for enhanced activity. The Opportunity rover is also still functioning, and Mars Odyssey and ESA’s Mars Express are still in orbit around the Red Planet and sending back data. But perhaps the most interesting possibilities for observations of the event are still en route: India’s Mars Orbiter Mission and NASA’s MAVEN orbiter arrive just before the comet. MAVEN was designed to study the upper atmosphere of Mars, and carries an ion-neutral mass spectrometer (NGIMS) which could yield information on the interaction of the coma with the Martian upper atmosphere and ionosphere. The NGIMS cover is slated for release just two days before the comet encounter. All spacecraft orbiting Mars may feel the increased drag effects of the encounter.

A simulation of Mars as seen from Comet A1 Siding Spring on closest approach. Created by the author using Starry Night Software.

Proposals for using Earth-based assets for further observations of the comet prior to the event in October are still pending. Amateur observers will be able to follow the approach telescopically, as Comet A1 Siding Spring is expected to reach +8^th magnitude in October and pass 7’ from Mars in the constellation Ophiuchus as seen from the Earth. Mars just passed opposition last month, but both will be low to the south west at dusk for northern hemisphere observers in October.

It’s also interesting to consider the potential for interactions of the coma with the surfaces of the moons of Mars as well, though the net amount of water vapor expected to be deposited will not be large.

UPDATE: Check out this nifty interactive simulator which includes Comet A1 Siding Springs courtesy of the Solar System Scope:

The H₂O coma of A1 Siding Spring is expected to have a radius of 150,000 kilometres when it passes Mars, just a shade over the nominal flyby distance.

“There is a more extended coma made up of H₂O dissociation products (such as hydrogen and hydroxide) that extends for ~1,000,000 kilometres,” researcher at the Department of Planetary Sciences at the University of Arizona and lead author on the paper Roger Yelle told Universe Today.

“Essentially, Mars is in the outer reaches of the coma. The main ion tail misses Mars but there will be some ions from the comet that do reach Mars. The dust tail just misses Mars, which is fortunate.”

The paper also notes that significant perturbations of the upper atmosphere of Mars will occur if the cometary production rate is 10^28 s-1 or larger, which corresponds to about 300 kilograms per second.

“The MAVEN spacecraft will make very interesting observations,” Roger Yelle also told Universe Today. “The comet will perturb primarily the upper atmosphere of Mars and MAVEN was designed to study the upper atmosphere of Mars. Also, it’s just such an incredible coincidence that the comet arrives at Mars less than one month after MAVEN does. MAVEN is nominally in its checkout phase then, and the main science phase of the mission was not scheduled to start until November 1^st. However, we are reassessing our plans to see what observations we can make. It’s all quite exciting, and we have to balance safety and the desire to make the best science measurements.”

It’s an unprecedented opportunity, that’s for sure… all eyes will be on the planet Mars and Comet A1 Siding Spring on October the 19^th!

May 7, 2014December 23, 2015 by David Dickinson

The Hunt for KBOs for New Horizons’ Post-Pluto Encounter Continues

An artist’s conception of a KBO encounter by New Horizons. Credit: JHUAPL/SwRI.

Are you ready for the summer of 2015? A showdown of epic proportions is in the making, as NASA’s New Horizons spacecraft is set to pass within 12,500 kilometres of Pluto — roughly a third of the distance of the ring of geosynchronous satellites orbiting the Earth — a little over a year from now on July 14th, 2015.

But another question is already being raised, one that’s assuming center stage even before we explore Pluto and its retinue of moons: will New Horizons have another target available to study for its post-Pluto encounter out in the Kuiper Belt? Researchers say time is of the essence to find it.

To be sure, it’s a big solar system out there, and it’s not that researchers haven’t been looking. New Horizons was launched from Cape Canaveral Air Force Station on January 19^th, 2006 atop an Atlas V rocket flying in a 551 configuration in one of the fastest departures from Earth ever: it took New Horizons just nine hours to pass Earth’s moon after launch.

New Horizons spends its last days on Earth pre-encapsulation. (Credit: NASA/KSC).

The idea has always been out there to send New Horizons onward to explore and object beyond Pluto in the Kuiper Belt, but thus far, searches for a potential target have turned up naught.

A recent joint statement from NASA’s Small Bodies and Outer Planets Assessment Groups (SBAG and OPAG) has emphasized the scientific priority needed for identifying a possible Kuiper Belt Object (KBO) for the New Horizons mission post-Pluto encounter. The assessment notes that such a chance to check out a KBO up close may only come once in our lifetimes: even though it’s currently moving at a heliocentric velocity of just under 15 kilometres a second, it will have taken New Horizons almost a decade to traverse the 32 A.U. distance to Pluto.

The report also highlights the fact that KBOs are expected to dynamically different from Pluto as well and worthy of study. The statement also notes that the window may be closing to find such a favorable target after 2014, as the upcoming observational apparition of Pluto as seen from Earth — and the direction New Horizons is headed afterwards — reaches opposition this summer on July 4^th.

But time is of the essence, as it will allow researchers to plan for a burn and trajectory change for New Horizons shortly after its encounter with Pluto and Charon using what little fuel it has left. Then there’s the issue of debris in the Pluto system that may require fine-tuning its trajectory pre-encounter as well. New Horizons will begin long range operations later this year in November, switching on permanently for two years of operations pre-, during and post- encounter with Pluto.

And there currently isn’t a short-list of “next best thing” targets for New Horizons post-Pluto encounter. One object, dubbed VNH0004, may be available for distant observations in January of next year, but even this object will only pass 75 million kilometres — about 0.5 A.U. — from New Horizons at its closest.

Ground based assets such as the Keck, Subaru and Gemini observatories have been repeatedly employed in the search over the past three years. The best hopes lie with the Hubble Space Telescope, which can go deeper and spy fainter targets.

Nor could New Horizons carry out a search for new targets on its own. Its eight inch (20 cm in diameter) LORRI instrument has a limiting magnitude of about +18, which is not even close to what would be required for such a discovery.

New Horizons currently has 130 metres/sec of hydrazine fuel available to send it onwards to a possible KBO encounter, limiting its range and maneuverability into a narrow cone straight ahead of the spacecraft. This restricts the parameters for a potential encounter to 0.35 A.U. off of its nominal path for a target candidate be to still be viable objective. New Horizons will exit the Kuiper Belt at around 55 A.U. from the Sun, and will probably end its days joining the Voyager missions probing the outer solar system environment. Like Pioneers 10 and 11, Voyagers 1 and 2 and the upper stage boosters that deployed them, New Horizons will escape our solar system and orbit the Milky Way galaxy for millions of years. We recently proposed a fun thought experiment concerning just how much extraterrestrial “space junk” might be out there, littering the galactic disk.

And while the crowd-sourced Ice Hunters project generated lots of public engagement, a suitable target wasn’t found. There is talk of a follow up Ice Investigators project, though it’s still in the pending stages.

Another issue compounding the problem is the fact that Pluto is currently crossing the star rich region of the Milky Way in the constellation Sagittarius. Telescopes looking in this direction must contend with the thousands of background stars nestled towards the galactic center, making the detection of a faint moving KBO difficult. Still, if any telescope is up to the task, it’s Hubble, which just entered its 25^th year of operations last month.

Credit Starry Night — The path of Pluto through the constellation Sagittarius through August 2015. Credit: Starry Night.

Shining at +14^th magnitude, Pluto will be very near the 3.5^th magnitude star Xi² Sagittarii during the July 2015 encounter.

New Horizons is currently 1.5 degrees from Pluto — about 3 times the angular size of a Full Moon —as seen from our Earthly vantage point, and although neither can be seen with the naked eye, you can wave in their general direction this month on May 18^th, using the nearby daytime Moon as a guide.

July 2015 will be an exciting and historic time in solar system exploration. Does Pluto have more undiscovered moons? A ring system of its own? Does it resemble Neptune’s moon Triton, or will it turn out looking entirely different ?

If nothing else, exploration of Pluto will finally give us science writers some new images to illustrate articles on the distant world, rather than recycling the half a dozen-odd photos and artist’s conceptions that are currently available. An abundance of surface features will then require naming as well. It would be great to see Pluto’s discoverer Clyde Tombaugh and Venetia Burney — the girl who named Pluto — get their due. We’ll even assume our space pundit’s hat and predict a resurgence of the “is it a planet?” debate once again in the coming year as the encounter nears…

Onward to Pluto and the brave new worlds beyond!

May 5, 2014December 23, 2015 by David Dickinson

Comet Jacques Brightens: How to See it in May

Comet Jacques as imaged on March 18th, shortly after discovery. Credit: Efrain Morales Rivera.

A recently discovered comet is headed northward and is set to put on one of two fine performances for binocular observers in 2014 starting this week.

Comet C/2014 E2 Jacques was discovered on March 13^th 2014 by Cristóvão Jacques, Eduardo Pimentel and João Ribeiro de Barros while observing from the Southern Observatory for Near Earth Asteroids Research (SONEAR) facility located near Oliveira, Brazil.

The comet was just about at +15^th magnitude at the time of discovery as it glided across the southern hemisphere constellation of Centaurus.

While a majority of comet discoveries are destined to remain small and faint, Comet Jacques was immediately shown to be something special. Upon discovery of any new comet, the first task is to gain several observations hours or nights apart to accurately gauge its distance and orbit. Are astronomers looking at a small, garden variety comet close up, or a large, active one far away?

In the case of Comet Jacques, it was something in between: a comet about 1.22 Astronomical Units (A.U.s) distant at time of discovery. Comet Jacques is headed towards perihelion 0.66 A.U. from the Sun in early July and will pass 0.56 A.U. from Earth on August 28th. Follow up observations carried out using the iTelescope at Siding Spring Australia showed a slightly elongated coma about 2 arc minutes across shortly after discovery, and the comet has recently jumped up to magnitude +8 — ahead of the projected light curve — in just the past week.

We caught our first good look at Comet Jacques last night while setting up for the Virtual Star Party. While +10 magnitude or brighter is usually a pretty good rule of thumb for binocular visibility, we found that the comet was only apparent as a fuzzy smudge viewing it with a 8” Schmidt-Cassegrain telescope using averted vision at low power. Remember, the brightness of a comet is spread out over its apparent surface area, similar to viewing a diffuse nebula. Our first telescopic views of the ill-fated comet ISON as it breeched +10^th magnitude were similar. Certainly, a nearby waxing crescent Moon in Gemini last night didn’t help.

How bright will Comet Jacques get? Current projections call for it to perhaps break naked eye visibility around +6^th magnitude after June 1^st and reach as bright as +4^th magnitude in early July near perihelion. After its first evening act in May and June, Comet Jacques will reemerge in the dawn sky for northern hemisphere observers for Act 2 and trace a path northward paralleling the galactic plane through the star rich fields of Perseus, Cassiopeia, Cepheus and Cygnus in August and September of this year. If our luck holds out, Comet Jacques will remain above 6^th magnitude until early September.

Credit JPL — The path of Comet Jacques through the inner solar system. Credit: JPL solar system small body generator.

This comet also created a brief flurry of interest when it was revealed that it will pass just 0.085 AUs or 12,700,000 kilometers from Venus on July 13^th, 2014. Though close, this is still 31 times the distance from Earth to the Moon. The only “eyes” that humanity has currently in operation around Venus is ESA’s Venus Express orbiter. During closest approach Comet Jacques will appear just over 3 degrees away from Venus as seen from our Earthly vantage point.

Another comet is also set to photobomb a planet, as Comet A1 Siding Spring passes a nominal distance of 0.0009 A.U.s or 135,000 kilometers from Mars this Fall on October 19th.

The closest recorded passage of a comet near Earth was Comet D/1770 L1 Lexell in 1770, which passed us 0.015 A.U.s or 233 million kilometres distant.

Now on to Act 1. May finds Comet Jacques spending most of the month in the long rambling constellation of Monoceros. Currently moving just under 2 degrees a day, Comet Jacques crosses the celestial equator northward this week on May 8^th. You’ll note its high orbital inclination of 156.4 degrees as it speeds northward. Comet Jacques has a long orbital period gauged at over 30,000 years — the last time Comet Jacques visited the inner solar system, our ancestors had the Last Glacial Maximum period to look forward to.

Light curve — The projected light curve of comet Jacques with recent observations. Credit: Seiichi Yoshida/aerith.net.

Comet Jacques is currently the brightest comet “with a bullet,” edging out the +9^th magnitude comets C/2012 K1 PanSTARRS gilding through Canes Venatici and comet C/2012 X1 LINEAR, currently residing in the constellation of Aquila the Eagle. A great place to keep up with current observations of comets is the Comet Observation Database. We’re also pinging the IAU Minor Planet Center’s quick look page for new discoveries daily.

Here are some highlights to watch out for as Comet Jacques heads towards perihelion. Passages within one degree — twice the size of the Full Moon — near stars brighter than +5^th magnitude are noted unless mentioned otherwise:

The celestial path of Comet Jacques from May 3rd through June 1st. Credit: Starry Night.

May 8^th: Passes the +4.1 magnitude star Delta Monocerotis and crosses north of the celestial equator.

May 10^th: Passes planetary nebula NGC 2346.

May 11^th: Passes briefly into Canis Minor before reentering the constellation Monoceros.

May 14^th: Full Moon occurs, marking the start of a favorable two week period of moonless evenings soon after.

May 24^th: Passes the +4.8 magnitude star 17 Monocerotis.

May 28^th: New Moon occurs, marking the return of the Moon to early evening skies.

May 29^th: Passes the +4.7 magnitude star 15 Monocerotis.

May 30^th: Passes the Christmas tree cluster. Photo op!

May 31^st: The waxing crescent Moon passes less than 8 degrees from Comet Jacques.

June 1^st: Comet Jacques reaches naked eye visibility?

June 6^th: Crosses into the constellation Gemini.

June 11^th: Crosses into the constellation Taurus.

June 13^th: Full Moon occurs.

June 14^th:Crosses the galactic plane.

June 21^st: Passes into the field of view of SOHO’s LASCO C3 camera.

June 27^th: New Moon occurs.

July 2^nd: Reaches perihelion at 0.6638 A.U. from the Sun.

July 8^th: Crosses north of the ecliptic plane.

July 13^th: Passes 0.085 A.U. from Venus.

August 28^th: Passes 0.56 A.U. from Earth.

And thus, Comet Jacques joins the parade of fine binocular comets in the 2014 night sky, as the stage is set for Act 2 this fall. And keep in mind, the next “big one” could grace our skies at anytime… more to come!

April 29, 2014December 23, 2015 by David Dickinson

Amazing Images of Today’s Solar Eclipse from Earth and Space

The images are pouring in. While most of North America slept this AM, Australians were treated to the very first solar eclipse of 2014 earlier today. And while this particular eclipse was a partial one only from the Australian continent, it still offered observers a fine view of an often elusive natural spectacle.

The partial eclipse as seen from Adelaide. Credit: Michael Drew (@MichaelDrew1234)

Although rain and clouds frustrated attempts to view the eclipse from much of southern Australia, clouds parted long enough in Queensland to the east and areas around Perth to the west to offer observers a fine view. Many eclipse watchers on the Australian east coast had the additional bonus of catching the setting Sun during the eclipse.

A quick screen shot from ESA’s Proba-2 spacecraft during one of the three passes of the solar eclipse. Credit: ESA/Proba-2.

We wrote about the prospects for catching this bizarre eclipse previously. The eclipse was a rare, non-central annular with one limit only, meaning the antumbra or inner core of the Moon’s shadow just grazed the edge of the planet over Antarctica. We haven’t yet heard if anyone witnessed it from the southern polar continent, though two year round research stations were located near the path of annularity. The European Space Agency operates Concordia Station nearby as part of its Human Spaceflight Activities program and they were aware of the upcoming event. We’ll keep you updated if reports or images surface!

The eclipse seen through clouds. Photographer David Herne also noted that while he used his D3100 DSLR for the shot, his homemade pinhole camera offered fine views as well! Credit: David Herne(@AunaEridu)/Perth Western Australia.

As predicted, another solar observing sentinel in low Earth orbit did indeed witness the eclipse. ESA’s Proba-2 spacecraft caught the eclipse on three passes in this amazing raw animation from its SWAP-2 camera. The final third pass goes by extremely quick –these are measured in minutes from Proba-2’s swift vantage point – but the Sun looks well nigh to greater than 95% eclipsed by the Moon as it flies by.

The partial solar eclipse as seen from Adelaide, Australia. Credit: Silveryway.

There’s no word as of yet if the joint NASA/JAXA mission Hinode caught the eclipse as well, but we’ll keep you posted!

UPDATE: Courtesy of the European Space Agency and the Royal Observatory of Belgium, we now give you the full YouTube timelapse of the eclipse courtesy of Proba-2:

You’ll note that Proba-2 caught the partial phases on four separate passes… we also checked the sequence frame by frame, and although it looks like Proba-2 “may” have seen an annular – or even total – eclipse from space, it looks like it did so between captures!

This eclipse is one of two solar eclipses and four eclipses total for 2014. An interesting discussion occurred leading up to this eclipse as to the minimum number of eclipses that can occur in a year, which is four. If, however, you exclude faint lunar penumbrals, that number does indeed drop to two, both of which must be solar, which occurs in 2016. This also sparked a lively debate as to the naming of such a year on Twitter, with everything from a “Dwarf Eclipse Year” to “Nano Eclipse Cycle” and “Spurious Eclipse Year” being proposed. We liked the suitably esoteric and ready tweet-able term “declipsy” ourselves… thanks for the proposals and the lively discussion!

The partially-eclipsed Sun sinks into the west as seen from Brisbane, Australia on April 29, 2014. Credit and copyright: Teale Britstra.

Partial solar eclipse in Adelaide, South Australia on April 29, 2014. Credit and copyright: Silveryway on Flickr.

Thanks also to all who sent in pics. We’ll be updating this post as more come in… and although eclipse season 1 of 2 may be over for now, 2014 still has another total lunar eclipse and a good partial solar in October, both visible from North America.

…And we’re only three years out and have just two more total solar eclipses to go until the historic total solar eclipse of August 21^st, 2017…

Let the countdown begin!

UPDATE: Missed out on the solar eclipse today? Hey so did we, it happens to the best of us… luckily, YOU can now relive the all of the excitement of the eclipse courtesy of the folks from the Virtual Telescope Project in YouTube Splendor:

And finally: got pics of the partial solar eclipse that you took today and you want to share with the world? Put ’em up on Universe Today’s Flickr community and let us know!

April 23, 2014December 23, 2015 by David Dickinson

Saturn at Opposition: Our 2014 Guide

Saturn as imaged from Aguadilla, Puerto Rico on April 15th. Credit: Efrain Morales.

Planet lovers can rejoice: one of the finest jewels of the solar system in returning to the evening night sky.

The planet Saturn reaches opposition next month on May 10^th. This means that as the Sun sets to the west, Saturn will rise “opposite” to it in the east, remaining well positioned for observation in the early evening hours throughout the summer season. In fact, we’ll have four of the five naked eye planets above the horizon at once for our evening viewing pleasure in the month of May, as Jupiter also rides high to the west at sunset, Mars just passed opposition last month and Mercury reaches greatest eastern elongation on May 25^th. Venus is the solitary holdout, spending a majority of 2014 in the dawn sky.

Saturn will shine at magnitude +0.3 this month and its disk spans an apparent 19,” or 44” if you take into account the apparent width of its rings. The rings are currently tipped open 22 degrees with respect to our line of sight. The ring opening is widening, and will reach a maximum of over 25 degrees in 2017 before the trend reverses. Anyone who remembers observing Saturn back in 2009 will recall that its rings were edge on to our view. This widening of Saturn’s rings also lends itself to a curious effect: although we’re in a cycle of oppositions that are getting farther away — Saturn is 12.5 million kilometres or 0.083 Astronomical Units (A.U.s) more distant in 2014 than it was during opposition last year as it’s headed towards aphelion in 2018 — its widening rings are actually making it appear a bit brighter.

The path of Saturn through the constellation Libra from April through October 2014. Created using Starry Night Education Software.

This year’s opposition will find Saturn in the astronomical constellation of Libra, where it’ll spend most of 2014. Oppositions of the ringed planet are set to continue to “head south” until 2018, and won’t occur north of the celestial equator again until 2026. I remember when oppositions of Saturn returned to the constellation Virgo a few years back — where I had first looked at it with my 60mm Jason refractor as a teenager — and realizing that I had now been into observational astronomy for roughly one “Saturnian year.”

The ancients had little knowledge of how unique Saturn was. The faintest and slowest moving of the classical planets, even Galileo knew that something was up when he turned his first primitive telescope towards it. His sketches depict Saturn as something similar to a double handled coffee cup, a testament to how poor his view really was. It wouldn’t be until Christiaan Huygens in 1655 that the true nature of Saturn’s rings was deduced as a flat and separate feature from the disk.

At opposition, the disk of the planet casts a shadow straight back from our point of view. This vantage slowly changes as the planet moves towards eastern quadrature on August 9th and we get a glimpse slightly off to one side of the planet. After opposition, the shadow of the disk can again be seen casting back onto the rings.

An outstanding IPhone 4S capture of Saturn on April 20th, 2014. Credit: Andrew Symes, @FailedProtostar.

Another interesting phenomenon to watch out for near opposition is known as the Seeliger effect. Also sometimes referred to as the “opposition surge,” this sudden brightening of the disk and rings is a subtle effect, as the globe of Saturn and all of those tiny little ice crystals reach 100% illumination. This effect can be noted to the naked eye on successive nights around opposition, and will get more prominent towards 2017. Coherent-backscattering of light has also been proposed as a possible explanation of this phenomenon. Perhaps a video sequence capturing this effect is in order for skilled astro-imagers in 2014.

Through a small telescope, the first feature that becomes apparent is Saturn’s glorious system of rings. Crank up the magnification, and you’ll note a dark groove in the ring system. This is the Cassini Division, first described by Giovanni Cassini in 1675.

Here’s a challenge we came across some years back: can you see the disk of Saturn through the Cassini Division? Right around opposition is a good time to attempt this unusual feat of visual athletics.

A sample simulation depicting the orientation of Saturn's observable moons on the night of May 9th. Created using Starry Night Education software. — A sample simulation depicting the orientation of Saturn’s observable moons on the night of May 9th. Created using Starry Night Education software.

Saturn’s large moon Titan is an easy catch at magnitude +8 in a small telescope. Titan is the second largest moon in the solar system. Place it in a direct orbit about the Sun, and it would be considered a planet, no problem. 7 of Saturn’s 62 known moons are within reach of a small telescope. In addition to Titan, they are, with quoted magnitudes: Mimas (+13), Enceladus (+12), Tethys (+10), Rhea (+10), Dione (+11) and Iapetus. Iapetus is of special interest, as it brightens from +11.9 to magnitude +10.2 as it traces out its 79 day orbit. We always knew there was something unique about this moon, and NASA’s Cassini mission revealed the world to have two distinctly different hemispheres with vastly different albedos during its close 2007 flyby.

The close passage of the Full Moon near Saturn on May 14th. Created using Stellarium.

Also, be sure to check out Saturn on the night of May 14^th — just 4 nights after opposition — as the Full Moon sits less than a degree south of the ringed planet. Can you see both in the same telescopic field of view? Can you nab Saturn next to the rising daytime Moon low to the horizon just before local sunset? The Moon will actually occult (pass in front of) Saturn for viewers based in Australia and New Zealand on the 14^th. This is only one of 11 occultations — nearly one for each lunation — of Saturn by the Moon in 2014. Unfortunately, the best one for North America occurs in the daytime on August 31^st, though it too may be observable telescopically.

The foot print of the May 14th occultation of Saturn by the Moon. Credit: Occult 4.0. — The footprint of the May 14th occultation of Saturn by the Moon. Credit: Occult 4.0.

Finally, this evening apparition of the planet runs through northern hemisphere summer and fall until Saturn reaches solar conjunction on November 18th. So get those homemade planetcams out, send those pics in to Universe Today, and be sure to join in to the Virtual Star Party every Sunday Night… Saturn is sure to be featured!