AEA Astronomy Club
Newsletter December
2016
Contents
AEA Astronomy Club News & Calendar p.1
Video(s) & Picture(s) of the Month p. 1
Astronomy News p. 6
General Calendar p. 11
AEA Astronomy Club News & Calendar p.1
Video(s) & Picture(s) of the Month p. 1
Astronomy News p. 6
General Calendar p. 11
Colloquia, lectures, mtgs. p. 11
Observing p. 13
Observing p. 13
Useful
Links p. 14
About the Club p. 15
Club News & Calendar.
Club Calendar
About the Club p. 15
Club News & Calendar.
Club Calendar
Club Meeting Schedule:
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1 Dec
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AEA Astronomy Club Meeting
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(A1/1735)
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5 Jan
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AEA Astronomy Club Meeting
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(A1/1735)
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AEA
Astronomy Club meetings are now on 1st Thursdays at 11:45 am. For all of 2016, the meeting room is A1/1735.
Club
News:
Mark
Clayson was re-elected president of the club, and Alan Olson was re-elected
treasurer. Any help from others will be
greatly appreciated, including finding club speakers, help with STEM or other
events – see Mark Clayson for any of those.
And help planning use of club equipment in the Aug. 21 total solar
eclipse – see David P. Taylor and Kirk Crawford to volunteer for that.
Astronomy Video(s)
& Picture(s) of the Month
(from Astronomy
Picture of the Day, APOD: http://apod.nasa.gov/apod/archivepix.html
VIDEO: ISS Fisheye Fly-Through https://apod.nasa.gov/apod/ap161105.html
Image Credit: NASA, ISS, Harmonic
Explanation: Shot
in Ultra HD, this stunning video can take you on a tour of the International Space
Station. A fisheye lens with sharp focus and extreme depth of field
provides an immersive visual experience of life in the orbital outpost. In the
18 minute fly-through, your point of view will float serenely while you watch
our fair planet go by 400 kilometers below the seven-windowed Cupola,
and explore the interior of the station's habitable nodes and modules from an
astronaut's perspective. The modular International Space Station is Earth's
largest artificial
satellite, about the size of a football field in overall length and
width. Its total pressurized volume is approximately
equal to that of a Boeing 747 aircraft.Image Credit: NASA, ISS, Harmonic
Arp 299: Black Holes in Colliding Galaxies
Image Credit: NASA, JPL-Caltech, GSFC, Hubble, NuSTAR
Explanation: Is only one black hole spewing high energy radiation -- or
two? To help find out,
astronomers trained NASA's Earth-orbiting NuSTAR and Chandra telescopes on Arp
299, the enigmatic colliding galaxies expelling the radiation. The
two galaxies of Arp
299 have been locked
in a gravitational combat for millions of years, while their
central black holes will soon do battle themselves. Featured,
the high-resolution visible-light image was taken by Hubble,
while the superposed diffuse glow of X-ray light was imaged by NuSTAR and shown in
false-color red, green, and blue. NuSTAR observations show that only one of the central black holes is seen fighting its way through a
region of gas and dust -- and so absorbing matter and emitting X-rays. The
energetic radiation, coming only from the galaxy center on the right, is surely created nearby -- but outside -- the central black
hole's event horizon.
In a billion years or so, only one composite galaxy will remain, and only one central supermassive
black hole. Soon thereafter, though, another galaxy may enter the
fray.Image Credit: NASA, JPL-Caltech, GSFC, Hubble, NuSTAR
Soyuz vs Supermoon
Image Credit: NASA, Bill Ingalls
Explanation: Faster
than a speeding bullet, more powerful than a locomotive, and able to
leap tall buildings in a single bound, this Soyuz rocket stands on the launch
pad at Baikonur Cosmodrome in Kazakhstan on November 14.Beyond
it rises a supermoon,
but fame for exceptional feats of speed, strength, and agility is not the
reason November's Full Moon was given this popular name. Instead, whenever a
Full Moon shines near perigee, the closest point in its elliptical
orbit around Earth, it appears larger and brighter than other more
distant Full Moons, and so a supermoon is born. In fact,
November's supermoon was the second of three consecutive supermoons in 2016. It
was also the closest and most superest Full Moon since 1948. Meanwhile, the
mild mannered Soyuz rocket is scheduled to launch its Expedition
50/51 crew to the
International Space Station today, November 17.Image Credit: NASA, Bill Ingalls
Cold Weather Delayed over North America
Image Credit: Climate Reanalyzer, CCI, U. Maine
Explanation: Why is it so warm in northern North America? Usually during
this time of year -- mid-November -- temperatures average as much as 30 degrees colder. Europe is not seeing a similar warming. One
factor appears to be
an unusually large and stable high
pressure region that
has formed over Canada,
keeping normally
colder arctic air
away. Although the fundamental cause of any weather pattern is typically
complex, speculation holds that this persistent Canadian anticyclonic region is related to warmer than
average sea surface temperatures in the mid-Pacific -- an El
Niño -- operating last
winter. North
Americans should enjoy
it while it lasts, though. In the next week or two, cooler-than-average
temperatures now being recorded in the mid-Pacific -- a La
Niña -- might well
begin to affect North American wind and temperature patterns.Image Credit: Climate Reanalyzer, CCI, U. Maine
Pluto's Sputnik Planum
Image Credit: NASA, Johns Hopkins U./APL, Southwest Research Inst.
Explanation: Is there an ocean below Sputnik Planum on Pluto? The
unusually smooth 1000-km wide golden expanse, visible in the featured
image from New Horizons,
appears segmented into convection cells.
But how was this region created? One hypothesis
now holds the answer to be a great impact that stirred up
an underground
ocean of salt water
roughly 100-kilometers thick. The featured
image of Sputnik Planum,
part of the larger heart-shapedTombaugh
Regio, was taken last July and shows true details in exaggerated colors.
Although the robotic New
Horizons spacecraft is off on a new
adventure, continued computer-modeling of this surprising surface
feature on Plutois
likely to lead to more refined speculations about what
lies beneath.Image Credit: NASA, Johns Hopkins U./APL, Southwest Research Inst.
Astronomy
News:
Astronomers observe star reborn in a flash
Published:
Tuesday, September 13, 2016 - 19:01 in Astronomy
& Space
Related images
ESA/Hubble & NASA
An international team of astronomers using
Hubble have been able to study stellar evolution in real time. Over a period of
30 years dramatic increases in the temperature of the star SAO 244567 have been
observed. Now the star is cooling again, having been reborn into an earlier
phase of stellar evolution. This makes it the first reborn star to have been
observed during both the heating and cooling stages of rebirth. Even though the
Universe is constantly changing, most processes are too slow to be observed
within a human lifespan. But now an international team of astronomers have
observed an exception to this rule. "SAO 244567 is one of the rare
examples of a star that allows us to witness stellar evolution in real
time", explains Nicole Reindl from the University of Leicester, UK, lead
author of the study. "Over only twenty years the star has doubled its
temperature and it was possible to watch the star ionising its previously
ejected envelope, which is now known as the Stingray Nebula."
SAO 244567, 2700 light-years from Earth, is
the central star of the Stingray Nebula and has been visibly evolving between
observations made over the last 45 years. Between 1971 and 2002 the surface
temperature of the star skyrocketed by almost 40 000 degrees Celsius. Now new
observations made with the Cosmic Origins Spectrograph (COS) on the NASA/ESA
Hubble Space Telescope have revealed that SAO 244567 has started to cool and
expand.
This is unusual, though not unheard-of [1],
and the rapid heating could easily be explained if one assumed that SAO 244567
had an initial mass of 3 to 4 times the mass of the Sun. However, the data show
that SAO 244567 must have had an original mass similar to that of our Sun. Such
low-mass stars usually evolve on much longer timescales, so the rapid heating
has been a mystery for decades.
Back in 2014 Reindl and her team proposed a
theory that resolved the issue of both SAO 244567's rapid increase in
temperature as well as the low mass of the star. They suggested that the
heating was due to what is known as a helium-shell flash event: a brief
ignition of helium outside the stellar core [2].
This theory has very clear implications for
SAO 244567's future: if it has indeed experienced such a flash, then this would
force the central star to begin to expand and cool again -- it would return
back to the previous phase of its evolution. This is exactly what the new
observations confirmed. As Reindl explains: "The release of nuclear energy
by the flash forces the already very compact star to expand back to giant
dimensions -- the born-again scenario."
It is not the only example of such a star,
but it is the first time ever that a star has been observed during both the
heating and cooling stages of such a transformation.
Yet no current stellar evolutionary models
can fully explain SAO 244567's behaviour. As Reindl elaborates: "We need
refined calculations to explain some still mysterious details in the behaviour
of SAO 244567. These could not only help us to better understand the star
itself but could also provide a deeper insight in the evolution of central stars
of planetary nebulae."
Until astronomers develop more refined models
for the life cycles of stars, aspects of SAO 244567's evolution will remain a
mystery.
Source: ESA/Hubble
Information Centre
The supernova that wasn't: A tale of 3 cosmic eruptions
Published:
Saturday, September 3, 2016 - 05:07 in Astronomy
& Space
Kiminki et al./NASA
1800s, astronomers surveying the night sky in
the Southern Hemisphere noticed something strange: Over the course of a few
years, a previously inconspicuous star named Eta Carinae grew brighter and
brighter, eventually outshining all other stars except Sirius, before fading
again over the next decade, becoming too dim to be seen with the naked eye.
What had happened to cause this outburst? Did 19th-century astronomers witness
some strange type of supernova, a star ending its life in a cataclysmic
explosion?
"Not quite," says Megan Kiminki, a
doctoral student in the University of Arizona's Department of Astronomy and
Steward Observatory. "Eta Carinae is what we call a supernova impostor.
The star became very bright as it blew off a lot of material, but it was still
there."
Indeed, in the mid-20th century Eta Carinae
began to brighten again.
The aftermath of the "Great
Eruption" of the mid-1800s, which is now readily visible through a small
telescope if you happen to be in the Southern Hemisphere, made Eta Carinae a
celebrity among objects in the universe known for their bizarre beauty. An
hourglass-shaped, billowing cloud of glowing gas and dust enshrouds the star
and its companion. Known as the Homunculus nebula, the cloud consists of stellar
material hurled into space during the Great Eruption, drifting away at 2
million miles per hour.
By carefully analyzing images of Eta Carinae
taken with NASA's Hubble Space Telescope, Kiminki and her team were surprised
to discover that the Great Eruption was only the latest in a series of massive
outbursts launched by the star system since the 13th century. Published in the
journal Monthly
Notices of the Royal Astronomical Society, the paper was co-authored by
Nathan Smith, associate professor in the UA's Department of Astronomy, and
Megan Reiter, who obtained her Ph.D. from the same department last year and is
now a postdoctoral fellow at the University of Michigan.
The expansion rate of gas that was far
outside the Homunculus indicated that it was moving slowly and must have been
ejected centuries before the observed 19th-century brightening. In fact, the
motions of the outer material point to two separate eruptions in the mid-13th
and mid-16th centuries.
For scientists trying to piece together what
makes star systems such as Eta Carinae tick, the findings are like the
stereotypical smoking gun in a detective story.
"From the first reports of its
19th-century outburst up to the most recent data obtained with advanced
capabilities on modern telescopes, Eta Carinae continues to baffle us,"
Smith says. "The most important unsolved problem has always been the
underlying cause of its eruption, and now we find that there were multiple
previous eruptions. This is a bit like reconstructing the eruption history of a
volcano by discovering ancient lava flows."
Although the glowing gases of the Homunculus
nebula prevent astronomers from getting a clear look at what's inside, they
have figured out that Eta Carinae is a binary system of two very massive stars
that orbit each other every 5.5 years. Both are much bigger than our sun and at
least one of them is nearing the end of its life.
"These are very large stars that appear
very volatile, even when they're not blowing off nebulae," Kiminki says.
"They have a dense core and very fluffy envelopes. If you replaced our sun
by the larger of the two, which has about 90-100 solar masses, it could very
well extend into the orbit of Mars."
Because the Homunculus nebula is such an
iconic and visually stunning object, it has been a popular target of
astronomical observations. A total of eight images, taken over the course of
two decades with Hubble, turned out to be a treasure trove for Kiminki and her
co-authors.
The original goal of the team's observing
program was to measure proper motions of stars and protostellar jets -- fast
streams of matter ejected by young stars during formation -- in the Carina
Nebula, but the same data also provided a powerful way to measure the motion of
debris ejected by Eta Carinae itself.
"As I was aligning the images, I noticed
that the one that Eta Carinae in it was more difficult to align," Kiminki
says. "We can only use objects as alignment points that aren't moving, and
I thought, 'Wow, a lot of this stuff is really moving.' And then we decided to
take a closer look."
By aligning the multi-epoch images of the
nebula, the team was able to track the movement of more than 800 blobs of gas
Eta Carinae had ejected over time and derived a likely ejection date for each.
The analyses showed that the Homunculus nebula and the observed 19th-century
brightening tell only part of the story. Measuring the speed with which wisps
of ejected material expand outward into space revealed that they must have
resulted from two separate eruptions that occurred about 600 and 300 years
before the Great Eruption of the 19th century.
In addition to having a separate origin in
time, the older material also showed a very different geometry from the
Homunculus, where material was ejected out from the star's poles and appears
symmetric about its rotation axis.
"We found one of the prior eruptions was
similarly symmetric, but at a totally different angle from the axis of the
Great Eruption," Kiminki explains. "Even more surprising was that the
oldest eruption was very one-sided, suggesting two stars were involved, because
it would be very unlikely for one star to blow material out toward just one
side."
Though perplexing, the findings are a big
step forward for astronomers trying to understand what causes the frequent
outbursts.
"We don't really know what's going on
with Eta Carinae," Kiminki says. "But knowing that Eta Carinae
erupted at least three times tells us that whatever causes those eruptions must
be a recurring process, because it wouldn't be very likely that each eruption
is caused by a different mechanism."
"Even though we still have not figured
out the underlying physical mechanism that caused the 19th-century eruption, we
now know that it isn't a one-time event," Smith says. "That makes it
harder to understand, but it is also a critical piece of the puzzle of how very
massive stars die. Stars like Eta Carinae apparently refuse to go quietly into
the night."
Eta Carinae's eruptions provide unique
insights into the last unstable phases of a very massive star's life.
Researchers who study supernovae have identified a subclass of supernova
explosions that appear to suffer violent eruptions shortly before they finally
explode. Smith notes that Eta Carinae might be our nearest example of this.
Because it takes light 7,000 years to travel
from Eta Carinae to Earth, much could have happened in the meantime, Kiminki
says. "Eta Carinae may have gone supernova by now, and we wouldn't know
until 7,000 years from now."
Source: University
of Arizona
General Calendar:
Colloquia, Lectures, Seminars, Meetings, Open Houses & Tours:
Colloquia, Lectures, Seminars, Meetings, Open Houses & Tours:
Colloquia: Carnegie (Tues.
4pm), UCLA, Caltech (Wed. 4pm), IPAC (Wed. 12:15pm) & other Pasadena (daily
12-4pm): http://obs.carnegiescience.edu/seminars/
Carnegie
astronomy lectures
– only 4 per year in the Spring www.obs.carnegiescience.edu. Visit www.huntington.org for directions. For more
information about the Carnegie Observatories or this lecture series, please
contact Reed Haynie. . Click here for more information.
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1 Dec
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AEA Astronomy Club Meeting
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(A1/1735)
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2
Dec
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Friday Night 7:30PM SBAS Monthly General Meeting
in the Planetarium at El Camino College (16007 Crenshaw
Bl. In Torrance)
Topic: “The Planet…VULCAN?! (The real one…sorta)”
David Nakamoto, LAAS
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10 Dec
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LAAS
LAAS General Meeting.
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Griffith
Observatory
Event Horizon Theater 8:00 PM to 10:00 PM |
December 15 & 16 The von Kármán Lecture Series: 2016
Spinning
Black Holes, Exploding Stars, and Hyperluminous Pulsars: Recent Results from
the NuSTAR Satellite
NASA's
Nuclear Spectroscopic Telescope Array, or NuSTAR, launched in June 2012 and
became the first telescope in orbit to focus high energy X-ray light. This
powerful X-ray emission provides a unique probe of the most energetic phenomena
in the universe, from flares on the surface of the Sun, to the explosions of
stars, to the extreme environments around neutron stars and black holes. The
crisp, sensitive images enabled by NuSTAR's new technology have dramatically
changed our picture of the extreme universe. This talk will present some of the
highlights from the first four years of NuSTAR observations, including the
surprising discovery of a new class of hyperluminous neutron stars,
measurements of how fast black holes spin, and unique insight into the physics
of supernova explosions.
Speaker:
Dr. Daniel K. Stern, NuSTAR Project Scientist, JPL
Dr. Daniel K. Stern, NuSTAR Project Scientist, JPL
Webcast:
Click here to watch the event live on Ustream (or archived after the event)
Click here to watch the event live on Ustream (or archived after the event)
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Locations:
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Thursday, Dec 15, 2016, 7pm
The von Kármán Auditorium at JPL 4800 Oak Grove Drive Pasadena, CA › Directions Friday, Dec 16, 2016, 7pm The Vosloh Forum at Pasadena City College 1570 East Colorado Blvd. Pasadena, CA › Directions |
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Webcast:
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We offer two
options to view the live streaming of our webcast on Thursday: › 1) Ustream with real-time web chat to take public questions. › 2) Flash Player with open captioning If you don't have Flash Player, you can download for free here. |
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5 Jan
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AEA Astronomy Club Meeting
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(A1/1735)
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13
January
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SBAS Friday
Evening 7:30 PM Monthly General
Meeting
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Topic: TBD Speaker: TBD
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22 Jan. Emeritus Prof. Bruce
Runnegar
The Cryogenian, coldest time
in Earth History
Location:
UCLA, Slichter 3853Time: 2:30PM
We are now in (and probably leaving) one of the coldest periods
in Earth history. Previous icehouse intervals occurred about 300, 700 and 2000
million years ago. During one of these periods, the Cryogenian, glacial ice
extended to sea level in the tropics. We shall discuss this so-called Snowball
Earth event in terms of its origin, and its effects on our planet and its life.
Image credit: Chris Butler/SPL
Observing:
The
following data are from the 2016 Observer’s Handbook, and Sky & Telescope’s
2016 Skygazer’s Almanac & monthly Sky at a Glance.
Current
sun & moon rise/set/phase data for L.A.:
http://www.timeanddate.com/astronomy/usa/los-angeles
Sun,
Moon & Planets for December:
Moon: Dec 7 1st
quarter, Dec 14 full, Dec 21 last quarter, Dec 29 new
Planets:
Mercury,
Venus& Mars are up for 1-3 hours after
sunset. Jupiter
& Saturn are visible for 1-3 hours before sunrise (Saturn only
beginning Dec. 27).
Other
Events:
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10 Dec
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LAAS
Public Star Party: Griffith Observatory Grounds 2-10pm
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7,14,21,28 Dec
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LAAS
The Garvey Ranch Observatory is open to the public every
Wednesday evening from 7:30 PM to 10 PM. Go into the dome to use the 8 Inch
Refractor or observe through one of our telescopes on the lawn. Visit our
workshop to learn how you can build your own telescope, grind your own
mirror, or sign up for our free seasonal astronomy classes.
Call 213-673-7355 for further information.
Time: 7:30
PM - 10:00 PM
Location: Garvey
Ranch Obs. , 781 Orange Ave., Monterey Park, CA 91755
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December Mercury at Greatest Eastern Elongation Easiest time to see
tiny Mercury after sunset.
12
December Moon Occults Aldebaran Watch bright
Aldebaran disappear behind the moon at 7:00 PM PST and then reappear at 8:05.
13
December Geminids Meteor Shower Peak Normally a good
meteor shower with 120-160 meteors/hour.
The full moon will limit observing to the brightest meteors.
22
December Ursids Meteor Shower Peak The Ursids come
from a very narrow stream of comet debris.
One has to be within 12 hours of the peak to seem much. During a good
outburst rates of 160/hour can be seen.
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24 Dec
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SBAS
Saturday Night In Town Dark Sky Observing Session at Ridgecrest Middle School– 28915 North Bay Rd. RPV, Weather
Permitting: Please contact Greg Benecke to confirm that the gate will be
opened! http://www.sbastro.net/
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31 Dec
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SBAS
out-of-town Dark Sky observing – contact Greg Benecke to coordinate a
location. http://www.sbastro.net/.
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LAAS Private dark sky Star Party
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Internet
Links:
Telescope, Binocular & Accessory Buying
Guides
General
About the
Club
Club Websites: Internal (Aerospace): https://aeropedia.aero.org/aeropedia/index.php/Astronomy_Club It is updated to reflect this newsletter, in addition to a listing of past club mtg. presentations, astronomy news, photos & events from prior newsletters, club equipment, membership & constitution. We have linked some presentation materials from past mtgs. Our club newsletters are also being posted to an external blog, “An Astronomical View” http://astronomicalview.blogspot.com/.
Club Websites: Internal (Aerospace): https://aeropedia.aero.org/aeropedia/index.php/Astronomy_Club It is updated to reflect this newsletter, in addition to a listing of past club mtg. presentations, astronomy news, photos & events from prior newsletters, club equipment, membership & constitution. We have linked some presentation materials from past mtgs. Our club newsletters are also being posted to an external blog, “An Astronomical View” http://astronomicalview.blogspot.com/.
Membership. For information, current dues & application, contact Alan Olson, or see the club website (or Aerolink folder) where a form is also available (go to the membership link/folder & look at the bottom). Benefits will include use of club telescope(s) & library/software, membership in The Astronomical League, discounts on Sky & Telescope magazine and Observer’s Handbook, field trips, great programs, having a say in club activities, acquisitions & elections, etc.
Committee Suggestions & Volunteers. Feel free to contact: Mark Clayson, President & Program Committee Chairman (& acting club VP), TBD Activities Committee Chairman (& club Secretary), or Alan Olson, Resource Committee Chairman (over equipment & library, and club Treasurer).
Mark Clayson,
AEA Astronomy Club President
