Salsa newsletter 07 2010

July 2010 Volume 1 Issue#3

TH E D A RK S ID E
N e w s l e t t e r
WWW.SALSA-ASTRO.COM

The Astronomy Club Everyone Is Talking About

THIS MONTH’S NOTES: Looking for Ideas for the
Next Meetup
Skipping a beat... April was a great success for
I’m sure that most of you were wondering where the June issue of “The Dark the ﬁrst ever SALSA meetup.
Side” was. Well frankly, June was a very demanding month in traveling and I Now its time again to have
one but to better address the
didn’t want to put out a newsletter if it wasn’t of good enough quality. So here
needs of members all around
we are two months later and back on track! We have been a bit snake bit when it the city, it would be best if we
has come to the weather and observing. July’s Garner State Park outing has been moved it around to make it as
canceled for the second time due to rain and poor observing. It’s going to be accessible as possible. That’s
ﬁne and dandy but it takes
pretty darn hot come August, so we are by-passing that month and resuming our input from all of you! If you
sessions out there on September 11th. Please take a look at the calendar on page have a favorite place to eat
3. You will see the usual events we take part in but you’ll see an event for or know of a good watering
hole to talk about astronomy,
diabetic children on July 29th in the afternoon where we could use your help.
please post it to the SALSA
This is a summer camp for this sick children that will take place for one week Yahoogroup or e-mail me your
with a space theme. If you can make it out to help that afternoon, please contact suggestions to
Scott Timmons or myself. btobias@sbcglobal.net. and
let’s take a look at
Also later this month in conjunction with a normal Wednesday night observing
it!
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.

Official Newsletter of san antonio league of sidewalk astronomers
1


TH E D A RK S ID E
Karl and Gary are two talented visionary UT astronomers. Between them, they
Texas Amateur Astronomer Scholarship came up with a proposal for discovering dark energy that has become the
Needs You! 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
by Hunter Scott technologies that haven't even been invented yet. That is the essence of the
Have you ever had to explain something that is so obvious to you that you can't beauty of HETDEX. It relies on technology that is on the shelf today. This
find the words to explain it? Well, that's what has happened to me with the approach allows two things to happen. First, it reduces the cost to millions
Texas Amateur Astronomer's Scholarship. Don't get me wrong, when Bryan (about 34 of them, to be exact), and it allows the project to get started now,
asked me to put down on paper why someone would want to support the today. When Karl and Gary published their proposal in professional journals,
scholarship, he did so with the intention of giving me some exposure in The the rest of the professional astronomy community had one of those Smith-
Dark Side, which I appreciate very much. Where do I begin.........? Barney moments. They stopped and listened to the proposal, and then quickly
As some of you know, I signed a one-page document in February that started had one of those slap-yourself-on-the-forehead and say,"Why didn't I think of
the ball rolling on a quest to raise and donate $25,000 to the University of that." moments.
Texas over the next five years. Sounds like a daunting task, doesn't it? My HETDEX is actually under development at UT, where as, other proposals are
original idea involved getting the SAAA membership to be obligated for this still on the drawing board. Last month I was lucky enough to be allowed to go
task, but it quickly got mired in a bunch of turmoil, so, based on some out to McDonald Observatory where I spent two sleepless nights with Jeremy
conversations I was having with Mr. Joel Barna of the University of Texas, I Murphy, and Guillermo Blanc, both very talented PhD graduate students. They
simply pulled the offer off the table in order to relieve the stress the subject was were at the observatory to put a prototype of one of the major components,
creating within SAAA. Ironically, the Executive Committee of SAAA finally VIRUS, to a test. They were actually doing some science in the process, and I
came around to a decision to support the scholarship, but by then, I had got to sit in the control room with them as they operated the 107" Harlan Smith
already made up my mind to do this without SAAA's help. Telescope with VIRUS attached. They actually allowed me to use the control
The scholarship very nearly went by the name "SAAA Scholarship." But, during paddle to slew the scope to a position where Guillermo crawled into the main
my conversations with Joel, I realized the The University of Texas (UT), and tube of the scope in order to remove a filter from VIRUS. Do I have to explain
more specifically, the Astronomy Department at UT, was willing to put every how exhilarating it was for me to be allowed into the inner circle of the workings
resource they have at my disposal in order to support my fundraising effort. I of McDonald Observatory? I hope not, because I can't do it.
began to see so many possibilities and opportunities for raising funds that I Jeremy and Guillermo are very good teachers, and were able to explain the
became convinced that I didn't need any one amateur astronomy club to do science and technology in a way that I could understand it easily. I hope to
this. Thus, the name Texas Amateur Astronomer's Scholarship. The name share some of those photos with you in a future issue of The Dark Side. The
implies that the scholarship belongs to all Texas Amateur Astronomy clubs, and purpose for me being there was to photograph and document what is going on
indeed, that is the intention of it, as explained below. with HETDEX as it happens so I can develop that Powerpoint presentation I
During the extended debate that was going on within SAAA's EC, I was already mentioned earlier. HETDEX will probably take 3-5 years to complete, and I
thinking about plan B. I was already aware of a huge project that is under hope to be there to photograph every step of the way, and report back to
development at McDonald Observatory called HETDEX. Joel presented SALSA members what is going on.
a program on the project when he addressed the membership during a regular What does this have to do with any of you? Well, for one thing, as members of
monthly meeting, the one where Keith Little was supposed to sign the SALSA you will be able to look over my shoulder as I document these historic
document on behalf of SAAA that would have established the scholarship. events. I will share my experiences with everyone. For those of you who have
HETDEX got me fired up, and still has me fired up today, and here's why. the time and the cost of a night's stay at the Astronomer's Lodge, I may be able
HETDEX stands for Hobby-Eberly Telescope Dark Energy Experiment. The to invite someone along with me occasionally. You can accompany me on
essence of the name tells you that the project is going to use the Hobby-Eberly these trips of exploration and discovery.
Telescope at McDonald Observatory to try to "discover" dark energy. Dark I'm not going to pull any punches here. Priority will be given to those of you
energy and dark matter are the Holy Grail in professional astronomy these who make monetary contributions to the scholarship fund, but invitations won't
days. Every major university in the world has a proposal on the table to necessarily be limited to donors. To me, that is one BIG reason to make a
discover dark energy. Actually, to say that astronomers are trying to "discover" donation, but there are many others. Of course, your contributions will be tax
dark energy is somewhat of a misnomer. There is already plenty of evidence deductible. Beyond that obvious reason, there is the pleasure you may get out
that dark energy exists. What astronomers are really trying to do is to of doing something altruistic. The scholarship will support a deserving
characterize or to learn the nature and source of dark energy. undergraduate as he/she pursues a career in astronomy.
On a little side trip here, Einstein's famous formula, E=mc squared, simply tells But to me, here's the most compelling reason to support TAAS. As I've already
us that energy can be turned into matter, and that matter can be turned into said, preference in gaining access to McDonald Observatory and HETDEX will
energy. Compared to dark energy, the discovery of dark matter should be a be given to those of you who make monetary contributions to the scholarship.
piece of cake. The Large Hadron Collider was built specifically to find a particle How much is it worth to you as an amateur astronomer to be able to be there
suspected of being responsible for dark matter. Scientists suspect that dark amongst the people, the technology, under the stars......to be in the very place
matter is made of a particle not too different from protons, electrons, neutrons, and time where dark energy may be discovered? To me, it is beyond value,
or neutrinos, and the Hadron Collider is poised to make that historic discovery, and I have gained access to this incredible spectacle through the scholarship
probably within the next year or so. effort. Is it worth anything to you? The discovery of dark energy is on a par
with the discovery of the atom, the discovery George Cooper expanding, or
But dark energy is a very different breed of cat. It is more like gravity, the Courtesy that the Universe is
strong nuclear force, the weak nuclear force, or the electromagnetic force. We the accomplishments of Galileo.
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 You may contribute to TAAS by sending your donation to:
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
UT Austin Astronomy
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 Attn: TAAS Endowment
accelerating, and dark energy is one very good explanation for it. Anyway, 1 University Station C1402
back to HETDEX. Austin, Texas 78712-0259
Over the last decade or so, astronomers have focused ever-increasing
attention on dark energy. As I said, the astronomy/cosmology community of Note: I have some SASE donation cards for anybody who wants one. Ask me
scientists around the world have made various proposals to discover dark for one the next time you see me.
energy, many of them costing more money than there is, and relying on
technology not even in existence yet. These proposals have been flying SEE PAGE 14 OF THIS NEWSLETTER!
around for years. Enter Karl Gebhardt and Gary Hill.

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TH E D A RK S ID E
Thruster firing puts New Horizons back on track
SALSA Calendar of Events BY STEPHEN CLARK
for the next month SPACEFLIGHT NOW
The New Horizons mission
speeding toward a fleeting visit
Wednesday Night in the Park - July to Pluto fired its thruster system
for 35.6 seconds Wednesday,
7th - McAllister Park correcting a small error in the
probe's trajectory into the outer
Wednesday Night in the Park - July fringes of the solar system.
The thruster burn occurred as
14th - McAllister Park planned Wednesday at 3 p.m.
EDT and accelerated the
Wednesday Night in the Park - July spacecraft by about one mile per
hour, according to an update
21st - McAllister Park - Friends of posted on the mission's website.
McAllister Park Presentation That doesn't seem like much
when you factor in the robot's
Wednesday Night in the Park - July dazzling speed. New Horizons
covers nearly a million miles per
28th - McAllister Park 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.
Astronomy Presentation for
At the time of the burn, New Horizons was 1.49 billion miles away from Earth, near the orbit of Uranus. It
Diabetic Children - St. Mary’s Hall - takes more than two hours for radio signals to travel from the spacecraft to Earth from such distances.
3-4 PM - Contact Bryan Tobias 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.
First Friday for Children - Scobee 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
Planetarium - August 6th - WILL energy, reflecting off the craft's high-speed communications antenna slowly altered its trajectory.
NOT HAPPEN DUE TO Controllers sent orders for the maneuver from Earth to New Horizons last week amid a two-month
PLANETARIUM UPGRADES 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
Perseids Meteor Shower observing 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.
weekend - August 14th,
On Feb. 25, New Horizons soared past the halfway point in mileage traveled from Earth to Pluto. The
Fredericksburg, Texas - More next spacecraft will mark half the days from launch to flyby on Oct. 17.
Month 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:
Garner State Park - September 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.
11th, Weather Permitting
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
September 18th - International atmosphere and measure the chemical composition of Pluto and its natural satellites.
Observe the Moon Night - Location New Horizons could target an even more distant object after careening past Pluto, extending its mission
to be determined. to 2020 or beyond.

The Moon has a Dark Side
Fort McKavett Stargazing, In 1973, British music group Pink Floyd released one of the all-
November 25th - 28th 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
Garner State Park - October 9th "farside" — permanently remains in darkness. That's not true.
What is true is that, at any given moment, half of the Moon is in
It doesn’t take much to volunteer at darkness. But the dark side is always the side that faces away
any of these events! If you would from the Sun. That's also the case with Earth. Half our planet
experiences day while night occurs on the other half. Because
like to help, contact Bryan Tobias the Earth and Moon rotate (spin), some areas are moving into
at btobias@sbcglobal.net to learn sunlight as different areas move into darkness. Earth rotates
once a day, while the Moon takes 27.3 days to spin once.
more about our outings and how
So, remember, half the of Moon is always dark, but that half is
you can play a part! constantly changing.

3


TH E D A RK
“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/
debated. Last year, studies of the metal abundances in the gas led to the belief
Mysterious giant gas ring origin identified that the ring was made of this famous primordial gas.
Provided by CFHT, Kamuela, Hawaii Thanks to the sensitivity of the CFHT MegaCam camera, the international team
An international team unveiled the origin of the giant gas ring in the Leo group observed for the first time the optical counterpart of the densest regions of the
of galaxies. With the Canada-France-Hawaii Telescope CFHT), the scientists ring in visible light instead of radio waves. Emitted by massive young stars, this
were able to detect an optical signature of the ring corresponding to star- light points to the fact that the ring gas is able to form stars.
forming regions. This observation rules out the primordial nature of the gas, A ring of gas and stars surrounding a galaxy immediately suggests another
which is of galactic origin. Thanks to numerical simulations made at the Centre kind of ring — a collisional ring — formed when two galaxies collide. Such a
d'Etudes Nucléaires (CEA) in France a scenario for the formation of this ring ring is seen in the famous Cartwheel Galaxy. Would the Leo ring be a
has been proposed — a violent collision between two galaxies, slightly more collisional ring, too?
than one billion years ago.
In order to secure this hypothesis, the team used numerical simulations
In the current theories on galaxy formation, the accretion of cold primordial gas (performed on supercomputers at CEA) to demonstrate that the ring was
is a key process in the early steps of galaxy growth. Two main features of indeed the result of a giant collision between two galaxies more than 38 million
primordial gas are that it has never sojourned in any galaxy and that it does not light-years apart. At the time of the collision, the disk of gas of one of the
satisfy the conditions required to form stars. Is such an accretion process still galaxies is blown away and will eventually form a ring outside the galaxy. The
ongoing in nearby galaxies? To answer the question, large sky surveys are simulations allowed the identification of the two galaxies that collided — NGC
undertaken attempting to detect the primordial gas. 3384, one of the galaxies at the center of the Leo group, and M96, a massive
The Leo ring, a giant ring of cold gas 650,000 light-years wide surrounding the spiral galaxy at the periphery of the group. They also gave the date of the
galaxies of the Leo group, is one of the most dramatic and mysterious clouds collision — more than a billion years ago.
of intergalactic gas. Since its discovery in the 1980s, its origin and nature were The gas in the Leo ring is definitely not primordial. The hunt for primordial gas
is still open.

4


TH E
Twinkle no more,
little star:
Adaptive optics
let Mt. Graham
scope reach its
potential
By Tom Beal, The Arizona
Daily Star, Tucson
The Large Binocular Telescope
on Mount Graham, beset for 20
years by wildfires, lawsuits over
endangered squirrels and
sacred Indian land, technical
setbacks and broken mirrors, is
beginning to achieve its vaunted
potential.
The world's best "adaptive
optics" system has been
installed on one of the
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. Hinz said he's kept busy using a prototype of the LBT's adaptive optics
It is a milestone for the LBT, said director Richard Green, and a system that UA astronomers and optical scientists created for the 6.5-
demonstration that ground-based telescopes can continue to have some meter MMT Telescope on Mount Hopkins, south of Tucson.
advantages over space-based ones. The LBT's bigger size and greater resolution "will lead us to be able to
"What impresses me is that this is the result they achieved in the lab get higher contrasts and see things much more faint," he said. That's
under controlled conditions, and they have now reproduced it in the essential, he said, when you are trying to make images of planets a
atmosphere," said Green. million times fainter than the stars they orbit.
The system is a deformable 36-inch mirror only 0.06 inch thick, with 672 Hinz said the LBT will work especially well in the infrared wavelengths.
magnets glued to the back that can change its shape every one- Green said the LBT's advantage in the infrared results from not adding a
thousandth of a second. It was developed by the University of Arizona's lens to the system to correct for the atmosphere. "Because the
Steward Observatory and partners at the Arceti Observatory of the instrument is actually the secondary mirror of the telescope, it doesn't
Italian National Institute of Astrophysics, where it was built. inject any thermal background," he said.
During tests, the new secondary mirror routinely erased 60 percent to 80 At 36 inches in diameter, it is the largest adaptive optics system in
percent of atmospheric disturbance and went as high as 84 percent operation. Its size and thinness make it extremely fragile as well.
distortion-free, according to a measurement known as the Strehl ratio. The first two produced by Arceti broke, one in fabrication and one in
Adaptive optics systems on other large telescopes deliver 30 percent to shipment. Three more have been produced, and the one for the second
50 percent improvement in the near-infrared wavelengths tested by the eye of the LBT will be installed next year.
LBT team. Without adaptive optics, the ratio is less than 1 percent. When that occurs, the instrument will finally be able to take advantage of
The astronomers were surprised. "The results on the first night were so its binocular design. Combining the light-gathering properties of both
extraordinary that we thought it might be a fluke, but every night since 8.4-meter mirrors will give it the resolution of a 22.8-meter (75-foot)
then the adaptive optics have continued to exceed all expectations," telescope. At that point, astronomers expect it to have 10 times the
Arceti's Simone Esposito said in a news release. resolution of the Hubble Space Telescope.
The tests were performed at an optimal time, Green said. The spring Much of the buzz in astronomy in the last two decades has centered on
skies over Arizona are relatively clear of moisture and atmospheric orbiting space telescopes such as Hubble, which can peer to the edges
disturbance. of the universe without the image-distorting effects of Earth's
The weather should be equally good this fall when Steward Observatory atmosphere.
astronomer Phil Hinz installs a planet-finding camera. With adaptive optics, ground-based telescopes can capitalize on their
Hinz hopes to produce images of planets that are known or suspected to huge advantage in size. The Hubble's primary mirror is 2.4 meters. The
be orbiting stars, but have never been directly imaged. next generation James Webb Space Telescope will deploy a folding
"We've been waiting for the AO system," Hinz said. "This is a major step. mirror of 6.5 meters -- the largest ever in space.
We've always known it's going to work. It was just a matter of when." The Large Binocular Telescope is owned by a consortium of universities
Hinz said he originally planned to start his search in 2007. "It's like and institutes that include a German group, Ohio State University and
anything you anticipate. It always takes longer than you'd like," he said. Tucson-based Research Corp., on behalf of Notre Dame and the
universities of Minnesota and Virginia.

5


A S TRO N A UTIC A L C A LEN D A R
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.

6


TH E D A RK S ID E
planet scattering, or disruption from the parent star’s binary companion
'Out of Whack' Planetary System Offers star, Upsilon Andromedae B,” McArthur said.
Clues to Disturbing Past Barnes, an expert in the dynamics of extrasolar planetary systems added,
MIAMI —The discovery of a planetary system “out of whack,” where the “Our dynamical analysis shows that the inclined orbits probably resulted
from the ejection of an original member of the planetary system. However,
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 we don’t know if the distant stellar companion forced that ejection, or if the
University of Texas at Austin McDonald Observatory. planetary system itself formed such that some original planets were
ejected. Furthermore, we find the revised configuration still lies right on the
This surprising finding will affect theories of how multi-planet systems
precipice of stability: The planets pull on each other so strongly that they
evolve and shows that some violent events can happen to disrupt planets’
are almost able to throw each other out of the system.”
orbits after a planetary system forms, say researchers.
The two different types of data combined in this research were
“The findings mean that future studies of exoplanetary systems will be
“astrometry” from Hubble Space Telescope and “radial velocity” from
more complicated. Astronomers can no longer assume all planets orbit
ground-based telescopes.
their parent star in a single plane,” McArthur says.
Astrometry is the measurement of the positions and motions of celestial
McArthur and her team used data from Hubble Space Telescope (HST),
bodies. McArthur’s group used one of the Fine Guidance Sensors (FGS)
the giant Hobby-Eberly Telescope, and other ground-based telescopes
on Hubble Space Telescope for the task. The FGS are so precise that they
combined with extensive modeling to unearth a landslide of information
can measure the width of a quarter in Denver from the vantage point of
about the planetary system surrounding the nearby star Upsilon
Miami. It was this precision that was used to trace the star’s motion on sky
Andromedae.
caused by its surrounding — and unseen — planets.
McArthur reported these findings in a press conference at the 216th
Radial velocity makes measurements of the star’s motion on the sky
meeting of the American Astronomical Society in Miami, along with her
toward and away from Earth. These measurements were made over 14
collaborator Fritz Benedict, also of McDonald Observatory, and team
years using ground-based telescopes, including two at McDonald
member Rory Barnes of the University of Washington. The work also will
Observatory and others at Lick, Haute-Provence, and Whipple
be published in the June 1 edition of the Astrophysical Journal.
Observatories. The radial velocity provides a long baseline of foundation
For just over a decade, astronomers have known that three Jupiter-type observations, which enabled the shorter
planets orbit the yellow-white dwarf star duration, but more precise and
Upsilon Andromedae. Similar to our complete, HST observations to better
Sun, Upsilon Andromedae lies about 44 define the orbital motions.
light-years away. It’s a bit younger, a bit
The fact that the team determined the
more massive, and a bit brighter than
orbital inclinations of planets c and d
the Sun.
allowed them to calculate the exact
Combining fundamentally different, yet masses of the two planets. The new
complementary, types of data from HST information changed which planet is
and ground-based telescopes, heavier. Previous minimum masses for
McArthur’s team has determined the the planets given by radial velocity
exact masses of two of the three known studies put the minimum mass for
planets, Ups And c and d. Much more planet c at 2 Jupiters and for planet d
startling, though, is their finding that not at 4 Jupiters. The new, exact, masses
all planets orbit this star in the same found by astrometry are 14 Jupiters for
plane. The orbits of planets c and d are planet c and 10 Jupiters for planet d.
inclined by 30 degrees with respect to
“The HST data show radial velocity
each other. This research marks the
isn’t the whole story,” Benedict said.
first time that the “mutual inclination” of
“The fact that the planets actually
two planets orbiting another star has
flipped in mass was really cute.”
been measured. And, the team has
uncovered hints that a fourth planet, e, orbits the star much farther out. The 14 years of radial velocity information compiled by the team
uncovered hints that a fourth, long-period planet may orbit beyond the
“Most probably Upsilon Andromedae had the same formation process as
three now known. There are only hints about that planet because it’s so far
our own solar system, although there could have been differences in the
out, the signal it creates does not yet reveal the curvature of an orbit.
late formation that seeded this divergent evolution,” McArthur said. “The
Another missing piece of the puzzle is the inclination of the innermost
premise of planetary evolution so far has been that planetary systems form
planet b, which would require precision astrometry 1,000 times greater
in the disk and remain relatively co-planar, like our own system, but now
than Hubble’s, a goal NASA’s planned Space Interferometry Mission (SIM)
we have measured a significant angle between these planets that
could attain.
indicates this isn’t always the case.”
The team’s Hubble data also confirmed Upsilon Andromedae’s status as a
Until now the conventional wisdom has been that a big cloud of gas
binary star. The companion star is a red dwarf less massive and much
collapses down to form a star, and planets are a natural byproduct. Left
dimmer than the Sun.
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 “We don’t have any idea what its orbit is,” Benedict said. “It could be very
same plane. eccentric. Maybe it comes in very close every once in a while. It may take
10,000 years.”
Several different gravitational scenarios could be responsible for the
surprisingly inclined orbits in Upsilon Andromadae. Such a close pass by the primary star could gravitationally perturb the
orbits of its planets.
“Possibilities include interactions occurring from the inward migration of
planets, the ejection of other planets from the system through planet-

7


TH E D A RK S ID E
For 15 bucks,
researchers make
Galileo proud
By Tom Beal, The Arizona Daily Star, Tucson
June 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 "Steve's approach was pretty clever," said Pfisterer. "Even though it's a $20 or
the various lenses and materials proposed for the kit. $30 plastic telescope, a lot of the engineering issues and the programmatic
They did so in the name of increasing interest in astronomy and science in elements are the same as the $100 million instruments."
general, said Pfisterer, president of Photon Engineering. He said most his firm's Pfisterer and Ellis are co-authors on the paper with Pompea, as are Richard
work on the Galileoscope was done by Ellis, the senior optical engineer. Tresch Fienberg of the American Astronomical Society, Douglas N. Arion of
"If we can inspire a couple kids to go into science, then it's worth it," he said. Carthage College and Thomas C. Smith of Merit Models, which made the
production molds.
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 Pompea said some members of the team are also "investors" in the telescope
they used to teach children how telescopes work. project. They had to kick in money to get the telescopes made when they didn't
find an angel or foundation to underwrite it.
The specific goal, said Stephen Pompea of the National Optical Astronomy
Observatory, was to put together a kit that children could assemble and Then they had to wait for payment to pour in before ordering a production run,
understand easily, but produce a telescope good enough to give them the causing a delay that annoyed some early purchasers.
"wow experience" of viewing the rings of Saturn from their own backyard. The important thing, he said, is that the telescopes got into the hands of
It worked. "It's a kid's telescope. It's a kit. It's inexpensive. But we applied the 180,000 youngsters and more are being ordered or donated.
latest techniques in optical engineering to it," said Pompea, head of education Pompea figures the telescopes, which originally sold for $15, are worth about
and public outreach at the National Optical Astronomy Observatory. $100. They are still available from the group's website, now priced at $30.
The telescope's four lenses produce up to 50X magnification with a field of Turnaround time these days is about a week, said Pompea.
view large enough to image the entire moon. It is much clearer and wider than Many were given away to science teachers for use with classroom materials
Galileo's original telescope but is versatile enough to reconfigure into a created as part of the project through NOAO's outreach programs locally,
telescope just like his, if you want a view that is akin to looking through a soda nationally and in Chile, where NOAO operates observatories.
straw.
Arizona Boys and Girls Clubs received telescopes donated by Science
"It does a remarkable job on the moon, on looking into people's houses or Foundation Arizona.
whatever," said Pfisterer. It is so good that it really needs a tripod to steady it,
Donations came from individuals who ordered two telescopes and donated
he said -- and a mount is built in.
one, and from major contributors such as Ric and Jean Edelman, who donated
He said the project is deserving of a paper that Pompea will pre-sent alongside $250,000 to buy 15,000 telescopes for use in science classrooms.
research on the largest, next-generation telescopes at the conference.

TO ACCESS THE SALSA YAHOOGROUP
Go 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!

8


TH E D A RK S ID E
Some of these ideas were questioned seriously when the great comet of 1577
A Primer on Comets attracted the attention of Danish observer Tycho Brahe. He could see no
by Francis Reddy, Astronomy.com 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
Comets are dark, to the stars at different times during the night in an effort to find its parallax —
solid bodies a few a clue to the object's true distance from Earth. His observations, which
kilometers across that indicated that the comet lay beyond the Moon but not as far off as Venus,
orbit the Sun in helped invigorate the scientific study of comets. More than a century later,
eccentric paths. Isaac Newton showed that comets obeyed Johannes Kepler's laws of
Comets can be planetary motion and concluded "comets are a sort of planet revolved in very
described as "dirty eccentric orbits around the Sun."
snowballs" containing
a mixture of dust and Future observations of the comet of 1682 would eventually remove any
frozen gases. Some lingering doubts. Newton's friend Edmond Halley began collecting accurate
of the icy material — cometary observations in 1695 to compare the orbits of many comets. Halley
perhaps less than 1 noticed that several comet orbits seemed similar and shared roughly the same
percent — evaporates period, between 75 and 76 years. "Many considerations incline me to believe
as the comet nears the comet of 1531 observed by Apianus to have been the same as that
the Sun, creating an described by Kepler … in 1607 and which I again observed in 1682," Halley
envelope of gas and wrote. "Whence I would venture confidently to predict its return, namely in the
dust that enshrouds year 1758. And if this occurs, there will be no further cause for doubt that the
the solid body. This other comets ought to return also." Halley's confidence proved well founded
envelope, called the coma, may be up to 620,000 miles (1,000,000 kilometers) — the first comet ever predicted to return was again spotted on
across. Swept back by the solar wind and the radiation pressure of sunlight, December 25, 1758. It has been known as Halley's Comet ever since.
this material forms the comet's tail. Comet tails can span a distance greater Naming comets
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 are more commonly named for their discoverers; up to three
comets as "the closest thing to nothing anything can be and still be independent co-discoverers may share the credit. Increasingly, those
something." discoverers are not individuals, but dedicated small-body discovery programs
or solar-observing satellites. Numerous comets have been named for the
To the naked eye, the coma of a bright comet looks star-like, a tiny ball of light Lincoln Near Earth Asteroid Research (LINEAR) project of the Massachusetts
set within a milky glow. The comet's tail or tails fan out from the coma. If Institute of Technology in Boston, the Near Earth Asteroid Tracking (NEAT)
present, a broad dust tail may be the most striking visual feature. The glowing program operated by the Jet Propulsion Laboratory in Pasadena, California,
gas tail is straighter, narrower and often fainter than the dust tail. Within the and the Lowell Observatory Near-Earth Object Search (LONEOS) run by
coma, and invisible to both the naked eye and the most powerful telescopes, Lowell Observatory in Flagstaff, Arizona. The pace of comet discovery has
lies the small icy body responsible for this grand apparition — the comet's more than doubled in recent decades, up from an average of about a dozen
nucleus. per year in the late 1980s to about 30
Bushy stars per year in this century's opening years.
The Sun-monitoring Solar and
The ancient Chinese names for Heliospheric Observatory (SOHO)
comets reflect their visual satellite has found 850 comets so far.
appearance. A comet with a This tally increases by an average of 80
prominent tail was called a "broom per year, making SOHO history's most
star" (huixing), while one with no prolific, if unintended, comet discoverer.
obvious tail was a "bushy
star" (poxing). Until the Because the names of discoverers don't
mid-1400s, the Chinese made the allow for a unique identification, comets
most detailed and complete receive a more prosaic official name.
observations of comets. As early This consists of a one-letter prefix,
as 200 b.c., they employed official usually a C for "comet" or a P for
skywatchers to record and "periodic," followed by the year of
interpret any new omens in the discovery and an uppercase letter that
heavens. These officials indicates the half-month in which the
recognized, some nine centuries discovery occurred. For example, an A
before their European represents January 1 though 15, B is
counterparts, that comet tails January 16 through 31, and so on. (The
always point away from the Sun. letter I isn't used to avoid confusion with
The Chinese interest in comets, earlier nomenclature that used Roman
however, was for their astrological numerals, and the letter Z isn't
importance as signs of coming necessary.) After this letter comes a
change. 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
The Greeks likewise recognized a comet with an extended tail as a "bearded of October 1982, therefore receives the designation P/1982U1. When the
star" (aster pogonias) and one without a tail as a "long-haired star" (aster return of a comet is well established, either through a recovery or by observing
kometes), from which our modern word derives. Aristotle regarded them as a a second passage through perihelion, astronomers add a number to the prefix.
fiery atmospheric phenomenon, to be lumped together with meteors and the Since Halley was the first comet whose return was identified, its full
aurora. They could not be planets, he reasoned, because comets can appear designation becomes 1P/1982U1.
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 Astronomers have accumulated detailed orbital information on more than
coming droughts and high winds. As these ideas were extended in the Middle 1,500 individual comets. Of those, only about 10 percent complete an orbit
Ages, comets became viewed less as a portent of disaster than as a cause. around the Sun in less than 200 years. A typical "short-period" comet travels
They were viewed as a fiery corruption of the air, pockets of hot contaminated once around the Sun every 7 years in an orbit inclined to Earth's by some 13°,
vapor that could bring earthquakes, disease, and famine. passing no closer to the Sun than about 1.5 AU, or just within the mean

9


TH E D A RK S ID E
distance of Mars. Halley's Comet is the brightest Sungrazers
and most active member of this group. The
remaining population consists of long-period Ikeya-Seki's punishing orbit places it into a category
comets, those that take at least 200 years to of comets known as the "sungrazers." Heinrich Kreutz
return to the inner solar system. So comet extensively examined the orbits of sungrazing comets
aficionados pin their hopes to the unanticipated and suggested that they shared a common ancestry.
arrival of an as-yet-unknown long-period comet. Kreutz argued that the comets he studied are possibly
fragments of some much larger comet that fell apart
How bright will it be? at a close approach to the Sun. Sungrazers have
perihelion distances less than 0.02 AU, orbital periods
The two most important considerations in
of a few centuries, and other distinguishing orbital
assessing the visibility of a comet are its distance
characteristics, but they were also apparently rare.
from the Sun at closest approach, which controls
Brian Marsden of the Harvard-Smithsonian Center for
the comet's activity, and its distance from Earth,
Astrophysics identified eight members, and suspected
preferably after the intense heating of it closest
three others, in his 1965 and 1989 studies of the
approach to the Sun. Halley, for example, was an
Kreutz group. By his second study, 15 apparent
impressive sight in 1910, but anemic in 1986 — a
sungrazing comets had been discovered by the
disappointment even to those who traveled far
SOLWIND and Solar Maximum Mission satellites, and
from city lights. The main difference between the
Marsden noted these "discoveries suggest that
two apparitions was the comet's distance from
members may in fact be coming back to the Sun more
Earth. Halley reached perihelion at a time when
or less continuously." Like these fragments, most of
Earth was on the opposite side of the Sun, and
the comets so far discovered by comet-champion
the comet never came closer to Earth than 0.417
SOHO also do not survive their passage. Marsden
AU (38.7 million miles or 62.4 million km), which
believes that nearly all of them belong to the Kreutz
is about three times the distance of its 1910
group, although there are too few observations to
approach.
uniquely determine their orbits. The SOHO
Another example of the importance of proximity sungrazers are probably just a few meters across.
was the 1983 display of comet IRAS-Araki- Marsden speculates that a historical sungrazer, one
Alcock (C/1983 H1). A small and relatively the Greek Ephorus reported to have split in two
inactive comet, it was discovered first by the pieces in the winter of 372 b.c., might even be the
Infrared Astronomical Satellite (IRAS) in late April granddaddy of them all.
and originally identified as an asteroid. In early
May, amateurs Genichi Araki of Japan and George Alcock of England Comet duds
independently discovered the object. It soon became an obvious sight to the Even when orbital geometry promises a good display, the comet itself may
unaided eye high in the northern sky, and on May 12 the comet brushed past simply fail to cooperate. Comet Kohoutek (C/1973 E1), which was widely
Earth at 0.0312 AU (2.9 million miles or 4.7 million km) — closer than any predicted to be the "comet of the century" in 1973, did manage to become a
comet since 1770. A typical comet might move across the sky by a degree or naked-eye object but never lived up to its publicity. Another example is Comet
so a day, too slowly for the eye to notice. IRAS-Araki-Alcock was so close that Austin (C/1989 X1), discovered in December 1989 by New Zealand amateur
its motion was clearly evident to observers, who compared its Rodney Austin. The comet's orbit was favorable, but as Austin closed on the
movement to that of the minute hand on a clock. At Sun, it failed to maintain its rapid brightening and, in the end, proved a bigger
its best, the comet was about twice the apparent dud than Kohoutek.
diameter of the Moon and looked like a star
nestled within a puff of smoke. It showed no Both Austin and Kohoutek appear to have been new
evidence of a tail — a fine example of a "bushy comets, those making their first close pass
star" — and faded from view by the third week of by the Sun. Astronomers believe that
May. comets originate from two "cold storage"
zones that surround the planetary system.
Intrinsically larger or more active comets can The inner portion of this comet cloud is a
produce a spectacle without getting quite so thick disk centered on the ecliptic that begins
close to us. Comet West (C/1975 V1) near the orbit of Neptune (about 30 AU) and
improved dramatically within a week of its very extends beyond the orbit of Pluto to 50 AU.
close approach to the Sun, aided in large part Often called the Kuiper Belt, it contains a few
by the breakup of its nucleus into four tens of thousands of icy objects larger than
fragments. West dominated the morning sky about a half-mile across; at least 800 are
of early March 1976 with complex gas and currently known. A much larger and more diffuse
dust tails extending 25° or more. A decade component, called the Oort cloud and containing
earlier, an even more spectacular comet, perhaps a trillion comets, forms a Sun-centered
Ikeya-Seki (C/1965 S1), could be seen spherical shell extending from the outer Kuiper Belt
even during the daylight as it raced past to about one-third of a light-year or more into
the Sun, skimming its surface by less space. Many astronomers believe that the Kuiper
than one solar diameter. This intense Belt is the source for the short-period comets and
heating led to the breakup of the that the Oort cloud, from which comets are more
nucleus into at least two fragments and easily dislodged, is the source for the long-period
a corresponding increase in brightness. comets. Feeble gravitational disturbances from
During the days around perihelion, passing stars and interstellar gas clouds remove
Ikeya-Seki could be seen as a star- enough orbital energy from Oort cloud comets that they
like object in broad daylight just by begin their million-year-long fall toward the Sun. Long-
blocking the Sun with a hand — the period comets may arrive from any direction, their
brightest comet of the 20th century. It elongated orbits randomly oriented to the orbits of the
emerged from the Sun's glare in the last week of planets, while the short-period comets are confined
October 1965 sporting a bright tail about 25° long. Any list of closer to the ecliptic. New arrivals from the comet cloud
"great comets" must include both West and Ikeya-Seki. probably retain a coating of highly volatile ices, such as

10


TH E D A RK S ID E
frozen carbon dioxide, that begins to evaporate at much lower temperatures than frozen water. Such comets "turn on" at relatively large distances from the
Sun, but brighten only until the coating evaporates.
Recent great comets
Comet 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 comets
Astronomers 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 ancient
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.

GARNER STATE PARK STAR PARTIES
SALSA 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

11


S KY LIN E
SKYLINE – San Antonio’s Celestial Highlights for July, 2010
From the Scobee Planetarium at San Antonio College
July 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 Phases
July 4th – Last Quarter Moon July 11th– New Moon
July 18th – First Quarter Moon July 25th – Full Moon
July Evening Planets
Venus, 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 Planets
Jupiter, 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 Kelley
Scobee Planetarium Coordinator

12


TH E D A RK S ID E
COMING TO YOU 09.18.2010
International Observe the Moon Night
SEEING THE MOON IN A WHOLE NEW LIGHT

CHECK US OUT ON

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WHO:
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Luna-lovers and anyone really!
he
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WHAT: International Observe the Moon Night
erv

(InOMN) 2010 is the first annual public
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outreach event dedicated to engaging the
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the lunar science and education community,
amateur astronomers, space enthusiasts, and
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the general public in annual lunar
observation campaigns that share the
excitement of lunar science and exploration.

WHERE: 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!

WHEN: September 18, 2010

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

Hosted by:

13


TH E D A RK S ID E
Remember when you looked through
a telescope for the ﬁrst time?

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 catseye@beecreek.net

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

Investing in future discoveries today...

14

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Mae r oi L t fr T eS a
r F i r : ai o “ h e
g s n od ma igio e fh y u g r r-
l, kn t n o te o n e ca
o C l”Mae r oi i lctdi te
f od, r F i r s oae n h
g s tr o te o .
es n h Mon
o tr ig o O e n s rcl r m.
ue r s f ca u P oel u
n a
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me s
moe o ua ln r e trs o a -
r p p lr u a fau e fr ma ee!
tr
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Mon
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Mae rn ulai T eato
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rtr a o e fh ae s o s rd
d
stot n
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h Mon
S hl r rtrS hl r rtrs
c ie C ae:c ie C ae i
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bo g n h p , kn t iee t
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ro s ln r rtr.
Mae r im: r C iim
r C i u Mae rsu
s
cv r 1 60 0su r klmees f
o es 7 ,0 q ae i o tr o
te u a s r c, n i te oaino
h ln r u f e a d s h lct
a o f Mae cai T eS ao Ne-
r Netr : h e f c
s
te o it a l rtr mi inL n
h S ve smpe eu n s o u a
s tr cnan o e t i a mu h
as o tis v r w c s c
e
2.
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aat8 ,0 u i k ta h B g
Iln o Ha ai3 ,0 c bc m)
s d f w i(50 0 u i k .
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to a t ln e n a te atr e g
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fh S a f ee i n ee e 1 ,
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I t r a i n lO s r et eMo n
n e n to a b e v h o
17.
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ih s p n o e y
C p r i s rtrOn o te
o enc C ae: e fh
u
mot rmie caes nte u a
s po n t rtr o h ln r
n a s e C p r i s rtr p n 9
e r i , o enc cae s a s 3
d u
k a di o l a o t 0 miiny as
m n s ny b u 8 0 lo e r
l

Salsa newsletter 07 2010

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