Webfooted Astronomer
The Seattle Astronomical Society
July 2006
Special points of interest:
•
Summer Observing
•
Galaxy
July Meeting:
•
Spirit Finds Meteorites
Meeting Information
Wednesday, July 19
7:30 p.m.
Physics-Astronomy Building
Room A102
University of Washington
Seattle
Come early at 7 p.m. for coffee
and snacks and to visit with
your fellow members!
Barnard's Galaxy
Dr Paul Hodge
Dept. of Astronomy, University of Washington
Dr. Paul Hodge from the University of Washington
will discuss Barnard's Galaxy.
If you have questions or suggestions for future
meetings, don't hesitate to contact me, Bruce Kelley Seattle Astronomical Society - Programs
[email protected]
In this issue:
From the President’s Desk
3
June Meeting Minutes
5
July/August Calendars
8
NASA Space Place:
10
Celebrating 40 Years of Intent
Listening
Space Bits: Current News
12
Seattle Astronomical Society
Address
PO Box 31746
Seattle, WA 98103-1746
SAS Info Line: 206-523-ASTR
Web Page:
http://seattleastro.org
WebfootWeb: [email protected]
E-mail: [email protected]
Board & Committees
Special Interest Groups
President: Thomas Vaughan,
206-772-1282,
[email protected]
Dark Sky Northwest: Bruce Weertman,
[email protected]
Board Chairperson: Stephen Van Rompaey,
425-564-8619,
[email protected]
First VP–Programs: Bruce Kelley,
425-869-8347,
[email protected]
Second VP–Education: Burley Packwood,
[email protected]
Third VP–Membership: Janice Edwards,
[email protected]
Fourth VP–Publicity: Greg Scheiderer,
206-938-5362,
[email protected]
Treasurer: Scott Cameron,
425-745-5057,
[email protected]
Secretary: Chris Karcher,
206-789-7945
[email protected]
Astronomical League: Bob Suryan,
206-789-0599,
[email protected]
Webmaster: Paul Rodman,
425-889-8273,
[email protected]
Club Telescopes & Equipment: Thomas Vaughan,
206-772-1282,
[email protected]
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Telescope Makers: Peter Hirtle,
206-363-0897,
[email protected]
Astrophotography: Keith Allred,
425-821-5820,
[email protected]
Vive La Lune (Moon): Pat Lewis,
206-524-2006,
[email protected]
Sidewalk Astronomers: Paul Ham,
206-522-7410,
[email protected]
Webfooted Astronomer
Editor: Vanessa Long
[email protected]
Circulation Managers: Pat Lewis & Joanne Green,
206-524-2006,
[email protected]
From the President’s Desk…
Summer Observing
By Thomas Vaughan
Summer Observing
I hope you've all had a chance to participate in some of the latest public Star Parties!
Although we don't have many hours of nighttime viewing, I think this is the best time
of year for public outreach. The weather has cooperated lately, and we've had great
turnout at a number of recent events.
I was at the Greenlake Star Party on July 1st, and it was one of my favorite in recent
memory. We had a good collection of telescopes set up, with many SAS members in
attendence. Best of all, there were a large number of people walking by on the lake
path who stopped to take a look. Even with around a dozen telescopes set up, there
were usually 1-2 people in line at each.
I had pointed my telescope at the moon, partly because it was still fairly light, and also
because I was trying to get my finder scope aligned. Many people wanted to look
through. More than one person exclaimed loudly when looking at the scarred features
of the surface: "Wow!" I sometimes take the Moon for granted but these star parties
always remind me to go back and look at it again in detail.
Later in the evening we had good shots and Jupiter and its 4 visible moons (Europa,
Ganymede, Io, and Callisto). I also enjoyed the views of the ring nebula. Several SAS
members were able to get very clear images of the smoky ring, which I always find
impressive from Greenlake.
Although I wasn't at Paramount Park, I've heard from several people that it was also
well-attended by both SAS members and the public.
Don't miss the upcoming public Star Parties! These are the reasons we put up with the
rainy winters :) Over the next 3 months, we have public star parties (at Greenlake and
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Paramount Park) on July 29th, August 26th, and September 30th. Definitely come on
out for one or more, and bring a telescope or binoculars if you have them.
July Events
Don't forget: Table Mountain is July 20th - 22nd. And if you aren't going to Table
Mountain, consider stopping by TrailsFest 2006 at Rattlesnake Lake (http://
www.wta.org/trailsfest/). The SAS will be there, along with a lot of other area
organizations, Saturday July 22nd.
Happy Observing-Thomas
Some Stellar Facts
Proxima Centauri, the second-closest, is 270,000 times farther away than the sun,
almost 25 trillion miles away.
The Summer Triangle is not a whole constellation, but what is called an asterism, a
distinctive pattern of stars.
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SAS June 2006 Club Meeting Minutes
Announcements:
Three new SAS members were welcomed.
The Goldendale star party will be held 9/22 - 9/24 at Brooks Memorial Sate Park..
Contact Karl Schroeder for details.
There is a new IMAX movie playing called “Cosmic Voyage”.
SAS Picnic pictures were shown.
The Dark Sky Site now has 30 members.
Meeting Topic
Maxine Nagel introduced a new meeting feature, “What’s Up”. The topics were:
The difference between an asterism and a constellation - i.e. the Big Dipper in Ursa
Major, “Arc to Arcturus” in the constellation Bootes, the constellation Cancer in the
West shortly after sunset, Saturn and Mars in close approach to M44 (the “Beehive
Cluster”), what it means when a planet is in opposition, Jupiter and its moons Io,
Europa, Ganymede and Callisto. The Milky Way
Meeting was adjourned around 9:00PM.
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Galaxy
A galaxy is a system of stars, dust, and gas held together
by gravity. Our solar system is in a galaxy called the
Milky Way. Scientists estimate that there are more than
100 billion galaxies scattered throughout the visible universe. Astronomers have photographed millions of them
through telescopes. The most distant galaxies ever photographed are as far as 10 billion to 13 billion light-years away. A light-year is the distance that light travels in a vacuum in a year -- about 5.88 trillion miles (9.46 trillion
kilometers). Galaxies range in diameter from a few thousand to a half-million lightyears. Small galaxies have fewer than a billion stars. Large galaxies have more than a
trillion.
The Milky Way has a diameter of about 100,000 light-years. The solar system lies about
25,000 light-years from the center of the galaxy. There are about 100 billion stars in the
Milky Way.
Only three galaxies outside the Milky Way are visible with the unaided eye. People in
the Northern Hemisphere can see the Andromeda Galaxy, which is about 2 million
light-years away. People in the Southern Hemisphere can see the Large Magellanic
Cloud, which is about 160,000 light-years from Earth, and the Small Magellanic Cloud,
which is about 180,000 light-years away.
Groups of galaxies
Galaxies are distributed unevenly in space. Some have no close neighbor. Others occur
in pairs, with each orbiting the other. But most of them are found in groups called clusters. A cluster may contain from a few dozen to several thousand galaxies. It may have
a diameter as large as 10 million light-years.
Clusters of galaxies, in turn, are grouped in larger structures called superclusters. On
even larger scales, galaxies are arranged in huge networks. The networks consist of interconnected strings or filaments of galaxies surrounding relatively empty regions
known as voids. One of the largest structures ever mapped is a network of galaxies
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known as the Great Wall. This structure is more than 500 million light-years long and
200 million light-years wide.
Shapes of galaxies
Astronomers classify most galaxies by shape as either spiral galaxies or elliptical galaxies. A spiral galaxy is shaped like a disk with a bulge in the center. The disk resembles
a pinwheel, with bright spiral arms that coil out from the central bulge. The Milky
Way is a spiral galaxy. Like pinwheels, all spiral galaxies rotate -- but slowly. The
Milky Way, for example, makes a complete revolution once every 250 million years or
so.
New stars are constantly forming out of gas and dust in spiral galaxies. Smaller groups
of stars called globular clusters often surround spiral galaxies. A typical globular cluster has about 1 million stars.
Elliptical galaxies range in shape from almost perfect spheres to flattened globes. The
light from an elliptical galaxy is brightest in the center and gradually becomes fainter
toward its outer regions. As far as astronomers can determine, elliptical galaxies rotate
much more slowly than spiral galaxies or not at all. The stars within them appear to
move in random orbits. Elliptical galaxies have much less dust and gas than spiral galaxies have, and few new stars appear to be forming in them.
Galaxies of a third kind, irregular galaxies, lack a simple shape. Some consist mostly of
blue stars and puffy clouds of gas, but little dust. The Magellanic Clouds are irregular
galaxies of this type. Others are made up mostly of bright young stars along with gas
and dust.
Galaxies move relative to one another, and occasionally two galaxies come so close to
each other that the gravitational force of each changes the shape of the other. Galaxies
can even collide. If two rapidly moving galaxies collide, they may pass right through
each other with little or no effect. However, when slow-moving galaxies collide, they
can merge into a single galaxy that is bigger than either of the original galaxies. Such
mergers can produce spiral filaments of stars that can extend more than 100,000 lightyears into space.
Read more at: http://www.nasa.gov/worldbook/galaxy_worldbook.html
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Celebrating 40 Years of
Intent Listening
[By Diane K. Fisher]
In nature, adjacent animals on the food chain tend to evolve together. As coyotes get
sneakier, rabbits get bigger ears. Hearing impaired rabbits die young. Clumsy coyotes
starve. So each species pushes the other to “improve.”
The technologies pushing robotic space exploration have been like that.
Improvements in the supporting communications and data processing infrastructure
on the ground (the “ears” of the scientists) have allowed spacecraft to go farther, be
smaller and smarter, and send increasingly faint signals back to Earth-and with a fire
hose instead of a squirt gun.
Since 1960, improvements in NASA’s Deep Space Network (DSN) of radio wave
antennas have made possible the improvements and advances in the robotic spacecraft
they support.
“In 1964, when Mariner IV flew past Mars and took a few photographs, the limitation
of the communication link meant that it took eight hours to return to Earth a single
photograph from the Red Planet. By 1989, when Voyager observed Neptune, the DSN
capability had increased so much that almost real-time video could be received from
the much more distant Planet, Neptune,” writes William H. Pickering, Director of JPL
from 1954 to 1976, in his Foreword to the book, Uplink-Downlink: A History of the Deep
Space Network, 1957-1997, by Douglas J. Mudgway.
Mudgway, an engineer from Australia, was involved in the planning and construction
of the first 64-m DSN antenna, which began operating in the Mojave Desert in
Goldstone, California, in 1966. This antenna, dubbed “Mars,” was so successful from
the start, that identical 64-m antennas were constructed at the other two DSN
complexes in Canberra, Australia, and Madrid, Spain.
As Mudgway noted in remarks made during the recent observance of the Mars
antenna’s 40 years of service, “In no time at all, the flight projects were competing with
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radio astronomy, radio science, radar astronomy, SETI [Search for Extraterrestrial Intelligence], geodynamics,
and VLBI [Very Long Baseline Interferometry] for time on the antenna . . . It
was like a scientific gold rush.”
In 1986 began an ambitious upgrade program to improve the antenna’s performance even further. Engineering studies
had shown that if the antenna’s diameter
were increased to 70 m and other improvements were made, the antenna’s
For over 40 years, the “Mars” 70-m Deep Space
performance could be improved by a fac- Network antenna at Goldstone, California, has
vigilantly listened for tiny signals from spacecraft
tor of 1.6. Thus it was that all three 64-m
DSN antennas around the world became 70-m antennas. Improvements have continued throughout the years.
“This antenna has played a key role in almost every United States planetary mission
since 1966 and quite a few international space missions as well. Together with its twins
in Spain and Australia, it has been a key element in asserting America’s pre-eminence
in the scientific exploration of the solar system,” remarks Mudgway.
Find out more about the DSN and the history of the Mars antenna at http://
deepspace.jpl.nasa.gov/dsn/features/40years.html. Kids (and grownups) can learn
how pictures are sent through space at http://spaceplace.nasa.gov/en/kids/
phonedrmarc/2003_august.shtml .
This article was provided by the Jet Propulsion Laboratory, California Institute of Technology,
under a contract with the National Aeronautics and Space Administration.
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Space Bits
Spirit Finds Meteorites?
NASA’s Spirit rover took this photograph of
the surrounding hilly terrain, as well as
several rocks. The two light-coloured, smooth
rocks at the bottom of the picture might be
iron meteorites. Mission controllers have
named them “Zhong Shan” and “Allan Hills”.
Spirit uncovered that the rocks have unusual
morphologies and thermal emission
spectrometer signatures that resemble a rock
called “Heat Shield” discovered by
Opportunity, and later identified as an iron meteorite.
Link: http://www.universetoday.com/2006/07/11/spirit-finds-a-meteorite/
First Pictures After Hubble’s
Breakdown
After its brief breakdown last month, the
Hubble Space Telescope’s main camera is
gathering science data again. The
Advanced Camera for Surveys stopped
functioning after power supply problems,
but engineers were able to switch to a
backup power system and get it back
online. This image was one of the first
taken after the camera resumed operations on July 4th. It shows a galaxy cluster
located 9 billion light-years away. Hubble located a supernova in June 2006, and then
returned to see its afterglow in July.
Link: http://www.universetoday.com/2006/07/13/first-pictures-after-hubbles12‧Seattle
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NASA's Undersea Crew Resurfaces
Three NASA astronauts and a Cincinnati
doctor completed a successful 18-day
undersea mission April 3 to 20, living and
working under the ocean to test space
medicine concepts and moon-walking
techniques.
Link: http://www.nasa.gov/mission_pages/
NEEMO/index.html
Inflatable Habitat Reaches Orbit
Robert Bigelow’s dream of a thriving space tourism
industry took a significant step forward today with
the launch of the Genesis 1 experimental spacecraft.
Bigelow Aerospace reported that the prototype
habitat was successfully lofted into orbit atop a
converted Russian inter-continental ballistic missile.
Once in orbit, it extended its solar panels and began
to inflate. The rocket launched at 6:53 pm Moscow Time, and the company released a
series of statements over the course of the day reporting that everything’s going well.
Link: http://www.universetoday.com/2006/07/12/inflatable-habitat-reaches-orbit/
Meteor explosion seen from Norway
A meteor explosion was recorded over the Oslo Fjord area of Norway last month,
Aftenposten reported Friday. On June 14, NORSAR -- a research foundation in
Norway that studies applied geophysics and seismology -- registered a signal from the
explosion. Officials at NORSAR and at the University of Oslo said remnants of the
meteor can probably be found lying on the ground between the northeast and
southeast of Oslo.
Link: http://www.sciencedaily.com/upi/index.php?feed=Science&article=UPI-120060715-00350700-bc-norway-meteor.xml
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We promise you the sun, moon and stars and we deliver...
The Seattle Astronomical Society is an organization created and sustained by
people who share a common interest in the observational, educational, and
social aspects of amateur astronomy. Established in 1948, the SAS is a
diverse collection of over 200 individuals. A variety of programs and
activities is presented by the SAS throughout the year. Monthly meetings feature speakers on a wide range of topics, from the Hubble
Space Telescope to electronic imaging to personal observing experiences. The club holds public observing "star parties" at Green Lake
every month, dark sky observing parties outside Seattle, plus such activities as meteor watches, public telescope and astronomy displays,
National Astronomy Day, and an annual Awards Banquet.
The Seattle Astronomical Society
PO Box 31746
Seattle, WA 98103-1746
SAS hotline: (206)-523-ASTR
E-mail: [email protected]
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Membership Information
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PO Box 31746
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The Webfooted Astronomer is the monthly publication of the Seattle Astronomical Society (SAS). All opinions
expressed herein are those of the contributors and not necessarily those of SAS. Advertising display rates: full page
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Webfooted Astronomer, PO Box 31746, Seattle, WA 98103, or e-mail to [email protected].
Contents copyright ©2005 for the contributors by the Seattle Astronomical Society.
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