Skywatching Archives

June 11, 2014December 23, 2015 by David Dickinson

An Astronomical Eloping: How Rare is a “Friday the 13th Honey Moon?”

The June 2012 "Honey Moon" rising. Photo credit: Stephen Rahn.

Ah, Friday the 13^th. Whether you fear it or it’s just your favorite slasher flick, it’s coming right around the bend later this week. And while it’s pretty much a non-event as far as astronomy is concerned, there’s bound to be some woo in the works, because the June Full Moon — dubbed the “Honey Moon” — falls on the same date.

Well, sort of. We made mention of this month’s Full Moon falling on Friday the 13^th in last week’s post on the occultation of Saturn by Earth’s Moon. We’re not out to alarm any triskaidekaphobics, but we always love the chance to have some fun with calendars in the name of astronomy.

What we’re seeing here is merely the intersection of three cycles of events… and nothing more. These sorts of things can be fun to calculate and can provide a teachable moment, even when that well meaning but often misinformed relative/coworker/stranger on Twitter sends it your way . Hey, some people golf or collect steel pennies, this is our shtick.

A “Friday the 13^th Honey Moon” is basically the subset of: 1. Fridays that fall on the 13^th day of the month (OK, that’s two input parameters, we know) that also 2. Fall in the month of June, and 3. Occur on a Full Moon.

Friday the 13^th occurs from one to three times a calendar year, so you can already see that one will occasionally happen to land on a Full Moon date fairly frequently… but how ‘bout in June? To this end, we compiled this handy listing of “Full Moons that fall on the 13th day of the month” — 15 in all — that occur from 1990 to 2030:

Full Moon's that fell on the 13th from 1990-2030 as reckoned in Universal Time. Only one (March 1998) fell on a Friday the 13th. Chart by author. — Full Moons that fell on the 13th from 1990-2030 as reckoned in Universal Time. Only two (March 1998 and June 2014) fall on a Friday the 13th. Chart by author.

That’s about one every two to three years. But you have to go aaaaall the way back to June 13^th, 1919 to find a Full Moon that fell on a Friday the 13^th in the month of June. This will next occur on June 13^th, 2098.

Of course, this is just an interesting intersection concerning the vagaries and nuances of our Gregorian calendar and the lunar cycle. You could just as easily see significance where there is none in the Full Moon coinciding with the next Superbowl or Academy Awards. Humans love to pick out patterns where often none exist.

(Fun homework assignment: When is the last/next total lunar eclipse that occurs on Friday the 13^th?)

And keep in mind, the instant of the Full Moon this week occurs on Friday at 4:13 UT… this means that from the U.S. Central time zone westward, the Full Moon actually falls on Thursday the 12^th.

The rising Moon just hours before Full on Thursday June 12th. Note Saturn to the upper right. Created using Stellarium.

Fun fact: the 13^th falls on a Friday more than any other day of the month! It’s true… in a span of 400 years following the institution of the Gregorian calendar in 1582, Friday fell on the 13^th a total of 688 times, while Thursday and Saturday the 13^th fell in last place at 684.

But there’s is something else that’s special about the June Full Moon. It also falls closest to the June solstice, marking the start of astronomical northern hemisphere summer and winter in the southern. This means that the Full Moon nearest the June solstice rides at its lowest to the southern horizon for northern hemisphere observers, but is high in the sky for observers south of the equator.

The June 2012 Full Honey (or do you say Strawberry?) Moon. Photo by author.

The June solstice this year falls on Saturday, June 21^st at 10:51 UT /6:51 AM EDT. The Full Moon closest to the June solstice is nearly, but not always, in June… It can occur up to July 6^th, and the last time it fell in July is 2012 and the next is 2015. The July Full Moon is known as the Full Buck Moon.

Our good friends over at Slooh will be webcasting the Full Honey Moon this Friday the starting at 1:30 UT/9:30 PM EDT (Thursday June 12^th) for two hours from its Canary Islands site and the Pontificia Universidad Católica de Chile observatory near Santiago, Chile. The broadcast will be hosted by Slooh astronomer Geoff Fox, astronomer and author of The Sun’s Heartbeat Bob Berman, and Slooh engineer Paul Cox.

Is there a connection between late spring weddings, the June Full Moon and the modern term “honeymoon”? Well, the rising June Full Moon certainly takes on an amber color for northern hemisphere observers as it rises low through the sultry summer skies. The Moon’s orbit is actually tilted five degrees relative to the ecliptic, which means it alternates from “flat” to “hilly” about every 9 years varying from 18 to 28 degrees relative to the celestial equator. We’re approaching a flat year — known as minimum or minor lunar standstill — in 2015, after which the Moon’s apparent path across the sky will begin to widen once again towards 2024.

The ~9 year variation between major and minor lunar standstill. Credit Wikimedia Commons graphic in the Public Domain.

Bob Berman has this to say about the origin of the term: “Is this Full Moon of June the true origin of the word honeymoon, since it is amber, and since weddings were traditionally held this month? That phrase dates back nearly half a millennium to 1552, but one thing has changed: weddings have shifted, and are now most often held in August or September. The idea back then was that a marriage is like the phases of the Moon, with the Full Moon being analogous to a wedding. Meaning, it’s the happiest and ‘brightest’ time in a relationship.”

It’s also worth noting the June Full Moon was known as the Strawberry Moon to the Algonquin Indians of North America. Huh… and here we thought most weddings were in May.

Whatever the case, you can get out enjoy the rising Full Moon with that significant other this week… and don’t fear the Honey Moon.

June 4, 2014December 23, 2015 by David Dickinson

Discovered: Two New Planets for Kapteyn’s Star

An artist's conception of the planets orbiting Kapteyn's Star (inset) and the stream of stars associated with an ancient galaxy merger. Credit: image courtesy of Victor Robles, James Bullock, and Miguel Rocha at University of California Irvine and Joel Primack at University of California Santa Cruz.

The exoplanet discoveries have been coming fast and furious this week, as astronomers announced a new set of curious worlds this past Monday at the ongoing American Astronomical Society’s 224th Meeting being held in Boston, Massachusetts.

Now, chalk up two more worlds for a famous red dwarf star in our own galactic neck of the woods. An international team of astronomers including five researchers from the Carnegie Institution announced the discovery this week of two exoplanets orbiting Kapteyn’s Star, about 13 light years distant. The discovery was made utilizing data from the HIRES spectrometer at the Keck Observatory in Hawaii, as well as the Planet Finding Spectrometer at the Magellan/Las Campanas Observatory and the European Southern Observatory’s La Silla facility, both located in Chile.

The Carnegie Institution astronomers involved in the discovery were Pamela Arriagada, Ian Thompson, Jeff Crane, Steve Shectman, and Paul Butler. The planets were discerned using radial velocity measurements, a planet-hunting technique which looks for tiny periodic changes in the motion of a star caused by the gravitational tugging of an unseen companion.

“That we can make such precise measurements of such subtle effects is a real technological marvel,” said Jeff Crane of the Carnegie Observatories.

Kapteyn’s Star (pronounced Kapt-I-ne’s Star) was discovered by Dutch astronomer Jacobus Kapteyn during a photographic survey of the southern hemisphere sky in 1898. At the time, it had the highest proper motion of any star known at over 8” arc seconds a year — Kapteyn’s Star moves the diameter of a Full Moon across the sky every 225 years — and held this distinction until the discovery of Barnard’s Star in 1916. About a third the mass of our Sun, Kapteyn’s Star is an M-type red dwarf and is the closest halo star to our own solar system. Such stars are thought to be remnants of an ancient elliptical galaxy that was shredded and subsequently absorbed by our own Milky Way galaxy early on in its history. Its high relative velocity and retrograde orbit identify Kapteyn’s Star as a member of a remnant moving group of stars, the core of which may have been the glorious Omega Centauri star cluster.

The worlds of Kapteyn’s Star are proving to be curious in their own right as well.

“We were surprised to find planets orbiting Kapteyn’s Star,” said lead author Dr. Guillem Anglada-Escude, a former Carnegie post-doc now with the Queen Mary University at London. “Previous data showed some irregular motion, so we were looking for very short period planets when the new signals showed up loud and clear.”

The location of Kapteyn's Star in teh constellation Pictor. Created using Stellarium. — The location of Kapteyn’s Star in the constellation Pictor. Created using Stellarium.

It’s curious that nearby stars such as Kapteyn’s, Teegarden’s and Barnard’s star, though the site of many early controversial claims of exoplanets pre-1990’s, have never joined the ranks of known worlds which currently sits at 1,794 and counting until the discoveries of Kapteyn B and C. Kapteyn’s star is the 25th closest to our own and is located in the southern constellation Pictor. And if the name sounds familiar, that’s because it made our recent list of red dwarf stars for backyard telescopes. Shining at magnitude +8.9, Kapteyn’s star is visible from latitude 40 degrees north southward.

Kapteyn B and C are both suspected to be rocky super-Earths, at a minimum mass of 4.5 and 7 times that of Earth respectively. Kapteyn B orbits its primary once every 48.6 days at 0.168 A.U.s distant (about 40% of Mercury’s distance from our Sun) and Kapteyn C orbits once every 122 days at 0.3 A.U.s distant.

This is really intriguing, as Kapteyn B sits in the habitable zone of its host star. Though cooler than our Sun, the habitable zone of a red dwarf sits much closer in than what we enjoy in our own solar system. And although such worlds may have to contend with world-sterilizing flares, recent studies suggest that atmospheric convection coupled with tidal locking may allow for liquid water to exist on such worlds inside the “snow line”.

And add to this the fact that Kapteyn’s Star is estimated to be 11.5 billion years old, compared with the age of the universe at 13.7 billion years and our own Sun at 4.6 billion years. Miserly red dwarfs measure their future life spans in the trillions of years, far older than the present age of the universe.

A comparison of habitable zones of Sol-like versus Red dwarf stars. Credit: Chewie/Ignacio Javier under a Wikimedia Commons 3.0 license). — A comparison of habitable zones of Sol-like versus red dwarf stars. Credit: Chewie/Ignacio Javier under a Wikimedia Commons 3.0 license).

“Finding a stable planetary system with a potentially habitable planet orbiting one of the very nearest stars in the sky is mind blowing,” said second author and Carnegie postdoctoral researcher Pamela Arriagada. “This is one more piece of evidence that nearly all stars have planets, and that potentially habitable planets in our galaxy are as common as grains of sand on the beach.”

Of course, radial velocity measurements only give you lower mass constraints, as we don’t know the inclination of the orbits of the planets with respect to our line of sight. Still, this exciting discovery could potentially rank as the oldest habitable super-Earth yet discovered, and would make a great follow-up target for the direct imaging efforts or the TESS space telescope set to launch in 2017.

“It does make you wonder what kind of life could have evolved on those planets over such a long time,” added Dr Anglada-Escude. And certainly, the worlds of Kapteyn’s Star have had a much longer span of time for evolution to have taken hold than Earth… an exciting prospect, indeed!

-Read author Alastair Reynolds’ short science fiction piece Sad Kapteyn accompanying this week’s announcement.

June 1, 2014December 28, 2015 by Bob King

Asteroid 2014 KH39 Zips Just 1.1 LD from Earth – Watch it LIVE June 3

Near Earth asteroid 2014 KH39, discovered on May 24, 2014, is the faint 'star' in the crosshairs in this photo made on May 31. The telescope tracked the asteroid, so the stars are trailed. The streak is a satellite. Credit: Gianluca Masi

Got any plans Tuesday? Good. Keep them but know this. That day around 3 p.m. CDT (20:00 UT) asteroid 2014 KH39 will silently zip by Earth at a distance of just 272,460 miles (438,480 km) or 1.14 LDs (lunar distance). Close as flybys go but not quite a record breaker. The hefty space rock will buzz across the constellation Cepheus at nearly 25,000 mph (11 km/sec) near the Little Dipper at the time.

Observers in central Europe and Africa will have dark skies for the event, however at magnitude +17 the asteroid will be too faint to spot in amateur telescopes. No worries. The Virtual Telescope Project, run by astrophysicist Gianluca Masi, will be up and running with real-time images and live commentary during the flyby. The webcast begins at 2:45 p.m. CDT June 3.

2014 KH39 was discovered on May 24 by Richard Kowalski of the Catalina Sky Survey. (Kowalski is the same astronomer who discovered asteroid 2008 TC3, the small asteroid that impacted in Sudan in 2008). Further observations by the CSS and additional telescopes like Pan-STARRS 1 in Hawaii nailed down its orbit as an Earth-approacher with an approximate size of 72 feet (22 meters). That’s a tad larger than the 65-foot Chelyabinsk asteroid that exploded into thousands of small stony meteorites over Russia in Feb. 2013.

Diagram showing the orbit of 2014 KH39. Yellow shows the portion of its orbit above the plane of Earth’s orbit (grey disk); blue is below the plane. When farthest, the asteroid travels beyond Mars into the asteroid belt. It passes closest to Earth around 3 p.m. CDT June 3. Credit: IAU Minor Planet Center

Since this asteroid will safely miss Earth we have nothing to fear from the flyby. I only report it here to point out how common near-Earth asteroids are and how remarkable it is that we can spot them at all. While we’re a long ways from finding and tracking all potentially hazardous asteroids, dedicated sky surveys turn up dozens of close-approaches every year. On the heels of 2014 KH39, the Earth-approaching asteroid 2014 HQ124 will pass 3.3 LDs away 5 days later on June 8. With a diameter estimated at more than 2,100 feet (650-m) it’s expected to become as bright as magnitude +13.7. Southern hemisphere observers might track it with 8-inch and larger telescopes as its speeds across Horologium and Eridanus the morning before closest approach.

The chart shows the cumulative known total of near-Earth asteroids (NEAs) vs. time. The blue area shows all NEAs while the red shows those roughly 1 km and larger. Thanks to many surveys underway as well as help from space probes like the Wide-Field Infrared Explorer (WISE), discovery totals have been ramping up. Credit: NASA — The chart shows the cumulative known total of near-Earth asteroids (NEAs) vs. time. The blue area shows all NEAs while the red shows those roughly 1 km and larger. Thanks to many ground-based surveys underway as well as space probes like the Wide-field Infrared Survey Explorer (WISE), discovery totals have ramped up in recent years. There are probably millions of NEOs smaller than 140 meters waiting to be discovered. Credit: NASA

Perusing the current list of upcoming asteroid approaches, these two will be our closest visitors at least through early August. Near-Earth objects (NEOs) are comets and asteroids whose original orbits have been re-worked by the gravity of the planets – primarily Jupiter – into new orbits that allow them to approach relatively close to Earth. The ones we’re most concerned about are a subset called Potentially Hazardous Asteroids or PHAs, defined as objects that approach within 4.65 million miles (7.48 million km) of Earth and span 500 feet (150-m) across or larger. The key word here is ‘potential’. PHAs won’t necessarily hit the Earth – they only have the potential to do so over the vastness of time. On the bright side, PHAs make excellent targets for sampling missions.

Most near-Earth asteroids fall into three classes named after the first asteroid discovered in that class. Apollo and Aten asteroids cross Earth's orbit; Amors orbit just beyond Earth but cross Mars' orbit. Credit: Wikipedia — Most near-Earth asteroids fall into three classes named after the first asteroid discovered in that class. Apollo and Aten asteroids cross Earth’s orbit; Amors orbit just beyond Earth but cross Mars’ orbit. Credit: Wikipedia

As of May 30, 2014, 11,107 near-Earth objects have been discovered with 860 having a diameter of 1 km or larger. 1,481 of them have been further classified as potentially hazardous. NASA’s Near-Earth Object Program estimates that over 90% of NEOs larger than 1 km (the most potentially lethal to the planet) have been discovered and they’re now working to find 90% of those larger than 459 feet (140 meters) across. Little by little we’re getting to better know the neighborhood.

The probability that either 2014 KH39 and 2014 HQ124 will hit Earth on this round is zero. Nor do we know of any asteroid in the near future on a collision course with the planet. Enjoy the day.

May 27, 2014December 23, 2015 by Bob King

Observing Alert – Space Station ‘Marathon’ Starts This Week

Time exposure showing the International Space Station making a bright pass across the northern sky. Credit: Bob King

What’s your favorite satellite? For me it’s the space station. Not only is it the brightest spacecraft in the sky, but it’s regularly visible from so many places. It’s also unique. Most satellites are either spent rocket stages or unmanned science and surveillance probes. The ISS is inhabited by a crew of astronauts. Real people.

Every time I see that bright, moving light I think of the crew floating about the cabin with their microgravity hair, performing experiments and pondering the meaning of it all while gazing out the cupola windows at the rolling blue Earth below. Starting Friday, the station will make up to 5 flybys a night from dusk till dawn. Marathon anyone?

The ISS’s orbit is inclined 51.6 degrees to the equator and passes overhead for anyone living between 51.6 degrees north and 51.6 degrees south latitude. It’s visible well beyond this zone also but never passes through the zenith outside of these limits. Traveling at a little more than 17,000 mph (27,350 kph) the station completes an orbit in 93 minutes.

Diagram showing the Earth in late May when the space station's orbital track is closely aligned with the day-night terminator. The astronauts see the sun 24-hours a day (midnight sun effect) while we on the ground get to watch repeated passes. Credit: Bob King — Diagram showing the Earth in late May when the space station’s orbital track is closely aligned with the day-night terminator. The astronauts see the sun 24-hours a day (midnight sun effect) while we on the ground get to watch repeated passes. Credit: Bob King

Most of the time we get one easy-to-see bright pass preceded or followed by a fainter partial pass. ‘Partials’ occur when the space station glides into Earth’s shadow and disappears from view during an appearance. But in late May-early June each year, the space station’s orbit and Earth’s day-night terminator nearly align. From the astronauts’ viewpoint, the sun never sets, much like seeing the midnight sun from the Arctic Circle. From down on the planet between latitudes 40-55 degrees north, the ISS remains in sunlight during repeated 90 minute-long orbits.

Instead of once or twice a night, we’ll see passes all night long from dusk till dawn starting about May 30. For instance, on May 31 from Minneapolis, Minn., skywatchers will be treated to four flybys at 12:12 a.m, 1:44 a.m., 3:20 a.m. and 11:23 p.m. The best nights are June 4 and 6 with five passes. By the 10th, the space station ‘marathon’ winds down and we return to 2-3 passes a night.

In late May-early June near the summer solstice, the sun doesn’t set on the International Space Station

The ISS always appears in the western sky first and travels east opposite to the movement of the stars. Low altitude flybys are fainter because there’s more lateral distance between you and the station. Even then the it still shines as bright as Vega. But when the ISS flies overhead, it’s only about 250 miles away, as close as it gets. Then it outshines everything in the night sky except Venus and the moon. Absolutely stunning.

The track of the ISS near Vega in Lyra. From right to left, the station is passing from sunlight into Earth's shadow. Its color transitions from white to red. Credit: Bob King — The track of the ISS near Vega in Lyra. From right to left, the station is passing from sunlight into Earth’s shadow. Its color transitions from white to red. Credit: Bob King

Have you ever noticed that satellites, including the ISS, appear to move in a jerky or zigzag fashion if you watch them closely? What you’re really are your own eyes not moving smoothly as you follow the satellite across the starry sky. My favorite passes are those where the space station fades away mid-flyby as it encounters Earth’s shadow. I always keep binoculars handy for these passes so I can watch the ISS turn color from pale yellow (caused by the gold Mylar plastic used in its many solar panels) to orange and red as it experiences one of its many orbital sunsets.

The phenomenon is easy to capture on camera too. Find out when the station will cross into shadow using the maps from Heavens-Above (see below) and point your tripod-mounted camera in that direction. I typically use a 35mm lens wide open to f/2.8 and a 30-second exposure at either ISO 400 – if still twilight – or 800 in a darker sky.

The multiple solar panels on the ISS give it the shape of the letter ‘H’ when viewed through a telescope. Other modules are visible too but hard to see as clearly. Credit: NASA

There are many ways to find out when the ISS will pass over your city. My favorite are the listings in Heavens-Above. Login with your city and you’ll see a complete list with links to create maps of the station’s track across the sky. There’s also Spaceweather’s Satellite Flyby tracker. Type in your zip code and hit enter. Couldn’t be easier. You can also have NASA send you an e-mail when the most favorable (highest, brightest) passes occur by adding your e-mail to the Spot the Station site. Be aware though that you won’t be notified of some of the less favorable passes.

Half-minute video of the space station tracked through a telescope

One last pleasure of space station watching is seeing it in a telescope. Notoriously tricky to track when magnified, after minimal research I’ve come up with a method that allows at least a half dozen people to see it up close during a good flyby. One person mans the finderscope, keeping the station in the center of the crosshairs, while one happy observer after another takes their turn for a look through the eyepiece. Sure, it’s a little herky-jerky, but you’d be surprised how much you can see at magnifications as low as 60x. The solar panels really jump out. Observing solo might mean a couple tries positioning the moving target ahead of where you think it will cross the field of view and then being ready to lock on and follow.

Well, I’m going to prep for the upcoming marathon. See you in spirit on the course!

May 27, 2014December 23, 2015 by David Dickinson

Seeing in Triplicate: Catching a Rare Triple Shadow Transit of Jupiter’s Moons

Hubble nabs a triple shadow transit in this false color image taken in 2004. Credit: NASA/HST.

The planet Jupiter is always fascinating to watch. Not only do surface features pop in and out of existence on its swirling cloud tops, but its super fast rotation — once every 9.9 hours — assures its face changes rapidly. And the motion of its four large Galilean moons is captivating to observe as well. Next week offers a special treat for well-placed observers: a triple shadow transit of the moons Callisto, Europa and Ganymede on the evening of June 3rd.

The view at 19:00 UT/3:00 PM EDT on June 3rd. Credit: Starry Night Education Software.

Now for the bad news: only a small slice of the planet will witness this rare treat in dusk skies. This is because Jupiter starts the month of June 40 degrees east of the Sun and currently sets around 11 PM local, just 3 hours after local sunset. Never fear, though, it may just be possible to spy a portion of this triple transit from North American longitudes with a little careful planning.

The action begins on June 3^rd at 15:20 Universal Time as Callisto’s shadow slides on to the disk of Jupiter, to be followed by Europa and Ganymede’s shadow in quick succession hours later. All three shadows are cast back onto the disk of Jupiter from 18:05 to 19:53 UT, favoring European and African longitudes at sunset. The final shadow, that of Ganymede, moves off the disk of Jupiter at 21:31 UT.

The hemisphere of the Earth facing towards Jupiter from the beginning of the triple shadow transit to the end. the red line marks the day/night terminator. Credit: Stellarium.

The following video simulation begins at around 15:00 UT just prior to the ingress of Callisto’s shadow and runs through 22:00 UT:

Triple shadow transits of Jupiter’s moons are fairly rare: the last such event occurred last year on October 12^th, 2013 favoring North America and the next won’t occur until January 24^th, 2015. Jean Meeus calculated that only 31 such events involving 3 different Jovian moons either transiting Jupiter and/or casting shadows onto its disk occur as seen from Earth between 1981 and 2040. The June 3^rd event is also the longest in the same 60 year period studied.

The 1:2:4 orbital resonance of the Jovian moons Io, Europa and Ganymede. Credit: Wikimedia Commons.

Can four shadow transits occur at once? Unfortunately, the answer is no. The inner three moons are in a 1:2:4 resonance, meaning that one will always be left out of the picture when two are in front. This also means that Callisto must be included for any triple shadow transit to occur. Next week’s event sees Callisto, Europa and Ganymede crossing in front of Jupiter and casting shadows onto its disk while Io is hidden behind Jupiter in its enormous shadow. Callisto is also the only one of the four large Jovian moons that can “miss” the disk of Jupiter on certain years, owing to the slight inclination of its orbit to the ecliptic. Callisto thus doesn’t always cast a shadow onto the disk of Jupiter, and we’re currently in the middle of a cycle of Callisto shadow transits that started in July of 2013 and runs through July 2016. These “Callisto transit seasons” occur twice during Jupiter’s 11.8 year orbit, and triple shadow transits must also occur within these periods.

So, what’s a North American observer to do? Well, it is possible to spot and track Jupiter with a telescope in the broad daylight. Jupiter rises at around 9:20 AM local in early June, and the waxing crescent Moon passes 5.4 degrees south of it on June 1^st. The Moon stands 30 degrees from the planet on June 3^rd, and it may be juuusst possible to use it as a guide to the daytime event. A “GoTo” telescope with precise pointing will make this task even easier, allowing you to track Jupiter and the triple shadow transit across the daytime sky from North American longitudes. But be sure to physically block the blazing June Sun behind a building or structure to avoid accidentally catching its blinding glare in the eyepiece!

The orientation of Jupiter the Moon and the Sun at 4PM EDT on June 3rd. Credit: Stellarium. — The orientation of Jupiter, the Moon and the Sun at 4PM EDT on June 3rd. Credit: Stellarium.

Do the shadows of the moons look slightly different to you? A triple shadow transit is a great time to compare them to one another, from the inky hard black dot of the inner moons Europa and Io, to the diffuse large shadow of Callisto. With practice, you can actually identify which moon is casting a shadow during any transit just by its size and appearance!

A study of three multi-shadow transits: last year's (upper left) a double shadow transit from early 2014 (upper right) and 2004 (bottom. Photos by author. — A study of three multi-shadow transits: last year’s (upper left) a double shadow transit from early 2014 (upper right) and 2004 (bottom). Photos by author.

Shadow transits of Jupiter’s moons also played an interesting role in the history of astronomy as well. Danish astronomer Ole Rømer noted that shadow transits were being observed at slightly different times than predicted depending on the distance of Jupiter and the Earth, and made the first rough calculation of the speed of light in 1676 based on this remarkable insight. Celestial navigators were also intrigued for centuries with the idea of using the phenomena of Jupiter’s moons as a natural clock to gauge longitude. It’s a sound idea in theory, though in practice, it proved tough to make accurate observations from the pitching deck of a ship at sea.

Jupiter captured near the daytime Moon. Photo by author.

Miss the June 3^rd event? There’s still two fine opportunities to see Jupiter do its impression of the Earth-Moon system and appear to have only one satellite – Callisto – on the evenings of May 30^th and June 7^th.

From there, Jupiter slides lower into the dusk as June progresses and heads towards solar conjunction on July 24^th.

Let us know if you manage to catch sight of this rare event!

-Send those shadow transit pics in to Universe Today at our Flickr forum.

May 24, 2014December 23, 2015 by Bob King

Camelopardalid Meteor Shower Skimpy but Sweet

A Camelopardalid meteor flashes across eastern Cassiopeia this morning May 24. Credit: Bob King

So how were the ‘Cams’ by you? Based on a few reports via e-mail and my own vigil of two and a half hours centered on the predicted maximum of 2 a.m. CDT (7 UT) Saturday morning the Camelopardalid meteor shower did not bring down the house. BUT it did produce some unusually slow meteors and (from my site) one exceptional fireball with a train that lasted more than 20 minutes.

The 'Cam' left a long train across the Milky Way in the Summer Triangle. Credit: Bob King — This ‘Cam’ left a long train across the Milky Way inside the Summer Triangle. Credit: Bob King

I saw 10 meteors in all, most of them slow and colorful with orange and yellow predominating. My hopes were high when the shower started with a bang. At 12:34 CDT, a brilliant, very slow moving meteor flashed below Polaris at about magnitude -1. A prominent train glowed many seconds after burnout and continued to show for more than 20 minutes in the camera and telescope. At low magnification in my 15-inch reflector (37-cm) the persistent glow looked like a brand new sausage-shaped diffuse nebula in Cassiopeia.

2.5 minute time exposure showing the persistent train left by a near-fireball brightness Camelopardalid meteor. The five bright stars form the familiar 'W' of Cassiopeia. Credit: Bob King — 2.5 minute time exposure showing the persistent train left by a brilliant Camelopardalid meteor. The five bright stars to the right outline the familiar ‘W’ of Cassiopeia. Credit: Bob King

Trains form when a meteoroid’s hypersonic velocity through the upper atmosphere ionizes the air along the object’s path. When the atoms return to their rest states, they release that pent up energy as a glowing streak of light that gradually fades. The train in the photos expands and changes shape depending on the vagaries of upper atmospheric winds. Absolutely fascinating to watch.

Pretty scene with the Big Dipper (upper left), a lake and a 'Cam' taken from Sudbury, Canada. Credit: Bill Longo — Lovely scene with the Big Dipper (upper left) and a ‘Cam’ taken from Sudbury, Canada. Credit: Bill Longo

Most activity occurred between 12:30 and 2 a.m. for my time zone in the U.S. Midwest. Surprisingly, the action dropped off around 2 and stayed that way until 3. I did get one ‘farewell Cam’ on that last look up before turning in for the night.

Malcolm Park of Toronto captured a bright Camelopardalid this morning.

The team working with Gianluca Masi at the Virtual Telescope Project reported a number of bright meteors as well but no storm. We share several of their photos here. As more information comes in, please drop by for a more complete report. You can also check out Dirk Ross’s Latest Worldwide Meteor News for additional first hand reports.

The strange streak with a moving satellite (?) at its center than drifted from Leo to Auriga early this morning. The starlike object makes a narrower streak inside the cloud during the time exposure. Credit: Bob King — The strange streak with a moving satellite (?) at its center that drifted from Leo to Auriga early this morning. The starlike object made a narrower streak inside the cloud during the time exposure. Credit: Bob King

Before signing off for the moment, I’d like to ask your help in explaining a strange phenomenon I saw while out watching and photographing the shower. Around 1 a.m. I looked up and noticed a comet-like streak about 15-degrees long drifting across northern Leo. My first thought was meteor train – a giant one – but then I noticed that the center of the streak was brighter and contained a starlike object that moved in tandem with the wispy glow. I quickly took a couple pictures as the streak traveled north and expanded into a large, nebulous ray that persisted for about 1o minutes. There were no other clouds in the sky and the aurora was not active at the time.

Photo taken a couple minutes after the first one showing the expanding ray. The starlike object is the brighter trail within the ray near bottom. Credit: Bob King

Can anyone shed light on what it was??

UPDATE: According Mike McCants, satellite tracking software developer, the plume is fuel dump connected to the launch of a new Japanese mapping satellite. One never knows sometimes what the night has in store.

May 22, 2014December 23, 2015 by Bob King

New Supernova Pops in Bright Galaxy M106 in the ‘Hunting Dogs’

The new Type II supernova is nestled up to the nucleus of the galaxy in this photo taken May 21 with a 17-inch telescope. Credit: Gianluca Masi, Francesca Nocentini and Patrick Schmeer

A supergiant star exploded 23.5 million years ago in one of the largest and brightest nearby galaxies. This spring we finally got the news. In April, the Katzman Automatic Imaging Telescope (KAIT) as part of the Lick Observatory Supernova Search, photographed a faint “new star” very close to the bright core of M106, a 9th magnitude galaxy in Canes Venatici the Hunting Dogs.

The core of a red or blue supergiant moments before exploding as a supernova looks like an onion with multiple elements "burning" through the fusion process to create the heat to stay the force of gravity. Fusion stops at iron. With no energy pouring from the central core to keep the other elements cooking, the star collapses and the rebounding shock wave tears it apart. — The inner core of a red or blue supergiant moments before exploding as a supernova looks like an onion with multiple elements “burning” through the fusion process to create the heat and pressure that stays the force of gravity. Fusion stops at iron. With no energy pouring from the central core to keep the other elements cooking, the star collapses and the rebounding shock wave tears it apart.

A study of its light curve indicated a Type II supernova – the signature of a rare supergiant star ending its life in the most violent way imaginable. A typical supergiant star is 8 to 12 times more massive than the sun and burns at a much hotter temperature, rapidly using up its available fuel supply as it cooks lighter elements like hydrogen and helium into heavier elements within its core. Supergiant lifetimes are measured in the millions of years (10-100 million) compared to the frugal sun’s 11 billion years. When silicon fuses to create iron, a supergiant reaches the end of the line – iron can’t be fused or cooked into another heavier element – and its internal “furnace” shuts down. Gravity takes over and the whole works collapses in upon itself at speeds up to 45,000 miles per second.

When the outer layers reached the core, they crushed it into a dense ball of subatomic particles and send a powerful shock wave back towards the surface that rips the star to shreds. A supernova is born! Newly-minted radioactive forms of elements like nickel and cobalt are created by the tremendous pressure and heat of the explosion. Their rapid decay into stable forms releases energy that contributes to the supernova’s light.

This Hubble Space Telescope image shows how spectacular M106 truly is. Its spiral arms are dotted with dark lanes of dust, young star clusters rich with hot, blue stars and tufts of pink nebulosity swaddling newborn stars. The galaxy is the 106th entry in the 18th century French astronomer Charles Messier's famous catalog. Credit: NASA / ESA — This Hubble Space Telescope image shows how spectacular M106 truly is. Dark filaments of dust are silhouetted against billions of unresolved suns. Young star clusters rich with hot, blue stars and tufts of pink nebulosity swaddling newborn stars ornament the galaxy’s spiral arms. A supermassive black hole rumbles at the heart of the galaxy. M106 is the 106th entry in Charles Messier’s famous catalog created in the 18th century. It’s located 23.5 million light years away. Credit: NASA / ESA

For two weeks, the supernova in M106 remained pinned at around magnitude +15, too faint to tease out from the galaxy’s bright, compact nucleus for most amateur telescopes. But a photograph taken by Gianluca Masi and team on May 21 indicate it may have brightened somewhat. They estimated its red magnitude – how bright it appears when photographed through a red filter – at +13.5. A spectrum made of the object reveals the ruby emission of hydrogen light, the telltale signature of a Type II supernova event.

At magnitude +9, M106 visible in almost any telescope and easy to find. Start just above the Bowl of the Big Dipper which stands high in the northwestern sky at nightfall in late May. The 5th magnitude stars 5 CVn (5 Canes Venatici) and 3 CVn lie near the galaxy. Star hop from the Bowl to these stars and then over to M106. Stars plotted to mag. +8. Click to enlarge. Stellarium

Visually the supernova will appear fainter because our eyes are more sensitive to light in the middle of the rainbow spectrum (green-yellow) than the reds and purple that bracket either side. I made a tentative observation of the object last night using a 15-inch (37-cm) telescope and hope to see it more clearly tonight from a darker sky. We’ll keep you updated on our new visitor’s brightness as more observations and photographs come in. You can also check Dave Bishop’s Latest Supernovae site for more information and current images.

Even if the supernova never gets bright enough to see in your telescope, stop by M106 anyway. It’s big, easy to find and shows lots of interesting structure. Spanning 80,000 light years in diameter, M106 would be faintly visible with the naked eye were it as close as the Andromeda Galaxy. In smaller scopes the galaxy’s bright nucleus stands out in a mottled haze of pearly light; 8-inch(20-cm) and larger instrument reveal the two most prominent spiral arms. M106 is often passed up for the nearby more famous Whirlpool Galaxy (M51). Next time, take the detour. You won’t be disappointed.

May 21, 2014December 23, 2015 by Bob King

Potential Weekend Meteor Shower Will Pelt the Moon Too!

the shaded or speckled area indicates where May Camelopardalids can stoke the lunar surface. telescopic observers will want to point their telescopes to the shaded dark area at the top right of the lunar disk.

If the hoped-for meteor blast materializes this Friday night / Saturday morning (May 23-24) Earth won’t be the only world getting peppered with debris strewn by comet 209P/LINEAR. The moon will zoom through the comet’s dusty filaments in tandem with us.

Bill Cooke, lead for NASA’s Meteoroid Environment Office, alerts skywatchers to the possibility of lunar meteorite impacts starting around 9:30 p.m. CDT Friday night through 6 a.m. CDT (2:30-11 UTC) Saturday morning with a peak around 1-3 a.m. CDT (6-8 UTC).

While western hemisphere observers will be in the best location, these times indicate that European and African skywatchers might also get a taste of the action around the start of the lunar shower. And while South America is too far south for viewing the Earth-directed Camelopardalids, the moon will be in a good position to have a go at lunar meteor hunting. Find your moonrise time HERE.

Earlier lunar impact on the earthlit portion of the moon. Credit: NASA — Earlier lunar impact on the earthlit portion of the moon recorded by video camera. Credit: NASA

The thick crescent moon will be well-placed around peak viewing time for East Coast skywatchers, shining above Venus in the eastern sky near the start of morning twilight. For the Midwest, the moon will just be rising at that hour, while skywatchers living in the western half of the country will have to wait until after maximum for a look:

“Anyone in the U.S. should monitor the moon until dawn,” said Cooke, who estimates that impacts might shine briefly at magnitude +8-9.

Any meteors hitting the moon will also be burning up as meteors in Earth's skies from the direction of the dim constellation Camelopardalis the Giraffe located in the northern sky below Polaris in the Little Dipper. Stellarium — Any meteors hitting the moon will also be burning up as meteors in Earth’s skies from the direction of the dim constellation Camelopardalis the Giraffe located in the northern sky below Polaris in the Little Dipper. Stellarium

“The models indicate the Camelopardalids have some big particles but move slowly around 16 ‘clicks’ a second (16 km/sec or 10 miles per second). It all depends on kinetic energy”, he added. Kinetic energy is the energy an object possesses due to its motion. Even small objects can pack a wallop if they’re moving swiftly.

Bright lunar meteorite impact recorded on video on September 11, 2013. The estimated 900-lb. space rock flared to 4th magnitude.

Lunar crescents are ideal for meteor impact monitoring because much of the moon is in shadow, illuminated only by the dim glow of earthlight. Any meteor strikes stand out as tiny flashes against the darkened moonscape. For casual watching of lunar meteor impacts, you’ll need a 4-inch or larger telescope magnifying from 40x up to around 100x. Higher magnification is unnecessary as it restricts the field of view.

I can’t say how easy it will be to catch one, but it will require patience and a sort of casual vigilance. In other words, don’t look too hard. Try to relax your eyes while taking in the view. That’s why the favored method for capturing lunar impacts is a video camera hooked up to a telescope set to automatically track the moon. That way you can examine your results later in the light of day. Seeing a meteor hit live would truly be the experience of a lifetime. Here are some additional helpful tips.

Meteorite impact flashes seen from 2005 to the present. Fewer are seen in the white areas (lunar highlands) because flashes blend in compared to those occurring on the darker lunar 'seas' or maria. Credit: NASA — Meteorite impact flashes seen from 2005 to the present. Fewer are recorded in the white areas (lunar highlands) because the flashes blend into the landscape compared to those occurring on the darker lunar ‘seas’ or maria. Click for more information on lunar impacts. Credit: NASA

On average, about 73,000 lbs. (33 metric tons) of meteoroid material strike Earth’s atmosphere every day with only tiny fraction of it falling to the ground as meteorites. But the moon has virtually no atmosphere. With nothing in the way, even small pebbles strike its surface with great energy. It’s estimated that a 10-lb. (5 kg) meteoroid can excavate a crater 30 feet (9 meters) across and hurl 165,000 lbs. of lunar soil across the surface.

A meteoroid that size on an Earth-bound trajectory would not only be slowed down by the atmosphere but the pressure and heat it experienced during the plunge would ablate it into very small, safe pieces.

NASA astronomers are just as excited as you and I are about the potential new meteor shower. If you plan to take pictures or video of meteors streaking through Earth’s skies or get lucky enough to see one striking the moon, please send your observations / photos / videos to Brooke Boen ([email protected]) at NASA’s Marshall Space Flight Center. Scientists there will use the data to better understand and characterize this newly born meteor blast.

On the night of May 23-24, Bill Cooke will host a live web chat from 11 p.m. to 3 a.m. EDT with a view of the skies over Huntsville, Alabama. Check it out.

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 20, 2014December 23, 2015 by Bob King

How to See 209P/LINEAR, the Comet Brewing Up Saturday’s Surprise Meteor Shower

Comet 209P/LINEAR may still be faint but it's a beautiful object in this time exposure by Austrian astrophotographer Michael Jaeger. The stars appear as trails because the photographer followed the comet during the exposure.

As we anxiously await the arrival of a potentially rich new meteor shower this weekend, its parent comet, 209P/LINEAR, draws ever closer and brighter. Today it shines feebly at around magnitude +13.7 yet possesses a classic form with bright head and tail. It’s rapidly approaching Earth, picking up speed every night and hopefully will be bright enough to see in your telescope very soon.

As it approaches Earth in the coming nights, comet 209P/LINEAR will appear to move quickly across the sky, traveling from Leo Minor to southern Hydra in little over a week. All maps created with Chris Marriott's SkyMap software — As it approaches Earth in the coming nights, comet 209P/LINEAR will move quickly across the sky, traveling from Ursa Major to southern Hydra in just 10 days. When closest on May 28-29, the comet will cover 10 degrees per day or just shy of 1/2 degree per hour. All maps created with Chris Marriott’s SkyMap software

The comet was discovered in Feb. 2004 by the Lincoln Laboratory Near-Earth Asteroid Research (LINEAR) automated sky survey. Given its stellar appearance at the time of discovery it was first thought to be an asteroid, but photos taken the following month photos by Rob McNaught (Siding Spring Observatory, Australia) revealed a narrow tail. Unlike long period comets Hale-Bopp and the late Comet ISON that swing around the sun once every few thousand years or few million years, this one’s a frequent visitor, dropping by every 5.09 years.

This detailed map shows the comet's path from Leo Minor across the backside of the Sickle of Leo May 23-26. Hopefully it will be bright enough then to spot in an 8-inch or larger telescope. Click to enlarge and then print out for use at the telescope. — This detailed map shows the comet’s path from Leo Minor across the backside of the Sickle of Leo May 23-26. Hopefully it will be bright enough then to spot in an 8-inch or larger telescope. On May 25, it passes close to the colorful double star Gamma Leonis and a pair of NGC galaxies. Stars plotted to magnitude +9. Click to enlarge and then print out for use at the telescope.

209P/LINEAR belongs to the Jupiter family of comets, a group of comets with periods of less than 20 years whose orbits are controlled by Jupiter. When closest at perihelion, 209P/LINEAR coasts some 90 million miles from the sun; the far end of its orbit crosses that of Jupiter. Comets that ply the gravitational domain of the solar system’s largest planet occasionally get their orbits realigned. In 2012, during a relatively close pass of that planet, Jupiter perturbed 209P’s orbit, bringing the comet and its debris trails to within 280,000 miles (450,000 km) of Earth’s orbit, close enough to spark the meteor shower predicted for this Friday night/Saturday morning May 23-24.

Track of the comet through from May 27-29 through the dim constellation Sextans south of Leo. — Track of the comet from May 27-29 through Sextans to the Hydra-Crater border with positions shown every 3 hours. Times are CDT. Click to enlarge.

This time around the sun, the comet itself will fly just 5.15 million miles (21 times the distance to the moon) from Earth around 3 a.m. CDT (8 hours UT) May 29 a little more than 3 weeks after perihelion, making it the 9th closest comet encounter ever observed. Given , you’d think 209P would become a bright object, perhaps even visible with the naked eye, but predictions call for it to reach about magnitude +11 at best. That means you’ll need an 8-inch telescope and dark sky to see it well. Either the comet’s very small or producing dust at a declining rate or both. Research published by Quanzhi Ye and Paul A. Wiegert describes the comet’s current dust production as low, a sign that 209P could be transitioning to a dormant comet or asteroid.

Light curve for comet 209P/LINEAR predicts a maximum magnitude of around 11. Click for more information. Credit: Seiichi Yoshida — Light curve for comet 209P/LINEAR forecasts a maximum magnitude of around 11. Dates are shown along the bottom and magnitude scale along the side. Click for additional information. Credit: Seiichi Yoshida

Fortunately, the moon’s out of the way this week and next when 209P/LINEAR is closest and brightest. Since we enjoy comets in part because of their unpredictability, maybe a few surprises will be in the offing including a brighter than expected appearance. The maps will help you track down 209P during the best part of its apparition. I deliberately chose ‘black stars on a white background’ for clarity in use at the telescope. It also saves on printer ink!

A brand new meteor shower shooting 100 and potentially as many as 400 meteors an hour may radiate from the dim constellation Camelopardalis below the North Star Saturday morning May 24. Each is crumb or pebble of debris lost by 209P/LINEAR during earlier cycles around the sun. This map shows the sky facing north around 2 a.m. from the Saturday May 24 from the central U.S. Stellarium

We’re grateful for the dust 209P/LINEAR carelessly lost during its many passes in the 19th and early 20th centuries. Earth is expected to pass through multiple filaments of debris overnight Friday May 23-24 with the peak of at least 100 meteors per hour – about as good as a typical Perseid or Geminid shower – occurring around 2 a.m. CDT (7 hours UT).

If it’s cloudy or you’re not in the sweet zone for viewing either the comet or the potential shower, astrophysicist Gianluca Masi will offer a live feed of the comet at the Virtual Telescope Project website scheduled to begin at 3 p.m. CDT (8 p.m. Greenwich Time) May 22. A second meteor shower live feed will start at 12:30 a.m. CDT (5:30 a.m. Greenwich Time) Friday night/Saturday morning May 23-24.

SLOOH will also cover 209P/LINEAR live on the Web with telescopes on the Canary Islands starting at 5 p.m. CDT (6 p.m. EDT, 4 p.m. MDT and 3 p.m. PDT) May 23. Live meteor shower coverage featuring astronomer Bob Berman of Astronomy Magazine begins at 10 p.m. CDT. Viewers can ask questions by using hashtag #slooh.

A very exciting weekend lies ahead!