Posted on by Jason Major

Galactic Close Call Leaves a Bridge of Gas

Illustration of a hydrogen gas bridge connecting the Andromeda and Triangulum galaxies (Bill Saxton, NRAO/AUI/NSF)

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An ancient passing between two nearby galaxies appears to have left the participants connected by a tenuous “bridge” of hydrogen gas, according to findings reported Monday, June 11 by astronomers with the National Radio Astronomy Observatory (NRAO).

Using the National Science Foundation’s Green Bank Telescope in West Virginia — the world’s largest fully-steerable radio telescope — astronomers have confirmed the existence of a vast bridge of hydrogen gas streaming between the Andromeda galaxy (M31) and the Triangulum galaxy (M33), indicating that they likely passed very closely billions of years ago.

The Robert C. Byrd Green Bank Telescope (GBT) in West Virginia (NRAO/AUI)

The faint bridge structure had first been identified in 2004 with the 14-dish Westerbork Synthesis Radio Telescope in the Netherlands but there was some scientific dispute over the findings. Observations with the GBT confirmed the bridge’s existence as well as revealed the presence of six large clumps of material within the stream.

Since the clumps are moving at the same velocity as the two galaxies relative to us, it seems to indicate the bridge of hydrogen gas is connecting them together.

“We think it’s very likely that the hydrogen gas we see between M31 and M33 is the remnant of a tidal tail that originated during a close encounter, probably billions of years ago,” said Spencer Wolfe of West Virginia University. “The encounter had to be long ago, because neither galaxy shows evidence of disruption today.”

The findings were announced Monday at the 220th Meeting of the American Astronomical Society in Anchorage, Alaska. Read more on the NRAO website here.

Posted on by Tammy Plotner

Weekly SkyWatcher’s Forecast: June 11-17, 2012

Messier 5 - Credit: Hillary Mathis, REU Program/NOAO/AURA/NSF

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Greetings, fellow SkyWatchers! You can breathe now… the Venus Transit is over and we’re back to the mundane astronomical excitement like great globular clusters, an early morning conjunction and two meteor showers – the Ophiuchids and June Lyrids. If you’re up to the ordinary, then follow along as we capture some great galaxies and a very challenging study! Dust off your optics and meet me in the back yard…

Monday, June 11 – Tonight we make the jump to Serpens Caput, which is in itself a challenge to recognize with the unaided eye. Using bright Spica as a guide, look about a handspan northeast for two of the brightest stars in the constellation – Alpha, and Lambda to its northeast. Using binoculars, locate a pairing with Delta to the north-northwest and Mu to the south. Now return to Alpha and hop a little less than a fistwidth to the southwest where you will encounter double star 5 Serpens and the mighty M5 (Right Ascension: 15 : 18.6 – Declination: +02 : 05).

While Gottfried Kirch and his wife Maria were watching a comet on May 5, 1702, they stumbled across a huge, bright object that they considered a “nebulous star.” Forty-two years later, it was found again by Messier who labeled it as M5 and described it as a round nebula which didn’t contain any stars. But, thank heaven for William Herschel! Some 27 years later he counted up to 200 resolvable stars in this globular cluster and reported “the middle is so compressed that it is impossible to distinguish the components.”

Even in today’s binoculars, M5 shows a grainy texture that begins resolution to even the smallest of telescopes and invites larger ones to an explosion of stellar population. Slightly elliptical in appearance, M5 is believed to be one of the oldest globular clusters with a calculated age of 13 billion years, and it contains 105 known variable stars – as well as a dwarf nova. At a distance of 24,500 light-years and stretching across 165 light-years of space, this magnificent object so dominates its territory that it would gather in any stars straying within 400 light-years of its tidal influence!

Mid-to-larger telescopes will begin such awesome resolution on M5?s many chains and its bright core region that it will be a cluster you will visit again and again over the years. No matter what size binoculars or telescope you use, this 5.6 magnitude class V globular cluster is one of the five brightest of all!

Tuesday, June 12 – As with all astronomical projects, there are sometimes difficult ones needed to complete certain study fields – such as challenging globular clusters. Tonight we’ll take a look at one such cluster needed to complete your list and you’ll find it by using M5 as a guide.

Palomar 5 is by no stretch of the imagination easy. For those using GoTo systems and large telescopes, aiming is easy… But for star hoppers a bit of instruction goes a long way. Starting at M5 drop south for the double 5 Serpens and again south and slightly west for another, fainter double. Don’t confuse it with 6 Serpens to the east. About half a degree west you’ll encounter an 8th magnitude star with 7th magnitude 4 Serpens a half degree south. Continue south another half degree where you will discover a triangle of 9th magnitude stars with a southern one at the apex. This is home to Palomar 5 (RA 15 16 05.30 Dec -00 06 41.0).

Discovered by Walter Baade in 1950, this 11.7 magnitude, Class XII globular is anything but easy. At first it was believed to be a dwarf elliptical and possibly a member of our own Local Group of galaxies due to some resolution. Later studies showed that Palomar 5 was indeed a globular cluster – but one that was being ripped apart by the tidal forces of the Milky Way.

75,000 light-years away from us and 60,000 light-years from the galactic center, Palomar 5?s members are escaping and leaving trails that span 13,000 light-years…a process which may have been happening for several billion years. Although it is of low surface brightness, even telescopes as small as 6? can distinguish just a few individual members northwest of the 9th magnitude marker star – but even telescopes as large as 31? fail to show much more than a faint sheen (under excellent conditions) with a handful of resolvable stars. Even though it may be one of the toughest you’ll ever tackle, be sure to take the time to make a quick sketch of the region to complete your studies. Good luck!

Wednesday, June 13 –Today in 1983, Pioneer 10 becomes the first manmade object to leave the solar system. What wonders would it see? Are there other galaxies out there like our own? Will there be life like ours? While we can’t see through Pioneer’s “eyes,” tonight let’s use our own as we quest for a look in the mirror…

Our object will be Herschel II.76 – also known as NGC 5970. Begin by identifying Beta and Delta Serpens Caput and look for finderscope Chi between them. Less than a degree southwest you will see a similar magnitude double star. Hop about 1/3 degree northwest and you will find your galaxy mark just a fraction southwest of a 7th magnitude star (RA 15 38 30.12 Dec -12 11 10.9).

NGC 5970 is not particularly easy for smaller scopes even near 11th magnitude because of low surface brightness, but it could be a distant twin of our own galaxy, so similar is it to the Milky Way in structure. At 105 million light-years away, it is no great surprise that we see it as faint – for its light left around the time the dinosaurs ruled the Earth. Stretching across 85,000 light-years of space, this grand spiral has been extensively studied in its nucleus region, obscuring dust regions, and stellar population. And – like us – it is also part of its own local group.

While smaller telescopes will make out a slight elongated mist, in mid-to-large aperture NGC 5970 will appear oval shaped with a bright core and evidence of a central bar. While the edges of the galaxy seem well defined, look closely at the narrower ends where material seems more wispy. While averted in this fashion, the nucleus will sometimes take on a stellar appearance – yet lose this property with direct vision. Be sure to mark your Herschel notes on this one!

Thursday, June 14 – As the new hours of the day begin and you wait on dawn, keep watch for the peak of the Ophiuchids meteor shower with the radiant near Scorpius. The fall rate is poor with only 3 per hour, but fast moving bolides are common. This meteor stream will last for 25 days.

Tonight, while we have plenty of dark skies to go around, let’s go south in Libra and have a look at the galaxy pairing NGC 5903 (Right Ascension: 15 : 18.6 – Declination: -24 : 04) and NGC 5898 (Right Ascension: 15 : 18.2 – Declination: -24 : 06). You’ll find them about three degrees northeast of Sigma, and just north of a pair of 7th magnitude stars.

While northernmost NGC 5903 seems to be nothing more than a faint elliptical with a brighter concentration towards the center and an almost identical elliptical – NGC 5898 – to the southwest, you’re probably asking yourself… Why the big deal over two small ellipticals? First off, NGC 5903 is Herschel III.139 and NGC 5898 is Herschel III.138… two more to add to your studies. And second? The Very Large Array has studied this galaxy pair in the spectral lines of neutral hydrogen. The brighter of the pair, NGC 5898, shows evidence of ionized gas which has been collected from outside its galactic realm – while NGC 5903 seems to be running streamers of material towards it. A double-galaxy, double-accretion event!

But there’s more…

Look to the southeast and you’ll double your pleasure and double your fun as you discover two double stars instead of just one! Sometimes we overlook field stars for reasons of study – but don’t do it tonight. Even mid-sized telescopes can easily reveal this twin pair of galaxies sharing “their stuff,” as well as a pair of double stars in the same low power field of view. (Psst… slim and dim MCG 043607 and quasar 1514-241 are also here!) Ain’t it grand?

Friday, June 15 – Tonight, before you hunt down the faint fuzzies and spend the rest of the night drooling on the Milky Way, let’s go globular and hunt up two very nice studies worthy of your time. Starting at Alpha Librae, head five degrees southeast for Tau and yet another degree southeast for the splendid field of NGC 5897 (RA 15 17 24.40 Dec -21 00 36.4).

This class XI globular might appear very faint to binoculars, but it definitely makes up for it in size and beauty of field. It was first viewed by William Herschel on April 25, 1784 and logged as H VI.8 – but with a less than perfect notation of position. When he reviewed it again on March 10, 1785 he logged it correctly and relabeled it as H VI.19. At a distance of a little more than 40,000 light-years away, this 8.5 magnitude globular will show some details to the larger telescope, but remain unresolved to smaller ones. As a halo globular cluster, NGC 5897 certainly shows signs of being disrupted and has a number of blue stragglers as well as four newly discovered variables of the RR Lyrae type.

Now let’s return to Alpha Librae and head about a fistwidth south across the border into Hydra and two degrees east of star 57 for NGC 5694 – also in an attractive field (RA 14 39 36.52 Dec -26 32 18.0).

Also discovered by Herschel, and cataloged as H II.196, this class VII cluster is far too faint for binoculars at magnitude 10, and barely within reach of smaller scopes. As one of the most remote globular clusters in our galaxy, few telescopes can hope to resolve this more than 113,000 light-year distant ball of stars whose brightest is magnitude 16.5 – and it also possesses no variables. Traveling at 190 kilometers per second, metal-poor NGC 5694 will not have the same fate as NGC 5897… For this is a globular cluster that is not being pulled apart by our galaxy – but escaping it!

Saturday, June 16 – No matter if you stayed up late chasing deep sky, or got up early, right now is the time to catch the peak of the June Lyrids meteor shower. Although it’s not the most outstanding of displays, no Moon will make it one of the best prospects of the year for those wishing to log their meteor observations. Look for the radiant near bright Vega – you may see up to 15 faint blue meteors per hour from this branch of the May Lyrid meteor stream.

Today in 1963, Valentina Tereshkova, aboard the Soviet Vostok 6, became the first woman ever to go into space. Her solo flight is still unique. Twenty years later, on the 18th, Sally Ride became the first American woman in orbit, aboard the Space Shuttle.

For observers of all skill levels and equipment, it’s simply time to stop and have a look at a seasonal favorite which is now nearly overhead – M13 (Right Ascension: 16 : 41.7 – Declination: +36 : 28). You’ll find this massive globular cluster quite easy to locate on the western side of the Hercules “keystone” about 1/3 the way between the northern and southern stars – Eta and Zeta.

At a little brighter than magnitude 6, this 25,100 light-year distant globular cluster can be seen unaided from a dark sky location. First noted by Edmond Halley in 1714, the “Great Hercules Cluster” was cataloged by Messier on June 1, 1764. Filled with hundreds of thousands of stars, yet only one young blue star, M13 could be as much as 14 billion years old.

Thirty-three years ago, the Great Hercules Cluster was chosen by the Arecibo Observatory as the target for the first radio message delivered into space, yet it will be a message that won’t be received for over 25 centuries. Look at it with wonder tonight… For the light that left as you are viewing it tonight did so at a time when the Earth was coming out of the Ice Age. Our early ancestors were living in caves and learning to use rudimentary tools. How evolved would our civilization be if we ever received an answer to our call?!

Sunday, June 17 – Celestial scenery alert! If you’re up before the Sun rises, be sure to check out the eastern skyline for the very close apparition of the Moon and Jupiter. The two will only be separated by about a half a degree. What a great way to wake up!

As the sky darkens tonight, let’s discover the wonderful world of low power. Start your journey by re-locating magnificent M13 and move about 3 degrees northwest. What you will find is a splendid loose open cluster of stars known as Dolidze/Dzimselejsvili (DoDz) 5 – and it looks much like a miniature of the constellation of Hercules. Just slightly more than 4 degrees to its east and just about a degree south of Eta Hercules is DoDz 6, which contains a perfect diamond pattern and an asterism of brighter stars which resembles the constellation of Sagitta.

Now we’re going to move across the constellation of Hercules towards Lyra. East of the “keystone” you will see a tight configuration of three stars – Omicron, Nu and Xi. About the same distance that separates these stars to the northeast you will find DoDz 9. Using minimal magnification, you’ll see a pretty open cluster of around two dozen mixed magnitude stars that are quite attractive. Now look again at the “keystone” and identify Lambda and Delta to its south. About midway between them and slightly to the southeast you will discover the stellar field of DoDz 8. The last is easy – all you need to do is know the beautiful red/green double, Ras Algethi (Alpha). Move about 1 degree to the northwest to discover the star-studded open cluster DoDz 7. These great open clusters are very much off the beaten path and will add a new dimension to your large binocular or low power telescoping experiences.

Until next week, keep your eyes on the skies!

Posted on by Ken Kremer

Clouds part for Transit of Venus from Princeton University

Transit of Venus snapped from Princeton University at 6:19 p.m. June 5, 2012. This image was taken with a Questar telescope at 6:19 p.m. as the clouds over Princeton, NJ parted to the delight of hundreds of onlookers and whole families. Hundreds attended the Transit of Venus observing event organized jointly by Princeton University Astrophysics Dept and telescopes provided by the Amateur Astronomers Association of Princeton (AAAP), local astronomy club. Credit: Robert Vanderbei

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Despite a horrendous weather forecast, the clouds parted – at least partially – just in the nick of time for a massive crowd of astronomy and space enthusiasts gathered at Princeton University to see for themselves the dramatic start of the Transit of Venus shortly after 6 p.m. EDT as it arrived at and crossed the limb of the Sun.

And what a glorious view it was for the well over 500 kids, teenagers and adults who descended on the campus of Princeton University in Princeton, New Jersey for a viewing event jointly organized by the Astrophysics Dept and the Amateur Astronomers Association of Princeton (AAAP), the local astronomy club to which I belong.

See Transit of Venus astrophotos snapped from Princeton, above and below by Astrophotographer and Prof. Bob Vanderbei of Princeton U and a AAAP club member.

Transit of Venus snapped from Princeton University - full sized image
This photo was taken with a Questar telescope at 6:26 p.m. on June 5, 2012 - it’s a stack of eight - 2 second images. Stacking essentially eliminates the clouds. Hundreds attended the Transit of Venus observing event organized jointly by Princeton University Astrophysics Dept and telescopes provided by the Amateur Astronomers Association of Princeton (AAAP), local astronomy club. Credit: Robert Vanderbei

It was gratifying to see so many children and whole families come out at dinner time to witness this ultra rare celestial event with their own eyes – almost certainly a last-in-a-lifetime experience that won’t occur again for another 105 years until 2117. The crowd gathered on the roof of Princeton’s Engineering Dept. parking deck – see photos

Excited crowd witnesses last-in-a-lifetime Transit of Venus from campus rooftop on Princeton University. Onlookers gathered to view the rare Transit of Venus event using solar telescopes provided by the Amateur Astronomers Association of Princeton (AAAP) and solar glasses provided by NASA and lectures from Princeton University Astrophysics Dept.
Credit: Ken Kremer

For the next two and a half hours until sunset at around 8:30 p.m. EDT, we enjoyed spectacular glimpses as Venus slowly and methodically moved across the northern face of the sun as the racing clouds came and went on numerous occasions, delighting everyone up to the very end when Venus was a bit more than a third of the way through the solar transit.

Indeed the flittering clouds passing by in front of Venus and the Sun’s active disk made for an especially eerie, otherworldly and constantly changing scene for all who observed through about a dozen AAAP provided telescopes properly outfitted with special solar filters for safely viewing the sun.

Kids of all ages enjoy the Transit of Venus from a rooftop at Princeton University. Solar telescopes provided by the Amateur Astronomers Association of Princeton (AAAP), solar glasses provided by NASA and lectures from Princeton University Astrophysics Dept. Credit: Ken Kremer

As part of this public outreach program, NASA also sent me special solar glasses to hand out as a safe and alternative way to directly view the sun during all solar eclipses and transits through your very own eyes – but not optical aids such as cameras or telescopes.

Transit of Venus snapped from Princeton University - quarter sized image
This photo was taken with a Questar telescope at 6:26 p.m. on June 5, 2012 - it’s a stack of eight - 2 second images. Credit: Robert Vanderbei

Altogether the Transit lasted 6 hours and 40 minutes for those in the prime viewing locations such as Hawaii – from where NASA was streaming a live Transit of Venus webcast.

You should NEVER look directly at the sun through any telescopes or binoculars not equipped with special eye protection – because that can result in severe eye injury or permanent blindness!

We in Princeton were quite lucky to observe anything because other astro friends and fans in nearby areas such as Philadelphia, PA and Brooklyn, NY reported seeing absolutely nothing for this last-in-a-lifetime celestial event.

Transit of Venus enthusiasts view the solar transit from Princeton University rooftop using special solar glasses provided by NASA. Credit: Ken Kremer

Princeton’s Astrophysics Department organized a series of lectures prior to the observing sessions about the Transit of Venus and how NASA’s Kepler Space Telescope currently uses the transit method to detect and discover well over a thousand exoplanet and planet candidates – a few of which are the size of Earth and even as small as Mars, the Red Planet.

NASA’s Curiosity rover is currently speeding towards Mars for an August 6 landing in search of signs of life. Astronomers goal with Kepler’s transit detection method is to search for Earth-sized planets in the habitable zone that could potentially harbor life !

So, NASA and astronomers worldwide are using the Transit of Venus in a scientifically valuable way – beyond mere enjoyment – to help refine their planet hunting techniques.

Doing an outreach program for NASA, science writer Dr Ken Kremer distributes special glasses to view the transit of Venus across the sun during a viewing session on the top level of a parking garage at the E-quad at Princeton University to see the transit of Venus across the sun on Tuesday evening, June 5, 2012. Michael Mancuso/The Times

Historically, scientists used the Transit of Venus over the past few centuries to help determine the size of our Solar System.

See more event photos from the local daily – The Trenton Times – here

And those who stayed late after sunset – and while the Transit of Venus was still visibly ongoing elsewhere – were treated to an extra astronomical bonus – at 10:07 p.m. EDT the International Space Station (ISS) coincidentally flew overhead and was visible between more break in the clouds.

The International Space Station (ISS) flew over Princeton University at 10:07 p.m. on June 5 after the sun had set but while the Transit of Venus was still in progress. Credit: Ken Kremer
Transit Of Venus image from Hinode Spacecraft. Click to enlarge. Credit: JAXA/NASA/Lockheed Martin/enhanced by Marco Di Lorenzo

Of course clouds are no issue if you’re watching the Transit of Venus from the ISS or the Hinode spacecraft. See this Hinode Transit image published on APOD on June 9 and enhanced by Marco Di Lorenzo.

This week, local NY & NJ residents also had another extra special space treat – the chance to see another last-in-a-lifetime celestial event: The Transit of Space Shuttle Enterprise across the Manhattan Skyline on a seagoing voyage to her permanent new home at the Intrepid Sea, Air and Space Museum.

Ken Kremer

Posted on by Jenny Winder

The Antikythera Time Machine

Antikythera by Marsyas via Wikimedia Commons
Antikythera by Marsyas via Wikimedia Commons

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Leonardo da Vinci may have left behind sketches of helicopters, tanks and submarines but it is rare that we find actual artifacts that seem so way ahead of their time. Almost like a science fiction tale of archaeologists finding a wristwatch buried deep in an Egyptian pyramid or motorcar under the foundations of Stonehenge, we do have an example of a scientific computer that was built between 150 and 100 BC. It was so advanced, nothing as complex would be developed again until the 14th century.

The Antikythera mechanism was lost to the world for centuries. The device was salvaged in 1900 from a ship that sank en route to Rome, in the 1st century BC, between Crete and the island of Antikythera in the Mediterranean. When one of the fragments was discovered to contain a bronze gear wheel, the idea that this was some kind of astronomical clock was dismissed as too fantastic an anachronism. It was not until 1951 that the investigation was picked up by a British science historian Derek J. de Solla Price. So far 82 fragments have been recovered of what is now considered the oldest known astronomical computer.

The device is made of bronze and contains 30 gears though it may have had as many as 72 originally. Each gear was meticulously hand cut with between 15 and 223 triangular teeth, which were the key to discovering the mechanism’s various functions. It was based on theories of astronomy and mathematics developed by Greek astronomers who may have drawn from earlier Babylonian astronomical theories and its construction could be attributed to the astronomer Hipparchus or, more likely, Archimedes the famous Greek mathematician, physicist, engineer, inventor and astronomer. Why it was built, or for whom is unknown.

Replica Antikythera Based on the research of Professor Derek de Solla Price, in collaboration with the National Scientific Research Center Demokritos and physicist CH Karakalos. image by Marsyas via Wikimedia Commons
Replica Antikythera Based on the research of Professor Derek de Solla Price, in collaboration with the National Scientific Research Center Demokritos and physicist CH Karakalos. image by Marsyas via Wikimedia Commons

The main front dial showed the 365 day Egyptian year and the Greek signs of the Zodiac and could be adjusted to compensate for the extra quarter day in the solar year. The dial probably bore three hands that marked the date and positions of the Sun and Moon, while a separate mechanism showed the Moon’s phases and it likely also displayed the 5 classically known planets, Mercury, Mars, Venus, Jupiter and Saturn.

On the back an upper dial showed 19 year Metonic cycle of Moon phases, the 76 year Callippic cycle (four Metonic cycles) and calculated the 4 year Olympic cycle (four games took place in two and four year cycles) The lower dial showed the 18 year 11 days Saros eclipse cycle and the 54 year 33 day Exeligmos or triple saros cycle. It was driven by a hand crank now sadly lost. It is small, compact and portable with full instructions engraved upon it in Greek, about 95% of which have now been deciphered.

The fragile pieces that remain have been examined and modeled using high-resolution X-ray tomography and gamma rays and various reconstructions and replicas have been built. It has even had a working model constructed out of Lego. I can’t helping thinking that Archimedes would have rather liked Lego, if only we could go back in time and give him a set…

Find out more at the  Antikythera Mechanism Research Project

Posted on by Jon Voisey

Earth Threatened By Glowing Green Asteroid?

Killer asteroid coming for the Earth?
Killer asteroid coming for the Earth?

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The Daily Mail is reporting that a youtube user has found a strange object while poking around in Google Sky. It looks suspiciously like a glowing green asteroid and he claims it’s heading right for us. But before we call in the experts, let’s do a little bit of critical analysis on our own.

First off, the image raises alarm bells because of the apparent size of the object. Without knowing how far away it may be, it’s hard to say how large it would actually be, but we can put some limits on it. I looked up the region on Aladin and the angular distance between the two stars just to the upper right of the object is 1 arc minute. The object seems to be about that size, so we can use that as a baseline.

Assuming that the object was somewhere in the vicinity of Pluto (roughly 6 billion km), doing a bit of quick geometry means the object would be somewhere around 580,000 km. To put that in context, that’s about 40% the diameter of the Sun. If that were the case, this wouldn’t be an asteroid, it would be a small star. The funny thing about stars is that they tend to be somewhat bright and a lot more round. So that rules out that extreme.

But what if it were very close? At the distance of the moon, that would mean the object would be about 300 km in diameter which would make this thing slightly smaller than the largest asteroid, Ceres. However, this raises another issue: With that much mass, the object should still be pretty round. Additionally, with such a size and distance, it would be very bright. And it’s not.

2011 MD on Monday, June 27, 2011 at 09:30 UTC with RGB filter. Credit: Ernesto Guido, Nick Howes and Giovanni Sostero at the Faulkes Telescope South.
Even closer we run into additional issues. Astronomical images aren’t taken as a single color image. Images like this are taken in 3 filters (RGB) and then combined to make a color image. If the object is nearby, it moves from image to image, showing up in the final image in 3 places, each as a different color. For example, here’s an image of 2011 MD illustrating the effect. Given the object in question doesn’t have this tri-color separation going on, it can’t be nearby.

So this has pretty much ruled out anything anywhere in our solar system. If it’s close, it should have color issues and be bright. If it’s far, it’s too massive to have been missed. Outside of our solar system and it wouldn’t have any apparent motion and should be visible in other images. And it’s not.

In fact, searching the various databases from which Google Sky draws its data (SDSS, DSS, HST, IRAS, and WMAP), the killer asteroid doesn’t appear at all. Thus, it would seem that this object is nothing more than a technical glitch introduced by Google’s stitching together of images. Sorry conspiracy theorists. No Planet X or Nibiru out there this time!

Posted on by Jason Major

Enter the Universe Today “Wonders of the Universe” Contest!

The iPad app features seven apps in one, all of which are linked 3D environments to explore: Subatomic, Atomic, Local Stars, Solar System, Milky Way, Galaxy and the Universe.

If you’ve seen the excellent BBC/Science Channel series “Wonders of the Universe,” you know that host Brian Cox’s natural enthusiasm for astronomy is nothing short of infectious. His explanations of far-out concepts bring the mysteries of our Universe down to Earth for everyone to understand… and now he and HarperCollins UK have brought them even closer — right to your iPad.

Now, here on Universe Today you can win a free copy of the app as well as a signed copy of his Wonders of the Universe or Wonders of the Solar System hardcover book!

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Brian Cox’s Wonders of the Universe is designed for people with any level of understanding of astronomy, from casual explorers interested in the aesthetics to those looking for a deeper educational experience. Users can travel with Professor Brian Cox on his personal tours through the Universe, or jet off on a solo voyage of discovery through the planets of the Solar System to local stars and onwards through the galaxy.

Additionally, the app takes full advantage of the extensive capabilities of the new iPad, using a powerful 3D engine capable of handling high-resolution textures and complex animations created exclusively for iOS5.

Watch a personal tour of the app given by Prof. Brian Cox above.

Brian Cox’s Wonders of the Universe is available on the iTunes store now for an introductory price of $6.99 USD… or you can enter for a chance to win a free download along with a signed copy of a Wonders of the Universe or Wonders of the Solar System hardcover book (four of each are available!) by emailing [email protected] with subject line “Wonders App”.

Be sure to put your mailing address in the body of the email, and we will randomly select 8 winners to receive a signed book (our discretion) and a download code for the app.

The contest is open to all U.S. residents. One winner per mailing address. Please allow 2-3 weeks for delivery of the books. Winners will be chosen by June 10, 2012.

These are beautiful books that are chock full of information about our Universe as well as signed by Brian Cox himself… don’t miss out on a chance to get one!

Wonders of the Universe and Wonders of the Solar System books (HarperCollins UK)

Also, be sure to check out the latest app from HarperCollins UK, Fragile Earth. It uses amazing satellite imagery from all across the planet to put a century of climate change at your fingertips. It’s currently available from the iTunes store for $2.99 USD.

(App downloads and books provided courtesy of HarperCollins UK and Walker Sands Communications.)

Posted on by Tammy Plotner

Weekly SkyWatcher’s Forecast: June 4-10, 2012

Graphic Courtesy of Dave Reneke.
Graphic Courtesy of Dave Reneke

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Greeting, fellow SkyWatchers! It’s gonna’ be a great week! We start off with a partial lunar eclipse of the Strawberry Moon, head into the historic Venus Transit, study some Herschel objects, catch both the Scorpid and Arietid Meteor Showers, practice some binocular astronomy and even take on some challenge objects! How awesome is that? Whenever you’re ready, just follow me into the back yard…

Monday, June 4 – Tonight the Moon is full. Often referred to as the Full Strawberry Moon, this name was a constant to every Algonquin tribe in North America. But, our friends in Europe referred to it as the Rose Moon. The North American version came about because the short season for harvesting strawberries comes each year during the month of June – so the full Moon that occurs during that month was named for this tasty red fruit!

This evening as the Sun sets and the Moon rises opposite of it, take advantage of some quiet time and really stop to look at the eastern horizon. If you are lucky enough to have clear skies, you will see the Earth’s shadow rising – like a dark, sometimes blue band – that stretches around 180 degrees of horizon. Look just above it for a Rayleigh scattering effect known as the “Belt of Venus”. This beautiful pinkish glow is caused by the backscattering of sunlight and is often referred to as the anti-twilight arch. As the Sun continues to set, this boundary between our shadow and the arch rises higher in the sky and gently blends with the coming night. What you are seeing is the shadow of the Earth’s translucent atmosphere, casting a shadow back upon itself. This happens every night! Pretty cool, huh?

For some of us, it’s eclipse time! According to NASA’s Fred Espenak, most of the Americas will experience moonset before the partial lunar eclipse ends while eastern Asia will miss the beginning of the eclipse because it occurs before moonrise. The Moon’s contact times with Earth’s shadows are: Penumbral Eclipse Begins: 08:48:09 UT, Partial Eclipse Begins: 09:59:53 UT, Greatest Eclipse: 11:03:13 UT, Partial Eclipse Ends: 12:06:30 UT, Penumbral Eclipse Ends: 13:18:17. At the instant of greatest eclipse the umbral eclipse magnitude will reach 0.3705. At that time the Moon will be at the zenith for observers in the South Pacific. In spite of the fact that just a third of the Moon enters the umbral shadow (the Moon’s southern limb dips 12.3 arc-minutes into the umbra) the partial phase still lasts over 2 hours. Be sure to visit the resource pages for a visibility map and links to precise times and locations!

Tuesday, June 5 – Heads up for all observers! Today’s universal date marks an historic event – Venus will transit the Sun! This event will cross international date lines, so be sure to know ahead of time when and where to watch. North America will be able to see the start of the transit, while South Asia, the Middle East, and most of Europe will catch the end of it. For some great information on when, where and how to watch, visit www.transitofvenus.org. If you’re clouded out, there’s plenty of resources on-line to view this rare event. One that promises to have plenty of extra bandwidth to serve visitors is Astronomy Live. Be there!!

For all you Stargazers, keep watch for the Scorpid meteor shower. Its radiant will be near the constellation of Ophiuchus, and the average fall rate will be about 20 per hour with some fireballs.

While you’re out, take the time to check out Alpha Herculis -Ras Algethi. You will find it not only to be an interesting variable, but a colorful double as well. The primary star is one of the largest known red giants and at about 430 light years away, it is also one of the coolest. Its 5.4 magnitude greenish companion star is easily separated in even small scopes – but even it is a binary! This entire star system is enclosed in an expanding gaseous shell that originates from the evolving red giant. Enjoy it tonight.

Wednesday, June 6 – So far we’ve studied many Herschel objects in disguise as Messier catalog items – but we haven’t really focused on some mighty fine galaxies that are within the power of the intermediate to large telescope. Tonight let’s take a serious skywalk as we head to 6 Comae and drop two degrees south.

At magnitude 10.9, Herschel catalog object H I.35 is also known by its New General Catalog number of 4216 (Right Ascension: 12 : 15.9 – Declination: +13 : 09). This splendid edge-on galaxy has a bright nucleus and will walk right out in larger telescopes with no aversion required. But, the most fascinating part about studying anything in the Virgo cluster is about to be revealed.

While studying structure in NGC 4216, averted vision picks up magnitude 12 NGC 4206 (Right Ascension:12 : 15.3 – Declination: +13 : 02) to the south. This is also a Herschel object – H II.135. While it is smaller and fainter, the nucleus will be the first thing to catch your attention – and then you’ll notice it is also an edge-on galaxy! As if this weren’t distracting enough, while re-centering NGC 4216, sometimes the movement is just enough to allow the viewer to catch yet another edge-on galaxy to the north – NGC 4222 (Right Ascension: 12 : 16.4 – Declination: +13 : 19). At magnitude 14, you can only expect to be able to see it in larger scopes, but what a treat this trio is!

Is there a connection between certain types of galaxy structures within the Virgo cluster? Science certainly seems to think so. While low metallicity studies involving these galaxies are going on, research into evolution of galaxy clusters themselves continue to make new strides forward in our understanding of the universe. Capture them tonight!

Thursday, June 7 – If you’re up before dawn the next two days or out just after sunset, enjoy the peak of the June Arietid meteors – the year’s strongest daylight shower – with up to 30 visible per hour.

If you’d like to try your ear at radio astronomy with the offspring of sungrazing asteroid Icarus, tune an FM radio to the lowest frequency not receiving a clear signal. An outdoor antenna pointed at the zenith increases your chances, but even a car radio can pick up strong bursts! Simply turn up the static and listen. Those hums, whistles, beeps, bongs, and occasional snatches of signals are our own radio signals being reflected off the meteor’s ion trail!

Tonight let’s study a radio-source galaxy so bright it can be seen in binoculars – 8.6 magnitude M87 (Right Ascension: 12 : 30.8 – Declination: +12 : 24), about two fingerwidths northwest of Rho Virginis. This giant elliptical was discovered by Charles Messier in 1781 and cataloged as M87. Spanning 120,000 light-years, it’s an incredibly luminous galaxy containing far more mass and stars than the Milky Way – gravitationally distorting its four dwarf satellites galaxies. M87 is known to contain in excess of several thousand globular clusters – up to 150,000 – and far more than our own 200.

In 1918, H. D. Curtis of Lick Observatory discovered something else – M87 has a jet of gaseous material extending from its core and pushing out several thousand light-years into space. This highly perturbed jet exhibits the same polarization as synchrotron radiation – a property of neutron stars. Containing a series of small knots and clouds as observed by Halton Arp at Palomar in 1977, he also discovered a second jet in 1966 erupting in the opposite direction. Thanks to these two properties, M87 made Arp’s “Catalog of Peculiar Galaxies” as number 152.

In 1954 Walter Baade and R. Minkowski identified M87 with radio source Virgo A, discovering a weaker halo in 1956. Its position over an x-ray cloud extending through the Virgo cluster make M87 a source of an incredible amount of x-rays. Because of its many strange properties, M87 remains a target of scientific investigation. The Hubble has shown a violent nucleus surrounded by a fast rotating accretion disc, whose gaseous make-up may be part of a huge system of interstellar matter. As of today, only one supernova event has been recorded – yet M87 remains one of the most active and highly prized study galaxies of all. Capture it tonight!

Friday, June 8 – Born on this date in 1625 was Giovanni Cassini – the most notable observer following Galileo. As head of the Paris Observatory for many years, he was the first to observe seasonal changes on Mars and measure its parallax (and so, its distance). This set the scale of the solar system for the first time. Cassini was the first to describe Jovian features, and studied the Galilean moons’ orbits. He also discovered four moons of Saturn, but he is best remembered for being the first to see the namesake division between the A and B rings.

Why not honor Cassini’s work by visiting Saturn tonight? In case you hadn’t noticed, the beautiful yellowish “star” has been on the move and is now around a degree away to the southeast from a previous study star – Porrima! Not only is this a lovely visual, but an easy way to find Saturn if you’re new to the game. Seeing the Cassini Division in Saturn’s ring structure and some of the smaller moons will require at least a 114mm telescope and steady seeing. Use as much magnification as conditions will allow and look for unusual things – like seeing the planet edge through the gap!

Tonight we’ll use Rho Virginis as a stepping stone to more galaxies. Get on your mark and move one and a half degrees north for M59 (Right Ascension:12 : 42.0 – Declination: +11 : 39)…

First discovered in 1779 by J. G. Koehler while studying a comet, this 11th magnitude elliptical galaxy was observed and labeled by Messier who was just a bit behind him. Much denser than our own galaxy, M59 is only about one-fourth the size of the Milky Way. In a smaller telescope, it will appear as a faint oval, while larger telescopes will make out a more concentrated core region.

Now shift one half degree east for brighter and larger M60. Also caught first by Koehler on the same night as M59, it was “discovered” a day later by yet another astronomer who had missed M59! It took Charles Messier another four days until this 10th magnitude galaxy interfered with his comet studies and was cataloged. At around 60 million light-years away, M59 is one of the largest ellipticals known and has five times more mass than our galaxy. As a study object of the Hubble Telescope, this giant has shown a concentrated core with over 2 billion solar masses. Photographed and studied by large terrestrial telescopes, M59 may contain as many as 5100 globular clusters in its halo.

While our backyard equipment is essentially revealing M59?s core, there is a curiosity here. It shares “space” with spiral galaxy NGC 4647 (Right Ascension: 12 : 43.5 – Declination: +11 : 35). Telescopes of even modest aperture will pick up the nucleus and faint structure of this small face-on galaxy. Harlow Shapely found the pair odd because – while they are relatively close in astronomical terms – they are very different in age and development. Halton Arp also studied this combination of an elliptical galaxy affecting a spiral and cataloged it as “Peculiar Galaxy 116.” Be sure to mark your notes!

Saturday, June 9 – Today is the birthday of Johann Gottfried Galle. Born in Germany in 1812, Galle was the first observer to locate Neptune. He is also known for being Encke’s assistant – and he’s one of the few astronomers ever to have observed Halley’s Comet twice. Unfortunately, he died two months after the comet passed perihelion in 1910, but at a ripe old age of 98! I wonder if he knew Mark Twain?

Tonight while we’re out, let’s have a look at a Virgo galaxy bright enough for smaller instruments and detailed enough to delight larger scopes. Starting at Delta Virginis, move about a fistwidth to the west where you will see two fainter stars, 16 (south) and 17 (north) Virginis. You’ll find M61 (Right Ascension:12 : 21.9 – Declination: +04 : 28) located about one-half degree south of the yellow double star 17.

Its discovery was credited to Barnabus Oriani during that fateful year of 1779 when Messier was so avid about chasing a comet that he mistook it for one. While Charles had seen it on the same night, it took him two days to figure out it wasn’t moving and four more before he cataloged it. Fortunately, 7 years later Mr. Herschel assigned it his own number of H I.139, even though he wasn’t fond of assigning his own number to Messier catalog objects.

At near 10th magnitude, this spiral galaxy will show a slightly elongated form and brighter core area to small telescopes, and really come to life in larger ones. Close to our own Milky Way galaxy in size, this larger member of the Virgo cluster has great spiral arm structure that displays both knots and dark dustlanes – as well as a beautifully developed nucleus region. M61 has also been host to four supernova events between 1926 and 1999 – all of which have been well within range of amateur telescopes.

For an added Herschel treat tonight for larger scopes, hop back to star 17 and head about one half degree due west for near galactic pair NGC 4281 (H II.573) and NGC 4273 (H II.569). Here is a study of two galaxies similar in magnitude (12) and size – but of different structure. Northeastern NGC 4281 (Right Ascension: 12 : 20.4 – Declination: +05 : 23) is an elliptical, and by virtue of its central concentration will appear slightly larger and brighter – while southwestern NGC 4273 (Right Ascension: 12 : 19.9 – Declination: +05 : 21) is an irregular spiral which will appear brighter in the middle but more elongated and faded along its frontiers. Sharp-eyed observers may also note fainter (13th magnitude) NGC 4270 (Right Ascension: 12 : 19.8 – Declination: +05 : 28) north of this pairing.

Now, go back to Rho once again and about a fingerwidth northwest for yet another bright galaxy – M58 – a spiral galaxy actually discovered by Messier in 1779! As one of the brightest galaxies in the Virgo cluster, M58 (Right Ascension: 12 : 37.7 – Declination: +11 : 49) is one of only four that have barred structure. It was cataloged by Lord Rosse as a spiral in 1850. In binoculars, it will look much like our previously studied ellipticals, but a small telescope under good conditions will pick up the bright nucleus and a faint halo of structure – while larger ones will see the central concentration of the bar across the core. Chalk up another Messier study for both binoculars and telescopes and let’s get on to something really cool!

Around a half degree southwest are NGC 4567 (Right Ascension: 12 : 36.5 – Declination: +11 : 15) and NGC 4569 (Right Ascension: 12 : 36.8 – Declination: +13 : 10). L. S. Copeland dubbed them the “Siamese Twins,” but this galaxy pair is also considered part of the Virgo cluster. While seen from our viewpoint as touching galaxies, no evidence exists of tidal filaments or distortions in structure, making them a line of sight phenomenon and not interacting members. While that might take little of the excitement away from the “Twins,” a supernova event has been spotted in NGC 4569 as recently as 2004. While the duo is visible in smaller scopes as two, with soft twin nuclei, intermediate and larger scopes will see an almost V-shaped or heart-shaped pattern where the structures overlap. If you’re doing double galaxy studies, this is a fine, bright one! If you see a faint galaxy in the field as well, be sure to add NGC 4564 (Right Ascension: 12 : 36.4 – Declination: +11 : 26) to your notes.

Sunday, June 10 – While I’m sure that unaided eye viewers and binocular users are tired of the galaxy hunt, be sure to take the time to look at many old favorites that are now in view. To the eye, one of the most splendid signs of the changing seasons is the Ursa Major Moving Group which sits above Polaris for northern hemisphere observers. For the southern hemisphere, the return of Crux serves the same purpose.

Old favorites have now begun to appear again, such as Hercules, Cygnus and Scorpius… and with them a wealth of starry clusters and nebulae that will soon come into view as the night deepens and the hour grows late. Before we leave Virgo for the year, there is one last object that is seldom explored and such a worthy target that we must visit it before we go. Its name is NGC 5634 and you’ll find it halfway between Iota and Mu Virginis (RA 14 29.37 Dec -05 58.35)…First discovered by Sir William Herschel on March 5, 1785 and cataloged as H I.70, this magnitude 9.5 small globular cluster isn’t for everyone, but thanks to an 11th magnitude line-of-sight star on its eastern edge, it sure is interesting. At class IV, it’s more concentrated than many globular clusters, although its 19th magnitude members make it near impossible to resolve with backyard equipment.

Located a bit more than 82,000 light-years from our solar system and about 69,000 light-years from the galactic center, you’ll truly enjoy this globular for the randomly scattered stellar field which accompanies it. In the finderscope, an 8th magnitude star will lead the way – not truly a member of the cluster, but one that lies between us. Capturable in scopes as small as 4.5?, look for a concentrated central area surrounded by a haze of stellar members – a huge number of which are recently discovered variables. While you look at this globular, keep this in mind… Based on observations with the Italian Telescopio Nazionale Galileo, it is now surmised that the NGC 5634 globular cluster has the same position and radial velocity as does the Sagittarius dwarf spheroidal galaxy. Because of the dwarf galaxy’s metal-poor population of stars, it is believed that NGC 5634 may have once been part of the dwarf galaxy – and been pulled away by our own tidal field to become part of the Sagittarius stream!

Until next week? Wishing you clear skies for the Partial Lunar Eclipse, Venus Transit and the meteor showers!

Posted on by Ray Sanders

Help Astronomers Collect Venus Transit Data!

In the Rapa Nui language, Hetu'u means stars. Image Credit: David Rodriguez (Universidad de Chile).

[/caption]During June 5th/6th 2012, Venus will be transiting the Sun, where it will make a rare appearance as a small dot moving across the face of the Sun. Astronomers around the world are planning observations, and one team is traveling to Easter Island in an attempt to reproduce the measurements first made/proposed by Edmund Halley in the late 1600’s, getting precise data of first contact between Venus and the Sun. They are working with students from around the world and are looking for help to connect with more students to participate in the event.

The team is asking for assistance from astronomy clubs and organizations, especially those who work with school children. Since the team will be observing on Easter Island, their view of the transit will be limited (it begins two hours before sunset). Since the team will only be measuring the time of ingress and not egress, the team is reaching out to additional observers to help collect data. So far, the team has colleagues in Hawaii, New York, Australia, Iran, and Holland who will be assisting with their efforts.

Keep reading to learn how your club (or school group) can help collect transit data!

Dr. Jacqueline Faherty states, “As part of the celebration, we are networking multiple school groups around the world that are also viewing the transit so we can make a measurement of the distance to the Sun, combining timing measurements of first and last contact from various points on the Earth.” Faherty also adds, “This is not about making an accurate measurement but rather an attempt to inspire young students, our next generation of scientists, when they see that astronomical phenomena (while rare) can be used to make real and extremely useful measurements while at the same time connecting a network of students from different countries, cultures, political histories, etc.”

To participate you only need do the following:

  • At the time of the transit have a calibrated clock (GPS clock preferred but not necessary)

  • From your location we need the time of ingress or egress interior (exterior as well if you can do it). This is the time that Venus has passed into the interior of the Sun. See this webpage for an estimated time of when you can expect the events to occur for your location: http://transitofvenus.nl/wp/where-when/local-transit-times/

  • As a secondary measurement of the transit we are also going to try to match images taken of the transit from different positions on Earth. If you will be photographing the event please try to capture an image exactly (or close to exactly) on the 10’s of each hour. We will coordinate the rest.

  • Be sure to take a photograph of you and your students watching/measuring/enjoying the transit

  • Email Dr. Faherty ([email protected]) saying that you are interested in participating in our group so we can add you to our global network and map: http://www.das.uchile.cl/~drodrigu/easter/transit.html

    • Once again the team is especially interested in school groups that will be viewing the transit. The team hopes to inspire the next generation of scientists, by demonstrating how astronomical phenomenon can be used for scientific purposes. The team will feature photos from participating groups and the results of their measurements in a blog series hosted by the American Museum of Natural History.

    For more information on the team, visit their website at: http://www.das.uchile.cl/~drodrigu/easter/index_en.html

    If you’d like to see the math behind the measurements, visit David Rodriguez’s blog: http://strakul.blogspot.com/2012/05/measuring-distance-to-sun-with-transit.html

    Visibility information for the transit of Venus can be found at: http://eclipse.gsfc.nasa.gov/OH/transit12.html.

    Source: Dr. Catherine Kaleida, Dr. Jacqueline Faherty, and the 2012 Transit of Venus Easter Island Public Outreach Team

    Posted on by Tammy Plotner

    Weekly SkyWatcher’s Forecast: May 28 – June 3, 2012

    Hadley Rille - Credit: Damien Peach

    [/caption]

    Greetings, fellow SkyWatchers! As the Venus Transit draws closer, our bright neighboring planet is quickly disappearing into the sunset glow. As we await this astronomical piece of history, let’s take the time this week to have a look at a host of wonderful lunar features and bright stars. Be sure to catch the conjunction of Spica, Saturn and the Moon – and to catch a shooting star from the Tau Herculid meteor shower! If you’re ready to learn more about the history, mystery and magic of astronomy, then grab your optics and meet me in the back yard…

    Monday, May 28 – On this day in 1959, the first primates made it to space. Abel (a rhesus monkey) and Baker (a squirrel monkey) lifted off in the nose cone of an Army Jupiter missile and were carried to sub-orbital flight. Recovered unharmed, Abel died just three days later from anesthesia during an electrode removal, but Baker lived on to a ripe old age of 27.

    Our first challenge for the evening will be a telescopic one on the lunar surface known as the Hadley Rille. Using our past knowledge of Mare Serenitatis, look for the break along its western shoreline that divides the Caucasus and Apennine mountain ranges. Just south of this break is the bright peak of Mons Hadley. You’ll find this area of highest interest for several reasons, so power up as much as possible.

    Impressive Mons Hadley measures about 24 by 48 kilometers at its base and reaches up an incredible 4572 meters. If this mountain was indeed caused by volcanic activity on the lunar surface, this would make it comparable to some of the very highest volcanically caused peaks on Earth, such as Mount Shasta or Mount Rainer. To its south is the secondary peak Mons Hadley Delta – the home of the Apollo 15 landing site just a breath north of where it extends into the cove created by Palus Putredinus.

    Along this ridgeline and smooth floor, look for a major fault line known as the Hadley Rille, winding its way across 120 kilometers of lunar surface. In places, the rille spans 1500 meters in width and drops to a depth of 300 meters below the surface. Believed to have been formed by volcanic activity some 3.3 billion years ago, we can see the impact that lower gravity has had on this type of formation, since earthly lava channels are less than 10 kilometers long and only around 100 meters wide.

    During the Apollo 15 mission, Hadley Rille was visited at a point where it was only 1.6 kilometers wide – still a considerable distance as seen in respect to astronaut James Irwin and the lunar rover. Over a period of time, its lava may have continued to flow through this area, yet it remains forever buried beneath years of regolith.

    Now let’s head about four fingerwidths northwest of Beta Virginis for another unusual star – Omega. Classed as an M-type red giant, this 480 light-year distant beauty is also an irregular variable which fluxes by about half a magnitude. Although you won’t notice much change in this 5th magnitude star, it has a very pretty red coloration and is worth the time to view.

    Tuesday, May 29 – Today in 1919, a total eclipse of the Sun occurred and stellar measurements taken along the limb agreed with predictions based on Einstein’s General Relativity theory – the first such confirmation. Although we call it gravity, space/time curvature deflects the light of stars near the limb, causing their apparent positions to differ slightly. Unlike today’s astronomy, at that time you could only observe stars near the Sun’s limb (within less than an arc second) during an eclipse. It’s interesting to note that even Newton had his own theories on light and gravitation which predicted some deflection!

    Tonight on the Moon we’ll be looking for another challenging feature and a crater which conjoins it – Stofler and Faraday.

    Located along the terminator to the south, crater Stofler was named for Dutch mathematician and astronomer Johan Stofler. Consuming lunar landscape with an immense diameter of 126 kilometers and dropping 2760 meters below the surface, Stofler is a wonderland of small details in an eroded surrounding. Breaking its wall on the north is Fernelius, but sharing the southeast boundary is Faraday. Named for English physicist and chemist Michael Faraday, it is more complex and deeper at 4090 meters, but far smaller at 70 kilometers in diameter. Look for myriad smaller strikes which bind the two together!

    If you’re up for a bit more of a challenge, then let’s head about 59 light-years away in Virgo for star 70. You’ll find it located about 6 degrees northeast of Eta and right in the corner of the Coma, Bootes, and Virgo border. So what’s so special about this G-type, very normal-looking 5th magnitude star?

    It’s a star that has a planet.

    Long believed to be a spectroscopic binary because of its 117 day shifts in color, closer inspection has revealed that 70 Virginis actually has a companion planet. Roughly 7 times larger than Jupiter and orbiting no further away than Mercury from its cooler-than-Sol parent star, 70 Virginis B just might well be a planet cool enough to support water in its liquid form.

    How “cool” is that? Try about 85 degrees Celsius…

    Wednesday, May 30 – Are you ready to explore some more history? Then tonight have a look at the Moon and identify Alphonsus – it’s the centermost in a line of rings which looks much like the Theophilus, Cyrillus and Catharina trio.

    Alphonsus is a very old, Class V crater which spans 118 kilometers in diameter and drops below the surface by about 2730 meters and contains a small central peak. Partially flooded, Eugene Shoemaker had made of study of this crater’s formation and found dark haloes on the floor. Again, this could be attributed to volcanism and Shoemaker believed them to be maar volcanoes, and the haloes to be dark ash. Power up and look closely at the central peak, for not only did Ranger 9 hard land just northeast, but this is the only area on the Moon where an astronomer has observed a change and back up that observation with photographic proof.

    On November 2, 1958 Nikolai Kozyrev’s long and arduous study of Alphonsus was about to be rewarded. Some two years earlier Dinsmore Alter had taken a series of photographs from the Mt. Wilson 60? reflector that showed hazy patches in this area that could not be accounted for. Night after night, Kozyrev continued to study at the Crimean Observatory – but with no success. During the process of guiding the scope for a spectrogram the unbelievable happened – a cloud of gas containing carbon molecules had been captured! Selected as the last target for the Ranger photographic mission series, Alphonsus delivered 5814 spectacular high-resolution images of this mysterious region before Ranger 9 splattered nearby.
    Capture it yourself tonight!

    Now let’s add to our double star list as we hunt down Zeta Bootes located about 7 degrees southeast of Arcturus. This is a delightful multiple star system for even small telescopes.

    Thursday, May 31 – As we begin the evening, be sure to note a splendid conjunction. Tonight the waxing Moon will dominate the sky, but it’s joined by the visage of Spica and Saturn. Look for the brilliant star located just to the lunar north and the gentle giant planet about 10 degrees or so further north.

    Now, let’s have a look at awesome crater Clavius. As a huge mountain-walled plain, Clavius will appear near the terminator tonight in the lunar southern hemisphere, rivaled only in sheer size by similar structured Deslandres and Baily. Rising 1646 meters above the surface, the interior wall slopes gently downward for a distance of almost 24 km and a span of 225 km. Its crater-strewn walls are over 56 km thick!

    Clavius is punctuated by many pockmarks and craters; the largest on the southeast wall is named Rutherford. Its twin, Porter, lies to the northeast. Long noted as a test of optics, Clavius crater can offer up to thirteen such small craters on a steady night at high power. How many can you see?

    While the glare will make it difficult to do many things, we can still have a look at other bright objects! Let’s start tonight by going just north of Zeta Bootes for Pi. With a wider separation, this pair of whites will easily resolve to the smaller telescope.

    Now skip up northeast about a degree for Omicron Bootes. While this is not a multiple system, it makes for a nice visual pairing for a binocular challenge. For telescopes, the southeastern star holds interest as a small asterism.
    Continue northeast another two degrees to discover Xi Bootes. This one is a genuine multiple star system with magnitude 5 and 7 companions. Not only will you enjoy this G-type sun for its duplicity, but for the fine field of stars in which it resides!

    Now have a look at Mars. Over the last few weeks it has dropped significantly in brightness and has now reached an approximate +0.5 magnitude. Have you been watching its progress against the background stars? It won’t be long until it crosses constellation boundaries again.

    Friday, June 1 – Tonight on the Moon, crater Copernicus will try to steal the scene, head further south to capture another lunar club challenge – Bullialdus. Even binoculars can make out this crater with ease near the center of Mare Nubium. If you’re scoping – power up – this one is fun! Very similar to Copernicus, note Bullialdus’ thick, terraced walls and central peak. If you examine the area around it carefully, you can note it is a much newer crater than shallow Lubiniezsky to its north and almost non-existent Kies to the south. On Bullialdus’ southern flank, it’s easy to make out its A and B craters, as well as the interesting little Koenig to the southwest.

    Now let’s have a look at a tasty red star – R Hydrae. You’ll find it about a fistwidth south of Spica or about a fingerwidth west of Gamma Hydrae.

    R was the third long term variable star to be discovered and it is credited to Maraldi in 1704. While it had been observed by Hevelius some 42 years earlier, it was not recognized immediately because its changes happen over more than a year. At maximum, R reaches near 4th magnitude – but drops well below human eye perception to magnitude 10. During Maraldi’s and Hevelius’ time, this incredible star took over 500 days to change, but it has speeded up to around 390 days in the present century.

    Why such a wide range? Science isn’t really sure. R Hydrae is a pulsing M-type giant whose evolution may be progressing more rapidly than expected due to changes in structure. What we do know is that it is around 325 light-years away and is approaching us at around 10 kilometers per second.

    In the telescope, R will have a pronounced red coloration which deepens near minima. Nearby is 12th magnitude visual companion star Ho 381, which was first measured for position angle and distance in 1891. Since that time no changes in separation have been noted, which leads us to believe that the pair may be a true binary.

    Saturday, June 2 – Tonight would be a wonderful opportunity for Moongazers to return to the surface and have a look at the peaceful Sinus Iridum area. If you’ve been clouded out before, be sure to have a look for telescopic lunar club challenges – Promontoriums Heraclides and LaPlace.

    Now let’s return again to R Hydrae. While observing a variable star with either the unaided eye, binoculars, or a telescope can be very rewarding, it’s often quite difficult to catch changes in long-term variables, because there are times when the constellation is not visible. While R Hydrae is unique in color, let’s drop about half a degree to the southeast to visit another variable star – SS Hydrae.

    SS is a quick change artist – the Algol-type. While you will need binoculars or a telescope to see this normally 7.7 magnitude star, at least its fluctuations are far more rapid, with a period of only 8.2 days. With R Hydrae we have a star that expands and contracts causing the changes in brightness – but SS is an eclipsing binary. While less than a half magnitude is not a noteworthy amount, you will notice a difference if you view it over a period of time. Be sure to note that this is actually a triple star system, for there is also a 13th magnitude companion star located 13? from the primary. Watch if as often as possible and see if you can detect changes in the next few weeks!

    Sunday, June 3 – If you’re up early, why not keep a watch out for the peak of the Tau Herculids meteor shower? These are the offspring of comet Schwassman-Wachmann 3, which broke up in 2006. The radiant is near Corona Borealis and we’ll be in this stream for about a month. At best when the parent comet has passed perihelion, you’ll catch about 15 per hour maximum. Most are quite faint and the westering Moon will interfere, but sharp-eyed observers will enjoy it.

    Tonight let’s have a look at a very bright and changeable lunar feature that is often over-looked. Starting with the great grey oval of Grimaldi, let your eyes slide along the terminator towards the south until you encounter the bright crater Byrgius. Named for Joost Burgi, who made a sextant for Tycho Brahe, this “seen on the curve” crater is really quite large with a diameter of 87 kilometers. Perhaps one of the most interesting features of all is high albedo Byrgius A, which sits along its east wall line and produces a wonderfully bright ray system. While it is not noted as a lunar club challenge, it’s a great crater to help add to your knowledge of selenography!

    Now let’s try a visual double for the unaided eye – Eta Virginis. Can you distinguish between a 4th and 6th magnitude pair?

    The brighter of the two is Zaniah (Eta), which through occultation had been discovered to be a triple star. In 2002, Zaniah became the first star imaged by combining multiple telescopes with the Navy Prototype Optical Interferometer. This was the first time the three were split. Two of them are so close that they orbit in less than half the distance between the Earth and Sun!

    Binocular users should take a look at visual double Rho Virginis about a fistwidth west-southwest of Epsilon. This pair is far closer and will require an optical aid to separate. The brighter of this pair – Rho – is a white, main sequence dwarf with a secret… It’s a variable! Known as a Delta Scuti type, this odd star can vary slightly in magnitude in anywhere from 30 minutes to two and a half hours as it pulsates.

    For mid-to-large telescopes, Rho offers just a little bit more. The visual companion star has a visual companion as well! Less than a half degree southwest of Rho is a small, faint spiral galaxy – NGC 4608 (Right Ascension: 12 : 41.2 – Declination: +10 : 09) – at 12th magnitude, it’s hard to see because of Rho’s brightness…but it’s not alone. Look for a small, but curiously shaped galaxy labeled NGC 4596 (Right Ascension: 12 : 39.9 – Declination: +10 : 11). Its resemblance to the planet Saturn makes it well worthwhile!

    Until next week? Ask for the Moon, but keep on reaching for the stars!

    Posted on by Jason Major

    How To Measure the Universe

    The Royal Observatory Greenwich is giving free presentations of "Measuring the Universe: from the Transit of Venus to the Edge of the Cosmos" from now until September 1.


    Measuring distance doesn’t sound like a very challenging thing to do — just pick your standard unit of choice and corresponding tool calibrated to it, and see how the numbers add up. Use a meter stick, a tape measure, or perhaps take a drive, and you can get a fairly accurate answer. But in astronomy, where the distances are vast and there’s no way to take measurements in person, how do scientists know how far this is from that and what’s going where?

    Luckily there are ways to figure such things out, and the methods that astronomers use are surprisingly familiar to things we experience every day.

    [/caption]The video above is shared by the Royal Observatory Greenwich and shows how geometry, physics and things called “standard candles” (brilliant!) allow scientists to measure distances on cosmic scales.

    Just in time for the upcoming transit of Venus, an event which also allows for some important measurements to be made of distances in our solar system, the video is part of a series of free presentations the Observatory is currently giving regarding our place in the Universe and how astronomers over the centuries have measured how oh-so-far it really is from here to there.

    Video credits:
    Design and direction: Richard Hogg
    Animation: Robert Milne, Ross Philips, Kwok Fung Lam
    Music and sound effects: George Demure
    Narration and Astro-smarts: Dr. Olivia Johnson
    Producer: Henry Holland