COMING EVENTS Public Observing

Prairie Park Nature Center Sunday, OCT. 27, 8:00 PM Sunday, DEC. 01, 8:00 PM

Monthly Meetings

FRIDAY, OCT. 18, 7:00 PM 3139 Wescoe

Cub Scout Belt Loop Program

FRIDAY, NOV. 15, 7:30 PM 2001 Malott

Learn to Use a Telescope

FRIDAY, DEC. 06, 7:30 PM 2001 Malott

President

Rick Heschmeyer rcjbm@sbcglobal.net

Webmaster Howard Edin

howard@howardedin.com Observing Clubs

Doug Fay dfay@ku.edu

ALCOR William Winkler

billwink10@yahoo.com

University Advisor Dr. Bruce Twarog btwarog@ku.edu

Report from the Officers Our first meeting of the new semester started off with an entranced crowd learning about the role that the tides have played in a few key military campaigns in history from Caesar and the battle of Britain to the Second World War. While astronomical phenomena are often noted for their regularity, the tides pro-vide an excellent example of how predictable processes on the large scale are modified by local details. A second relevant example is supplied the weather. The skies may be won-derful to look at with the same pattern of ob-jects appearing on your meridian every 23 hours and 56 minutes, but how well you see them depends on local weather conditions,

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Volume 39 Number 10 October 2013

INSIDE THIS ISSUE

Asteroid Retrieval 2

Coma Colossus 3

NASA Space Place 4

OCT. MEETING POSTER 5

Missing Link Pulsar 6

Hide in Plain Sight 7

Exoplanet Clouds 8

Star Clusters Galore 9

Star Clusters (continued) 10

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Of Local Interest Asteroid Retrieval

During the last week in Sept., KU was visited by Dr. Dave Tholen, a 1978 grad in Physics and Astronomy, who went on to get a PhD at Arizona and now works out of the Institute for Astronomy at the University of Hawaii. Dave’s first love and primary research interest is, surprise, surprise, Pluto, but he also is heavily in-vested in the study of other solar system objects like asteroids. Dave was visiting the area for a high school reunion en route to a meeting of the Division of Plane-tary Science in Denver next week. As part of the DPS

meeting, there is also a Pro-Am workshop on Oct. 10 at the Sheraton Denver Down-town Hotel. The professional-amateur workshop is where professionals present what opportunities are out there for collaborations with NASA missions and amateurs show samples of their observations. A few examples include: observing Pluto during the New Horizons flyby, observing Jupiter's clouds while Juno flies over the poles, taking images of comet ISON to find time-variability, light-curves of asteroids, follow-up on NEOs, searches for Moon impacts (perhaps related to LADEE), Mars observations during the Mars mission - MAVEN, etc.

Dave’s presentation locally was on the ARM project at NASA - ARM stands for Aster-oid Retrieval Mission, also known as the Asteroid Initiative. Still in the early stages of planning and development, ARM is a mission to bring a small Near-Earth-Object (NEO) into lunar orbit, where it could be further analyzed both by unmanned craft and by a future manned mission. NASA hopes to complete the mission, which may take anywhere from six to ten years, in time to accomplish its stated goal of landing hu-mans on an asteroid by 2025.

The ARM, excluding any manned missions to an asteroid which it may enable, is predicted by a Keck Institute for Space Studies study to cost about $2.6 billion, of

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About the Astronomy Associates of Lawrence

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The club is open to all people interested in sharing their love for astronomy. Monthly meetings are typically on the second Friday of each month and often feature guest speakers, presentations by club members, and a chance to exchange amateur astronomy tips. Approximately the last Sunday of each month we have an open house at the Prairie Park Nature Center. Periodic star parties

are scheduled as well. For more information, please contact the club officers: president, Rick Heschmeyer at rcjbm@sbcglobal.net; webmaster, Howard Edin, at howard@howardedin.com; AlCor William Winkler, at

billwink10@yahoo.com; or faculty advisor, Prof. Bruce Twarog at btwarog@ku.edu. Because of the flexibility of the schedule due to holidays and alternate events, it is always best to check the Web site for the exact Fridays and Sundays when events are

scheduled. The information about AAL can be found at http://groups.ku.edu/~astronomy

Copies of the Celestial Mechanic can also be found on the web at http://groups.ku.edu/~astronomy/celestialmechanic

coupled to the quality of the viewing site. As further clarification, the same sky seen from a mountain in Ari-zona looks very different compared to the view from Lawrence. Even in Lawrence, the sky looks dramatically different from one night to the next. Speaking of viewing from Lawrence, those who attended the last public observing session had sky conditions that may have been the best we’ve seen at a public viewing session in years, coupled with dark skies. With five scopes set up, there was plenty of time for checking the view and friendly discussion among the participants. Our next session is Sunday, October 27, the last weekend before the end of Daylight Savings Time. Our next meeting is actually our annual major public service event, the Cub Scout Astronomy program run out of Wescoe 3139. Note, the presentation by Rick starts at 7:00, not 7:30, and should be completed by 8 PM. If you want to bring a scope to set up for observing outside Wescoe, please arrive in time to be ready to go by 8PM. As always, the observing will be defined by the weather. If it’s overcast and/or raining, the observing will be cancelled. For November, the regular meeting will also be somewhat non-traditional. A number of club members new to amateur astron-omy have requested help in learning how to use a telescope. To those unfamiliar with the sky and /or the equipment, setting up a small telescope and learning where to point it is a huge barrier to involvement in the hobby, compounded by the cost of the equipment for even a small system. A bad first experience can turn off a potential amateur forever. So, the plan is to spend the meeting providing some of the basics on how the sky operates and then show, using a variety of designs, how to point and use a telescope. So, if you’ve been intimidated by the prospect of using that telescope sitting in your garage for the last two years or are thinking about getting one for the new year, now’s the time to attend (and bring a friend who might be interested). Any suggestions for improving the club or the newsletter are always welcome.

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which $105 million has been proposed for 2014. NASA Adminis-trator Charles Bolden has stated that: "This mission represents an unprecedented technological feat that will lead to new scientific discoveries and technological capabilities and help protect our home planet." The spacecraft for the ARM would be built with a large, 15-metre (50 ft) capture bag, containing a small asteroid with a diameter of about 8.2 metres (27 ft). The spacecraft would be equipped with Hall-effect Ion thrusters for propulsion, which fire at low acceleration but can fire for many years to move the space-craft at high speed. These engines would be powered by ring-shaped solar panels.

The technological challenges aside, an obvious problem is where do you find the candidate asteroid. Note the size limit imposed by the capture bag. For cost purposes you want it close to an Earth orbit, well away from the asteroid belt. Finally, you want the object to be either spinning slowly or not at all. After discussing the se-vere restrictions imposed by the mission and the difficulty of ob-serving, tracking, and determining the size and spin rate of an asteroid less than 10 meters across, Dave and his collaborators

have identified asteroid 2009 BD as, for now, an ideal choice. For more on this intriguing object while the NASA sites are off-line, check out http://www.universetoday.com/24131/strange-asteroid-2009-bd-stalks-the-earth/.

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Coma Cluster: Clues to the Growth of the Colossus in Coma

A team of astronomers has discovered enormous arms of hot gas in the Coma cluster of galaxies by using NASA's Chandra X-ray Observatory and ESA's XMM-Newton. These features, which span at least half a million light years, pro-vide insight into how the Coma cluster has grown through mergers of smaller groups and clusters of galaxies to become one of the largest structures in the Universe held together by gravity.

A new composite image, with Chandra data in pink and optical data from the Sloan Digital Sky Survey appearing in white and blue, features these spectacular arms. In this image, the Chandra data have been processed so extra detail can be seen.

The X-ray emission is from multimillion-degree gas and the optical data shows gal-axies in the Coma Cluster, which contain only about 1/6 the mass in hot gas. Only the brightest X-ray emission is shown here, to emphasize the arms, but the hot gas is present over the entire field of view.

Researchers think that these arms were most likely formed when smaller galaxy clusters had their gas stripped away by the head wind created by the motion of the cluster through the hot gas, in much the same way that the headwind created by a roller coaster blows the hats off riders.

Coma is an unusual galaxy cluster because it contains not one, but two giant ellip-tical galaxies near its cen-ter. These two giant ellipti-cal galaxies are probably the vestiges from each of the two largest clusters that merged with Coma in the past. The researchers also uncovered other signs of past collisions and mergers in the data.

From their length, and the speed of sound in the hot gas (~4 million km/hr), the newly discovered X-ray arms are esti-mated to be about 300 million years old, and they appear to have a rather smooth shape. This gives researchers some clues about the conditions of the hot gas in Coma. Most theoretical models expect that mergers between clusters like those in Coma will produce strong turbulence, like ocean water that has been churned by many passing ships. Instead, the smooth shape of these lengthy arms points to a rather calm setting for the hot gas in the Coma cluster, even after many mergers.

Large-scale magnetic fields are likely responsible for the small amount of turbulence that is present in Coma. Estimating the amount of turbulence in a galaxy cluster has been a challenging problem for astrophysicists. Researchers have found a range of answers, some of them conflicting, and so observations of other clusters are needed.

Two of the arms appear to be connected to a group of galaxies located about two million light years from the center of Coma. One or both of these arms connects to a larger structure seen in the XMM-Newton data, and spans a distance or at least 1.5 million light years. A very thin tail also appears behind one of the galaxies in Coma. This is probably evi-dence of gas being stripped from a single galaxy, in addition to the groups or clusters that have merged there.

4

How to hunt for your very own supernova!

By Dr. Ethan Siegel

In our day-to-day lives, stars seem like the most fixed and unchanging of all the night

sky objects. Shining relentlessly and constantly for billions of years, it's only the long-term motion of these individual nu-clear furnaces and our own motion through the cosmos that results in the most minute, barely-perceptible changes.

Unless, that is, you're talking about a star reaching the end of its life. A star like our Sun will burn through all the hydrogen in its core after approximately 10 billion years, after which the core contracts and heats up, and the heavier element helium begins to fuse. About a quarter of all stars are mas-sive enough that they'll reach this giant stage, but the most massive ones -- only about 0.1% of all stars -- will continue to fuse leaner elements past carbon, oxygen, neon, magnesium, silicon, sulphur and all the way up to iron, cobalt, and, nickel in their core. For the rare ultra-massive stars that make it this far, their cores become so massive that they're unstable against gravi-tational collapse. When they run out of fuel, the core implodes.

The inrushing matter approaches the center of the star, then rebounds and bounces outwards, creating a shockwave that even-tually causes what we see as a core-collapse supernova, the most common type of supernova in the Universe! These occur only a few times a century in most galaxies, but because it's the most massive, hottest, shortest-lived stars that create these core-collapse supernovae, we can increase our odds of finding one by watching the most actively star-forming galaxies very closely. Want to maximize your chances of finding one for yourself? Here's how.

Pick a galaxy in the process of a major merger, and get to know it. Learn where the foreground stars are, where the appar-ent bright spots are, what its distinctive features are. If a supernova occurs, it will appear first as a barely perceptible bright spot that wasn't there before, and it will

quickly brighten over a few nights. If you find what appears to be a "new star" in one of these galaxies and it checks out, report it immediately; you just might have discovered a new supernova!

This is one of the few cutting-edge astronomical discoveries well-suited to amateurs; Australian Robert Evans holds the all-time record with 42 (and counting) original supernova discoveries. If you ever find one for yourself, you'll have seen an exploding star whose light traveled millions of light-years across the Universe right to you, and you'll be the very first per-son who's ever seen it! Read more about the evolution and ultimate fate of the stars in our universe: http://science.nasa.gov/astrophysics/focus-areas/how-do-stars-form-and-evolve/. While you are out looking for supernovas, kids can have a blast finding constella-tions using the Space Place star finder: http://spaceplace.nasa.gov/starfinder/

SN 2013ai, via its discoverer, Emmanuel Conseil, taken with the Slooh.com robotic telescope just a few days after its emergence in NGC 2207 (top); NASA, ESA and the Hubble Heritage Team (STScI) of the same interacting galaxies prior to the supernova (bottom).

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6

Astronomers find missing link pulsar

An international team of astronomers using CSIRO radio telescopes and other ground and space-based instruments has caught a small star called a pulsar undergoing a radical transformation, described today in the journal Nature.

"For the first time we see both X-rays and extremely fast radio pulses from the one pulsar. This is the first direct evi-dence of a pulsar changing from one kind of object into another - like a caterpillar turning into a butterfly," said Dr Simon Johnston, Head of Astrophysics at CSIRO's Astronomy and Space Science division.

The cosmic drama is being played out 18,000 light-years away, in a small cluster of stars (M28) in the constellation of Sagittarius. The pulsar (called PSR J1824-2452I) has a tiny companion star, with about a fifth the mass of the Sun. Al-though small, the companion is fierce, pounding the pulsar with streams of matter. Normally the pulsar shields itself from this onslaught, its magnetic field deflecting the matter stream into space. But sometimes the stream swells to a flood, overwhelming the pulsar's protective 'force field'. When the stream hits the pulsar's surface its energy is released

as blasts of X-rays. Eventually the torrent slackens. Once again the pulsar's magnetic field re-asserts itself and fends off the companion's attacks.

"We've been fortunate enough to see all stages of this process, with a range of ground and space telescopes. We've been looking for such evidence for more than a decade," said Dr Alessandro Papitto, the Nature paper's lead author. Dr Papitto is an astronomer of the Institute of Space Studies (ICE, CSIC-IEEC) of Barcelona.

The pulsar and its companion form what is called a 'low-mass X-ray binary' system. In such a system, the matter trans-ferred from the companion lights up the pulsar in X-rays and makes it spin faster and faster, until it becomes a 'millisecond pulsar' that spins at hundreds of times a second and emits radio waves. The process takes about a billion years, astronomers think. In its current state the pulsar is exhibiting behaviour typical of both kinds of systems: millisec-ond X-ray pulses when the companion is flooding the pulsar with matter, and radio pulses when it is not.

"It's like a teenager who switches between acting like a child and acting like an adult," said Mr John Sarkissian, who observed the system with CSIRO's Parkes radio telescope. "Interestingly, the pulsar swings back and forth between its two states in just a matter of weeks."

The pulsar was initially detected as an X-ray source with the European Space Agency's INTEGRAL satellite. X-ray pul-sations were seen with another satellite, ESA's XMM-Newton; further observations were made with NASA's Swift. NASA's Chandra X-ray telescope got a precise position for the object. Then, crucially, the object was checked against the pulsar catalogue generated by CSIRO's Australia Telescope National Facility, and other pulsar observations. This established that it had already been identified as a radio pulsar. The source was detected in the radio with CSIRO's Australia Telescope Compact Array, and then re-observed with CSIRO's Parkes radio telescope, NRAO's Robert C. Byrd Green Bank Telescope in the USA, and the Westerbork Synthesis Radio Telescope in The Netherlands. Pulses were detected in a number of these later observations, showing that the pulsar had 'revived' as a normal radio pulsar only a couple of weeks after the last detection of the X-rays.

7

Comet Found Hiding in Plain Sight

For 30 years, a large near-Earth asteroid wandered its lone, intrepid path, passing before the scrutinizing eyes of scien-tists armed with telescopes while keeping something to itself. The object, known as Don Quixote, whose journey stretches to the orbit of Jupiter, now appears to be a comet.

The discovery resulted from an ongoing project coordinated by researchers at Northern Arizona University, Flagstaff, Ariz., using NASA's Spitzer Space Telescope. Through a lot of focused attention and a little luck, they found evidence of comet activity, which had evaded detection for three decades.

The results show that Don Quixote is not, in fact, a dead comet, as previously believed, but it has a faint coma and tail. In fact, this object, the third-biggest near-Earth asteroid known, skirts Earth with an erratic, extended orbit and is "sopping

wet," said David Trilling of Northern Arizona University, with large deposits of carbon dioxide and presumably water ice. Don Quixote is about 11 miles (18 kilometers) long.

"This discovery of carbon dioxide emission from Don Quixote required the sensitivity and infrared wavelengths of the Spitzer telescope and would not have been possible using telescopes on the ground," said Michael Mommert, who con-ducted the research at the German Aerospace Center, Berlin, before moving to Northern Arizona University. This discov-ery implies that carbon dioxide and water ice might be present on other near-Earth asteroids, as well.

The implications have less to do with a potential impact, which is extremely unlikely in this case, and more with "the ori-gins of water on Earth," Trilling said. Impacts with comets like Don Quixote over geological time may be the source of at least some of it, and the amount on Don Quixote represents about 100 billion tons of water -- roughly the same amount that can be found in Lake Tahoe, Calif.

With the help of NASA's Spitzer Space Telescope, astronomers have discovered that what was thought to be a large as-teroid called Don Quixote is in fact a comet. The left image shows Don Quixote's coma and tail -- features of comets -- as revealed in infrared light by Spitzer. The coma appears as a faint glow around the center of the body, caused by dust and gas. The tail, which appears more clearly in the right image, points towards the right-hand side of Don Quixote, into the direction opposite of the sun. The right image represents a more elaborate image processing step, in which the glow of the coma has been removed based on a model comet coma. Bright speckles around Don Quixote are background stars; the horizontal bar covers image artifacts caused by the image processing.

8

NASA Space Telescopes Find Patchy Clouds on Exotic World

Astronomers using data from NASA's Kepler and Spitzer space telescopes have created the first cloud map of a planet beyond our solar system, a sizzling, Jupiter-like world known as Kepler-7b. The planet is marked by high clouds in the west and clear skies in the east. Previous studies from Spitzer have resulted in temperature maps of planets orbiting other stars, but this is the first look at cloud structures on a distant world.

"By observing this planet with Spitzer and Kepler for more than three years, we were able to pro-duce a very low-resolution 'map' of this giant, gaseous planet," said Brice-Olivier Demory of Massachu-setts Institute of Technology in Cam-bridge. Demory is lead author of a paper accepted for publication in the Astrophysical Journal Letters. "We wouldn't expect to see oceans or continents on this type of world, but we detected a clear, reflective signa-ture that we interpreted as clouds."

Kepler has discovered more than 150 exoplanets, which are planets outside our solar system, and Ke-pler-7b was one of the first. The telescope's problematic reaction wheels prevent it from hunting plan-ets any more, but astronomers con-tinue to pore over almost four years' worth of collected data. Kepler's visible-light observations of Kepler-7b's moon-like phases led to a

rough map of the planet that showed a bright spot on its western hemisphere. But these data were not enough on their own to decipher whether the bright spot was coming from clouds or heat. The Spitzer Space Telescope played a crucial role in answering this question. Like Kepler, Spitzer can fix its gaze at a star system as a planet orbits around the star, gathering clues about the planet's atmosphere. Spitzer's ability to detect infrared light means it was able to measure Kepler-7b's temperature, estimating it to be between 1,500 and 1,800 degrees Fahrenheit (1,100 and 1,300 Kelvin). This is relatively cool for a planet that orbits so close to its star -- within 0.06 astronomical units (one astro-nomical unit is the distance from Earth and the sun) -- and, according to astronomers, too cool to be the source of light Kepler observed. Instead, they determined, light from the planet's star is bouncing off cloud tops located on the west side of the planet.

"Kepler-7b reflects much more light than most giant planets we've found, which we attribute to clouds in the upper atmosphere," said Thomas Barclay, Kepler scientist at NASA's Ames Research Center in Moffett Field, Calif. "Unlike those on Earth, the cloud patterns on this planet do not seem to change much over time -- it has a remarkably stable climate." The findings are an early step toward using similar techniques to study the atmospheres of planets more like Earth in composition and size.

"With Spitzer and Kepler together, we have a multi-wavelength tool for getting a good look at planets that are trillions of miles away," said Paul Hertz, director of NASA's Astrophysics Division in Washington. "We're at a point now in exoplanet science where we are moving beyond just detecting exoplanets, and into the exciting science of under-standing them."

Kepler identified planets by watching for dips in starlight that occur as the planets transit, or pass in front of their stars, blocking the light. This technique and other observations of Kepler-7b previously revealed that it is one of the puffiest planets known: if it could somehow be placed in a tub of water, it would float. The planet was also found to whip around its star in just less than five days. Explore all 900-plus exoplanet discoveries with NASA's "Eyes on Exoplan-ets," a fully rendered 3D visualization tool, available for download at http://eyes.nasa.gov/exoplanets. The program is updated daily with the latest findings from NASA's Kepler mission and ground-based observatories around the world as they search for planets like our own.

Kepler-7b (left), which is 1.5 times the radius of Jupiter (right), is the first exoplanet to have its clouds mapped. The cloud map was produced using data from NASA's Kepler and Spitzer space telescopes. The map shows that clouds cover the western side of the gaseous planet, leaving the east cloud-free. Re-searchers speculate the clouds are made up of minerals containing silicates. Kepler-7b is one of the puffiest, or least dense, planets known. While it is 1.5 times the size of Jupiter is has only about half the mass.

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Hubble Uncovers Largest Known Population of Star Clusters

NASA's Hubble Space Telescope has uncovered the largest known population of globular star clusters, an estimated 160,000, swarming like bees inside the crowded core of the giant grouping of galaxies Abell 1689. By comparison, our Milky Way galaxy hosts about 150 such clusters.

Studying globular clusters is critical to understanding the early, intense star-forming episodes that marked galaxy for-mation. The Hubble observations also confirm that these compact stellar groupings can be used as reliable tracers of the amount of dark matter locked away in immense galaxy clusters.

Globular clusters, dense bunches of hundreds of thousands of stars, are the homesteaders of galaxies, containing some of the oldest surviving stars in the universe. Almost 95 percent of globular cluster formation occurred within the first 1 billion or 2 billion years after our universe was born in the big bang 13.8 billion years ago.

A team of astronomers, led by John Blakeslee of the NRC Herzberg Astrophysics Program at the Dominion Astro-physical Observatory in Victoria, B.C., used Hubble's sensitivity and sharpness to discover a bounty of these stellar fossils, which is roughly twice as large as any other population found in previous globular cluster surveys. The Hubble

observations also win the distance record for the far-thest such systems ever studied, at 2.25 billion light-years away.

The research team found that the globular clusters are intimately inter-twined with dark matter. "In our study of Abell 1689, we show how the relationship be-tween globular clus-ters and dark mat-ter depends on the distance from the galaxy cluster's center," explained team member Karla Alamo-Martinez of the Center for Ra-dio Astronomy and Astrophysics of the National Autono-mous University of Mexico in Morelia. "In other words, if you know how many globular clus-ters are within a certain distance, we can give you an estimate of the amount of dark matter."

Although dark mat-ter is invisible, it is considered the un-

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AAL Astronomy Associates of Lawrence

University of Kansas Malott Hall 1251 Wescoe Hall Dr, Room 1082 Lawrence, KS 66045-7582

Celestial Mechanic October 2013

derlying gravitational scaffolding upon which stars and galaxies are built. Understanding dark matter can yield clues on how large structures such as galaxies and galaxy clusters were assembled billions of years ago.

The Hubble study shows that most of the globular clusters in Abell 1689 formed near the center of the galaxy clus-ter, which contains a deep well of dark matter. Their number decreases the farther away Hubble looked from the core, corresponding with a comparable drop in the amount of dark matter.

"The globular clusters are fossils of the earliest star formation in Abell 1689, and our work shows they were very efficient in forming in the denser regions of dark matter near the center of the galaxy cluster," Blakeslee said. "Our findings are consistent with studies of globular clusters in other galaxy clusters, but extend our knowledge to re-gions of higher dark matter density."

The astronomers used Hubble's Advanced Camera for Surveys to peer deep inside the heart of Abell 1689, detect-ing the visible-light glow of 10,000 globular clusters, some as dim as 29th magnitude. Based on that number, Blakeslee's team estimated that more than 160,000 globular clusters are huddled within a diameter of 2.4 million light-years. "Even though we are looking deep into the cluster, we're only seeing the brightest globular clusters, and only near the center of Abell 1689 where Hubble was pointed," he said.

The brightness of most of the globular clusters is estimated to be 31st magnitude. This is out of reach for Hubble, but not for NASA's James Webb Space Telescope, an infrared observatory scheduled to launch later this decade. By going fainter, Webb should be able to see many more of the globular clusters.

Blakeslee's quest to use Hubble to conduct a globular cluster census in Abell 1689 began 10 years ago after astro-nauts added the Advanced Camera for Surveys to Hubble's arsenal of science instruments. While analyzing some gravitational lensing data of Abell 1689 obtained with the newly installed camera, Blakeslee spotted dots of light peppered throughout the images. The dots turned out to be the brightest members of a teeming population of globular clusters.

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