Salsa newsletter 07 2010

J u l y 2 0 1 0 V o l u m e 1 I s s u e # 3

O f f i c i a l N e w s l e t t e r o f s a n a n t o n i o l e a g u e o f s i d e w a l k a s t r o n o m e r s1

Looking for Ideas for the Next MeetupApril was a great success for the first ever SALSA meetup. Now its time again to have one but to better address the needs of members all around the city, it would be best if we moved it around to make it as accessible as possible. That’s fine and dandy but it takes input from all of you! If you have a favorite place to eat or know of a good watering hole to talk about astronomy, please post it to the SALSA Yahoogroup or e-mail me your s u g g e s t i o n s t o [email protected]. and

let’s take a look at it!

THE DARK SIDEN e w s l e t t e r

THIS MONTH’S NOTES:Skipping a beat...I’m sure that most of you were wondering where the June issue of “The Dark

Side” was. Well frankly, June was a very demanding month in traveling and I

didn’t want to put out a newsletter if it wasn’t of good enough quality. So here

we are two months later and back on track! We have been a bit snake bit when it

has come to the weather and observing. July’s Garner State Park outing has been

canceled for the second time due to rain and poor observing. It’s going to be

pretty darn hot come August, so we are by-passing that month and resuming our

sessions out there on September 11th. Please take a look at the calendar on page

3. You will see the usual events we take part in but you’ll see an event for

diabetic children on July 29th in the afternoon where we could use your help.

This is a summer camp for this sick children that will take place for one week

with a space theme. If you can make it out to help that afternoon, please contact

Scott Timmons or myself.

Also later this month in conjunction with a normal Wednesday night observing

at McAllister Park, we will be be hosting a stargazing event with our partnered

organization “The Friends of McAllister Park” on July 21st. Don’t be

surprised if members of the San Antonio City Council will be in attendance

too as I have been speaking to a few of them about that event and have

expressed interest in attending. Last but not least we will be focusing for

more on developing our observing skills leading up to the Perseids meteor

shower observing weekend in August. Challenges will be posted by

SALSA members, and remember, if you need help, JUST ASK! Clear

Skies and Keep Looking Up! - Bryan T.

WWW.SALSA-ASTRO.COM

The Astronomy Club Everyone Is Talking About

mailto:[email protected]


http://WWW.SALSA-ASTRO.COM

http://WWW.SALSA-ASTRO.COM



THE DARK SIDE

Courtesy George Cooper

Texas Amateur Astronomer Scholarship Needs You!by Hunter ScottHave you ever had to explain something that is so obvious to you that you can't find the words to explain it? Well, that's what has happened to me with the Texas Amateur Astronomer's Scholarship. Don't get me wrong, when Bryan asked me to put down on paper why someone would want to support the scholarship, he did so with the intention of giving me some exposure in The Dark Side, which I appreciate very much. Where do I begin.........?As some of you know, I signed a one-page document in February that started the ball rolling on a quest to raise and donate $25,000 to the University of Texas over the next five years. Sounds like a daunting task, doesn't it? My original idea involved getting the SAAA membership to be obligated for this task, but it quickly got mired in a bunch of turmoil, so, based on some conversations I was having with Mr. Joel Barna of the University of Texas, I simply pulled the offer off the table in order to relieve the stress the subject was creating within SAAA. Ironically, the Executive Committee of SAAA finally came around to a decision to support the scholarship, but by then, I had already made up my mind to do this without SAAA's help. The scholarship very nearly went by the name "SAAA Scholarship." But, during my conversations with Joel, I realized the The University of Texas (UT), and more specifically, the Astronomy Department at UT, was willing to put every resource they have at my disposal in order to support my fundraising effort. I began to see so many possibilities and opportunities for raising funds that I became convinced that I didn't need any one amateur astronomy club to do this. Thus, the name Texas Amateur Astronomer's Scholarship. The name implies that the scholarship belongs to all Texas Amateur Astronomy clubs, and indeed, that is the intention of it, as explained below.During the extended debate that was going on within SAAA's EC, I was already thinking about plan B. I was already aware of a huge project that is under development at McDonald Observatory called HETDEX. Joel presented a program on the project when he addressed the membership during a regular monthly meeting, the one where Keith Little was supposed to sign the document on behalf of SAAA that would have established the scholarship. HETDEX got me fired up, and still has me fired up today, and here's why. HETDEX stands for Hobby-Eberly Telescope Dark Energy Experiment. The essence of the name tells you that the project is going to use the Hobby-Eberly Telescope at McDonald Observatory to try to "discover" dark energy. Dark energy and dark matter are the Holy Grail in professional astronomy these days. Every major university in the world has a proposal on the table to discover dark energy. Actually, to say that astronomers are trying to "discover" dark energy is somewhat of a misnomer. There is already plenty of evidence that dark energy exists. What astronomers are really trying to do is to characterize or to learn the nature and source of dark energy. On a little side trip here, Einstein's famous formula, E=mc squared, simply tells us that energy can be turned into matter, and that matter can be turned into energy. Compared to dark energy, the discovery of dark matter should be a piece of cake. The Large Hadron Collider was built specifically to find a particle suspected of being responsible for dark matter. Scientists suspect that dark matter is made of a particle not too different from protons, electrons, neutrons, or neutrinos, and the Hadron Collider is poised to make that historic discovery, probably within the next year or so. But dark energy is a very different breed of cat. It is more like gravity, the strong nuclear force, the weak nuclear force, or the electromagnetic force. We can't "see" the forces themselves, but we know they're there, because we can see the effects they have on our Universe. By the way, dark energy and dark matter together make up an estimated 95% of the content of the Universe. That's pretty astonishing, don't you think? Furthermore, there is plenty of evidence that dark energy is a repulsive, rather than an attractive force. We know this because the Universe is not only expanding, its expansion is accelerating, and dark energy is one very good explanation for it. Anyway, back to HETDEX.Over the last decade or so, astronomers have focused ever-increasing attention on dark energy. As I said, the astronomy/cosmology community of scientists around the world have made various proposals to discover dark energy, many of them costing more money than there is, and relying on technology not even in existence yet. These proposals have been flying around for years. Enter Karl Gebhardt and Gary Hill.

Karl and Gary are two talented visionary UT astronomers. Between them, they came up with a proposal for discovering dark energy that has become the odds-on favorite to actually do the job. Many of the proposals presented before Karl and Gary came up with their idea require billions of dollars and rely on technologies that haven't even been invented yet. That is the essence of the beauty of HETDEX. It relies on technology that is on the shelf today. This approach allows two things to happen. First, it reduces the cost to millions (about 34 of them, to be exact), and it allows the project to get started now, today. When Karl and Gary published their proposal in professional journals, the rest of the professional astronomy community had one of those Smith-Barney moments. They stopped and listened to the proposal, and then quickly had one of those slap-yourself-on-the-forehead and say,"Why didn't I think of that." moments. HETDEX is actually under development at UT, where as, other proposals are still on the drawing board. Last month I was lucky enough to be allowed to go out to McDonald Observatory where I spent two sleepless nights with Jeremy Murphy, and Guillermo Blanc, both very talented PhD graduate students. They were at the observatory to put a prototype of one of the major components, VIRUS, to a test. They were actually doing some science in the process, and I got to sit in the control room with them as they operated the 107" Harlan Smith Telescope with VIRUS attached. They actually allowed me to use the control paddle to slew the scope to a position where Guillermo crawled into the main tube of the scope in order to remove a filter from VIRUS. Do I have to explain how exhilarating it was for me to be allowed into the inner circle of the workings of McDonald Observatory? I hope not, because I can't do it. Jeremy and Guillermo are very good teachers, and were able to explain the science and technology in a way that I could understand it easily. I hope to share some of those photos with you in a future issue of The Dark Side. The purpose for me being there was to photograph and document what is going on with HETDEX as it happens so I can develop that Powerpoint presentation I mentioned earlier. HETDEX will probably take 3-5 years to complete, and I hope to be there to photograph every step of the way, and report back to SALSA members what is going on. What does this have to do with any of you? Well, for one thing, as members of SALSA you will be able to look over my shoulder as I document these historic events. I will share my experiences with everyone. For those of you who have the time and the cost of a night's stay at the Astronomer's Lodge, I may be able to invite someone along with me occasionally. You can accompany me on these trips of exploration and discovery. I'm not going to pull any punches here. Priority will be given to those of you who make monetary contributions to the scholarship fund, but invitations won't necessarily be limited to donors. To me, that is one BIG reason to make a donation, but there are many others. Of course, your contributions will be tax deductible. Beyond that obvious reason, there is the pleasure you may get out of doing something altruistic. The scholarship will support a deserving undergraduate as he/she pursues a career in astronomy.But to me, here's the most compelling reason to support TAAS. As I've already said, preference in gaining access to McDonald Observatory and HETDEX will be given to those of you who make monetary contributions to the scholarship. How much is it worth to you as an amateur astronomer to be able to be there amongst the people, the technology, under the stars......to be in the very place and time where dark energy may be discovered? To me, it is beyond value, and I have gained access to this incredible spectacle through the scholarship effort. Is it worth anything to you? The discovery of dark energy is on a par with the discovery of the atom, the discovery that the Universe is expanding, or the accomplishments of Galileo. You may contribute to TAAS by sending your donation to: UT Austin AstronomyAttn: TAAS Endowment1 University Station C1402Austin, Texas 78712-0259 Note: I have some SASE donation cards for anybody who wants one. Ask me for one the next time you see me.

SEE PAGE 14 OF THIS NEWSLETTER!



THE DARK SIDE

SALSA Calendar of Events for the next month

Wednesday Night in the Park - July 7th - McAllister Park


Wednesday Night in the Park - July 21st - McAllister Park - Friends of McAllister Park Presentation


Astronomy Presentation for Diabetic Children - St. Mary’s Hall - 3-4 PM - Contact Bryan Tobias

First Friday for Children - Scobee Planetarium - August 6th - WILL NOT HAPPEN DUE TO PLANETARIUM UPGRADES

Perseids Meteor Shower observing weekend - August 14th, Fredericksburg, Texas - More next Month

Garner State Park - September 11th, Weather Permitting

September 18th - International Observe the Moon Night - Location to be determined.

Fort McKavett Stargazing, November 25th - 28th

Garner State Park - October 9th

It doesn’t take much to volunteer at any of these events! If you would like to help, contact Bryan Tobias at [email protected] to learn more about our outings and how you can play a part!

Thruster firing puts New Horizons back on trackBY STEPHEN CLARKSPACEFLIGHT NOWThe New Horizons mission speeding toward a fleeting visit to Pluto fired its thruster system for 35.6 seconds Wednesday, correcting a small error in the probe's trajectory into the outer fringes of the solar system.The thruster burn occurred as planned Wednesday at 3 p.m. EDT and acce lera ted the spacecraft by about one mile per hour, according to an update posted on the mission's website.That doesn't seem like much when you factor in the robot's dazzling speed. New Horizons covers nearly a million miles per day, but with so much time between now and its 2015 flyby of Pluto, just one mile per hour is the difference between a scientific bonanza and a researcher's doomsday.At the time of the burn, New Horizons was 1.49 billion miles away from Earth, near the orbit of Uranus. It takes more than two hours for radio signals to travel from the spacecraft to Earth from such distances.It was the fourth time the piano-sized spacecraft has trimmed its flight path since launching Jan. 19, 2006. The last time New Horizons fired its propulsion system was October 2007.Mission officials say the New Horizons navigation team discovered radiative thermal energy from the spacecraft's nuclear power source drove the probe slightly off course. Photons, or tiny particles of energy, reflecting off the craft's high-speed communications antenna slowly altered its trajectory.Controllers sent orders for the maneuver from Earth to New Horizons last week amid a two-month checkout and testing campaign while the spacecraft is out of hibernation.New Horizons spends most of its cruise from Earth to Pluto in a deep slumber, and engineers only occasionally wake up the spacecraft for annual check-ups, flyby rehearsals and science observations.This year marks several halfway points on the trek to Pluto.On Feb. 25, New Horizons soared past the halfway point in mileage traveled from Earth to Pluto. The spacecraft will mark half the days from launch to flyby on Oct. 17.Managers plan more minor burns over the next few years to keep New Horizons on track for a flyby of Pluto and its three moons in 2015. Engineers have already nailed down the time of closest approach: 7:49 a.m. EDT on Wednesday, July 15, 2015.The closest New Horizons will get to Pluto will be 7,767 miles, according to the latest projections.The $700 million mission is the first to study a new class of bodies -- icy dwarf planets stranded on the frontier of the solar system. New Horizons will take pictures of Pluto and its three moons, analyze Pluto's atmosphere and measure the chemical composition of Pluto and its natural satellites.New Horizons could target an even more distant object after careening past Pluto, extending its mission to 2020 or beyond.

The Moon has a Dark SideIn 1973, British music group Pink Floyd released one of the all-time best-selling albums, The Dark Side of the Moon. Since then, many people have assumed that one-half of the Moon — the side that faces away from Earth, sometimes called the "farside" — permanently remains in darkness. That's not true.

What is true is that, at any given moment, half of the Moon is in darkness. But the dark side is always the side that faces away from the Sun. That's also the case with Earth. Half our planet experiences day while night occurs on the other half. Because the Earth and Moon rotate (spin), some areas are moving into sunlight as different areas move into darkness. Earth rotates once a day, while the Moon takes 27.3 days to spin once.

So, remember, half the of Moon is always dark, but that half is constantly changing.







THE DARK “ATTACK OF THE SPACE PIRATES” The Scobee Planetarium announces a new action adventure space show, one that is sure to appeal to the whole family – “Attack of the Space Pirates.”Hidden somewhere in the vast reaches of space is an alien technology so powerful that it threatens the very galaxy itself. A gang of rogue pirates will stop at nothing to find that technology and unleash its awesome power against the rest of the universe. Now, only one valiant ship stands between the pirates and their total domination of space. It’s a race against time for the Starship Intrepid as it seeks to find the alien technology first while defending itself against the attack of the space pirates!This show is rendered in a stunning photo-realistic style, one that will not only transport you into the stars, but to the very edge of the galaxy itself. Embark on a thrilling adventure that has something for everyone: alien planets, exploding stars, black holes, evil villains and a series of space battles that will keep you on the edge of your seat. If you think our other shows put you into the action, wait until this one grabs you!“Attack of the Space Pirates” is produced by the Clark Planetarium in Salt Lake City, Utah.

This show will soon be on the public show schedule. Please check the Scobee Planetarium’s website for dates and times at:

http://www.alamo.edu/sac/ce/scobee/

Mysterious giant gas ring origin identifiedProvided by CFHT, Kamuela, HawaiiAn international team unveiled the origin of the giant gas ring in the Leo group of galaxies. With the Canada-France-Hawaii Telescope CFHT), the scientists were able to detect an optical signature of the ring corresponding to star-forming regions. This observation rules out the primordial nature of the gas, which is of galactic origin. Thanks to numerical simulations made at the Centre d'Etudes Nucléaires (CEA) in France a scenario for the formation of this ring has been proposed — a violent collision between two galaxies, slightly more than one billion years ago.In the current theories on galaxy formation, the accretion of cold primordial gas is a key process in the early steps of galaxy growth. Two main features of primordial gas are that it has never sojourned in any galaxy and that it does not satisfy the conditions required to form stars. Is such an accretion process still ongoing in nearby galaxies? To answer the question, large sky surveys are undertaken attempting to detect the primordial gas.The Leo ring, a giant ring of cold gas 650,000 light-years wide surrounding the galaxies of the Leo group, is one of the most dramatic and mysterious clouds of intergalactic gas. Since its discovery in the 1980s, its origin and nature were

debated. Last year, studies of the metal abundances in the gas led to the belief that the ring was made of this famous primordial gas.Thanks to the sensitivity of the CFHT MegaCam camera, the international team observed for the first time the optical counterpart of the densest regions of the ring in visible light instead of radio waves. Emitted by massive young stars, this light points to the fact that the ring gas is able to form stars.A ring of gas and stars surrounding a galaxy immediately suggests another kind of ring — a collisional ring — formed when two galaxies collide. Such a ring is seen in the famous Cartwheel Galaxy. Would the Leo ring be a collisional ring, too?In order to secure this hypothesis, the team used numerical simulations (performed on supercomputers at CEA) to demonstrate that the ring was indeed the result of a giant collision between two galaxies more than 38 million light-years apart. At the time of the collision, the disk of gas of one of the galaxies is blown away and will eventually form a ring outside the galaxy. The simulations allowed the identification of the two galaxies that collided — NGC 3384, one of the galaxies at the center of the Leo group, and M96, a massive spiral galaxy at the periphery of the group. They also gave the date of the collision — more than a billion years ago.The gas in the Leo ring is definitely not primordial. The hunt for primordial gas is still open.





THE Twinkle no more, little star: Adaptive optics let Mt. Graham scope reach its potentialBy Tom Beal, The Arizona Daily Star, TucsonThe Large Binocular Telescope on Mount Graham, beset for 20 years by wildfires, lawsuits over endangered squi r re ls and sacred Indian land, technical setbacks and broken mirrors, is beginning to achieve its vaunted potential.The world's best "adaptive op t i cs " sys tem has been i n s t a l l e d o n o n e o f t h e telescope's two massive mirrors, erasing most of the "twinkle" from distant stars and creating images with three times the resolution of the Hubble Space Telescope in tests conducted over the last month.It is a milestone for the LBT, said director Richard Green, and a demonstration that ground-based telescopes can continue to have some advantages over space-based ones."What impresses me is that this is the result they achieved in the lab under controlled conditions, and they have now reproduced it in the atmosphere," said Green.The system is a deformable 36-inch mirror only 0.06 inch thick, with 672 magnets glued to the back that can change its shape every one-thousandth of a second. It was developed by the University of Arizona's Steward Observatory and partners at the Arceti Observatory of the Italian National Institute of Astrophysics, where it was built.During tests, the new secondary mirror routinely erased 60 percent to 80 percent of atmospheric disturbance and went as high as 84 percent distortion-free, according to a measurement known as the Strehl ratio. Adaptive optics systems on other large telescopes deliver 30 percent to 50 percent improvement in the near-infrared wavelengths tested by the LBT team. Without adaptive optics, the ratio is less than 1 percent.The astronomers were surprised. "The results on the first night were so extraordinary that we thought it might be a fluke, but every night since then the adaptive optics have continued to exceed all expectations," Arceti's Simone Esposito said in a news release.The tests were performed at an optimal time, Green said. The spring skies over Arizona are relatively clear of moisture and atmospheric disturbance.The weather should be equally good this fall when Steward Observatory astronomer Phil Hinz installs a planet-finding camera.Hinz hopes to produce images of planets that are known or suspected to be orbiting stars, but have never been directly imaged."We've been waiting for the AO system," Hinz said. "This is a major step. We've always known it's going to work. It was just a matter of when." Hinz said he originally planned to start his search in 2007. "It's like anything you anticipate. It always takes longer than you'd like," he said.

Hinz said he's kept busy using a prototype of the LBT's adaptive optics system that UA astronomers and optical scientists created for the 6.5-meter MMT Telescope on Mount Hopkins, south of Tucson.The LBT's bigger size and greater resolution "will lead us to be able to get higher contrasts and see things much more faint," he said. That's essential, he said, when you are trying to make images of planets a million times fainter than the stars they orbit.Hinz said the LBT will work especially well in the infrared wavelengths.Green said the LBT's advantage in the infrared results from not adding a lens to the system to correct for the atmosphere. "Because the instrument is actually the secondary mirror of the telescope, it doesn't inject any thermal background," he said.At 36 inches in diameter, it is the largest adaptive optics system in operation. Its size and thinness make it extremely fragile as well.The first two produced by Arceti broke, one in fabrication and one in shipment. Three more have been produced, and the one for the second eye of the LBT will be installed next year.When that occurs, the instrument will finally be able to take advantage of its binocular design. Combining the light-gathering properties of both 8.4-meter mirrors will give it the resolution of a 22.8-meter (75-foot) telescope. At that point, astronomers expect it to have 10 times the resolution of the Hubble Space Telescope.Much of the buzz in astronomy in the last two decades has centered on orbiting space telescopes such as Hubble, which can peer to the edges of the universe without the image-distorting effects of Earth's atmosphere.With adaptive optics, ground-based telescopes can capitalize on their huge advantage in size. The Hubble's primary mirror is 2.4 meters. The next generation James Webb Space Telescope will deploy a folding mirror of 6.5 meters -- the largest ever in space.The Large Binocular Telescope is owned by a consortium of universities and institutes that include a German group, Ohio State University and Tucson-based Research Corp., on behalf of Notre Dame and the universities of Minnesota and Virginia.



ASTRONAUTICAL CALENDAR

July 2010

Did You Know....At the end of July, and through the first week of August, look to the West immediately after sunset. You will be able to see a beautiful ballet of the planets forming what is called a “Triple Conjunction”. Venus (The bright one), along with Mars, and Saturn will form a changing triangle from night-to-night. If you want to see these planets up close and personal, drop by our weekly get together at McAllister Park on Wednesday evenings in the dog park parking lot.



THE DARK SIDE'Out of Whack' Planetary System Offers Clues to Disturbing PastMIAMI —The discovery of a planetary system “out of whack,” where the orbits of two planets are at a steep angle to each other, was reported today (May 24) by a team of astronomers led by Barbara McArthur of The University of Texas at Austin McDonald Observatory.This surprising finding will affect theories of how multi-planet systems evolve and shows that some violent events can happen to disrupt planets’ orbits after a planetary system forms, say researchers.“The findings mean that future studies of exoplanetary systems will be more complicated. Astronomers can no longer assume all planets orbit their parent star in a single plane,” McArthur says.McArthur and her team used data from Hubble Space Telescope (HST), the giant Hobby-Eberly Telescope, and other ground-based telescopes combined with extensive modeling to unearth a landslide of information about the planetary system surrounding the nearby star Upsilon Andromedae.McArthur reported these findings in a press conference at the 216th meeting of the American Astronomical Society in Miami, along with her collaborator Fritz Benedict, also of McDonald Observatory, and team member Rory Barnes of the University of Washington. The work also will be published in the June 1 edition of the Astrophysical Journal.For just over a decade, astronomers have known that three Jupiter-type planets orbit the yellow-white dwarf star Upsilon Andromedae. Similar to our Sun, Upsilon Andromedae lies about 44 light-years away. It’s a bit younger, a bit more massive, and a bit brighter than the Sun.Combining fundamentally different, yet complementary, types of data from HST and g round -based t e l escopes , McArthur’s team has determined the exact masses of two of the three known planets, Ups And c and d. Much more startling, though, is their finding that not all planets orbit this star in the same plane. The orbits of planets c and d are inclined by 30 degrees with respect to each other. This research marks the first time that the “mutual inclination” of two planets orbiting another star has been measured. And, the team has uncovered hints that a fourth planet, e, orbits the star much farther out.“Most probably Upsilon Andromedae had the same formation process as our own solar system, although there could have been differences in the late formation that seeded this divergent evolution,” McArthur said. “The premise of planetary evolution so far has been that planetary systems form in the disk and remain relatively co-planar, like our own system, but now we have measured a significant angle between these planets that indicates this isn’t always the case.”Until now the conventional wisdom has been that a big cloud of gas collapses down to form a star, and planets are a natural byproduct. Left over material forms a disk. In our solar system, there’s a fossil of that creation event because all of the eight major planets orbit in nearly the same plane.Several different gravitational scenarios could be responsible for the surprisingly inclined orbits in Upsilon Andromadae.“Possibilities include interactions occurring from the inward migration of planets, the ejection of other planets from the system through planet-

planet scattering, or disruption from the parent star’s binary companion star, Upsilon Andromedae B,” McArthur said.Barnes, an expert in the dynamics of extrasolar planetary systems added, “Our dynamical analysis shows that the inclined orbits probably resulted from the ejection of an original member of the planetary system. However, we don’t know if the distant stellar companion forced that ejection, or if the planetary system itself formed such that some original planets were ejected. Furthermore, we find the revised configuration still lies right on the precipice of stability: The planets pull on each other so strongly that they are almost able to throw each other out of the system.”The two different types of data combined in this research were “astrometry” from Hubble Space Telescope and “radial velocity” from ground-based telescopes.Astrometry is the measurement of the positions and motions of celestial bodies. McArthur’s group used one of the Fine Guidance Sensors (FGS) on Hubble Space Telescope for the task. The FGS are so precise that they can measure the width of a quarter in Denver from the vantage point of Miami. It was this precision that was used to trace the star’s motion on sky caused by its surrounding — and unseen — planets.Radial velocity makes measurements of the star’s motion on the sky toward and away from Earth. These measurements were made over 14 years using ground-based telescopes, including two at McDonald Observatory and others at Lick, Haute-Provence, and Whipple Observatories. The radial velocity provides a long baseline of foundation

observations, which enabled the shorter duration, but more precise and complete, HST observations to better define the orbital motions.The fact that the team determined the orbital inclinations of planets c and d allowed them to calculate the exact masses of the two planets. The new information changed which planet is heavier. Previous minimum masses for the planets given by radial velocity studies put the minimum mass for planet c at 2 Jupiters and for planet d at 4 Jupiters. The new, exact, masses found by astrometry are 14 Jupiters for planet c and 10 Jupiters for planet d.“The HST data show radial velocity isn’t the whole story,” Benedict said. “The fact that the planets actually flipped in mass was really cute.”

The 14 years of radial velocity information compiled by the team uncovered hints that a fourth, long-period planet may orbit beyond the three now known. There are only hints about that planet because it’s so far out, the signal it creates does not yet reveal the curvature of an orbit. Another missing piece of the puzzle is the inclination of the innermost planet b, which would require precision astrometry 1,000 times greater than Hubble’s, a goal NASA’s planned Space Interferometry Mission (SIM) could attain.The team’s Hubble data also confirmed Upsilon Andromedae’s status as a binary star. The companion star is a red dwarf less massive and much dimmer than the Sun.“We don’t have any idea what its orbit is,” Benedict said. “It could be very eccentric. Maybe it comes in very close every once in a while. It may take 10,000 years.”Such a close pass by the primary star could gravitationally perturb the orbits of its planets.



THE DARK SIDEFor 15 bucks, researchers make Galileo proudBy Tom Beal, The Arizona Daily Star, TucsonJune 26--Researchers from Tucson will present a scientific paper Sunday at the International Society for Optical Engineering Conference on Astronomical Instrumentation in San Diego. Subject: a $15, molded-plastic telescope kit.Scott Ellis and Richard N. Pfisterer of Photon Engineering said the paper is no farce.They applied the same science, engineering and analysis to the "Galileoscope" as they do to development and testing of optics for the world's largest telescope or NASA's next-generation space observatory.Their work would have cost "thousands and thousands of dollars" had they billed for it, Pfisterer said, but they donated their time and that of FRED, the company's proprietary software program, which was used to analyze the various lenses and materials proposed for the kit.They did so in the name of increasing interest in astronomy and science in general, said Pfisterer, president of Photon Engineering. He said most his firm's work on the Galileoscope was done by Ellis, the senior optical engineer."If we can inspire a couple kids to go into science, then it's worth it," he said.The Galileoscope was a project dreamed up for the International Astronomical Year in 2009 by a team of science educators who wanted to improve the kits they used to teach children how telescopes work.The specific goal, said Stephen Pompea of the National Optical Astronomy Observatory, was to put together a kit that children could assemble and understand easily, but produce a telescope good enough to give them the "wow experience" of viewing the rings of Saturn from their own backyard.It worked. "It's a kid's telescope. It's a kit. It's inexpensive. But we applied the latest techniques in optical engineering to it," said Pompea, head of education and public outreach at the National Optical Astronomy Observatory.The telescope's four lenses produce up to 50X magnification with a field of view large enough to image the entire moon. It is much clearer and wider than Galileo's original telescope but is versatile enough to reconfigure into a telescope just like his, if you want a view that is akin to looking through a soda straw."It does a remarkable job on the moon, on looking into people's houses or whatever," said Pfisterer. It is so good that it really needs a tripod to steady it, he said -- and a mount is built in.He said the project is deserving of a paper that Pompea will pre-sent alongside research on the largest, next-generation telescopes at the conference.

"Steve's approach was pretty clever," said Pfisterer. "Even though it's a $20 or $30 plastic telescope, a lot of the engineering issues and the programmatic elements are the same as the $100 million instruments."Pfisterer and Ellis are co-authors on the paper with Pompea, as are Richard Tresch Fienberg of the American Astronomical Society, Douglas N. Arion of Carthage College and Thomas C. Smith of Merit Models, which made the production molds.Pompea said some members of the team are also "investors" in the telescope project. They had to kick in money to get the telescopes made when they didn't find an angel or foundation to underwrite it.Then they had to wait for payment to pour in before ordering a production run, causing a delay that annoyed some early purchasers.The important thing, he said, is that the telescopes got into the hands of 180,000 youngsters and more are being ordered or donated.Pompea figures the telescopes, which originally sold for $15, are worth about $100. They are still available from the group's website, now priced at $30. Turnaround time these days is about a week, said Pompea.Many were given away to science teachers for use with classroom materials created as part of the project through NOAO's outreach programs locally, nationally and in Chile, where NOAO operates observatories.Arizona Boys and Girls Clubs received telescopes donated by Science Foundation Arizona.Donations came from individuals who ordered two telescopes and donated one, and from major contributors such as Ric and Jean Edelman, who donated $250,000 to buy 15,000 telescopes for use in science classrooms.

TO ACCESS THE SALSA YAHOOGROUPGo to the following website:

http://tech.groups.yahoo.com/group/SALSA-ASTRO/

Apply for membership and we will get you approved as soon as we can! Membership is free with no commitment! This is active daily discussion forum on all things in space and astronomy. Often

decisions made to go out and observe as a group will be made here. Much better than a monthly publication such as this one!





THE DARK SIDEA Primer on Cometsby Francis Reddy, Astronomy.comComets are dark , solid bodies a few kilometers across that o r b i t t h e S u n i n e c c e n t r i c p a t h s . C o m e t s c a n b e described as "dirty snowballs" containing a mixture of dust and frozen gases. Some of the icy material — perhaps less than 1 percent — evaporates as the comet nears the Sun, creating an envelope of gas and dust that enshrouds the solid body. This envelope, called the coma, may be up to 620,000 miles (1,000,000 kilometers) across. Swept back by the solar wind and the radiation pressure of sunlight, this material forms the comet's tail. Comet tails can span a distance greater than that separating the Earth from the Sun. That such a small amount of material could create visible features so large has led some to describe comets as "the closest thing to nothing anything can be and still be something."To the naked eye, the coma of a bright comet looks star-like, a tiny ball of light set within a milky glow. The comet's tail or tails fan out from the coma. If present, a broad dust tail may be the most striking visual feature. The glowing gas tail is straighter, narrower and often fainter than the dust tail. Within the coma, and invisible to both the naked eye and the most powerful telescopes, lies the small icy body responsible for this grand apparition — the comet's nucleus.

Bushy starsThe ancient Chinese names for comets re f lec t the i r v isua l appearance. A comet with a prominent tail was called a "broom star" (huixing), while one with no obv ious ta i l was a "bushy s t a r " ( p o x i n g ) . U n t i l t h e mid-1400s, the Chinese made the most detailed and complete observations of comets. As early as 200 b.c., they employed official skywatchers to record and interpret any new omens in the h e a v e n s . T h e s e o f f i c i a l s recognized, some nine centuries b e f o r e t h e i r E u r o p e a n counterparts, that comet tails always point away from the Sun. The Chinese interest in comets, however, was for their astrological importance as signs of coming change. The Greeks likewise recognized a comet with an extended tail as a "bearded star" (aster pogonias) and one without a tail as a "long-haired star" (aster kometes), from which our modern word derives. Aristotle regarded them as a fiery atmospheric phenomenon, to be lumped together with meteors and the aurora. They could not be planets, he reasoned, because comets can appear far from the ecliptic. He thought of comets as being whipped up by the motion of the Sun and stars around the Earth. Their appearance was a warning of coming droughts and high winds. As these ideas were extended in the Middle Ages, comets became viewed less as a portent of disaster than as a cause. They were viewed as a fiery corruption of the air, pockets of hot contaminated vapor that could bring earthquakes, disease, and famine.

Some of these ideas were questioned seriously when the great comet of 1577 attracted the attention of Danish observer Tycho Brahe. He could see no reason why comet tails should always point away from the Sun if they were products of the weather. He measured the position of the comet with respect to the stars at different times during the night in an effort to find its parallax — a clue to the object's true distance from Earth. His observations, which indicated that the comet lay beyond the Moon but not as far off as Venus, helped invigorate the scientific study of comets. More than a century later, Isaac Newton showed that comets obeyed Johannes Kepler's laws of planetary motion and concluded "comets are a sort of planet revolved in very eccentric orbits around the Sun."Future observations of the comet of 1682 would eventually remove any lingering doubts. Newton's friend Edmond Halley began collecting accurate cometary observations in 1695 to compare the orbits of many comets. Halley noticed that several comet orbits seemed similar and shared roughly the same period, between 75 and 76 years. "Many considerations incline me to believe the comet of 1531 observed by Apianus to have been the same as that described by Kepler … in 1607 and which I again observed in 1682," Halley wrote. "Whence I would venture confidently to predict its return, namely in the year 1758. And if this occurs, there will be no further cause for doubt that the other comets ought to return also." Halley's confidence proved well founded — the first comet ever predicted to return was again spotted on December 25, 1758. It has been known as Halley's Comet ever since.

Naming cometsComets are more commonly named for their discoverers; up to three independent co-discoverers may share the credit. Increasingly, those discoverers are not individuals, but dedicated small-body discovery programs or solar-observing satellites. Numerous comets have been named for the Lincoln Near Earth Asteroid Research (LINEAR) project of the Massachusetts Institute of Technology in Boston, the Near Earth Asteroid Tracking (NEAT) program operated by the Jet Propulsion Laboratory in Pasadena, California, and the Lowell Observatory Near-Earth Object Search (LONEOS) run by Lowell Observatory in Flagstaff, Arizona. The pace of comet discovery has more than doubled in recent decades, up from an average of about a dozen

per year in the late 1980s to about 30 per year in this century's opening years. T h e S u n - m o n i t o r i n g S o l a r a n d Heliospheric Observatory (SOHO) satellite has found 850 comets so far. This tally increases by an average of 80 per year, making SOHO history's most prolific, if unintended, comet discoverer.Because the names of discoverers don't allow for a unique identification, comets receive a more prosaic official name. This consists of a one-letter prefix, usually a C for "comet" or a P for "periodic," followed by the year of discovery and an uppercase letter that indicates the half-month in which the discovery occurred. For example, an A represents January 1 though 15, B is January 16 through 31, and so on. (The letter I isn't used to avoid confusion with earlier nomenclature that used Roman numerals, and the letter Z isn't necessary.) After this letter comes a

number that represents the order of discovery during the half-month. Halley's Comet, which was the first comet discovered or recovered in the second half of October 1982, therefore receives the designation P/1982U1. When the return of a comet is well established, either through a recovery or by observing a second passage through perihelion, astronomers add a number to the prefix. Since Halley was the first comet whose return was identified, its full designation becomes 1P/1982U1. Astronomers have accumulated detailed orbital information on more than 1,500 individual comets. Of those, only about 10 percent complete an orbit around the Sun in less than 200 years. A typical "short-period" comet travels once around the Sun every 7 years in an orbit inclined to Earth's by some 13°, passing no closer to the Sun than about 1.5 AU, or just within the mean



THE DARK SIDEdistance of Mars. Halley's Comet is the brightest and most active member of this group. The remaining population consists of long-period comets, those that take at least 200 years to return to the inner solar system. So comet aficionados pin their hopes to the unanticipated arrival of an as-yet-unknown long-period comet.

How bright will it be?The two most important considerations in assessing the visibility of a comet are its distance from the Sun at closest approach, which controls the comet's activity, and its distance from Earth, preferably after the intense heating of it closest approach to the Sun. Halley, for example, was an impressive sight in 1910, but anemic in 1986 — a disappointment even to those who traveled far from city lights. The main difference between the two apparitions was the comet's distance from Earth. Halley reached perihelion at a time when Earth was on the opposite side of the Sun, and the comet never came closer to Earth than 0.417 AU (38.7 million miles or 62.4 million km), which is about three times the distance of its 1910 approach.Another example of the importance of proximity was the 1983 display of comet IRAS-Araki-Alcock (C/1983 H1). A small and relatively inactive comet, it was discovered first by the Infrared Astronomical Satellite (IRAS) in late April and originally identified as an asteroid. In early May, amateurs Genichi Araki of Japan and George Alcock of England independently discovered the object. It soon became an obvious sight to the unaided eye high in the northern sky, and on May 12 the comet brushed past Earth at 0.0312 AU (2.9 million miles or 4.7 million km) — closer than any comet since 1770. A typical comet might move across the sky by a degree or so a day, too slowly for the eye to notice. IRAS-Araki-Alcock was so close that its motion was clearly evident to observers, who compared its movement to that of the minute hand on a clock. At its best, the comet was about twice the apparent diameter of the Moon and looked like a star nestled within a puff of smoke. It showed no evidence of a tail — a fine example of a "bushy star" — and faded from view by the third week of May.Intrinsically larger or more active comets can produce a spectacle without getting quite so close to us. Comet West (C/1975 V1) improved dramatically within a week of its very close approach to the Sun, aided in large part by the breakup of its nucleus into four fragments. West dominated the morning sky of early March 1976 with complex gas and dust tails extending 25° or more. A decade earlier, an even more spectacular comet, Ikeya-Seki (C/1965 S1), could be seen even during the daylight as it raced past the Sun, skimming its surface by less than one solar diameter. This intense heating led to the breakup of the nucleus into at least two fragments and a corresponding increase in brightness. During the days around perihelion, Ikeya-Seki could be seen as a star-like object in broad daylight just by blocking the Sun with a hand — the brightest comet of the 20th century. It emerged from the Sun's glare in the last week of October 1965 sporting a bright tail about 25° long. Any list of "great comets" must include both West and Ikeya-Seki.

SungrazersIkeya-Seki's punishing orbit places it into a category of comets known as the "sungrazers." Heinrich Kreutz extensively examined the orbits of sungrazing comets and suggested that they shared a common ancestry. Kreutz argued that the comets he studied are possibly fragments of some much larger comet that fell apart at a close approach to the Sun. Sungrazers have perihelion distances less than 0.02 AU, orbital periods of a few centuries, and other distinguishing orbital characteristics, but they were also apparently rare. Brian Marsden of the Harvard-Smithsonian Center for Astrophysics identified eight members, and suspected three others, in his 1965 and 1989 studies of the Kreutz group. By his second study, 15 apparent sungrazing comets had been discovered by the SOLWIND and Solar Maximum Mission satellites, and Marsden noted these "discoveries suggest that members may in fact be coming back to the Sun more or less continuously." Like these fragments, most of the comets so far discovered by comet-champion SOHO also do not survive their passage. Marsden believes that nearly all of them belong to the Kreutz group, although there are too few observations to uniquely determine their orbits. The SOHO sungrazers are probably just a few meters across. Marsden speculates that a historical sungrazer, one the Greek Ephorus reported to have split in two pieces in the winter of 372 b.c., might even be the granddaddy of them all.

Comet dudsEven when orbital geometry promises a good display, the comet itself may simply fail to cooperate. Comet Kohoutek (C/1973 E1), which was widely predicted to be the "comet of the century" in 1973, did manage to become a naked-eye object but never lived up to its publicity. Another example is Comet Austin (C/1989 X1), discovered in December 1989 by New Zealand amateur Rodney Austin. The comet's orbit was favorable, but as Austin closed on the Sun, it failed to maintain its rapid brightening and, in the end, proved a bigger

dud than Kohoutek.Both Austin and Kohoutek appear to have been new

comets, those making their first close pass by the Sun. Astronomers believe that comets originate from two "cold storage" zones that surround the planetary system. The inner portion of this comet cloud is a thick disk centered on the ecliptic that begins near the orbit of Neptune (about 30 AU) and extends beyond the orbit of Pluto to 50 AU. Often called the Kuiper Belt, it contains a few tens of thousands of icy objects larger than about a half-mile across; at least 800 are currently known. A much larger and more diffuse component, called the Oort cloud and containing perhaps a trillion comets, forms a Sun-centered spherical shell extending from the outer Kuiper Belt to about one-third of a light-year or more into space. Many astronomers believe that the Kuiper Belt is the source for the short-period comets and that the Oort cloud, from which comets are more easily dislodged, is the source for the long-period comets. Feeble gravitational disturbances from passing stars and interstellar gas clouds remove enough orbital energy from Oort cloud comets that they begin their million-year-long fall toward the Sun. Long-period comets may arrive from any direction, their elongated orbits randomly oriented to the orbits of the planets, while the short-period comets are confined closer to the ecliptic. New arrivals from the comet cloud probably retain a coating of highly volatile ices, such as



THE DARK SIDE

GARNER STATE PARK STAR PARTIESSALSA will be conducting several public observing star parties at Garner State Park over the course of the Summer and Fall seasons. SALSA members get into the park free of charge provided they are on the list that is submitted the Thursday before the event. Camping is provided to SALSA members in the large observing field where the star party is held. Traditionally astronomers meet in the morning at a restaurant in San Antonio and then caravan to the park afterwards to enjoy some time in the river and relaxing. The public star party starts about 30 minutes before sunset and usually lasts until around 10 or 11 PM then private observing takes place. More information will be announced in the next newsletter.Dates are as follows: September 11th, October 9th

frozen carbon dioxide, that begins to evaporate at much lower temperatures than frozen water. Such comets "turn on" at relatively large distances from the S u n , b u t b r i g h t e n o n l y u n t i l t h e c o a t i n g e v a p o r a t e s .

Recent great cometsComet Hyakutake (C/1996 B2) was, in the words of Brooks Observatory comet expert John Bortle, "one of the grandest of the millennium." It was discovered visually by Japanese amateur Yuji Hyakutake when at a distance of 2.0 AU — and only 55 days before its closest approach to Earth (March 25, 1996, 0.102 AU). By late March, mid-northern observers could see it directly overhead before dawn with a tail at least 30°long. In the days around closest approach it was an easy object even from cities, and its motion against the stars, like that of IRAS-Araki-Alcock, was evident in minutes. On March 27, as it moved near Polaris, Hyakutake was visible all night long and could easily be seen from the suburbs. From a reasonably dark sky the comet was truly something special, showing a tail that spanned some 70° or longer — all the more impressive because it seemed to contain relatively little dust. Hyakutake took us by complete surprise, upstaging the appearance of another comet that was already widely anticipated.That comet was Hale-Bopp (C/1995 O1). What made Hyakutake a great comet was its unusually close pass, which turned a faint and relatively inactive comet into an apparently bright one. But Hale-Bopp was another matter. It was the brightest and most active comet to pass inside Earth's orbit since the one Tycho Brahe examined in 1577. Hale-Bopp showed unusually high activity even at great distance from the Sun and was widely expected to be the one that would end the bright comet drought. It was discovered July 23, 1995, by Alan Hale in New Mexico and Thomas Bopp in Arizona within minutes of one another. After perihelion on April 1, 1997, Hale-Bopp became a striking object in the northwestern sky, cruising through Cassiopeia and Perseus with a pair of tails. The straight, faint gaseous tail was easy to see from a moderately dark site, but the comet's most striking aspect was its dramatically curved 25-degree-long dust tail. Observers in the Northern Hemisphere could see Hale-Bopp with the naked eye, even from urban sites, and it remained well-placed for viewing throughout April and into May. As an indication of the comet's unusual activity, consider that it was never closer to Earth than 122 million miles (197 million km) and passed no closer to the Sun than 91 percent of Earth's distance.

Exploring cometsAstronomers believe comets may be the best-preserved remnants of the cloud of dust and gas in which the Sun and planets formed. In the deep-freeze of the outermost solar system, they have remained largely unchanged during the 4 billion years the solar system has existed. Planetary scientists study comets for the same reason paleontologists study fossils: to catch a glimpse of the most a n c i e n t past. And what better way to scrutinize comets than by visiting them directly? Japan, the European Space Agency (ESA), and the Soviet Union began the direct exploration of comets in 1985 by sending separate missions past Halley's Comet. The ESA probe, Giotto, returned the first detailed images of a comet's nucleus, revealing a dark, peanut-shaped body, a hint of hills and craters, and several bright jets spewing streams of gas and dust. Another burst of comet exploration is now under way:

• ESA has launched its ambitious mission for Rosetta, which will rendezvous with and orbit the inbound Comet 67P/Churyumov-Gerasimenko in 2014. It will also place a small lander on the comet's surface.

• The Discovery mission New Exploration of Tempel 1 (NExT) is scheduled to fly by Comet Tempel 1 on February 14, 2011. The mission will reuse NASA's Stardust spacecraft to examine the changes to a comet's nucleus after its close approach to the Sun.

• The Comet Sample Return Mission, a Design Reference Mission, is scheduled to launch in 2013 and collect samples from the surface of an organic-rich comet nucleus. Researchers will study the samples' chemical composition in order to learn more about the chemical origins of our solar system.



SKYLINESKYLINE – San Antonio’s Celestial Highlights for July, 2010From the Scobee Planetarium at San Antonio CollegeJuly Sun – Though you wouldn’t suspect it from the sizzling temperatures, believe it or not, the days are getting shorter! As we move farther from the Summer Solstice and the longest day of the year which occurred on June 21st, the amount of time our star actually spends above the horizon decreases ever so slightly. For example, on July 1st, the Sun rises at 6:37am and sets at 8:37pm – spending exactly 14 hours in the San Antonio sky. At the end of the month, our star rises at 6:53am, sets at 8:27pm, and is above our horizon for 13 hours and 34 minutes - a decrease of 26 minutes of possible sunshine. Not much of a change, but this trend of decreasing sunshine eventually heralds the return of autumn. Another slight change to the July daytime sky also involves the Sun’s maximum elevation above the southern horizon. Known as “solar noon,” the Sun’s greatest height above the southern horizon drops from 83.3 degrees on July 1st, to about 78.3 degrees by month’s end. While a decrease of 5 degrees in the Sun’s maximum elevation at solar noon is not very perceptible, this combination of slightly lower sun angles and shorter days marks the slow shift towards the next season.One other item involves the July Sun. On July 6th, the Earth reaches “aphelion” – its farthest point from the Sun. On this date our planet is approximately 94.5 million miles from our parent star. July Moon - Our lunar companion begins the month in the late night skies, rising just before midnight on July 1st. A late night or predawn glance above the eastern to southeastern horizon on July 3rd finds the Moon above the brightest morning planet, Jupiter. The Last Quarter Moon also shares the morning sky with Jupiter prior to sunrise on July 4th. Gliding eastward through the constellations, a waning (thinning) crescent Moon hovers just below the Pleiades star cluster prior to sunrise on July 8th. Three days later the Moon passes invisibly between the Earth and Sun, reaching New phase on July 11th. A total eclipse of the Sun takes place on this date over the far southern reaches of the Pacific Ocean. No portion of this solar eclipse is visible from the United States. Returning to the evening sky, an exceptionally thin crescent Moon might be glimpsed low in the western sky on July 13th. The following evening, July 14th, a splendid view of our lunar crescent and the brightest of all planets, Venus, graces the western twilight. The next evening, a slightly thicker lunar crescent is situated beneath the pair of Mars and Saturn on July 15th. The apparent distance between Moon and planets widens by the 16th with Saturn much farther to the right and above the Moon. Two nights later, the First Quarter Moon stands high above the southern horizon between the stars of Virgo and Libra. The Moon visits Antares, brightest star of Scorpius the Scorpion on July 21st. On that night, the sparkle of orange-red Antares is just to the right of the waxing gibbous Moon. Full phase takes place four nights later on July 25th. Full phase this month is sometimes called the “Hay Moon” or “Thunder Moon.” Rising progressively later each night, the Moon has one more encounter with Jupiter during the late night hours of both July 30th and 31st.

July Moon PhasesJuly 4th – Last Quarter Moon July 11th– New Moon

July 18th – First Quarter Moon July 25th – Full MoonJuly Evening PlanetsVenus, the brightest of all planets, dominates the western horizon this month. As the sky darkens following a July sunset, the brilliant sparkle of the “evening star” beckons in the summer twilight. This month, Venus leaves the constellation of Cancer the Crab and takes aim on Leo the Lion. Be sure to note the changing positions between Venus and Regulus, brightest star of Leo. Early in the month, Venus is below and right of Regulus, but by July 9th, brilliant Venus sparkles directly alongside Regulus. As noted earlier, the crescent Moon glistens below Venus after sunset on July 14th. The next targets for Venus will be the two planets Mars and Saturn. Venus races quickly through the stars, almost reaching both Mars and Venus by month’s end. A wonderful “triangle” of Venus, Mars and Saturn will be visible after sunset during early August.Venus sets below the western horizon about 2 and 1/2 hours after the Sun.Mars, the orange red planet, is one of three planets visible above the western horizon following a July sunset. Early in the month, the orange red sparkle of Mars is situated between the two brighter planets, Venus and Saturn. Located in Leo the Lion, the distance between Mars and Earth is very great and as a result Mars is a rather small and disappointing. Nonetheless, Mars participates in a rather unique celestial that highlights this month’s sky and continues into August. With each passing evening, notice how Mars appears to glide toward Saturn, while Venus races to catch up. By month’s end, Mars and Saturn are passing one another, with Venus having climbed almost high enough to join this pairing. In fact, early in August, all three planets combine in a “planetary triangle” above the sunset horizon. Look for the Moon and Mars together on July 15th. Saturn, the planet with the brightest rings, remains nicely placed above the western horizon after a July sunset. Look for the yellow-white glow of Saturn amidst the stars of Virgo. A small telescope reveals that Saturn’s fabled rings remain nearly edge on. As noted earlier, Saturn is one of three planets above the western horizon, Saturn being the highest. However, as the month progresses take note of how Mars appears to ascend towards the ringed planet, with Venus racing to join the scene. As July comes to an end, Saturn is just above the dimmer red sparkle of Mars. In early August, Venus also joins this unique planetary cluster. The Moon and Saturn share the sky on both July 15th and 16th. In mid-July, Saturn sets in the west at about midnight.Mercury, innermost world of the Sun, emerges out of the solar glow by mid July to join the other evening planets. Although deep in the evening twilight and barely above the sunset horizon, this elusive world will prove to be the most challenging of the four worlds to view, as the angle the planet’s orbit makes with the horizon is quite shallow. Nonetheless, Mercury reaches and passes by Regulus, brightest star of Leo as the month comes to a close. July Late Night PlanetsJupiter, giant world of the Solar System, is the brightest planet to appear in the late night hours of July. At the beginning of the month, Jupiter rises above the eastern horizon at about 1:00am and is situated between among the stars of Pisces. Early morning sky gazers will enjoy Jupiter standing high in the south at sunrise. Look for the Moon and Jupiter together during the late night hours of both July 3rd and 4th. The Moon visits Jupiter once more at the end of July on the 31st. As July comes to an end, Jupiter is rising at 11:00pm. A pair of binoculars easily reveals the planet’s four largest moons. Wishing you clear skies!Bob KelleyScobee Planetarium Coordinator



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International Observe the Moon Night (InOMN) 2010 is the first annual public outreach event dedicated to engaging the the lunar science and education community, amateur astronomers, space enthusiasts, and the general public in annual lunar observation campaigns that share the excitement of lunar science and exploration. Many institutions across the country will participate, and local institutions are encouraged to join in the fun. InOMN events are already occuring at Ames Research Center (Moffett Field, CA), Goddard Space Flight Center (Greenbelt, MD), Lunar and Planetary Institute (Houston, TX), and Marshall Space Flight Center (Huntsville, AL). You can help raise awareness of this exciting opportunity and bring a local InOMN event to your town!

September 18, 2010

COMING TO YOU

International Observe the Moon Night SEEING THE MOON IN A WHOLE NEW LIGHT

09.18.2010

CHECK US OUT ON

Hosted by:

Tentatively at Scobee Planetarium on the campus of San Antonio College hosted by the Scobee Planetarium and the San Antonio League of Sidewalk Astronomers

In San Antonio:



THE DARK SIDERemember when you looked througha telescope for the first time?

The Texas Amateur Astronomers’ Scholarship at the University of Texas Austin

Investing in future discoveries today...

Your tax-deductible donations can be submitted by filling out the information block below and mail it to:

UT Austin Astronomy

ATTN: TAAS Endowment

1 University Station C1402

Austin, Texas 78712-0259

For any questions, contact the Scholarship creator,

Mr. Hunter Scott at [email protected]



The Moon as it appears on 18 September 2010

SEEING THE MOON... in a whole new lightInternational Observe the Moon Night

Mare Imbrium

Sinus Iridum

Mare Frigoris

Mare Crisium

Copernicus

Gassendi Crater

Schiller Crater

Kepler

Tycho

Mare Nubium

Mare Serenitatis

Mare Tranquillitatis

Image Credit: David Haworth

Mare Nectaris

LUNAR FEATURESMare Frigoris: Latin for “The Sea of Cold”, Mare Frigoris is located in the outer rings of Oceanus Procellarum.

Sinus Iridum: Sinus Iridum: Latin for “Bay of Rainbows,” Sinus Iridum is one of the more popular lunar features for ama-teur astronomers due to its morphol-ogy.

Mare Imbrium: At 1123 km across, Mare Imbrium is the second largest mare on the near side of the Moon.

Mare Tranquilitatis: The astro-nauts of Apollo 11 made history in the Sea of Tranquility: it was here they became the first humans to set foot onthe Moon.

Mare Crisium: Mare Crisium covers 176,000 square kilometers of the lunar surface, and is the location of the Soviet sample return mission Luna 24.Mare Serenitatis: AMare Serenitatis: Apollo 17 as-tronauts landed near the eastern edge of the Sea of Serenity on December 17, 1972.Copernicus Crater: One of the most prominet craters on the lunar near side, Copernicus crater spans 93 km and is only about 800 million years

old, making it one of the younger cra-ters on the Moon.

Kepler Crater: Kepler's rays extend over 300 km from the crater - almost 10 times farther than the crater's 32 km diam-eter!

Tycho Crater: Tycho is one of the most recognized craters on the Moon. Its fresh ejecta rays span 1,500 km across the lunar surspan 1,500 km across the lunar sur-face.

Gassendi Crater: Gassendi Crater was one of the areas considered for the Apollo 17 mission.

Schiller Crater: Schiller Crater is oblong in shape, making it different from most lunar craters.

Mare Nectaris: The Sea of Nec-tars contains over twice as much basalt (87,000 cubic km) than the Big Island of Hawaii (35,000 cubic km).

International Observe the Moon Night is Sponsored by:

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ANDROMEDA CASSIOPEIA

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SKY MAP SHOWS HOWTHE NIGHT SKY LOOKS EARLY JUL 10 PM

LATE JUL 9 PMSKY MAP DRAWN FOR

A LATITUDE OF 40° NORTH AND IS SUITABLE FOR LATITUDES UP TO 15° NORTH

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NORTHERN HEMISPHEREJULY 2010

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Sky Calendar – July 20101 Moon at apogee (farthest from Earth) at 10h UT (distance 405,036 km;

angular size 29.8').

3 Moon near Jupiter (morning sky) at 20h UT. Mag. –2.5.

4 Last Quarter Moon at 14:35 UT.

6 Earth at Aphelion (farthest from Sun) at 11h UT. The Sun- Earth distance is 1.01670 a.u. or about 152.1 million km.

8 Moon near Pleiades (morning sky) at 6h UT.

9 Moon near Aldebaran (morning sky) at 2h UT.

10 Venus 1.0° NNE of Regulus (evening sky) at 12h UT. Mags. –4.1 and 1.4.

11 Total Solar Eclipse visible from South Pacific Ocean. Path of totality includes parts of the Cook Islands, Tahiti, Tuamotu Archipelago, Easter Island, and southern Chile and Argentina. Greatest totality (5m 20s) occurs in open ocean at 19:34 UT.

11 New Moon at 19:40 UT. Start of lunation 1083.

13 Moon at perigee (closest to Earth) at 11h UT (361,115 km; 32.1').

14 Moon near Regulus (evening sky) at 13h UT.

14 Moon near Venus (evening sky) at 22h UT. Mag. –4.1.

16 Moon near Mars (evening sky) at 0h UT. Mag. +1.4.

16 Moon near Saturn (evening sky) at 14h UT. Mag. +1.1.

18 Moon near Spica (evening sky) at 6h UT.

18 First Quarter Moon at 10:11 UT.

21 Moon near Antares (evening sky) at 20h UT.

26 Full Moon at 1:37 UT.

27 Mercury 0.3° SSW of Regulus (25° from Sun, evening sky) at 22h UT. Mags. +0.1 and +1.3.

29 Moon at apogee (farthest from Earth) at 0h UT (distance 405,955 km; angular size 29.3').

31 Moon near Jupiter (morning sky) at 2h UT. Mag. –2.7.

31 Mars 1.8° SSW of Saturn (evening sky) at 6h UT. Mags. +1.5 and +1.1.

More sky events and links at http://Skymaps.com/skycalendar/All times in Universal Time (UT). (USA Eastern Summer Time = UT – 4 hours.)

GalaxyDouble Star

Variable StarDiffuse Nebula

Planetary NebulaOpen Star Cluster

Globular Star Cluster

Star Magnitudes

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INSTRUCTIONS: THE SKY MAP SHOWS THE ENTIRE NIGHT SKY FR

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E ZENITH AND THE HORIZON. COMPASS DIRECTIONS ARE INDICATED ALONG THE HORIZON CIRCLE (FOR EXAMPLE “NORTH”). TURN THE SKY MAP AROUND ITS CENTER (JUST AS YOU ARE DOING NOW

) SO THE COMPASS DIRECTION THAT APPEARS ALONG THE BOTTOM

OF THE MAP IS THE SAME AS THE DIRECTION THAT YOU FACE. BEGIN BY USING THE SKY MAP TO FIND A BRIGHT STAR PATTERN IN THE SKY.

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Easily Seen with the Naked Eye

Easily Seen with Binoculars

Telescopic Objects

Altair Aql Brightest star in Aquila. Name means "the flying eagle". Dist=16.7 ly.Arcturus Boo Orange, giant K star. Name means "bear watcher". Dist=36.7 ly. Cephei Cep Cepheid prototype. Mag varies between 3.5 & 4.4 over 5.366 days. Mag 6 companion.

Deneb Cyg Brightest star in Cygnus. One of the greatest known supergiants. Dist=1,400±200 ly. Herculis Her Semi-regular variable. Magnitude varies between 3.1 & 3.9 over 90 days. Mag 5.4 companion.

Vega Lyr The 5th brightest star in the sky. A blue-white star. Dist=25.0 ly.Antares Sco Red, supergiant star. Name means "rival of Mars". Dist=135.9 ly.Polaris UMi The North Pole Star. A telescope reveals an unrelated mag 8 companion star. Dist=433 ly.Spica Vir Latin name means "ear of wheat" and shown held in Virgo's left hand. Dist=250 ly.

Aquilae Aql Bright Cepheid variable. Mag varies between 3.6 & 4.5 over 7.166 days. Dist=1,200 ly.M3 CVn Easy to find in binoculars. Might be glimpsed with the naked eye. Cephei Cep Herschel's Garnet Star. One of the reddest stars. Mag 3.4 to 5.1 over 730 days.

Mel 111 Com Coma Berenices. 80 mag 5-6 stars in 5 deg. Dist=283 ly. Age=400 million years. Cygni Cyg Long period pulsating red giant. Magnitude varies between 3.3 & 14.2 over 407 days.

M39 Cyg May be visible to the naked eye under good conditions. Dist=900 ly. Draconis Dra Wide pair of white stars. One of the finest binocular pairs in the sky. Dist=100 ly.

M13 Her Best globular in northern skies. Discovered by Halley in 1714. Dist=23,000 ly.M92 Her Fainter and smaller than M13. Use a telescope to resolve its stars. Lyrae Lyr Famous Double Double. Binoculars show a double star. High power reveals each a double.

R Lyrae Lyr Semi-regular variable. Magnitude varies between 3.9 & 5.0 over 46.0 days.M12 Oph Close to the brighter M10. Dist=18,000 ly.M10 Oph 3 degrees from the fainter M12. Both may be glimpsed in binoculars. Dist=14,000 ly.IC 4665 Oph Large, scattered open cluster. Visible with binoculars.6633 Oph Scattered open cluster. Visible with binoculars.M15 Peg Only globular known to contain a planetary nebula (Mag 14, d=1"). Dist=30,000 ly.M8 Sgr Lagoon Nebula. Bright nebula bisected by a dark lane. Dist=5,200 ly.M25 Sgr Bright cluster located about 6 deg N of "teapot's" lid. Dist=1,900 ly.M22 Sgr A spectacular globular star cluster. Telescope will show stars. Dist=10,000 ly.M4 Sco A close globular. May just be visible without optical aid. Dist=7,000 ly.M6 Sco Butterfly Cluster. 30+ stars in 7x binoculars. Dist=1,960 ly.M7 Sco Superb open cluster. Visible to the naked eye. Age=260 million years. Dist=780 ly.M5 Ser Fine globular star cluster. Telescope will reveal individual stars. Dist=25,000 ly.Mizar & Alcor UMa Good eyesight or binoculars reveals 2 stars. Not a binary. Mizar has a mag 4 companion.Cr 399 Vul Coathanger asterism or "Brocchi's Cluster". Not a true star cluster. Dist=218 to 1,140 ly.

7009 Aqr Saturn Nebula. Requires 8-inch telescope to see Saturn-like appendages. Boötis Boo Red giant star (mag 2.5) with a blue-green mag 4.9 companion. Sep=2.8". Difficult to split.

M94 CVn Compact nearly face-on spiral galaxy. Dist=15 million ly.M51 CVn Whirlpool Galaxy. First recognised to have spiral structure. Dist=25 million ly.M64 Com Black-Eye Galaxy. Discovered by J.E. Bode in 1775 - "a small, nebulous star".Albireo Cyg Beautiful double star. Contrasting colours of orange and blue-green. Sep=34.4".61 Cygni Cyg Attractive double star. Mags 5.2 & 6.1 orange dwarfs. Dist=11.4 ly. Sep=28.4". Delphini Del Appear yellow & white. Mags 4.3 & 5.2. Dist=100 ly. Struve 2725 double in same field. Lyrae Lyr Eclipsing binary. Mag varies between 3.3 & 4.3 over 12.940 days. Fainter mag 7.2 blue star.

M57 Lyr Ring Nebula. Magnificent object. Smoke-ring shape. Dist=4,100 ly.M23 Sgr Elongated star cluster. Telescope required to show stars. Dist=2,100 ly.M20 Sgr Trifid Nebula. A telescope shows 3 dust lanes trisecting nebula. Dist=5,200 ly.M21 Sgr A fine and impressive cluster. Dist=4,200 ly.M17 Sgr Omega Nebula. Contains the star cluster NGC 6618. Dist=4,900 ly.M11 Sct Wild Duck Cluster. Resembles a globular through binoculars. V-shaped. Dist=5,600 ly.M16 Ser Eagle Nebula. Requires a telescope of large aperture. Dist=8,150 ly.M81 UMa Beautiful spiral galaxy visible with binoculars. Easy to see in a telescope.M82 UMa Close to M81 but much fainter and smaller.M27 Vul Dumbbell Nebula. Large, twin-lobed shape. Most spectacular planetary. Dist=975 ly.

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10About the Celestial ObjectsListed on this page are several of the brighter, more interesting celestial objects visible in the evening sky this month (refer to the monthly sky map). The objects are grouped into three categories. Those that can be easily seen with the naked eye (that is, without optical aid), those easily seen with binoculars, and those requiring a telescope to be appreciated. Note, all of the objects (except single stars) will appear more impressive when viewed through a telescope or very large binoculars. They are grouped in this way to highlight objects that can be seen using the optical equipment that may be available to the star gazer.

Tips for Observing the Night Sky When observing the night sky, and in particular deep-sky objects such as star clusters, nebulae, and galaxies, it’s always best to observe from a dark location. Avoid direct light from street lights and other sources. If possible observe from a dark location away from the light pollution that surrounds many of today’s large cities. You will see more stars after your eyes adapt to the darkness—usually about 10 to 20 minutes after you go outside. Also, if you need to use a torch to view the sky map, cover the light bulb with red cellophane. This will preserve your dark vision. Finally, even though the Moon is one of the most stunning objects to view through a telescope, its light is so bright that it brightens the sky and makes many of the fainter objects very difficult to see. So try to observe the evening sky on moonless nights around either New Moon or Last Quarter.

Astronomical GlossaryConjunction – An alignment of two celestial bodies such that they present the least angular separation as viewed from Earth.Constellation – A defined area of the sky containing a star pattern.Diffuse Nebula – A cloud of gas illuminated by nearby stars.Double Star – Two stars that appear close to each other in the sky; either linked by gravity so that they orbit each other (binary star) or lying at different distances from Earth (optical double). Apparent separation of stars is given in seconds of arc (").Ecliptic – The path of the Sun’s center on the celestial sphere as seen from Earth.Elongation – The angular separation of two celestial bodies. For Mercury and Venus the greatest elongation occurs when they are at their most angular distance from the Sun as viewed from Earth.Galaxy – A mass of up to several billion stars held together by gravity.Globular Star Cluster – A ball-shaped group of several thousand old stars.Light Year (ly) – The distance a beam of light travels at 300,000 km/sec in one year.Magnitude – The brightness of a celestial object as it appears in the sky.Open Star Cluster – A group of tens or hundreds of relatively young stars.Opposition – When a celestial body is opposite the Sun in the sky.Planetary Nebula – The remnants of a shell of gas blown off by a star.Universal Time (UT) – A time system used by astronomers. Also known as Greenwich Mean Time. USA Eastern Standard Time (for example, New York) is 5 hours behind UT.Variable Star – A star that changes brightness over a period of time.

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Copyright © 2000–2010 Kym Thalassoudis. All Rights Reserved.

Salsa newsletter 07 2010

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Transcript of Salsa newsletter 07 2010