31 December 2005

Amazing Astrophotography

Technological advances over the years have made astrophotography & CCD imaging more accessible than ever to interested amateurs. Those willing to sacrifice the time, effort, capital (and sleep ;-)), while maintaining the necessary intestinal fortitude to tackle a substantially long learning curve inevitably reap the sweet fruits of their labor by producing breathtaking imagery. As if observational astronomy weren't already rewarding enough, astrophotography opens our window to the cosmos even wider, providing the opportunity for immense amounts of detail to be captured beyond what our eyes can distinguish via astronomical optics alone.

It's simple enough to muster "decent" images with a relative minimum of gear and modest cunning. Since I presently lack the required funds to delve into high-end imaging equipment and the obligatory peripherals, I can cheat a bit with my trusty 10" dobsonian by snapping images afocally -- just barely enough to scratch my ever-growing astrophotographical itch. For now. Unlike my hackish, photon-thieving chicanery, the experienced, dedicated astrophotographers out there have converted an enjoyable hobby into a truly polished form of art.

With that in mind...

Some purely awe-inspiring images were released in 2005. I felt utterly compelled to compose an entry paying homage to my personal favorites in the hope of sharing their beauty with others. The authors featured in this article have generously allowed me to showcase their works, and for that I'm most appreciative. Please note that the images below are all copyrighted works and property of their respective owners.

I can think of no better way to begin the new year by celebrating the magnificent beauty of the universe and the steadfast efforts of those who capture its wondrous nature so beautifully.


Lets begin our tour on terra firma. Astronomer Jim Scotti captured this brilliant scene in November:

Meteor, clouds and domes
© James V. Scotti pixofmyuniverse.blogspot.com


He writes:

"This is the view out my back door - well, sort of. While observing at the Spacewatch 1.8-m telescope on Saturday morning, Nov. 26 (or not observing in this case thanks to wind and clouds), I took this photo as part of a timelapse set. I caught a rather nice meteor to go along with the clouds and domes. From the left is the Spacewatch 36 inch (0.9-m) telescope, the Steward Observatory 90 inch Bok telescope and the KPNO 4-meter Mayall telescope. The clouds and domes are lit by the crescent moon (partly obscured by the clouds) & the lights of Tucson."

Marvelous! Be sure to visit Jim's photoblog -- he serves up excellent photographs spanning numerous subjects. Wish I had the benefit of a professional observatory to serve as a backdrop for the subjects I shoot. ;-)

Next stop: Space.

Russell Croman is undoubtedly one of my favorite astro- photographers. His images have garnered widespread acclaim, and I'm truly envious of both the arsenal at his disposal as well as his technical expertise and painstaking attention to detail. The following series highlights my personal favorites he's assembled in the last year. Clicking on each image will take you to the corresponding entries on Russell's website where you may view larger-resolution versions and the pertinent image details.


The Merope Nebula
© 2005 Russell Croman
, www.rc-astro.com


Merope, one of the Seven Sisters in the Pleiades (M45) open cluster resides with its siblings in the constellation Taurus, a cozy 385 light-years away from Earth. The star basks in a prominent reflection nebula, NGC 1435, illuminating the molecular cloud's wispy tendrils. This is without question the finest image of the region I've ever seen. Absolutely stunning.


Spiral Galaxy M81
© 2005 Russell Croman, www.rc-astro.com


Bode's Galaxy, M81 (NGC 3031), originally discovered by Johann Elert Bode in 1774, is a striking type Sb spiral galaxy in the constellation Ursa Major. Its beauty remains completely intact even at a distance of 12,000,000 LY. A truly magnificent spiral specimen.



The Fox Fur Nebula
© 2005 Russell Croman, www.rc-astro.com


This image was featured as the Astronomy Picture of the Day on March 14th 2005. Located in the constellation Monoceros, this dynamic region is, in my opinion, one of the cosmos' finest artistic formations. Variable mammoth S Monocerotis, the brightest star (well, binary) visible in the field above & left of center, blazes away yielding 217,000 times the luminosity of our Sun -- the heavyweight accounts for a mindboggling 35 solar masses -- and illuminates surrounding dust via reflection with a surreal bluish hue. Truly an amazing region, and an equally incredible image.


Leg two of our journey through space...


No mention of my favorite imagers would be complete without praising Robert Gendler. I don't think I'd be able to add up the countless hours I've spent browsing his image galleries and the jaw-dropping shots contained therein. His passion clearly shines through in every photograph -- and the sheer dedication of time and effort necessary to assemble numerous masterpieces serves as an inspriation to astro-addicted amateurs like myself. Robert has published so extensively that I can't help but wonder how many people have seen his work without being aware of its author. Like the previous series, clicking on each photo will take you to the corresponding pages on Robert's website.




NGC 2170, Complex Nebula in Monoceros©2005 Robert Gendler, robgendlerastropics.com


Picking up (almost) where we left off, in Monoceros -- this star birth region is one of my all-time favorites. Note the marvelous contrast offered by (blue) reflection and (red) emission nebulae and the resulting textural complexities deep in the heart of Mon R2. Robert's recent image simply dazzles, and I'd contend it's the best of this area taken to date.



NGC 1973-75-77, Complex Nebula in Orion
© 2005 Robert Gendler, robgendlerastropics.com

Yet another of my favorite regions, located in The Hunter. Read about the comprehensive details as offered by the author, here: NGC 1973-75-77; the Orion Molecular Cloud.



And now, la piece de resistance:



The Andromeda Galaxy (M31)
© 2005 Robert Gendler, robgendlerastropics.com


This is without question my favorite astrophotograph of 2005 -- a truly splendid mosaic of our large spiral neighbor and culmination of some 90 cumulative hours of exposure. I can't imagine the amount of processing time tacked on in order to achieve this absolutely majestic result. Gendler's previous mosaic of M31 invoked similar feelings of awe; I didn't think it could be bested. While I still adore the prior incarnation, this new image, for the lack of a better phrase, completely blew me away. I discovered and marvelled over the image when it was freshly added to Robert's gallery page and again thereafter when it was featured as the Astronomy Picture of the Day on December 22nd, 2005. In my book, it's the astronomy picture of the year.

Thus concludes our little tour through the heavens. I certainly didn't mean to exclude any number of fantastic images compiled by other astrophotographers; those contained in this entry each struck me in a unique way. Besides, I'd overload this poor software by including photos from everyone I'd have liked. ;-)

Special thanks once again to Russell Croman, Robert Gendler, and Jim Scotti for allowing me to grace my cozy niche with their amazing work. Please make it a point to visit through their image galleries and enjoy the sheer beauty they have to offer.

My goal is to follow in the footsteps of these dedicated individuals when I've the resources to tackle this pursuit to the fullest. In the meantime, I hope these images have provided you with the same degree of inspiration they have myself. Awesome work, gentlemen -- I greatly look forward to seeing what the future brings.

Best wishes for a peaceful and fruitful New Year.


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Dazzling Color

If I didn't know better, I'd swear the fine folks at Cassini were determined to keep me jumping through hoops. It's proving quite a challenge to stay on top of the magnificent imagery returned with such an impressive degree of frequency.

In Time for Saturn, I'd already selected my favorite Cassini releases for 2005. After that came The Face of Beauty which necessitated an addendum to my prior list. That'll teach me post prematurely in the future. ;-)

Well, enter gorgeous addendum #2. Somehow the below press release and photo eluded my radar until earlier today.

Image Credit: NASA/JPL/Space Science Institute

Cool and icy Dione floats in front of giant Saturn bedecked in a dazzling array of colors.

The surface of Dione, which exhibits contrasting bright and dark areas when viewed up close, appears pale in this image. It is Saturn's multi-hued cloud bands that boldly steal the show. Discrete clouds and eddies in Saturn's northern hemisphere can be seen within the faint shadows of the rings on the planet. Dione is 1,118 kilometers (695 miles) across.

Cassini is in a phase of its mission in which its orbit will be nearly equatorial for some time. This view was obtained from about one-third of a degree out of the ring plane.

Images taken with red, green and blue filters were used to create this natural-color view. The images were obtained with the wide-angle camera on Sept. 22, 2005, from a distance of approximately 803,000 kilometers (499,000 miles) from Dione and at a sun-Dione-spacecraft, or phase, angle of about 43 degrees. The image scale is about 48 kilometers (30 miles) per pixel.

Here's the complete press release (including larger-resolution imagery) courtesy of NASA's Planetary Photojournal.

What next? Cassini has developed this nasty habit of exponentially raising the bar for beauty with each stride. Incredible.

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30 December 2005

New Horizons Gears for Launch


Image Credit: Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute (JHUAPL/SwRI)

Artist's concept of the New Horizons spacecraft during a planned encounter with Pluto and its moon, Charon. The craft's miniature cameras, radio science experiment, ultraviolet and infrared spectrometers and space plasma experiments would characterize the global geology and geomorphology of Pluto and Charon, map their surface compositions and temperatures, and examine Pluto's atmosphere in detail. The spacecraft's most prominent design feature is a nearly 8-foot (2.1-meter) dish antenna, through which it would communicate with Earth from as far as 4.7 billion miles (7.5 billion kilometers) away.


"The First Mission to the Last Planet" draws closer to liftoff, with the launch window for NASA's New Horizons probe opening in just under three weeks. This mission is particularly exciting -- it aims to offer invaluable observations & data about the more distant reaches of our solar system on into the Kuiper Belt. Announcement of recent discoveries like the two new moons found orbiting Pluto greatly underscores our need to further study these distant bodies. (Speaking of which, Max Mutchler from STScI will be speaking on that very topic January 3rd, 2006.) There's still much to learn about Pluto, Charon and its smaller neighbors -- the study of which will also further aid our understanding of our own backyard, and more.

Among the probe's goals:

New Horizons: Mission Objectives

  • Map surface composition of Pluto and Charon
  • Characterize geology and morphology ("the look") of Pluto and Charon
  • Characterize the neutral atmosphere of Pluto and its escape rate
  • Search for an atmosphere around Charon
  • Map surface temperatures on Pluto and Charon
  • Search for rings and additional satellites around Pluto
  • PLUS... conduct similar investigations of one or more Kuiper Belt Objects



Almost ready! Image credit: NASA

KENNEDY SPACE CENTER, FLA. – The fairing enclosing New Horizons awaits further processing upon its arrival atop a Lockheed Martin Atlas V launch vehicle in the Vertical Integration Facility at Complex 41 on Cape Canaveral Air Force Station. New Horizons carries seven scientific instruments that will characterize the global geology and geomorphology of Pluto and its moon Charon, map their surface compositions and temperatures, and examine Pluto's complex atmosphere. After that, flybys of Kuiper Belt objects from even farther in the solar system may be undertaken in an extended mission. New Horizons is the first mission in NASA's New Frontiers program of medium-class planetary missions. The spacecraft, designed for NASA by the Johns Hopkins University Applied Physics Laboratory in Laurel, Md., will launch aboard a Lockheed Martin Atlas V rocket and fly by Pluto and Charon as early as summer 2015.


This recent press release offers an excellent overview:

NASA is preparing to launch the first spacecraft to distant Pluto and its moon Charon. The January 2006 launch of New Horizons will complete the initial reconnaissance of the planets in the solar system.

"New Horizons will study a unique world, and we can only imagine what we may learn. This is a prime example of scientific missions that complement the Vision for Space Exploration," said Mary Cleave, associate administrator for NASA's Science Mission Directorate.

The Vision for Space Exploration is a bold new course into the cosmos, a journey that will return the space shuttle safely to flight, complete the construction of the International Space Station, take humans back to the moon and eventually to Mars and beyond.

The National Academy of Sciences has ranked the exploration of Pluto-Charon and the Kuiper Belt among the highest priorities for space exploration, citing the fundamental scientific importance of these bodies to advancing understanding of our solar system.

Different than the inner, rocky planets (like Earth) or the outer gas giants, Pluto is a different type of planet known as an "ice dwarf," commonly found in the Kuiper Belt region billions of miles from the sun.

"Exploring Pluto and the Kuiper Belt is like conducting an archeological dig into the history of the outer solar system, a place where we can peek into the ancient era of planetary formation," said Alan Stern, New Horizons principal investigator, Southwest Research Institute Department of Space Studies, Boulder, Colo.

Designed and built at the Johns Hopkins University Applied Physics Laboratory, Laurel, Md., pending launch approval, New Horizons is set to launch from Cape Canaveral Air Force Station, Fla., no earlier than Jan. 17, 2006. The launch window extends until Feb. 14, 2006.

The compact, 1,050-pound piano-sized probe will launch aboard an Atlas V expendable launch vehicle, followed by a boost from a kick-stage solid propellant motor. New Horizons will be the fastest spacecraft ever launched, reaching lunar orbit distance in just nine hours and passing Jupiter 13 months later.

Launch before Feb. 3 allows New Horizons to fly past Jupiter in early 2007 and use the planet's gravity as a slingshot toward Pluto. The Jupiter flyby trims the trip to Pluto by five years and provides opportunities to test the spacecraft's instruments and flyby capabilities on the Jupiter system.

The New Horizons science payload, developed under direction of Southwest Research Institute, includes imaging infrared and ultraviolet spectrometers, a multi-color camera, a long-range telescopic camera, two particle spectrometers, a space-dust detector and a radio science experiment. The dust counter was designed and built by students at the University of Colorado, Boulder.

Depending on its launch date, New Horizons could reach the Pluto system as early as mid-2015, conducting a five-month-long study possible only from the close-up vantage of a spacecraft. It will characterize the global geology and geomorphology of Pluto and Charon, map their surface compositions and temperatures, and examine Pluto's atmospheric composition and structure. New Horizons also will study the small moons recently discovered in the Pluto system.

The spacecraft will "sleep" in electronic hibernation for much of the cruise to Pluto. Operators will turn off all but the most critical electronic systems and monitor the spacecraft once a year to check out critical systems, calibrate instruments and perform course corrections, if necessary.

The spacecraft will send back a beacon signal each week to give operators an instant read on spacecraft health. The entire spacecraft, drawing electricity from a single radioisotope thermoelectric generator, operates on less power than a pair of 100-watt household light bulbs.


Ambitious to say the least, and the science return from this endeavor promises to be fantastic even though a noteworthy wait is involved. The mission logistics are highly complex, as illustrated by the timeline of events -- just navigating successfully and accurately over such phenomenal distances is no simple task. Principal Investigator Alan Stern and the New Horizons team definitely have a great deal of work ahead which will take years to culminate.

Best wishes to all involved for a great launch and smooth sailing.
Stay tuned!

For more goodies, drop by the coverage offered by The Planetary Society.

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Cassini Spots Tethys' Steep Scarps

Image Credit: NASA/JPL/Space Science Institute

What an intriguing landscape! Saturn's moon Tethys is relatively small, a mere 659 miles in diameter, and orbits the ringed gas giant at a distance of over 180,000 mi. As evidenced by an increasing number of similar fantastic images though, great things do indeed come in small packages.

Image details are in this latest press release:

This view of the surface of Saturn's moon Tethys, taken during Cassini's close approach to the moon on Sept. 24, 2005, reveals an icy land of steep cliffs. The view is of the southernmost extent of Ithaca Chasma, in a region not seen by NASA's Voyager spacecraft.

The ridges around Ithaca Chasma have been thoroughly hammered by impacts. This appearance suggests that Ithaca Chasma as a whole is very old.

There is brighter material in the floors of many craters on Tethys. That's the opposite situation from Saturn's oddly tumbling moon Hyperion, where dark material is concentrated in the bottoms of many craters.

This view is centered on terrain at approximately 2.5 degrees south latitude and 352 degrees west longitude on Tethys. North on Tethys is toward the right in this view.

This clear filter view was obtained using the Cassini spacecraft narrow-angle camera at a distance of approximately 32,300 kilometers (20,000 miles) from Tethys and at a Sun-Tethys-spacecraft, or phase, angle of 20 degrees. Image scale is 190 meters (620 feet) per pixel.

For more on Tethys, visit Bill Arnett's page and view previous entries in NASA's Planetary Photojournal.

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29 December 2005

Chandra Turns Earthbound!


On February 15, 2004, Chandra observed X-rays produced by an aurora in the north-polar region of Earth. The X-rays, superimposed on a model of Earth, are seen as the violet-yellow-red arc stretching from northern Canada on the upper left to the Hudson Bay on the lower right. To obtain this data, Chandra was aimed at a fixed point in the sky, and the Earth's motion carried the auroral regions through the field of view. The shadowed area defines the day-night boundary at sea level. The X-ray activity is taking place at approximately 100 kilometers above the Earth. Scale: Distance from the North pole to the black circle is 3,340 km (2,075 miles)


Now this came as a welcome surprise to me. The Chandra X-Ray Observatory has been returning marvelous science for some time now, but I was unaware that direct terrestrial study was within its capabilities! This new press release contains some really neat tidbits:

Image Credits: NASA/MSFC/CXC/A.Bhardwaj & R.Elsner, et al.;
Earth model: NASA/GSFC/L.Perkins & G.Shirah


In an unusual observation, a team of scientists has scanned the northern polar region of Earth with NASA's Chandra X-ray Observatory. The results show that the aurora borealis, or "northern lights," also dance in X-ray light, creating changing bright arcs of X-ray energy above the Earth's surface.

While other satellite observations had previously detected high-energy X-rays from the Earth auroras, the latest Chandra observations reveal low-energy X-rays generated during auroral activity for the first time.

The researchers, led by Dr. Ron Elsner of NASA's Marshall Space Flight Center in Huntsville, Ala., used Chandra to observe the Earth 10 times over a four-month period in 2004. The images were created from approximately 20-minute scans during which Chandra was aimed at a fixed point in the sky and the Earth's motion carried the auroral regions through Chandra's field of view.

From the ground, the aurora are well known to change dramatically over time and this is the case in X-ray light as well. The X-rays in this sample of the Chandra observations, which have been superimposed on a simulated image of the Earth, are seen here at four different epochs.

Nice!

Speaking of aurorae, Dr. Tony Phillips has just added a most impressive "mega-gallery" of aurora photographs, including every single image ever posted on Spaceweather.com. If you haven't surfed the aurora galleries there in the past, be sure to check it out -- I could kill untold hours there. For more, also visit this page devoted to aurorae courtesy of the Exploratorium.

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Sunset Series

Gorgeous central Texas sunset photographed by yours truly, December 28th. This lovely sequence ended a relatively persistent bout of bland twilit evenings. All images taken manually with Canon 20D & EF 17-40mm f/4L lens @ f/5.6, ISO 100.


1/80"; 23mm (larger res.)


1/100", 23mm (larger res.)


1/125", 40mm (larger res.)


1/125", 40mm (larger res.)


1/80", 27mm (larger res.)


1/80", 40mm (larger res.)


1/40", 40mm (larger res.)



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28 December 2005

Media Mooned by Uranus

Illustration Credit: NASA, ESA, and A. Feild (STScI)

Bad media alert!

This press release from last week (which I posted about here) details the Hubble Telescope's discovery of two new Uranian moons as well as a pair of newly observed rings around the distant gas giant. Unfortunately, a syndicated news story has circulated and been reproduced without some necessary fact-checking. Lisa M. Krieger's article, Discoveries on Uranus full of drama, mystery is currently making its rounds on affilliated outlets, proclaiming:

The new moons, named Cupid and Mab after Shakespearean characters, bring the number of moons circling Uranus to 27 - the most of any planet.

Doh! I'm not quite sure how she arrived at that conclusion, but it's wrong. Jupiter currently has 63 confirmed satellites; Saturn has 47 to its credit including newly-discovered bodies in 2005. Uranus trails in third place behind its more massive neighbors with 27. You can view the current tallies on Scott Sheppard's web page.

Okay, errors happen. This one's just rather, well, surprising.

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T9 / Titan's Halo

Cassini closed out its 2005 itinerary with another Titan fly-by on December 26th, marking its ninth close encounter with Saturn's largest and most enigmatic moon. The latest image released from this most recent rendezvous has just been posted, here. Meanwhile, the below image was just published today on NASA's Planetary Photojournal. Clicking the image will take you to the site and press release. It's a beaut. :-)


Image Credit: NASA/JPL/Space Science Institute

With its thick, distended atmosphere, Titan's orange globe shines softly, encircled by a thin halo of purple light-scattering haze.

Images taken using blue, green and red spectral filters were used to create this enhanced-color view; the color images were combined with an ultraviolet view that makes the high-altitude, detached layer of haze visible. The ultraviolet part of the composite image was given a purplish hue to match the bluish-purple color of the upper atmospheric haze seen in visible light.

Small particles that populate high hazes in Titan's atmosphere scatter short wavelengths more efficiently than longer visible or infrared wavelengths, so the best possible observations of the detached layer are made in ultraviolet light.

The images in this view were taken by the Cassini narrow-angle camera on May 5, 2005, at a distance of approximately 1.4 million kilometers (900,000 miles) from Titan and at a sun-Titan-spacecraft, or phase, angle of 137 degrees. Image scale is 8 kilometers (5 miles) per pixel.


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27 December 2005

Cometary Medley

Comet C/2001 Q4 (NEAT)

Image Credit: NASA, NOAO, NSF, T. Rector (University of Alaska Anchorage),
Z. Levay and L.Frattare (Space Telescope Science Institute)



The folks over at Space.com have added a spiffy new feature on comets as part of their Universal Sky Tour.

Check out the presentation:
Comets: Marvelous Messengers/Deliverers of Dread.


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25 December 2005

The Face of Beauty

Leave it to the Cassini team to release another awe-inspiring image of Saturn after I'd already posted my favorites of 2005. Consider this an addendum to that list.


Image Credit: NASA/JPL/Space Science Institute

Few sights in the solar system are more strikingly beautiful than softly hued Saturn embraced by the shadows of its stately rings.

The gas planet's subtle northward gradation from gold to azure is a striking visual effect that scientists don't fully understand. Current thinking says that it may be related to seasonal influences, tied to the cold temperatures in the northern (winter) hemisphere. Despite Cassini's revelations, Saturn remains a world of mystery.

Currently, the rings' shadows shield the mid-northern latitudes from the harshest of the sun's rays. As Saturn travels around the sun in its 29-year orbit, the shadows will narrow and head southward, eventually blanketing the opposite hemisphere.

Images taken with blue, green and red spectral filters were used to create this color view, which approximates the scene as it would appear to the human eye. The view was brightened to enhance detail visible in the rings and within their shadows.

The images were obtained with the Cassini wide-angle camera from a distance of approximately 999,000 kilometers (621,000 miles) from Saturn on May 4, 2005, as the spacecraft cruised a few degrees above the ring plane. The image scale is about 60 kilometers (37 miles) per pixel on Saturn.


Just... wow.

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Luna

The more time I spend observing the Moon, the more fascinated I become with lunar geology and surface features. For being a rather barren place it sure has a great deal to offer. Here's a recent series of afocal photos taken with a Canon 20D and powered by my venerable 10" dobsonian.

Langrenus, Vendelinus, Petavius & Fernerius on the limb.



Mmm. Maria.

Centered on Copernicus. At the far left, the Hortensius volcanic domes are visible.


Eratosthenes and the Montes Apenninus.

Copernicus, Eratosthenes & co.



Target: Clavius.



Get the spackle!



The ejecta from Tycho (out of the frame) prominently spans across the lunar surface.

If you have the time, equipment, and motivation, give the Lunar 100 a shot.


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Favorite Photos of the Year

The title says it all. The following images were taken by me using my trusty Canon 20D.



State Capitol here in beautiful Austin, Texas.



Bee visiting a bluebonnet in my yard.


Mare Imbrium on the Moon.



The Moon & Venus. Dr. Tony Phillips published this image on Spaceweather.com -- it was featured on the main page for several days. :-)


Storm brewing, Memorial Day 2005. Thankfully it didn't clobber me.

Beautiful sunset. The image does no justice.


Thanks for looking. ;-)

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23 December 2005

HST Hits '05

The Hubble Space Telescope continues to impress, delivering yet another year of breathtaking imagery. With 2005 being nearly history I thought I'd share my favorites.




Credit: NASA, ESA, and The Hubble Heritage Team (STScI/AURA); Full press release

The Hubble Space Telescope's latest image of the star V838 Monocerotis (V838 Mon) reveals dramatic changes in the illumination of surrounding dusty cloud structures. The effect, called a light echo, has been unveiling never-before-seen dust patterns ever since the star suddenly brightened for several weeks in early 2002.

The illumination of interstellar dust comes from the red supergiant star at the middle of the image, which gave off a pulse of light three years ago, somewhat similar to setting off a flashbulb in a darkened room. The dust surrounding V838 Mon may have been ejected from the star during a previous explosion, similar to the 2002 event.
The echoing of light through space is similar to the echoing of sound through air. As light from the stellar explosion continues to propagate outwards, different parts of the surrounding dust are illuminated, just as a sound echo bounces off of objects near the source, and later, objects further from the source. Eventually, when light from the back side of the nebula begins to arrive, the light echo will give the illusion of contracting, and finally it will disappear.





Credit: NASA, ESA, J. Clarke (Boston University), and Z. Levay (STScI)
Full press release

These images reveal the dynamic nature of Saturn's auroras. Viewing the planet's southern polar region for several days, NASA's Hubble Space Telescope snapped a series of photographs of the aurora dancing in the sky. The snapshots show that Saturn's auroras differ in character from day to day, as they do on Earth, moving around on some days and remaining stationary on others. But compared with Earth, where auroral storms develop in about 10 minutes and may last for a few hours, Saturn's auroral displays always appear bright and may last for several days.

The observations, made by Hubble and the Cassini spacecraft, while enroute to the planet, suggest that Saturn's auroral storms are driven mainly by the pressure of the solar wind — a stream of charged particles from the Sun — rather than by the Sun's magnetic field.





Credit: NASA, ESA, S. Beckwith (STScI), and The Hubble Heritage Team (STScI/AURA)

The graceful, winding arms of the majestic spiral galaxy M51 (NGC 5194) appear like a grand spiral staircase sweeping through space. They are actually long lanes of stars and gas laced with dust.
This sharpest-ever image of the Whirlpool Galaxy, taken in January 2005 with the Advanced Camera for Surveys aboard NASA's Hubble Space Telescope, illustrates a spiral galaxy's grand design, from its curving spiral arms, where young stars reside, to its yellowish central core, a home of older stars. The galaxy is nicknamed the Whirlpool because of its swirling structure.




Credit: NASA, ESA, and The Hubble Heritage Team (STScI/AURA ); Full press release

Appearing like a winged fairy-tale creature poised on a pedestal, this object is actually a billowing tower of cold gas and dust rising from a stellar nursery called the Eagle Nebula. The soaring tower is 9.5 light-years or about 57 trillion miles high, about twice the distance from our Sun to the next nearest star.

Stars in the Eagle Nebula are born in clouds of cold hydrogen gas that reside in chaotic neighborhoods, where energy from young stars sculpts fantasy-like landscapes in the gas. The tower may be a giant incubator for those newborn stars. A torrent of ultraviolet light from a band of massive, hot, young stars [off the top of the image] is eroding the pillar.

The starlight also is responsible for illuminating the tower's rough surface. Ghostly streamers of gas can be seen boiling off this surface, creating the haze around the structure and highlighting its three-dimensional shape. The column is silhouetted against the background glow of more distant gas.

The edge of the dark hydrogen cloud at the top of the tower is resisting erosion, in a manner similar to that of brush among a field of prairie grass that is being swept up by fire. The fire quickly burns the grass but slows down when it encounters the dense brush. In this celestial case, thick clouds of hydrogen gas and dust have survived longer than their surroundings in the face of a blast of ultraviolet light from the hot, young stars.




Credit: NASA, ESA, The Hubble Heritage Team (STScI/AURA), J. Bell (Cornell University) and M. Wolff (Space Science Institute); Full press release
NASA's Hubble Space Telescope snapped this picture of Mars on October 28, within a day of its closest approach to Earth on the night of October 29. Hubble astronomers were also excited to have captured a regional dust storm on Mars that has been growing and evolving over the past few weeks.




Credit: NASA, ESA, J. Hester and A. Loll (Arizona State University)
Full press release

This is a mosaic image, one of the largest ever taken by NASA's Hubble Space Telescope of the Crab Nebula, a six-light-year-wide expanding remnant of a star's supernova explosion. Japanese and Chinese astronomers recorded this violent event nearly 1,000 years ago in 1054, as did, almost certainly, Native Americans.

The orange filaments are the tattered remains of the star and consist mostly of hydrogen. The rapidly spinning neutron star embedded in the center of the nebula is the dynamo powering the nebula's eerie interior bluish glow. The blue light comes from electrons whirling at nearly the speed of light around magnetic field lines from the neutron star. The neutron star, like a lighthouse, ejects twin beams of radiation that appear to pulse 30 times a second due to the neutron star's rotation. A neutron star is the crushed ultra-dense core of the exploded star.

Visit the Hubble Heritage Gallery and HubbleSite for a great deal more.

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22 December 2005

Presto! New Rings & Moons

Photo Credit: NASA, ESA, and M. Showalter (SETI Institute)

Hot off the presses:

To the surprise of astronomers, NASA's Hubble Space Telescope has photographed a pair of new rings around the distant planet Uranus. The largest is twice the diameter of the planet's previously known rings. The new rings are so far away that they are being called Uranus's "second ring system."

In addition, Hubble has spied two small satellites, one sharing its orbit with one of the newly discovered rings. Even more surprisingly, precise analysis of the data reveals that the orbits of Uranus's family of inner moons have changed significantly in the last decade. Collectively, these new discoveries mean that Uranus has a densely packed, rapidly changing, and possibly unstable dynamical system of orbiting bodies. "The new discoveries dramatically demonstrate that Uranus has a youthful and dynamic system of rings and moons," says Mark Showalter of the SETI Institute. "Until now nobody had a clue the rings were there, we had no right to expect them."


Read the full press release from Hubble here.

Sweet!

Drop by the BA Blog to catch Phil Plait's take on the news.

*Addendum (12/23): There was a minor error in the above entry, which Phil corrected in this subsequent addition.

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21 December 2005

Stardust Nears Home

Image credit: NASA

We are stardust, we are golden
And we got to get ourselves back to the garden
-- Crosby, Stills & Nash


After a rendezvous with comet Wild 2 (pronounced "Vilt") in January of 2004, Stardust's cometary sample return is presently speeding back home to the garden for a highly anticipated arrival January 15th. I find this mission particularly exciting, as it offers our first opportunity to perform an Earthbound examination of materials from one of the cosmos' many time capsules. The propect of capturing invaluable cometary particles and interstellar dust may sound relatively simple. It isn't. Enter: Aerogel.

The primary objective of the Stardust mission is to capture both cometary samples and interstellar dust. Main challenges to accomplishing this successfully involve slowing down the particles from their high velocity with minimal heating or other effects that would cause their physical alteration. When the Stardust Spacecraft encounters the Comet Wild 2, the impact velocity of the particles will be up to 6 times the speed of a rifle bullet. Although the captured particles will each be smaller than a grain of sand, high-speed capture could alter their shape and chemical composition - or even vaporize them entirely.

To collect particles without damaging them, Stardust uses an extraordinary substance called aerogel. This is a silicon-based solid with a porous, sponge-like structure in which 99.8 percent of the volume is empty space. By comparison, aerogel is 1,000 times less dense than glass, which is another silicon-based solid. When a particle hits the aerogel, it buries itself in the material, creating a carrot-shaped track up to 200 times its own length. This slows it down and brings the sample to a relatively gradual stop. Since aerogel is mostly transparent - with a distinctive smoky blue cast - scientists will use these tracks to find the tiny particles.


The scientific payoff yielded by this endeavor promises to be magnificent, as noted by Stardust's Principal Investigator, Dr. Donald Brownlee:

It is widely believed that comets are the best bodies for preserving the very materials that the solar system was built from. Like a fantastic library, they have stored preserved materials and records of our formation. The gaseous emissions can be analyzed from a distance either by telescopes on or orbiting Earth or by instruments on spacecraft sent to comets. The dust and rocks are another matter. They are believed to be samples of the solid building blocks of the solar system, samples of the solids that began the process of collision and sticking in the early history of the solar system that began with dust and produced ever larger bodies, and ultimately whole solid planets like Earth, Mars and Pluto. Some information can be obtained by telescopic study of the dust but the real secrets of the material cannot be examined remotely. On scales from kilometers to microns (a hair is about 100 microns in diameter) primitive materials just look like black charcoal. They are black due to their high content of carbon and other light absorbing materials and most of their components are so small that they cannot be individually seen by the naked eye. Like books in a library, they have to be opened and read but in this case the words are small, very small. So small they can only be read by large microscopes and other instruments that are too heavy, complex and power hungry to be put onto robotic spacecraft.




Stardust's current view of home.

In September 8th of 2004, a similar sample return mission designed to directly measure the solar wind, Genesis, unfortunately experienced a nasty 193 m.p.h. (311 k.p.h.) introduction to the Utah soil. An oboard design flaw resulted in the capsule's parachutes failure to deploy. Thankfully, however, it appears the Genesis team will be able to complete some if not all of their science objectives.

The Genesis mishap prompted a thorough review of Stardust's design. Project manager Thomas Duxbury remains confident that Stardust's sample return capsule will fare much better than its predecessor.

NASA issued this press release today:

NASA Prepares for Return of Interstellar Cargo

NASA's Stardust mission is nearing Earth after a 2.88 billion mile round-trip journey to return cometary and interstellar dust particles back to Earth. Scientists believe the cargo will help provide answers to fundamental questions about comets and the origins of the solar system.

The velocity of the sample return capsule, as it enters the Earth's atmosphere at 28,860 mph, will be the fastest of any human-made object on record. It surpasses the record set in May 1969 during the return of the Apollo 10 command module. The capsule is scheduled to return on Jan. 15.

"Comets are some of the most informative occupants of the solar system. The more we can learn from science exploration missions like Stardust, the more we can prepare for human exploration to the moon, Mars and beyond," said Mary Cleave, associate administrator for NASA's Science Mission Directorate.

Several events must occur before scientists can retrieve cosmic samples from the capsule landing at the U.S. Air Force Utah Test and Training Range, southwest of Salt Lake City. Mission navigators will command the spacecraft to perform targeting maneuvers on Jan. 5 and 13. On Jan. 15 at 12:57 a.m. EST, Stardust will release its sample return capsule. Four hours later, the capsule will enter Earth's atmosphere 410,000 feet over the Pacific Ocean.

The capsule will release a drogue parachute at approximately 105,000 feet. Once the capsule has descended to about 10,000 feet, the main parachute will deploy. The capsule is scheduled to land on the range at 5:12 a.m. EST.

After the capsule lands, if conditions allow, a helicopter crew will fly it to the U.S. Army Dugway Proving Ground, Utah, for initial processing. If weather does not allow helicopters to fly, special off-road vehicles will retrieve the capsule and return it to Dugway. Samples will be moved to a special laboratory at NASA's Johnson Space Center, Houston, where they will be preserved and studied.

"Locked within the cometary particles is unique chemical and physical information that could be the record of the formation of the planets and the materials from which they were made," said Don Brownlee, Stardust principal investigator at the University of Washington, Seattle.

NASA expects most of the collected particles to be no more than a third of a millimeter across. Scientists will slice these particle samples into even smaller pieces for study.


Best wishes for a smooth return and soft landing!



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