David Dickinson, Author at Universe Today

December 12, 2013December 23, 2015 by David Dickinson

IRIS Glimpses an Elusive Region of the Sun

An innovative solar observatory is adding a key piece to the puzzle of the enigma that is our Sun.

Its two of key questions in heliophysics: why does our Sun have a corona? And why is the temperature of the corona actually higher than the surface of the Sun?

This week, researchers released results from the preliminary first six months of data from NASA’s Interface Region Imaging Spectrograph, known as IRIS. The findings were presented at the Fall American Geophysical Union Meeting this past Monday.

IRIS was launched on June 27^th of this year on a Pegasus-XL rocket deployed from the belly of a Lockheed L-1011 aircraft flying out of Vandenberg Air Force Base. IRIS can focus in on a very specific interface region of the Sun sandwiched between the dazzling solar photosphere and the transition to the corona. To accomplish this, IRIS employs an ultraviolet slit spectrograph looking at ionized gas spectra.

IRIS in the clean room. The spacecraft is only about 2 metres in length, about the height of a person. (Credit: Lockheed Martin).

“The quality of images and spectra we are receiving is amazing,” IRIS Principal Investigator Alan Title said in a recent press release from the NASA Goddard Space Flight Center. While other missions may take over a decade to go from the drawing board to the launch pad, IRIS was developed and deployed into Low Earth Orbit in just 44 months.

IRIS offers scientists a new tool to probe the Sun and a complimentary instrument to platforms such as Hinode, the Solar Heliospheric Observatory (SOHO) and NASA’s Solar Dynamics Observatory. In fact, IRIS has a better resolution than SDO’s AIA imagers or Hinode when it comes to this key solar interface region. IRIS has a 20x greater resolution in time, and 25x the spatial resolution of any former space-based UV spectrometer deployed.

“We are seeing rich and unprecedented images of violent events in which gases are accelerated to very high velocities while being rapidly heated to hundreds of thousands of degrees,” said Lockheed Martin science lead on the IRIS mission Bart De Pontieu. These observations are key to backing up theoretical models of solar dynamics as well as testing and formulating new ones of how our Sun works.

IRIS bridges this crucial gap between the photosphere and the lower chromosphere of the Sun. While the solar surface roils at relatively placid 6,000 degrees Celsius, temperatures rise into the range of 2-3 million degrees Celsius as you move up through the transition region and into the corona.

Two key solar phenomena that are of concern to solar researchers can be examined by IRIS in detail. One is the formation of prominences, which show up as long looping swirls of solar material rising up from the surface of the Sun. Prominences can be seen from backyard telescopes at hydrogen alpha wavelengths. IRIS can catch and track their early modeling with unprecedented resolution. Images released from IRIS show the fine structure of targeted prominences as they evolve and rise off the surface of the Sun. When a prominence and accompanying coronal mass ejection is launched in our direction, disruption of our local space environment caused by massive solar storm can result.

Slit jaw spectra images (the two strips to the left) and imaging a spicules 9to the right as seen by IRIS. (Credit: NASA/IRIS). — Slit jaw spectra images (the two strips to the left) and imaging of spicules (to the right) as seen by IRIS. (Credit: NASA/IRIS).

The second phenomenon targeted by IRIS is the formation of spicules, which are giant columns of gas rising from the photosphere. Although the spicules look like hair-fine structures through Earth-based solar telescopes, they can be several hundred kilometres wide and as long as the Earth. Short-lived, spicules race up from the surface of the Sun at up to 240,000 kilometres per hour and seem to play a key role in energy and heat transfer from the solar surface up through the atmosphere. IRIS is giving us a view of the evolution of spicules for the first time, and they’re proving to be even more complex than theory previously suggested.

“We see discrepancies between these observations and the models, and that is great news for advancing knowledge. By seeing something we don’t understand, we have a chance of learning something new,” Said University of Oslo astrophysicist Mats Carlsson.

Like SDO and SOHO, data and images from IRIS are free for the public to access online. Though the field of view for IRIS is a narrow 2’ to 4’ arc minutes on a side – the solar disk spans about 30’ as seen from the Earth – IRIS gives us a refined view of “where the action is.”

Where is IRIS looking? This snapshot gives some context of the IRIS field of view (green and red boxes) and black and white insets versus SDO's AIA full disk view of the Sun. (Credit: NASA/SDO/IRIS). — Where is IRIS looking? This snapshot gives some context of the IRIS field of view (green and red boxes) and black and white insets versus SDO’s AIA full disk view of the Sun. (Credit: NASA/SDO/IRIS).

And this all comes at an interesting time, as our nearest star crosses the sputtering solar maximum for Cycle #24.

The equivalent of 50 million CPU hours were utilized in constructing and modeling what IRIS sees. The reconstruction was an international effort, spanning the Partnership for Advanced Computing in Europe, the Norwegian supercomputing collaboration, and NASA’s Ames Research Center.

IRIS also faced the additional challenge of weathering a 2.5 week period of inactivity due to the U.S. government shutdown this fall. Potential impacts due to sequestration remain an issue, though small explorer missions such as IRIS demonstrate how we can do more with less.

“We’ve made a giant step forward in characterizing the heat transfer properties of this region between the visible surface and the corona, which is key to understanding how the outer atmosphere of the Sun exists, and is key to understanding the outer atmosphere that the Earth lies in,” said Alan Title, referring to the tenuous heliosphere of the Sun extending out through the solar system.

Understanding the inner working of our Sun is vital: no other astronomical body has as big an impact on life here on Earth.

IRIS is slated for a two-year mission, though as is the case with most space-based platforms, researchers will work to get every bit of usefulness out of the spacecraft that they can. And it’s already returning some first-rate science at a relatively low production cost. This is all knowledge that will help us as a civilization live with and understand our often tempestuous star.

December 9, 2013December 23, 2015 by David Dickinson

Get Ready for the 2013 Geminid Meteor Shower

The rising radiant of the Geminids-Looking east at 9PM local from latitude 30 degrees north. (Credit-Stellarium).

One of the best annual meteor showers occurs this coming weekend.

The 2013 Geminid meteors peak this coming Saturday on December 14^th. This shower has a broad maximum, assuring that observers worldwide get a good look. In 2013, the maximum for the Geminids is forecast to span from 13:00 Universal Time (UT) on Friday, December 13^th to 10:00UT/5:00AM EST on Saturday, December 14^th, with a projected maximum centered a few hours earlier at 2:00 UT Saturday morning.

This is good news for observers spanning both sides of the Atlantic, who should be well placed to catch the event. Keep in mind, meteor showers often peak hours before or after predictions… we certainly don’t know everything that a given meteor stream might have in store!

An all-sky composite of the 2008 Geminid meteor shower. (Credit: NASA/MSFC/Bill Cooke, NASA's Meteoroid Environment Office). — An all-sky composite of the 2008 Geminid meteor shower. (Credit: NASA/MSFC/Bill Cooke, NASA’s Meteoroid Environment Office).

But the time to start watching is now. We’ve already seen a few early Geminids this past weekend, and this shower is notable for showing early activity for northern hemisphere observers before local midnight. This is because the radiant, or the direction that the meteors seem to emanate from lies at a high northern declination of 33 degrees north near the star Castor, also known as Alpha Geminorum.

The typical Zenithal Hourly Rate for the Geminids is 80-120, or about 1 to 2 per minute. Keep in mind, the ZHR is an ideal rate, assuming dark skies, with the radiant positioned directly overhead. Most observers will see significantly less activity.

The 2013 Geminids also have to contend with the waxing gibbous Moon, which reaches Full just 3 days after the shower’s expected maximum. This will give observers a dwindling window between moonset and the start of dawn twilight to catch the Geminids at their best.

We always thought that the Geminids had a bit of an undeserved PR problem among annual showers. This no doubt stems from the fact that they arrive in the chilly month of December, a time when fingers go numb, camera batteries die, and conducting a vigil for meteors is challenging.

A 2012 Geminid captured by the author from Mars Hill. North Carolina. — A 2012 Geminid captured by the author from Mars Hill, North Carolina.

This shower is an interesting one though, with an equally interesting history and source. The Geminids were first identified as a distinct meteor shower by R.P. Greg of Manchester UK in 1862, and the estimated ZHR rose from about 20 to 80 through the 20^th century. The parent source of the Geminids remained unknown until 1983, when astronomer Fred Whipple linked them to the strange “rock-comet” body 3200 Phaethon. An Apollo asteroid also thought to be a member of the Pallas family of asteroids, 3200 Phaethon seems to be shedding enough material to produce the annual Geminid meteor shower. This makes the annual shower rare as one not produced by a comet. It’s worth noting that 3200 Phaethon also passes extremely close – 0.14 AU – from the Sun at perihelion, and gets periodically “baked” during each 1.4 year passage.

In the 21^st century, rates for the Geminids have stayed above a ZHR of 120, currently the highest of any annual shower. It’s worth noting that an extrapolated ZHR of almost 200 were seen in 2011 when the Moon was at an equally unfavorable waning gibbous phase! The Geminids always produce lots of fireballs, capable of being seen even under moonlit skies.

There are also two other showers currently active to watch for this week. One is the Ursid meteors, which radiate from the Little Dipper (Ursa Minor) with a peak ZHR of 10-50 occurring on December 22^nd. Also, keep an eye out for Andromedid meteors this week, a defunct shower that may be making a comeback. The source of several great meteor storms in the late 19^th century, the Andromedid parent source is the shattered comet formerly known as 3D/Biela.

An early Geminid crosses pathes with Comet 2013 R1 Lovejoy. (Credit: Jason Hullinger). — An early Geminid crosses paths with Comet 2013 R1 Lovejoy. (Credit: Jason Hullinger).

Though the Geminids appear to radiate from the constellation Gemini, they can appear anywhere in the sky. Tracing the path back can determine the source constellation and the “membership” of a given meteor. Random meteors not associated with any identified shower are known as “sporadics.” Block that pesky light-polluting Moon behind a building or hill to optimize your chances of catching sight of a meteor. Employing a friend or two to watch in different directions will also maximize the number seen. The International Meteor Organization always welcomes reports from observers… this is real science that you can contribute to using nothing more sophisticated than your eyes!

The Geminids are medium-speed meteors with an average atmospheric velocity of about 35 kilometres per second, often leaving long, glowing trails worth examining with a pair of binoculars. You might note an apparent surge in speed to this shower past local midnight, as your vantage point turns into the oncoming shower, adding the velocity of the Earth to the approaching Geminids.

Photographing meteors is fun and easy to do; all you’ll need is a DSLR camera mounted on a tripod. Take several manual setting exposures to get the combination of ISO,F-stop, and shutter speed correct for your local sky conditions. Then simply set the focus to infinity, and use the widest field of view possible. Catching meteors is surreptitious, as they can appear anywhere – and at any time – in the sky. Be sure to thoroughly review those images afterwards… nearly every meteor we’ve caught photographically went unnoticed during observation!

Also, remember that cold weather plus long exposure times can conspire to drain camera batteries in a hurry. Be sure to keep a spare set of charged batteries ready to go in a warm pocket!

How powerful will the Geminids become? Are we in for a “return of the Andromedids” moving towards 2014? One thing is for sure: you won’t see any meteors if you don’t try. So be sure to get out there, pour a mug of your favorite warming beverage, and don’t miss the 2013 Geminid meteor shower!

– Got meteors? Be sure and tweet ‘em to #Meteorwatch.

– Be sure to send those pics of Geminids and more in to Universe Today.

December 4, 2013December 23, 2015 by David Dickinson

A Naked Eye Nova Erupts in Centaurus

If you live in the southern hemisphere, the southern sky constellation of Centaurus may look a little different to you tonight, as a bright nova has been identified in the region early this week.

An animation showing a comparison between the constellation Centaurus before and after a nova eruption. Credit and copyright: Ernesto Guido, Nick Howes and Martino Nicolini/Remanzacco Observatory. Click for larger version.

The initial discovery of Nova Centauri 2013 (Nova Cen 2013) was made by observer John Seach based out of Chatsworth Island in New South Wales Australia. The preliminary discovery magnitude for Nova Cen 2013 was magnitude +5.5, just above naked eye visibility from a good dark sky site. Estimates by observers over the past 24 hours place Nova Cen 2013 between magnitudes +4 and +5 “with a bullet,” meaning this one may get brighter still as the week progresses.

We first got wind of the discovery via the American Association of Variable Star Observers yesterday afternoon when alert notice 492 was issued. Established in 1911, the AAVSO is a great resource for info and a fine example of amateur collaboration in the effort to conduct real scientific observation.

Follow-up spectra measurements by Rob Kaufman in White Cliffs Australia and Malcolm Locke in Christchurch New Zealand demonstrated the presence of strong hydrogen alpha and hydrogen beta emission lines, the classic hallmark of an erupting nova. Like Nova Delphini 2013 witnessed by observers in the northern hemisphere, this is a garden variety nova located in our own galaxy, going off as seen along the galactic plane from our Earthbound perspective. A handful of galactic novae are seen each year, but such a stellar conflagration reaching naked eye visibility is worthy of note. In fact, Nova Cen 2013 is already knocking on the ranks of the 30 brightest novae observed of all time.

This is not to be confused with a supernova, the last of which observed in our galaxy was Kepler’s Supernova in 1604, just before the advent of the telescope in modern astronomy. Supernovae are seen in other galaxies all the time, but here at home, you could say we’re “due”.

So, who can see Nova Cen 2013, and who’s left out? Well, the coordinates for the nova are:

Right Ascension: 13 Hours 54’ 45”

Declination: -59°S 09’ 04”

That puts it deep in the southern celestial hemisphere sky where the constellation Centaurus meets up with the constellations of Circinus, Musca and the Crux. Located within three degrees of the +0.6^th magnitude star Hadar — also named Beta Centauri — it would be possible to capture the southern deep sky objects of the Coal Sack and Omega Centauri with Nova Cen 2013 in the same wide field of view.

The field of view of Nova Centauri 2013 with a five degree Telrad “bullseye” added for scale. Note that magnitude for selected comparison stars are quoted, minus the decimal points. (Created using Stellarium).

Though Nova Cen 2013 technically peeks above the southern horizon from the extreme southern United States, the viewing circumstances aren’t great. In fact, the nova only rises just before the Sun as seen from Miami in December, at 25 degrees north latitude. The Centaurus region is much better placed in northern hemisphere during the springtime, when many southern tier states can actually glimpse the celestial jewels that lie south, such as Omega Centauri.

But the situation gets better, the farther south you go. From Guayaquil, Ecuador just below the equator, the nova rises to the southeast at about 3 AM local, and sits 20 degrees above the horizon at sunrise.

11PM local from latitude (Created by the author using Starry Night Education Software). — 11PM local, from latitude 40 degrees south looking to the southeast. (Created by the author using Starry Night Education Software).

The nova will be circumpolar for observers south of -30 degrees latitude, including cities of Buenos Aires, Cape Town, Sydney and Auckland. Remember, its springtime currently in the southern hemisphere, as we head towards the solstice on December 21^st and the start of southern hemisphere summer. We’ve been south of the equator about a half dozen times and it’s a unique experience – for northern star gazers, at least – to see familiar northern constellations such as Orion and Leo hang “upside down” as strange a wonderful new constellations beckon the eye to the south. Also, though the Sun still rises to the east, it transits to the north as you get deep into the southern hemisphere, a fun effect to note!

Latitudes, such as those on par with New Zealand, will get the best views of Nova Cen 2013. Based near latitude 40 degrees south, observers will see the nova about 10 degrees above the southern horizon at lower culmination at a few hour after sunset, headed towards 40 degrees above the southeastern horizon at sunrise.

All indications are that Nova Cen 2013 is a classical nova, a white dwarf star accreting matter from a binary companion until a new round of nuclear fusion occurs. Recurrent novae such as T Pyxidis or U Scorpii may erupt erratically in this fashion over the span of decades.

As of yet, there is no firm distance measurement for Nova Cen 2013, though radio observations with southern sky assets may pin it down. One northern hemisphere based program, known as the EVLA Nova Project, seeks to do just that.

Congrats to John Seach on his discovery, and if you find yourself under southern skies, be sure to check out this astrophysical wonder!

Got pics of Nova Centauri 2013? Be sure to send ‘em in to Universe Today!

December 3, 2013December 23, 2015 by David Dickinson

Now is a Great Time to Try Seeing Venus in the Daytime Sky

Venus (arrowed) imaged near the waning crescent Moon on August 13th, 2012. (Photo by author).

Here’s a feat of visual athletics to amaze your friends with this week. During your daily routine, you may have noticed the daytime Moon hanging against the azure blue sky. But did you know that, with careful practice and a little planning, you can see Venus in the broad daylight as well?

This week offers a great chance to try, using the daytime Moon as a guide. We recently wrote about the unique circumstances of this season’s evening apparition of the planet Venus. On Friday, December 6^th, Venus will reach a maximum brilliancy of magnitude -4.7, over 16 times brighter than Sirius, the brightest star in the sky. And just one evening prior on Thursday December 5^th, the 3-day old crescent Moon passes eight degrees above it, slightly closer together than the span of your palm held at arm’s length.

The orientation of Venus and the Moon on Thursday, December 5th as it crosses the local meridian at 3PM EST. Created using Starry Night Education software.

The Moon will thus make an excellent guide to spot Venus in the broad daylight. It’s even possible to nab the pair with a camera, if you can gauge the sky conditions and tweak the manual settings of your DSLR just right.

The best time to attempt this feat on Thursday will be when the pair transits the local meridian due south of your location. Deep in the southern hemisphere, the Moon and Venus will appear to transit to the north. This occurs right around 3:00 PM local. The fingernail Moon will be easy to spot, then simply begin scanning the sky to the south of it with the naked eye or binoculars for the brilliant diamond of Venus. High contrast and blocking the Sun out of view is key — Venus will easily pop right out against a clear deep blue sky, but it may disappear all together against a washed out white background.

The Moon will be at a 10% illuminated phase on Thursday, while Venus presents a slimming crescent at 27% illumination. Though tougher to find, Venus is actually brighter than the Moon in terms of albedo… expand it up to the apparent size of a Full Moon and it would be over four times as bright!

Church and Venus as seen from Westgate River Ranch, Florida. Photo by author.

You’ll be amazed what an easy catch Venus is in the daytime once you’ve spotted it — we’ve included views of Venus in the daytime when visible during sidewalk star parties for years.

Due to its brilliancy, Venus has also been implicated in more UFO sightings than any other planet, and even caused the Indian Army to mistake the pair for snooping Chinese drones earlier this year when it was in conjunction with the planet Jupiter. A daytime sighting of the planet Venus near the Moon was almost certainly the “curious star” reported by startled villagers observing from Saint-Denis, France on January 13^th, 1589.

Venus can also cast a noticeable shadow near greatest brilliancy, an effect that can be discerned against a fresh snow-covered landscape. Can’t see it? Take a time exposure shot of the ground and you may just be able to tease it out… but hurry, as the waxing Moon will soon be dominating the early evening night sky show!

Another phenomenon to watch for this week on the face of the waxing crescent Moon is known as Earthshine. Can you just make out the dark limb of the Moon? This is caused by the Earth acting as a “mirror” reflecting sunlight back at the nighttime side of the Moon. And don’t forget, China’s Chang’e-3 lander plus rover will be landing on the lunar surface in the Sinus Iridum region later this month on December 14^th, the first lunar soft landing since 1976!

The imaginary line of the ecliptic currently bisects the Moon and Venus, as Venus sits at an extreme southern point 2.5 degrees below the ecliptic — in fact, 2013 the farthest south it’s been since 1930 — and the Moon sits over four degrees above the ecliptic this week. The Moon also reached another notable point today, as it reached its most northern “southerly point” for 2013 at a declination of -19.6 degrees. The Moon’s apparent path is headed for a “shallow year” in 2015, after which it’ll begin to slowly widen over its 18.6 year cycle out to a maximum declination range in 2024. It’s a weird but true fact that the motion of the Moon is not fixed to the Earth’s equatorial plane, but to the path of our orbit traced out by the ecliptic, to which its orbit is tilted an average of five degrees.

And speaking of the Moon, there’s another fun naked-eye feat you can attempt tonight. At dusk, U.S. East Coast observers might just be able to pick up the razor thin crescent Moon hanging low to the West, only 23 hours past New. Begin scanning the western horizon about 10 minutes after sunset. Can you see it with binoculars? The naked eye? Chances get better for sighting the slim crescent Moon the farther west you go. North American observers will have a chance at a “personal best” during next lunation in the first few days of 2014… more to come!

Be sure to send those Venus-Moon conjunction pics in to Universe Today!

November 27, 2013December 23, 2015 by David Dickinson

ISON Watch: A Post-Perihelion Viewing Guide

ISON: A 2013 pre-perihelion portrait. (Credit and copyright: Efrain Morales/Jaicoa observatory. Used with permission).

“ISON Lives!!!”

“ISON R.I.P…”

Those are just some of the possible headlines that we’ve wrestled with this week, as Comet C/2012 S1 ISON approaches perihelion tomorrow evening. It’s been a rollercoaster ride of a week, and this sungrazing comet promises to keep us guessing right up until the very end.

Comet ISON reaches perihelion on U.S. Thanksgiving Day Thursday, November 28^th at around 18:44 Universal Time/ 1:44 PM Eastern Standard Time. ISON will pass 1.2 million kilometres from the surface of the Sun, just over eight times farther than Comet C/2011 W3 Lovejoy did in 2011, and about 38 times closer to the Sun than Mercury reaches at perihelion.

Comet ISON as seen from Ottawa, Canada on the morning of November 20th. (Credit: Andrew Symes/@FailedProtostar).

Earth-based observers essentially lost sight of ISON in the dawn twilight this past weekend, and there were fears that the comet might’ve disintegrated all together as it was tracked by NASA’s STEREO spacecraft. Troubling reports circulated early this week that emission rates for the comet had dropped while dust production had risen, possibly signaling that fragmentation of the nucleus was imminent. Certainly, this comet is full of surprises, and our observational experience with large sungrazing comets of this sort is pretty meager.

Credit: SOHO — ISON (entering frame, to the right) currently “photobombing” SOHO’s LASCO C3 camera. Credit: NASA/ESA/SOHO.

However, as ISON entered the field of view of the Solar and Heliospheric Observatory’s LASCO C3 camera earlier today it still appeared to have some game left in it. NASA’s Solar Dynamics Observatory will pick up ISON starting at around 17:09UT/12:09 PM EST tomorrow, and track it through its history-making perihelion passage for just over two hours until 19:09UT/2:19PM EST.

And just as with Comet Lovejoy a few years ago, all eyes will be glued to the webcast from NASA’s Solar Dynamics Observatory as ISON rounds the bend towards its date with destiny… don’t miss it!

Note: you can also follow ISON’s current progress as seen from SOHO at their website!

The tracking plan for the Solar Dynamics Observatory on November 28th as ISON passes through perihelion. (Credit: NASA/SDO).

For over the past year since its discovery, pundits have pondered what is now the astronomical question of the approaching hour: just what is ISON going to do post-perihelion? Will it dazzle or fizzle? In this context, ISON has truly become “Schrödinger’s Comet,” both alive and dead in the minds of those who would attempt to divine its fate.

Recent estimates place ISON’s nucleus at between 950 and 1,250 metres in diameter. This is well above the 200 metre size that’s considered the “point of no return” for a comet passing this close to the Sun. But again, another key factor to consider is how well put together the nucleus of the comet is: a lumpy rubble pile may not hold up against the intense heat and the gravitational tug of the Sun!

Current updated light curve for ISON. Be sure to check with NASA's Comet ISON Observing Campaign for the latest updates. (Compiled by Matthew Knight on November 24th, 2013). — Current updated light curve for ISON. Be sure to check with NASA’s Comet ISON Observing Campaign for the latest updates. (Compiled by Matthew Knight on November 24th, 2013).

But what are the current prospects for spotting ISON after its fiery perihelion passage?

If the comet holds together, reasonable estimates put its maximum brightness near perihelion at between magnitudes -3 and -5, in the range of the planet Venus at maximum brilliancy. ISON will, however, only stand 14’ arc minutes from the disk of the Sun (less than half its apparent diameter) at perihelion, and spying it will be a tough feat that should only be attempted by advanced observers.

Note that for observers based at high northern latitudes “north of the 60,” the shallow angle of the ecliptic might just make it possible to spot Comet ISON low in the dawn after perihelion and before sunrise November 29^th:

ISON Perihelion 1730UT Fairbanks — ISON post-perihelion at sunrise on November 29th as seen from Fairbanks, Alaska. (Created using Starry Night Education software.

We’ve managed to see the planet Venus the day of solar conjunction during similar circumstances with the Sun just below the horizon while observing from North Pole, Alaska.

Most northern hemisphere observers may catch first sight of Comet ISON post-perihelion around the morning of December 1^st. Look low to the east, about half an hour before local sunrise. Use binoculars to sweep back and forth on your morning comet dawn patrol. Note that on December 1^st, Saturn, Mercury, and the slim waning crescent Moon will also perch nearby!

Comet ISON will rapidly gain elevation on successive mornings as it heads off to the northeast, but will also rapidly decrease in brightness as well. If current projections hold, ISON will dip back below magnitude 0 just a few days after perihelion, and back below naked eye visibility by late December. Observers may also be able to start picking it up low to the west at dusk by mid-December, but mornings will be your best bet.

ISON path — The path of comet ISON for the first week of December as seen from latitude 30 degrees north. Note: the planets and the Moon are depicted for December 1st. (Created using Stellarium).

Keep in mind, if ISON fizzles, this could become a “death-watch” for the remnants of the comet, as fragments that might only be visible with binoculars or a telescope follow its outward path. If this turns out to be the case, then the best views of the “Comet formerly known as ISON” have already occurred.

Another possible scenario is that the comet might fragment right around perihelion, leaving us with a brief but brilliant “headless comet,” similar to W3 Lovejoy back in late 2011. The forward light scattering angle for any comet is key to visibility, and in this aspect, ISON is just on the grim edge in terms of its potential to enter the annals of “great” comets, such as Comet Ikeya-Seki back in 1965.

ISON will then run nearly parallel to the 16 hour line in right ascension from south to north through the month of December as it crosses the celestial equator, headed for a date with the north celestial pole just past New Years Day, 2014.

Whether as fragments or whole, comets have to obey Sir Isaac and his laws of physics as they trace their elliptical path back out of the solar system. Keep in mind, a comet’s dust tail actually precedes it on its way outbound as the solar wind sweeps past, a counter-intuitive but neat concept we may just get to see in action soon.

Here are some key dates to watch for as ISON makes tracks across the northern hemisphere sky. Passages are noted near stars brighter than +5^th magnitude and closer than one degree except as mentioned:

November 29th through December 15th. — The celestial path of ISON from November 29th to December 15th. (Credit: Starry Night).

December 1st: ISON is grouped with Saturn, Mercury and the slim crescent Moon in the dawn.

December 2nd: Passes near the +4.9 magnitude star Psi Scorpii.

December 3rd: Passes into the constellation Ophiuchus.

December 5th: Passes near the +2.7 magnitude multiple star Yed Prior.

December 6th: Crosses into the constellation Serpens Caput.

December 8th: Crosses from south to north of the celestial equator.

December 15th: Passes into the constellation Hercules and near the +5^th magnitude star Kappa Herculis.

December 17th: The Moon reaches Full, marking the middle of a week with decreased visibility for the comet.

December 19th: Passes into the constellation of Corona Borealis.

December 20th: Passes near the +4.8^th magnitude star Xi Coronae Borealis.

December 22nd: Passes 5 degrees from the globular cluster M13. Photo op!

Dec 16-Jan 8 — The path of Comet ISON from December 16th to January 8th. (Credit: Starry Night).

December 23^rd: Crosses back into the constellation Hercules.

December 24^th: Passes near the +3.9 magnitude star Tau Herculis.

December 26^th: Comet ISON passes closest to Earth at 0.43 A.U. or 64 million kilometres distant, now moving with a maximum apparent motion of nearly 4 degrees a day.

December 26^th: Crosses into the constellation Draco and becomes circumpolar for observers based at latitude 40 north.

December 28^th: Passes the +2.7 magnitude star Aldhibain.

December 29^th: Passes the +4.8 magnitude star 18 Draconis.

December 31^st: Passes the 4.9 magnitude star 15 Draconis.

January 2^nd: Crosses into the constellation Ursa Minor.

January 4th: Crosses briefly back into the constellation Draco.

January 6th: Crosses back into the constellation Ursa Minor.

January 7th: Crosses into Cepheus; passes within 2.5 degrees of Polaris and the North Celestial Pole.

And after what is (hopefully) a brilliant show, ISON will head back out into the depths of the solar system, perhaps never to return. Whatever the case turns out to be, observations of ISON will have produced some first-rate science… and no planets, popes or prophets will have been harmed in the process. And while those in the business of predicting doom will have moved on to the next apocalypse in 2014, the rest of us will have hopefully witnessed a dazzling spectacle from this icy Oort Cloud visitor, as we await the appearance of the next Great Comet.

Enjoy the show!

ISON: "Great Comet" or the "Great Pumpkin?" Photo and gourd-based artwork by author. — ISON: “Great Comet” or “Great Pumpkin?” Photo and gourd-based artwork by author.

– Got question about Comet ISON? Lights in the Dark has answers!

– Be sure to post those amazing post-perihelion pics of Comet ISON on Universe Today’s Flickr page.

November 21, 2013December 23, 2015 by David Dickinson

NASA Halts Work on its New Nuclear Generator for Deep Space Exploration

MSL's MMRTG in the laboratory. (Credit: NASA).

Another blow was dealt to deep space exploration this past weekend. The announcement comes from Jim Green, NASA’s Planetary Science Division Director. The statement outlines some key changes in NASA’s radioisotope program, and will have implications for the future exploration of the outer solar system.

An Advanced Stirling Converter prototype in the laboratory. (Credit: NASA).

We’ve written about the impending plutonium shortage and what it means for the future of spaceflight, as well as the recent restart of plutonium production. NASA is the only space agency that has conducted missions to the outer planets — even the European Space Agency’s Huygens lander had to hitch a ride with Cassini to get to Titan — and plutonium made this exploration possible. Continue reading “NASA Halts Work on its New Nuclear Generator for Deep Space Exploration”

November 20, 2013December 23, 2015 by David Dickinson

Get Out Your Comet Scorecards: Comet Nevski Now Visible With Binoculars

Capture of Comet Nevski shortly after discovery using the ITelescope Observatory in New Mexico. (Credit: Ernesto Guido, Nick Howes & Martino Nicolini).

Is 2013 truly the “Year of the Comet?” Perhaps “Comets” might be a better term, as no less than five comets brighter than +10^th magnitude grace the pre-dawn sky for northern hemisphere observers.

Comet C/2013 V3 Nevski has just brightened up 6 magnitudes — just over a 250-fold increase in brightness — and now sits at around magnitude +8.8. Comet Nevski was just recently discovered by Vitali Nevski using a 0.4 metre reflecting telescope 12 days ago on November 8^th. If that name sounds familiar, it’s because Nevski discovered the comet from the Kislovodsk observatory located near Kislovodsk, Russia which is part of the International Scientific Optical Network survey which located comet ISON last year. In fact, there was some brief controversy early on in its discovery that Comet C/2012 S1 ISON should have had the moniker Comet Nevski-Novichonok.

At the time of discovery, Comet Nevski appeared to be nothing special: shining at magnitude +15.1, it was well below our +10 magnitude limit for consideration as “interesting,” and was projected to linger there for the duration of its passage through the inner solar system. About a dozen odd such comet discoveries crop up per year, most of which give astronomers a brief pause as the orbit and size of the comet become better known, only to discern that they’re most likely to be nothing extraordinary.

The orbit of comet Nevski, as seen during the closest approach to the Earth on December 21st. (Credit: The Solar System Dynamics JPL Small-Body Database Browser).

Such was to be the case with Comet Nevski, until it suddenly flared up this past weekend.

Observer Gianluca Masi caught Comet Nevski in outburst, using a Celestron C14 remotely as part of the Virtual Telescope 2.0 project:

Comet Nevski captured on November 14th by Gianluca Masi. (Credit: The Virtual Telescope 2.0 Project).

You’ll note that Comet Nevski shows a small, spiky tail on the brief exposure. As of this writing, it currently sits at between magnitudes +8 and +9 and should remain there for the coming week if this current outburst holds.

Comet Nevski is well placed for northern hemisphere observers high in the morning sky, and will spend the remainder of November and early December crossing the astronomical constellation of Leo.

The celestial path of Comet Nevski from mid-November to the end of December. (Created by the author using Starry Night Education simulation software).

Here’s a blow-by-blow rundown on noteworthy events for this comet for the remainder of 2013:

November 23rd: Passes the +5.3 magnitude star Psi Leonis and crosses north of the ecliptic plane.

December 1st: Passes +3.4 magnitude star Eta Leonis.

December 6th: Passes +4.8 magnitude 40 Leonis and the bright +2nd magnitude star Algieba.

December 15th: Crosses into the constellation Leo Minor.

December 17th: Passes near the +5.5^th magnitude star 40 Leonis Minoris.

December 21st: Passes closest to Earth, at 0.847 Astronomical Units (A.U.s), or 126 million kilometres distant.

December 30th: Passes into the constellation Ursae Majoris.

Note that a “close pass” denotes a passage of the comet within a degree of a bright or interesting object.

The orbit of Comet Nevski is inclined 31.5 degrees relative to the ecliptic, and it will be headed for circumpolar for observers based in high northern latitudes as it dips back down below our “interesting” threshold of magnitude +10 in early 2014.

This comet passed perihelion on October 27^th, 2013 just over a week prior to discovery. Comet Nevski is Halley-type comet, with a 27.5 year orbit.

So, looking at the “Comet Scorecard,” we currently have:

Comet C/2012 X1 LINEAR: Still undergoing a moderate outburst at magnitude +8.2, very low to the north east for northern hemisphere observers at dawn in the constellation Boötes.

Comet 2P/Encke: Reaches perihelion tomorrow at 0.33 AU’s from the Sun, shining at magnitude +7.7 near Mercury in the dawn sky but is now mostly lost in the Sun’s glare.

Comet C/2013 R1 Lovejoy: is currently well placed in the constellation Ursa Major crossing into Canes Venatici in the hours before dawn. Currently shining at magnitude +5.4, Comet R1 Lovejoy is visible to the unaided eye from a dark sky site. We caught sight of the comet last week with binoculars, looking like an unresolved globular cluster as it passed through the constellations of Leo and Leo Minor.

And of course, Comet C/2012 S1 ISON: As of this writing, ISON is performing up to expectations as it approaches Mercury low in the dawn shining at just above +4^th magnitude. We’ve seen some stunning pictures as of late as ISON unfurls its tail, and now the eyes of the astronomical community will turn towards the main act: perihelion on November 28^th. Will it fizzle or dazzle? More to come next week!

The recent outbursts of Comets X1 LINEAR and V3 Nevski are reminiscent of the major outburst of Comet Holmes back in 2007. Of course, the inevitable attempts to link these outbursts to the current sputtering solar max will ensue, but to our knowledge, no conclusive correlations exist. Remember, the outburst from Comet Holmes occurred as we were approaching what was to become a profound solar minimum.

Also, it might be tempting to imagine that all of these comets are somehow related, but they are in fact each on unique and very different orbits, and only appear in the rough general direction in the sky as seen from our Earthly vantage point… a boon for dawn patrol sky watchers!

Got pics? Send ‘em in to Universe Today!

November 14, 2013December 23, 2015 by David Dickinson

Here Comes the Weekend Leonid Meteor Shower!

November 2013 offers a chance to catch a dependable meteor shower, albeit on an off year. The Leonid meteors are set to reach their annual peak this coming weekend on Sunday, November 17th. We say it’s an off-year, but not that it should discourage you from attempting to catch the Leonids this weekend in the early dawn.

Projections for 2013 suggest a twin-peaked maximum, with the first peak arriving on November 17^th at 10:00 UT/5:00 AM EST favoring North America, and the second one reaching Earth on the same date six hours later at 16:00 UT/11:00, favoring the central Pacific.

Unfortunately, the Full Moon also occurs the on very date that the Leonids peak at 10:16 AM EST/ 15:16UT, right between the two peaks! This will definitely cut down on the number of meteors you’ll see in the early AM hours.

That’s strike one against the 2013 Leonids. The next is the curious sporadic nature of this shower. Normally a minor shower with a zenithal hourly rate (ZHR) in the range of 10-20 per hour, the Leonids are prone to great storms topping a ZHR of 1,000+ every 33 years. We last experienced such an event in 1998 and 1999, and we’re now approaching the mid-point lull between storms in the 2014-2016 time frame.

An early Leonid meteor captured last week from the United Kingdom Meteor Observing Network's Church Crookham station. (Credit: UKMON/Peter-Campbell-Burns). — An early Leonid meteor captured last week from the United Kingdom Meteor Observing Network’s Church Crookham station. (Credit: UKMON/Peter-Campbell-Burns).

Still, this is one shower that’s always worth monitoring. The source of the Leonids is Comet 55p/Tempel-Tuttle, which is on a 33-year orbit and is due to reach perihelion again in 2031.

Note that the Leonids have also continued to show enhanced activity in past years even when the Moon was a factor:

2012- ZHR=47.

2011- ZHR=22, Moon=8% waning gibbous.

2010- ZHR=40, 86% waxing gibbous.

2009- ZHR=79.

2008-70 ZHR=72% waning gibbous

We even managed to observe the Leonid meteors from Vail, Arizona in 2002 and 2005, on years when the Moon was nearly Full.

Now, for the good news. The Leonids have a characteristic r value of 2.5, meaning that they produce a higher than normal ratio of fireballs. About 50-70% of Leonid meteors are estimated to leave persistent trains, a good reason to keep a pair of binoculars handy. And hey, at least the 2013 Leonids peak on the weekend, and there’s always comet’s ISON, X1 LINEAR, 2P/Encke and R1 Lovejoy to track down to boot!

A 2002 Leonid captured over Redstone Arsenal, Alabama. (Credit: NASA/MSFC/MEO/Bill Cooke).

Here’s a few tips and tricks that you can use to “beat the Moon” on your Leonid quest. One is to start observing now, on the moonless mornings leading up to the 17^th. You’ll always see more Leonid meteors past local midnight as the radiant rises to the northeast. This is because you’re standing on the portion of the Earth turning forward into the meteor stream. Remember, the front windshield of your car (the Earth) always collects the most bugs (meteors). Observers who witnessed the 1966 Leonid storm reported a ZHR in excess of thousands per hour, producing a Star Trek-like effect of the Earth plowing through a “snowstorm” of meteors!

The radiant of the Leonids sits in the center of the backwards question mark asterism of the “Sickle” in the astronomical constellation Leo (hence name of the shower).

You can also improve your prospects for seeing meteors by blocking the Moon behind a building or hill. Though the Leonids will appear to radiate from Leo, they can appear anywhere in the sky. Several other minor showers, such as the Taurids and the Monocerotids, are also active in November.

Meteor shower photography is simple and can be done with nothing more than a DSLR camera on a tripod. This year, you’ll probably want to keep manual exposures short due to the Full Moon and in the 20 seconds or faster range. Simply set the camera to a low f-stop/high ISO setting and a wide field of view and shoot continuously. Catching a meteor involves luck and patience, and be sure to examine the frames after a session; every meteor I’ve caught on camera went unnoticed during observation! Don’t be afraid to experiment with different combinations to get the sky conditions just right. Also, be sure to carry and extra set of charged camera batteries, as long exposures combined with chilly November mornings can drain DSLR batteries in a hurry!

A Woodcut print depicting the 1933 Leonids as seem from Niagara Falls. (Wikimedia Commons image in the Public Domian). — A Woodcut print depicting the 1933 Leonids as seem from Niagara Falls. (Wikimedia Commons image in the Public Domain).

The Leonids certainly have a storied history, dating back to before meteors where understood to be dust grains left by comets. The 1833 Leonids were and awesome and terrifying spectacle to those who witnessed them up and down the eastern seaboard of the U.S. In fact, the single 1833 outburst has been cited as contributing to the multiple religious fundamentalist movements that cropped up in the U.S. in the 1830s.

We witnessed the 1998 Leonids from the deserts of Kuwait while stationed at Al Jabber Air Base. It was easily one of the best meteor displays we ever saw, with a ZHR reaching in access of 500 per hour before dawn. It was intense enough that fireballs behind us would often light up the foreground like camera flashes!

Reporting rates and activity for meteor showers is always fun and easy to do — its real science that you can do using nothing more than a stopwatch and your eyes. The International Meteor Association is always looking for current meteor counts from observers. Data goes towards refining our understanding and modeling of meteor streams and future predictions. The IMO should also have a live ZHR graph for the 2013 Leonids running soon.

Have fun, stay warm, send those Leonid captures in to Universe Today, and don’t forget to tweet those meteors to #Meteorwatch!

November 11, 2013December 23, 2015 by David Dickinson

Tracking Comet C/2013 R1 Lovejoy through November

Comet R1 Lovejoy passes the Beehive Cluster: (Credit Damian Peach).

Tired of comets yet? Right now, northern hemisphere observers have four (!) comets within range of binoculars in the dawn sky. Comet C/2012 S1 ISON, is, of course, expected to dazzle towards month’s end. Comet 2P/Encke is an “old standby,” with the shortest orbital period of any comet known at 3.3 years, and is making a favorable appearance this Fall. And comet C/2012 X1 LINEAR added to the morning display recently, reaching about +8^th magnitude in an unexpected outburst…

But the brightest and best placed comet for morning viewing is currently Comet C/2013 R1 Lovejoy. Shining at +6^th magnitude, R1 Lovejoy just passed into the constellation Leo after a photogenic pass near the Beehive Cluster (M44) in Cancer last week. We caught sight of R1 Lovejoy a few mornings ago, and it’s an easy binocular object, looking like a fuzzy unresolved globular cluster with barely the hint of a tail.

If the name sounds familiar, that’s because the comet was discovered by Australian observer Terry Lovejoy, the prolific discoverer of four comets, including the brilliant sungrazing Comet C/2011 W3 Lovejoy that survived its 140,000 kilometre perihelion passage above the surface of the Sun on December 16th and went on to dazzle southern hemisphere observers in late 2011 and early 2012.

Comet R1 Lovejoy as imaged by Rob Sparks (@HalfAstro) from Tucson, Arizona near the Beehive cluster. (Credit: Rob Sparks). — Comet R1 Lovejoy as imaged by Rob Sparks (@HalfAstro) from Tucson, Arizona passing near the Beehive cluster. (Credit: Rob Sparks).

Terry discovered R1 Lovejoy on September 7^th, 2013 while it was still at magnitude +14.4. The comet is expected to top out at +4^th magnitude in late November as it passes 61.4 million kilometres from Earth on November 19^th and heads for perihelion at 0.877 AUs from the Sun on December 25^nd, 2013. Comet R1 Lovejoy is on a 64 degree orbit highly inclined to the ecliptic, and has a period roughly 7,000 years long. The last time R1 Lovejoy graced Earthly skies, our early ancestors still thought copper smelting was a pretty hip idea!

The orbital path of Comet R1 Lovejoy through the inner solar system. (Credit: NASA/JPL Solar System Dynamics explorer).

And unlike comets Encke and ISON that are plunging near the Sun, Comet R1 Lovejoy never gets closer than 19 degrees elongation from our nearest star in late December. It also reaches a maximum northern declination of 43 degrees on November 28^th, the same day that ISON reaches perihelion. For mid-latitude northern hemisphere observers, R1 Lovejoy will remain well placed at 35 to 45 degrees above the northeastern horizon about an hour before sunrise through late November.

Here are some key dates to aid you in your quest to spy Comet R1 Lovejoy in late November:

November 11^th: Passes near +4.5 Kappa Leonis.

November 14^th: Passes from Leo into the constellation Leo Minor & passes near the +5.3 star 20 Leonis Minoris.

November 16^th: Passes near the +5^th magnitude stars 28, 30, and 34 Leonis Minoris.

November 18^th: Passes into the constellation Ursa Major.

November 19^th: Passes near the +4.8 magnitude star 55 Ursae Majoris & +5.3 magnitude star 57 Ursae Majoris.

November 19^th: Closest to Earth, at 0.4 AUs distant.

The celestial path of Comet R1 Lovejoy spanning November 11th to the 30th. (Created using Starry Night Education software).

November 21^st: Passes into the constellation Canes Venatici.

November 22^nd: Passes near the +6^th magnitude star 4 Canum Venaticorum & the +4.2 magnitude star Chara (Beta Canum Venaticorum).

November 24^th: Passes near the Sunflower Galaxy (M63).

November 27^th: Passes into the constellation Boötes.

December 1^st: Passes near +3.5 magnitude star Nekkar (Beta Boötis).

December 4^th: crosses into Corona Borealis.

Note that passes on the list above denote passages closer than one degree of Comet R1 Lovejoy near bright objects.

Perihelion for the comet is December 25^th at 0.877 AU, and its closest approach to Earth is November 19^th. On this date, it will also be moving at its maximum apparent speed as seen from Earth, covering about 3 degrees of the sky every 24 hours, or the angular span of the Full Moon every 4 hours.

United Kingdom observer Pete Lawrence imaged Comet R1 Lovejoy this past weekend from his backyard garden using a 4-inch apochromatic refractor and a Canon 40D DSLR:

Comet R1 Lovejoy as imaged by Pete Lawrence on November 9th. (Credit: Pete Lawrence).

He also made his first confirmed binocular sighting of Comet ISON using a pair of 15×70 binocs, noting to Universe Today that “ISON’s head appears to be small and stellar compared to Lovejoy’s extended coma, which is obvious in binoculars, and also brighter!”

It’s worth noting that all four of these morning comets are on separate orbital paths, and only seem to be in the same general region of the sky as seen from our Earthly vantage point… and none of them are passing near the Earth!

This week is also a good time to hunt for comets in the pre-dawn sky for another reason: the Moon reaches Full this coming weekend on Sunday, November 17^th. After this week, it will start to creep into the morning sky and interfere with deep sky observations for the next two weeks.

Comet R1 Lovejoy imaged on November 10th by astrophtographer Justin Ng. (Credit: Justin Ng).

It’s also interesting to note that amateur observers discovered two more faint comets this past weekend. Though comets C/2013 V3 Nevski and C/2013 V2 Borisov aren’t slated to be anything spectacular, that brings the number of amateur discoveries to 13 for 2013. Are amateur comet hunters mounting a comeback?

In this age of automated surveys, the question is often raised as to whether amateurs can still discover comets. Keep in mind, Terry Lovejoy found Comet R1 Lovejoy with a medium-sized 8-inch Schmidt Cassegrain reflecting telescope… the age of amateur comet hunters seemes far from over in 2013!

November 6, 2013December 23, 2015 by David Dickinson

Bright Venus Takes Center Stage in November

(Credit: Brian McGaffney/Nutwood Observatory).

“What’s that bright object to the southwest at dusk?” We’ve already fielded more than a few such questions as Earth’s sister world shines in the dusk sky. Venus just passed its maximum elongation 47 degrees east of the Sun on November 1^st, and currently shines at a brilliant magnitude -4.46. This is almost 16 times brighter than the brightest star in the sky, -1.46th magnitude Sirius.

Venus and the waxing crescent Moon, looking to the west tonite at 30 minutes after sunset for latitude 30 degrees north. (Created using Stellarium).

Just like the Moon, Venus goes through a full range of phases. Through the telescope, Venus currently presents a 26.7” diameter disk. That size will swell to almost 40” by month’s end, as Venus begins to approach the Earth and presents a noticeable crescent phase. We just passed dichotomy — the theoretical point where Venus presents a half-illuminated phase as seen from Earth — on October 31^st, and Venus already shows a noticeable crescent:

Venus on the night of November 5th 2013, a quick stack of about 200 frames. (Photo by Author)

Note that we say “theoretical” because there’s typically a discrepancy of a day or two between predicted and observed dichotomy. This is also known as Schröter’s Effect. One probable cause for this is the dazzling appearance of the disk of Venus. We typically use a variable polarizing filter to cut the glare of Venus down at the eyepiece.

You might also note that Venus currently occupies the “basement” of the zodiac in the constellation Sagittarius. In fact, the planet is currently as far south as it can go, sitting at a declination of -27° 14’ on this very evening. You have to go all the way back to 1930 to find a more southerly declination of Venus, just 12’ lower!

But you won’t have to wait much longer to break that record, as the chart below shows for the most southerly declinations of Venus for the next half century:

Year	Date	Declination
2013	November 6^th	-27° 09’
2021	“ “	-27° 14’
2029	“ “	-27° 18’
2037	“ “	-27° 23’
2045	“ “	-27° 29’
2053	“ “	-27° 34’
2061	“ “	-27° 39’

Note that each event occurs on November 6^th, and they’re spaced 8 years apart. Apparitions of Venus closely duplicate their paths in the sky over an 8 year cycle. This is because the planet nearly completes 13 orbits of the Sun for our 8. Venus “catches up” to the Earth on its interior orbit once every 584 days to reach inferior conjunction. It usually passes above or below the Sun from our vantage point, though last year it transited, a feat that won’t be witnessed again until 2117 AD.

How far south can Venus go? Well, its orbit is tilted 3.4 degrees relative to the ecliptic. It can reach a southern declination of -28 05’, though you have to go way back to 1874 for its last occurrence!

Today is also a great time to try your hand at spotting Venus in the daytime, as a 3-day old waxing crescent Moon lies about eight degrees to its upper right:

A daytime Venus near the Moon transiting to the south at about 3:30PM EST today. A 5 degree wide Telrad "bullseye" is provided for scale. (Credit: Stellarium). — A daytime Venus near the Moon, transiting to the south at about 3:30PM EST today. A 5 degree wide Telrad “bullseye” is provided for scale. (Credit: Stellarium).

Note that seeing Venus in the daytime is surprisingly easy, once you known exactly where to look for it. Your best chances are around mid-afternoon at about 3PM local, when the daytime Moon and Venus lie highest in the southern sky. Did you know that Venus is actually intrinsically brighter per square arc second than the Moon? It’s true! The Moon actually has a very low reflective albedo of 12% — about the equivalent of fresh asphalt — while the cloud tops of Venus are more akin the fresh snow with an albedo of about 80%.

Its also worth checking out Venus and its local environs after nightfall as it passes near the Lagoon (M8) and the Trifid nebula (M8) on the night of November 6^th. Continuing with its trek across the star rich plane of the heart of the Milky Way galaxy, Venus also passes near the globular cluster M22 on November 13^th.

Venus also sits in the general of Pluto on November 15^th, lying just 6.6 degrees south of it. Be sure to wave in the general direction of NASA’s New Horizons spacecraft bound for Pluto in July 2015 tonight as well, using the Moon and Venus for a guide:

The position of the Moon, Venus, Pluto, & New Horizons on the night of November 6th, 2013. (Created using Starry Night Education Software). — The position of the Moon, Venus, Pluto, & New Horizons at 14UT on November 7th, 2013. (Created using Starry Night Education Software).

Another shot at seeing Venus paired with the Moon occurs on December 5^th.

Venus also presents a maximum area of illumination on December 6^th, and will shine at its brightest on December 10^th at magnitude -4.7. Can you catch it casting a shadow? The best time to search for this illusive phenomenon would be just before New Moon on December 2^nd. A dark sky site away from any other sources of illumination, and a snow covered ground providing high contrast also helps. Fortunately, snow isn’t in short supply in the northern hemisphere in December!

Venus is currently the only naked eye planet in the November early evening sky. We always thought that it’s a bit of a cosmic irony that the nearest planet presents a dazzling, but featureless white disk as seen from Earth. Diligent amateurs have, however, been able to tease out cloud patterns on Venus using UV filters.

Another elusive phenomenon to watch for as Venus reaches a crescent phase is ashen light. Long reported by observers, a faint glow on the night side of Venus is something that persists, but shouldn’t be. A similar effect seen on the night side of the Moon known as Earthshine is easily explained by sunlight being reflected off of the Earth… but Venus has no moon. What gives? Frequent explanations over the years have been aurorae, electrical activity, airglow, or, more frequently cited, observer bias. The brain wants to see a filled in space, and promptly inserts it betwixt the dazzling horns of the planet.

Keep an eye on Venus as it reaches maximum brilliancy and heads towards inferior conjunction on January 11^th, 2014, and a rare chance to see it on said date… more to come!