Posted on by Mark Mortimer

Book Review: Stars and Planets

Stars and Planets

Ian Ridpath has been adding to his impressive list of publications with the recently updated fourth edition of “Stars and Planets“. Or, consider its more accurate and complete title “Princeton Field Guides Stars & Planets – The Most Complete Guide to the Stars, Planets, Galaxies and the Solar System“. The title’s quite a mouthful, but the book lives up to the billing. Within it, Ian Ridpath’s texts and Wil Tirion’s illustrations cover all that would interest an active, backyard astronomer.

Being the fourth edition, this review should assess changes from the book’s predecessor. Lacking the third edition means I’m considering the book in isolation.

This book has two parts. The first includes star charts; four per month, with the northern latitude facing south and then north and the same for the southern latitude. The charts show about 5000 separate stars, all being a white dot on a pale blue background with black lettering. After this inclusion, there’s notes on each of the 88 constellations. Again, star charts accompany each. To further entice the reader, nearly each constellation description has a wonderful, colour photograph of a particularly rewarding view, usually as seen from the National Optical Astronomy Observatory (NOAO) in Arizona.

However, as much as the NOAO facility is for the big league, this book stays true to being a guide for the amateur. As such, nearly all comments on viewing, and there are many, relate to either binoculars or small to mid-size home telescopes.

The second part of the book starts off with a look into the life cycle of stars and the particular and useful intricacies of the electromagnetic spectrum. Then, it proceeds to describe viewing pleasures on a planet by planet meander through our solar system. Further, twelve full page maps completely identify features shown on the Moon’s near side. Again, the perspective is for that of a person using amateur level equipment. To help the reader along, the book concludes with a short discussion on choosing binoculars and telescopes.

Being a field guide, this book is of smaller stature than most. Yet, it still won’t fit easily into most pant pockets. However, it would be a great asset to have on hand when deciding how to coordinate a star party or optimize personal evening viewing. And, though not stated in the title, it is for observers, so there’s not a great depth of detail on why or what-for. Thus, for observers, it is of a just the right stature.

Though I’m not in a position to assess the title’s proclamation of being the most complete guide, I will say that it is the best one that I’ve read. With Ian Ridpath’s text and Wil Tirion’s illustrations, the “Princeton Field Guides Stars & Planets” is a wonderful guide to the stars, planets, galaxies and our own solar system. It will help in getting that illusive target into the finder and onto the eagerly awaiting eye.

Read more reviews or purchase a copy online from Amazon.com

Posted on by Nancy Atkinson

Where Are All the Kuiper Belt Objects?

Occultations of KBOs. Credit: TAOS

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A group of astronomers spent two years photographing portions of the sky to look for small chunks of rock and ice orbiting beyond Neptune, in the Kuiper Belt region of our Solar System. The survey targeted Kuiper Belt objects (KBOs) with sizes between 2 miles (3 km) and 17 miles (28 km). The researchers are surprised, as well as a little disappointed with the results. They came up empty. Nada. Not a single KBO within those parameters was spotted. But these researchers from the Taiwanese-American Occultation Survey (TAOS) are ‘glass-half-full’ types, and say that defeat can provide as much information as a successful search, so they are making the most of their data. What this means is that there are less KBOs out there than previously thought.

Since the KBO’s this group searched for are too small to see directly, the survey watched for stars to dim as KBOs passed in front of and occulted them. After accumulating more than 200 hours of data watching for stellar flickers lasting a second or less, TAOS did not spot any occultations.

Here’s a movie that illustrates their search.

The Kuiper Belt contains objects in a range of sizes: a few very large ones (like the dwarf planets Pluto, Eris, Makemake and Haumea) and many more smaller ones. The commonness of a given size tells us information about the history of planet formation and dynamics. In particular, the size distribution of KBOs reflects a history of agglomeration, in which colliding objects tended to stick together, followed by destructive collisions, where collisional velocities were high enough to shatter the rocks involved.

Astronomers questioned whether they would find more and more objects as sizes decreased further, or whether the distribution leveled out. The fact that no occultations were seen sets a stringent upper limit on the number density of KBOs between 2 and 17 miles in diameter. The outer solar system, therefore, appears not as crowded as some theories suggest, perhaps because small KBOs have already stuck together to form larger bodies or frequent collisions have ground down small KBOs into even smaller bits below the threshold of the survey.

The paper announcing this result, co-authored by CfA director Charles Alcock, was published in the October 1 issue of the Astrophysical Journal Letters.

Sources: TAOS, CfA

Posted on by Nancy Atkinson

Did Our Solar System Start With a “Little Bang?”

Artist illustration of supernova. Credit: NASA

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What prompted the formation of our little corner of the universe – our sun and planetary system? For several decades, scientists have thought that the Solar System formed as a result of a shock wave from an exploding star—a supernova—that triggered the collapse of a dense, dusty gas cloud, which then contracted to form the Sun and the planets. But detailed models of this formation process have only worked under the simplifying assumption that the temperatures during the violent events remained constant. That, of course, is very unlikely. But now, astrophysicists at the Carnegie Institution’s Department of Terrestrial Magnetism (DTM) have shown for the first time that a supernova could indeed have triggered the Solar System’s formation under the more likely conditions of rapid heating and cooling. So have these new findings resolved this long-standing debate?

“We’ve had chemical evidence from meteorites that points to a supernova triggering our Solar System’s formation since the 1970s,” remarked lead author, Carnegie’s Alan Boss. “But the devil has been in the details. Until this study, scientists have not been able to work out a self-consistent scenario, where collapse is triggered at the same time that newly created isotopes from the supernova are injected into the collapsing cloud.”

Short-lived radioactive isotopes—versions of elements with the same number of protons, but a different number of neutrons—found in very old meteorites decay on time scales of millions of years and turn into different (so-called daughter) elements. Finding the daughter elements in primitive meteorites implies that the parent short-lived radioisotopes must have been created only a million or so years before the meteorites themselves were formed. “One of these parent isotopes, iron-60, can be made in significant amounts only in the potent nuclear furnaces of massive or evolved stars,” explained Boss. “Iron-60 decays into nickel-60, and nickel-60 has been found in primitive meteorites. So we’ve known where and when the parent isotope was made, but not how it got here.”

Cross-sectional view of one-half of a solar-mass target cloud being struck by a supernova shock front that is traveling downward. Credit: Carnigie Institution for Science
Cross-sectional view of one-half of a solar-mass target cloud being struck by a supernova shock front that is traveling downward. Credit: Carnigie Institution for Science

Previous models by Boss and former DTM Fellow Prudence Foster showed that the isotopes could be deposited into a pre-solar cloud if a shock wave from a supernova explosion slowed to 6 to 25 miles per second and the wave and cloud had a constant temperature of -440 °F (10 K). “Those models didn’t work if the material was heated by compression and cooled by radiation, and this conundrum has left serious doubts in the community about whether a supernova shock started these events over four billion years ago or not,” remarked Harri Vanhala, who found the negative result in his Ph.D. thesis work at the Harvard-Smithsonian Center for Astrophysics in 1997.

Using an adaptive mesh refinement hydrodynamics code, FLASH2.5, designed to handle shock fronts, as well as an improved cooling law, the Carnegie researchers considered several different situations. In all of the models, the shock front struck a pre-solar cloud with the mass of our Sun, consisting of dust, water, carbon monoxide, and molecular hydrogen, reaching temperatures as high as 1,340°F (1000 K). In the absence of cooling, the cloud could not collapse. However, with the new cooling law, they found that after 100,000 years the pre-solar cloud was 1,000 times denser than before, and that heat from the shock front was rapidly lost, resulting in only a thin layer with temperatures close to 1,340°F (1000 K). After 160,000 years, the cloud center had collapsed to become a million times denser, forming the protosun. The researchers found that isotopes from the shock front were mixed into the protosun in a manner consistent with their origin in a supernova.

“This is the first time a detailed model for a supernova triggering the formation of our solar system has been shown to work,” said Boss. “We started with a Little Bang 9 billion years after the Big Bang.”

Source: Carnegie Institution for Science

Posted on by Tammy Plotner

Weekend SkyWatcher’s Forecast – October 3-5, 2008

Greetings, fellow SkyWatchers! It’s Friiiiiiday… And time to head out to the Moon to begin some lunar exploration. Why not? This weekend commemorates Robert Goddard’s birthday! While we’re rocketing skyward, we’ll take a look at a great globular cluster that’s easy in both binoculars and telescopes, plus a few great stars you might or might not know about. For lucky viewers in South Africa and Australia? Head’s up for an Antares occultation! Are you ready? Then let’s head out into the night….

Friday, October 3, 2008 – Tonight we’ll begin on the lunar surface and go out on a limb – the southeastern limb – to have a look at an unusual crater. Named for the French agrochemist and botanist Jean-Baptiste Boussingault, this elliptical-appearing crater actually spans a handsome 71 kilometers. What makes Boussingault so unusual is that it is home to its own large interior crater – A. This double-ring formation gives it a unique stepped, concentric look that’s worth your time!

Now wait for the Moon to wester a bit and we’ll return to Pegasus and the incredible M15. Although skies are a bit bright, you can still have a very satisfactory look at M15 through any size binoculars or telescope.

You can find it easily just about two fingerwidths northwest of red Epsilon Pegasi – Enif (RA 21 29 58 Dec +12 10 00). Shining brightly at magnitude 6.4, low power users will find it a delightfully tight ball of stars, but scope users will find it unique. As resolution begins, sharp-eyed observers will note the presence of a planetary nebula – Pease 1. This famous X-ray source you have just seen with your eyes may have supernova remnants buried deep inside…

When we’re done? Let’s go have a look at Gamma Aquilae just for the heck of it. Just northwest of bright Altair, Gamma (RA 19 46 15 Dec +10 36 47) has the very cool name of Tarazed and is believed to be over 300 light-years away. This K3-type giant will show just a slight yellow coloration – but what really makes this one special is the low power field! Enjoy it in binoculars or drop in your favorite panoramic eyepiece and just relax… Sometimes there is peace and contentment in the light.

Saturday, October 4, 2008 – Today in 1957, the USSR’s Sputnik 1 made space history as it became the first manmade object to orbit the earth. The Earth’s first artificial satellite was tiny, roughly the size of a basketball, and weighed no more than the average man. Every 98 minutes it swung around Earth in its elliptical orbit…and changed everything. It was the beginning of the “Space Race.” Many of us old enough to remember Sputnik’s grand passes will also recall just how inspiring it was. Take the time with your children or grandchildren to check www.heavens-above.com for visible passes of the ISS, and think about how much our world has changed in just over half a century!

Do you remember the Professor Burg who discovered Antares’ companion during an occultation? Well, tonight we’re going to become a whole lot more familiar with the good professor, because it’s about to happen again! For almost all observers, at some time brilliant red Antares will be less than half a degree to the north of tonight’s crescent Moon. For South African and Australia, this will be a spectacular occultation, so be sure to check IOTA for precise times and locations on this universal date.

While we’re waiting on the event, let’s have a look at the crater named for Burg as we begin by using past study crater Posidonius as our guide. How many more of these craters can you identify?

If you walk along the terminator to the northwest, you’ll see the punctuation of 40 kilometer wide Burg just emerging from the shadows. While it doesn’t appear to be a grand crater like Posidonius, it has a redeeming feature: it’s deep – really deep. If Burg were filled with water here on Earth, it would require a deep submergence vehicle like ALVIN to reach its 3680 meter floor! This class II crater stands nearly alone on an expanse of lunarscape known as Lacus Mortis. If the terminator has advanced enough at your time of viewing, you may be able to see this walled-plain’s western boundary peeking out of the shadows.

Sunday, October 5, 2008 – Today marks the birthdate of Robert Goddard. Born in 1882, Goddard is known as the father of modern rocketry – and with good reason. In 1907, Goddard came into the public eye when a cloud of smoke erupted from the basement of the physics building in Worcester Polytechnic Institute, from which he had just fired a powder rocket. By 1914, he had patented the use of liquid rocket fuel, and the design of two- or three-stage solid fuel rockets. His work continued as he sought methods of lofting equipment ever higher, and by 1920 he had envisioned his rockets reaching the Moon. Among his many achievements, he proved that a rocket would work in a vacuum. By 1926 the first scientific equipment went along for the ride; by 1932, Goddard was guiding those flights; and by 1937 his motors were pivoting on gimbals and being controlled gyroscopically. His lifetime of work went pretty much unnoticed until the dawn of the Space Age, but in 1959 (14 years after his death) he received acclaim at last as NASA’s Goddard Space Flight Center was established in his memory.

Tonight let’s rocket to the Moon to explore a binocular curiosity located on the northeast shore of Mare Serenitatis. Look for the bright ring of Posidonius, which contains several equally bright points both around and within it. Now look at Mare Crisium and get a feel for its size. A little more than one Crisium’s length west of Posidonius you’ll meet Aristotle and Eudoxus. Drop a similar length south and you will be at the tiny, bright crater Linne on the expanse of Mare Serenitatis. So what’s so cool about this little white dot? With only binoculars you are resolving a crater that is one mile wide, in a seven mile wide patch of bright ejecta – from close to 400,000 kilometers away!

Tonight in 1923, Edwin Hubble was also busy as he discovered the first Cepheid variable in the Andromeda Galaxy. Hubble’s discovery was crucial in proving that the objects once classed as “spiral nebulae” were actually independent and external stellar systems like our own Milky Way.

While we’re out, let’s have a look at a Mira type variable, as we look about halfway between Beta and Gamma Cygni for Chi (RA 19 50 33 Dec +32 54 51).

Noted for being the second long-term variable discovered (by Gottfried Kirch in 1868), Chi is visible to the unaided eye when at maximum – but demands a telescope at minimum. Fluxing between magnitude 4 and 12, you’ll know if you’ve caught it at its lowest point when you can’t distinguish it from background stars! Of course, this is another wonderful cosmic joke on Bayer – for it was several years until the star he classed as visual returned to view. Maximum or minimum? Enjoy your own perceptions of this lovely red star!

Now, as the days pass… Watch as Jupiter and the Moon draw closer and then part company! It’s a lovely sight that doesn’t require any special equipment and makes for a relaxing evening of stargazing. Until next time, I wish you clear skies and a great weekend!

This week’s awesome images are: Crater Boussingault – Credit: Jim Mosher (LPOD), M15 – Credit: NOAO/AURA/NSF, Gamma Aquilae – Credit: Palomar Observatory, courtesy of Caltech, Sputnik 1 – Credit: NASA, 2005 Antares Occultation – Credit: John Chumack, Detail view of Posidonius – Credit: Greg Konkel, Robert Goddard – Credit: NASA, Crater Linne – Credit: Greg Konkel Annotations: Tammy Plotner and Chi Cygni at minimum (center of field) – Credit: Palomar Observatory, courtesy of Caltech. Many, many thanks! Each time we see these images it improves our understanding of what we look at and what we are looking for and their use is greatly appreciated!!

Posted on by Nancy Atkinson

Hubble’s Heritage

Credit: NASA, ESA, and The Hubble Heritage Team (STScI/AURA) Acknowledgment: N. Smith (University of California, Berkeley)

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Here’s another anniversary for you and more fodder to either ease or add to your Hubble “angst”: Ten years ago, the Hubble Heritage Project began. What is Hubble Heritage? After the Hubble Space Telescope was fixed of its spherical aberration problem in December of 1993, HST started churning out incredible images. After a few years, the images started to pile up, and the astronomers working with Hubble wanted to share them with the public. So with the Hubble Heritage Project, each month, some of the most breathtaking and attractive images are released and showcased to the public. Along with the images, the astronomers explain the science behind the images, as well. Over the past ten years of doing this, the Heritage team has presented to the public aesthetic images that present the universe from an artistic perspective. Its science as art, and these images are some of the most gorgeous “real” art available anywhere. To celebrate the 10th anniversary of this project, above is the latest release. So while we await the fate of Hubble, enjoy this latest release!

This month’s three-dimensional-looking Hubble image shows the edge of the giant gaseous cavity within the star-forming region called NGC 3324. The glowing nebula has been carved out by intense ultraviolet radiation and stellar winds from several hot, young stars. A cluster of extremely massive stars, located well outside this image in the center of the nebula, is responsible for the ionization of the nebula and excavation of the cavity.

The image also reveals dramatic dark towers of cool gas and dust that rise above the glowing wall of gas. The dense gas at the top resists the blistering ultraviolet radiation from the central stars, and creates a tower that points in the direction of the energy flow. The high-energy radiation blazing out from the hot young stars in NGC 3324 is sculpting the wall of the nebula by slowly eroding it away.

Credit: NASA, ESA, and The Hubble Heritage Team (STScI/AURA) Acknowledgment: N. Smith (University of California, Berkeley)
Credit: NASA, ESA, and The Hubble Heritage Team (STScI/AURA) Acknowledgment: N. Smith (University of California, Berkeley)

Located in the southern hemisphere, NGC 3324 is at the northwest corner of the Carina Nebula (NGC 3372), home of the Keyhole Nebula and the active, outbursting star Eta Carinae. The entire Carina Nebula Complex is located at a distance of roughly 7,200 light-years, and lies in the constellation Carina.

This image is a composite of data taken with the Advanced Camera for Surveys (ACS) and the Wide Field Planetary Camera 2 (WFPC2).

The Hubble Heritage Project, which began in October 1998, has released nearly 130 images mined from the Hubble data archive as well as a number of observations taken specifically for the project.

Source: Hubble Heritage , HubbleSite

Posted on by Ian O'Neill

The Particle Zoo: Collecting Your Own Subatomic Particles

All the particles (excluding their anti-particles) gather for a photo opportunity (Particle Zoo)

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This is a must for any particle physics enthusiast: collect your own particles in the form of a soft, cuddly plushie. From the theoretical Higgs boson to the well known electron, all the quantum particles from the Standard Model can be browsed and chosen for your personal collection. The Particle Zoo is the brain child of Los Angeles-based Julie Peasley, who is making it her duty to give our beloved particles a face and personality. For example: due to his popularity, the Higgs particle is a “bit of a snob” and therefore has a huge smile on his face (after all, wouldn’t you be really smug if everyone wanted to interview you?); the muon (or heavy electron) “lives fast and dies young“; or, hilariously, the unobserved graviton “has big legs for jumping branes.” All the particles have a story and a loving personality. Who would have thought quantum physics could be so much fun?

So that's what the LHC is looking for! Meet the Higgs particle (The Particle Zoo)
So that's what the LHC is looking for! Meet the Higgs particle (The Particle Zoo)
When I first stumbled across The Particle Zoo website I was in awe of the effort Particle Zookeeper Julie Peasley had put into her creations. On reading the descriptions of each particle’s personalities I realised these fun characters were more than just for entertainment purposes; they were a way to communicate the complex physics behind the quantum world to an audience who didn’t necessarily have a specialist background, but would appeal greatly to physicists too.

“If the particle toys can generate an interest in physics and the subatomic world, I’m grateful. At the very least now all my friends and family know what a boson is,” Julie responded when I asked about the educational uses for these cute creations. Teachers, professors and science educators have ordered whole sets of the particles for use in their physics lessons, proving that The Particle Zoo is not simply ‘just for fun.’

Identifying a face and personality for all the quarks, leptons, bosons, nucleons and theoreticals is not a task to be taken lightly, however. Every characteristic of the professionally-made particles must be likened to their real-world counterpart, thereby ensuring scientific accuracy. If the particle is heavy, it will be filled with something weighty, like gravel (check out the vital statistics for the Higgs boson for example); if it is massless, it is filled with light weight poly fill (such as the photon).

“The particles seem to be catching on more and more. I had a “special” on the Higgs particle all day on September 10 to celebrate the startup. I sold a record amount of particles in a short time. So I am now only $999,999,689 away from buying my own LHC.” – Particle Zookeeper Julie Peasley.

Julie spends some quality time with her Standard Model particles (The Particle Zoo)
Julie spends some quality time with her Standard Model particles (The Particle Zoo)
But there is a lot more to it than matching the physical characteristics of the quanta with the plushie. Julie realised after a compelling lecture by Dr. Lawrence Krauss at UCLA that subatomic particles could have different “personalities” that could be embodied through her talents as an artist (she holds a Fine Arts degree from the University of Colorado) and her lifelong interest in cosmology, the quantum mechanics and theoretical physics. After Krauss’ lecture on The Beginning and End of Time, she hit the textbooks, finding Lisa Randall’s Warped Passages to be a key element to her enthusiasm to giving the particles a face. Each particle has a face that reflects its “personality” – take the neutron with a neutral expression, or the hard-to-detect neutrinos who are all dressed up like little ninjas; every one is designed with a subtle touch.

Select your favourite particle (and don't forget your anti-particles!) (Particle Zoo)
Select your favourite particle (and don't forget your anti-particles!) (Particle Zoo)
In reference to the light-hearted organization, the People for the Ethical Treatment of Hadrons, or simply “PETH” (a group set up to protect the rights of hadrons in particle colliders. After all, how do we know protons don’t feel pain?), Julie said, “I love the idea of hadron’s rights, that is hilarious. Actually, I’m quite jealous of the little hadrons who get to collide at the LHC. They get to go 99.999999% the speed of light. How cool is that?”

Although the LHC has suffered a technical hitch, and the first particle collisions aren’t expected to commence until spring 2009, The Particle Zoo will allow you to explore the quantum world for the time being. I for one have ordered my very own Higgs boson in preparation for my celebrations for when the first particles are collided by the LHC.

“I had a collection of the Giant Microbes toys and thought if people enjoyed those, maybe they would enjoy taking it a step further (well, to be honest, many orders of magnitude further). I honestly had no idea if anyone would be interested but I’m happy to say I’ve gotten over and beyond the positive response I could have imagined.” – Particle Zookeeper Julie Peasley.

So for now, any Higgs boson discovery will fall to Julie’s skilled hands in her “sweatshop of one” until the real force carrier is either proven or disproven in a few months time…

(Warning: Be sure not to leave any anti-particles mingling with the “normal” particles on the same shelf… the resulting annihilation may leave you swamped with fluffy photons…)

Source: Astroengine.com

Posted on by Nancy Atkinson

Little Star Twinkles, Then Vanishes

Illustration of the flare from magnetar Swift J195509+261406. A starquake is probably what triggered the object's 40 optical flares. Credit: NASA/Swift/Sonoma State University/A. Simonnet

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Swift has made another unusual discovery. The orbiting satellite detected a very strange star that “twinkled” with gamma rays, X-rays, and light — and then vanished. Back in June the satellite detected a spike of gamma-rays that lasted less than five seconds. But this high-energy flash wasn’t a gamma-ray burst — the birth cry of a black hole far across the universe. It was something much closer to home. During the next three days, the object brightened and faded in visible light. It flashed over 40 times! Eleven days later, it flashed again, this time at infrared wavelengths. Then, it disappeared from view!

Swift had reported the event’s position to astronomers all over the world, so within minutes, robotic telescopes turned to a spot in the constellation Vulpecula. It was cataloged as “Swift J195509+261406.” So, several astronomers had a look at this unusual object before it disappeared.

Astronomers think the object was a special kind of neutron star called a magnetar. “We are dealing with an object that was hibernating for decades before entering a brief activity period,” explains Alberto J. Castro-Tirado, lead author of the paper that was published in the Sept. 25 edition of Nature. “Magnetars remain quiet for decades.”

Although measuring only about 12 miles across — about the size of a city — neutron stars have the strongest magnetic fields in the cosmos. Sometimes, those magnetic fields are super strong — more than 100 times the strength of typical neutron stars.

Astronomers put these magnetic monsters in their own class: magnetars. Only about a dozen magnetars are known, but scientists suspect our galaxy contains many more. We just don’t see them because they’re quiet most of the time.

So what happened last year? Why did this previously unseen star begin behaving so badly? And why did it stop?

Combine a magnetar’s pumped-up magnetic field with its rapid spin, and sooner or later something has to give. Every now and then, the magnetar’s rigid crust snaps under the strain.

This “starquake” releases pent-up magnetic energy, which creates bursts of light and radiation. Once the star’s crust and magnetic field settle down, the star goes dark and disappears from our view. At least until the next quake.

Astronomers suspect that magnetars lose their punch as time passes, but Swift J195509+261406 provides the missing link between objects exhibiting regular activity and those that have settled into retirement — and invisibility.
“I love it when Swift enables a discovery like this,” says Neil Gehrels, the mission’s lead scientist at NASA Goddard Space Flight Center in Greenbelt, Md. “The observatory is an astronomical robot built for gamma-ray burst studies, but it can also quickly point at other bizarre objects with bright flares.”

Read two papers published on this object here and here.

Source: Goddard Spaceflight Center

Posted on by Nancy Atkinson

The Telescope Has a Birthday Party

Galileo's Telescope

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All sorts of anniversaries going on these days — yesterday was NASA’s 50th birthday, on Saturday, Oct. 4 is the 51st anniversary of Sputnik’s launch, and today we celebrate the birthday of the telescope. 400 years ago, officials in the Netherlands were pondering over a patent application by a spectacle maker named Hans Lipperhey. The patent was for a “device by means of which all things at a very great distance can be seen as if they were nearby.” This is the earliest known record of a telescope. A few months later, scientist Galileo Galilei would get his hands on one.

Over at Wired, they are having a big celebration for the telescope’s birthday, including an article by some writer named Nancy Atkinson that includes a gallery of images and descriptions of the ten largest ground-based telescopes on Earth. It’s called “Giants of Earth and Space.” But there’s all sort of other interesting features, including a place where you can upload your favorite astronomical image that was taken by a ground-based telescope.

So check it out to celebrate. But of course this biggest party will be next year — the whole year of 2009 in fact, during the International Year of Astronomy. Look for more info and features about all the great events and ways you can participate in future articles on Universe Today

Posted on by Nancy Atkinson

Best Ground-Based Image of Jupiter — Ever!

Jupiter from the VLT. Credit: ESO

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Everyone loves twinkling stars and moonlit nights—EXCEPT astronomers. But astronomers are crafty people, so they’ve come up with ways to mitigate the distortion that Earth’s thick atmosphere causes for ground based telescopes (from which stars appear to twinkle). And now, a new image-correction technique has delivered the sharpest whole-planet ground-based picture ever. The Very Large Telescope (VLT) performed a record two-hour observation of Jupiter using a breakthrough technique to remove atmospheric blur. And what a result! Just take a look at that gorgeous image…And this new image reveals changes in Jupiter’s smog-like haze, probably in response to a planet-wide upheaval more than a year ago.

Being able to correct wide field images for atmospheric distortions has been the dream of scientists and engineers for decades. Astronomers used a new device called the Multi-Conjugate Adaptive Optics Demonstrator (MAD) prototype instrument mounted on ESO’s Very Large Telescope (VLT)
The new images of Jupiter prove the value of the advanced technology used by MAD, which uses two or more guide stars instead of one as references to remove the blur caused by atmospheric turbulence over a field of view thirty times larger than existing techniques.

“This type of adaptive optics has a big advantage for looking at large objects, such as planets, star clusters or nebulae,” says lead researcher Franck Marchis, from UC Berkeley and the SETI Institute in Mountain View, California, USA. “While regular adaptive optics provides excellent correction in a small field of view, MAD provides good correction over a larger area of sky. And in fact, were it not for MAD, we would not have been able to perform these amazing observations.”

MAD allowed the researchers to observe Jupiter for almost two hours on 16 and 17 August 2008, a record duration, according to the observing team. They were able to take a series of 265 snapshots. Conventional adaptive optics systems using a single Jupiter moon as reference cannot monitor Jupiter for so long because the moon moves too far from the planet. The Hubble Space Telescope cannot observe Jupiter continuously for more than about 50 minutes, because its view is regularly blocked by the Earth during Hubble’s 96-minute orbit.

Using MAD, ESO astronomer Paola Amico, MAD project manager Enrico Marchetti and Sébastien Tordo from the MAD team tracked two of Jupiter’s largest moons, Europa and Io – one on each side of the planet – to provide a good correction across the full disc of the planet. “It was the most challenging observation we performed with MAD, because we had to track with high accuracy two moons moving at different speeds, while simultaneously chasing Jupiter,” says Marchetti.

With this unique series of images, the team found a major alteration in the brightness of the equatorial haze, which lies in a 16,000-kilometer wide belt over Jupiter’s equator. More sunlight reflecting off upper atmospheric haze means that the amount of haze has increased, or that it has moved up to higher altitudes. “The brightest portion had shifted south by more than 6,000 kilometers,” explains team member Mike Wong.

This conclusion came after comparison with images taken in 2005 by Wong and colleague Imke de Pater using the Hubble Space Telescope. The Hubble images, taken at infrared wavelengths very close to those used for the VLT study, show more haze in the northern half of the bright Equatorial Zone, while the 2008 VLT images show a clear shift to the south.

“The change we see in the haze could be related to big changes in cloud patterns associated with last year’s planet-wide upheaval, but we need to look at more data to narrow down precisely when the changes occurred,” declares Wong

Source: ESO