july 2011 - Astronomical Society of Southern Africa

july 2011
monthly newsletter of the johannesburg centre of assa
Total Lunar Eclipse, 15 June 2011
(Read further on page 4)
Photo: Gary Els, 10” Meade LX200, Canon 550D

canopus july 2011
page 2
8 June 2011: Space Shuttle and Space Station Photographed Together
Credit: NASA (http://apod.nasa.gov/apod/ap110608.html)
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Notice of Next Meeting – ASSA Johannesburg
canopus july 2011
Next meeting at Johannesburg Observatory, 18a Gill St, Observatory
Wednesday, 13 July 2011 at 7.30 pm
The Annual General Meeting of the ASSA Johannesburg Centre
(Read more on page 8)
Portfolio/Interest Name E-mail Contact Details
Chairman Gary Els gels@randwater.co.za 082 389 2250
Vice-Chairman Constant Volschenk starmanza@gmail.com 083 442 8169
Secretary, Membership
Secretary & Librarian
Alec Jamieson alec.jamieson@telkomsa.net 082 654 5336
Treasurer Heather Dalgleish hdalgleish@groupfive.co.za 082 417 6350 a/h
Viewing Officer Eric Brindeau eric.brindeau@gmail.com 083 698 8310
Curator of Instruments Michael Robins m.robins@ziehl-abegg.co.za 082 900 8371
Asst. Curator of Instruments Dave Hughes --- 082 412 6665
Public Relations Officer Sharon Tait labelconnection@mweb.co.za 082 455 0819
Webmaster Barend Botha bjbotha@yahoo.com 083 284 3496
Committee member Melvyn Hannibal Melvynh@iburst.co.za 011 435 6007
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Canopus Team
Editor: Eric Brindeau (eric.brindeau@gmail.com)
Advertising: Alec Jamieson (alec.jamieson@telkomsa.net)
Printing and Distribution: Alec and Sue Jamieson
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Chairman’s Chat
By Gary Els
What a wonderful sight, the Total Lunar Eclipse on the 15 th of June — I trust many of
our members were able to experience this heavenly phenomenon. The next day I
was watching BBC World News where they showed and interviewed people from
Johannesburg and around the world during the event, all so overwhelmed at the
beautiful red Moon. Those in Asia reported that the Moon had a more coppery
colour due to the volcanic ash in the atmosphere.
I spent the evening with a small group of friends in my observatory at home. Some
had never seen a Lunar Eclipse before, and their amazement was wonderful to see.
With my laptop attached to the camera on my telescope, we were able to see the
Moon “live” on the screen and with each image captured and reviewed all were
able to comment and make suggestions for the next exposure. It really gave a
participatory feeling about the whole event, which I thoroughly enjoyed.
Before eclipse day, I did some reading about Solar and Lunar eclipse stories
throughout the ages on the Astronomy Today website, in order to share with my
visitors, and I would like to mention just two of them from that site.
Ho and Hi, the Drunk Astronomers (2137 BCE)
page 4
Throughout the centuries, Chinese astronomers devoted substantial efforts towards
predicting eclipses. However, like all similar efforts prior to the Renaissance, this could only
be by empirical research. The earliest record of a solar eclipse comes from ancient
Chinese history since October 22, 2137 BCE. Ancient Chinese astronomy was primarily a
governmental activity. It was the astronomer's role to keep track of solar, lunar and
planetary motions and explain what they meant to the ruling emperor.
Eclipse observation in China around 1840: Astronomers calmly observe an eclipse and the servants,
terrified, prostrate themselves on the ground to placate the bad omen.
According to legend, the royal astronomers Ho and Hi dedicated too much of their time
to consuming alcohol and failed to predict a forthcoming eclipse. Traditionally, the solar

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eclipse recorded in the Shu Ching was regarded as having occurred the 3rd millennium
BCE. On the first day of the month, in the last month of autumn, the Sun and the Moon did
not meet (harmoniously) in Fang' ... so runs the text. The emperor became very unhappy
because, without knowing that there was an eclipse coming, he was unable to organize
teams to beat drums and shoot arrows in the air to frighten away the invisible dragon. The
Sun did survive, but the two astronomers lost their heads for such negligence. Since then, a
legend arose that no one has ever seen an astronomer drunk during an eclipse.
Now I wonder if the legend of drunken astronomers is still true today!!? Of cause on
eclipse night in the observatory, we were totally sober sipping a glass of wine.
Christopher Columbus' Eclipse (1504 CE)
After a long trip to the Americas in 1503, in his fourth voyage, Columbus was stranded on
the island of Jamaica. In principle, he managed to obtain provisions from the Caciques
natives in exchange for some trinkets and rubbish. As the months went by, novelty and
hospitality started to decrease and also the sailors became more aggressive with the
natives in order to obtain food. Then the native Jamaicans communicated to the Spanish
that they would not provide any more supplies.
Columbus became desperate with the
threat of famine and came up with an
ingenious plan. He checked his
Calendarium, which contained
predictions of lunar eclipses for several
years. In particular, it predicted a total
eclipse of the Moon on the Antilles on
February 29, 1504 CE. That evening, he
invited the Caciques on-board his
Capitana for a serious conversation. He
told them that they were Christians and
their God did not like the way they had
been treating them and would punish
the Indians with famine and pestilence
and, as a sign of dissatisfaction, he would darken the Moon. As soon as he said that, the
Earth's shadow started to cover the white disk. Terrified, the natives begged Columbus to
bring back the light.
He replied that he needed to consult his God. He shut himself in a cabin for nearly two
hours. Just before the end of totality, he reappeared and announced that God had
given his pardon, and would bring them back the Moon provided that the Christians were
given provisions. Immediately, the Moon reappeared. Astonished, the natives
immediately provided Columbus and his crew their needed provisions until they were able
to return to Europe.
With all the nonsense doing its rounds again on the internet, such as two suns will appear
in the night sky, it’s great to see real predictions being enjoyed by so many, and I hope
no one was manipulated as Columbus did in 1504 AD.
Gary
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Notes on the Monthly Meeting
By Melvyn Hannibal
The evening commenced with feedback from Gary Els about the dark-sky weekend
at Suikerbos Nature Reserve. He showed us some of his photos of the resort and some
he took through our 12" telescope.
Dave Blane gave us brief run down on his work with double stars, showing us photos
of his equipment, and extracts from various double star catalogues.
Constant Volschenk told us about the current night skies, and demonstrated the
eclipse on the 15th.
The main speaker was Jonny Rizos from the “South African
National Space Agency”. No, we are not going into
competition with NASA.
This local organisation is concerned with using satellites
that observe the Earth. The Facility is based at
Hartebeesthoek near Krugersdorp. The site was originally
set up by the Americans, and then passed to the CSIR. In
April this year SANSA was formed and given the use of the
site. This is a Radio facility. The data is used to follow urban
growth, land usage, and studies of that nature, and covers
a circular area from three degrees South of the equator.
This covers all of southern Africa.
Melvyn
page 6
Right: Jonny Rizos, from SANSA (Photo: M Hannibal)
Late News Item — 25 June: ASSA website http://assa.saao.ac.za/ states “ASSA
constitution accepted”. The new draft constitution that has been accepted can be
seen at http://assa.saao.ac.za/resource/ASSAConstitutionRedraft2011-05-26.pdf
More information is expected to follow shortly on the consequences of the new
constitution on ASSA Centres and will be notified via ASSA Announce maillist, placed on
the website and in the next Canopus.
Alec Jamieson - Secretary
Upcoming Events
Friday, 1 July 2011
Public viewing
Venue: Johannesburg Observatory, 18a Gill St, Observatory
Starting time: 7:00pm

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Saturday, 2 July 2011
Dark sky viewing from Suikerbosrand (members only)
Venue: Suikerbosrand Nature Reserve, outside Heidelberg
Time: gates close at 4pm
Bring: chairs, food and drink (bring and braai)
Contact: Constant - starmanza@gmail.com (have your car registration available)
Wednesday, 13 July 2011
The Annual General Meeting of the ASSA Johannesburg Centre
Members will be able to nominate candidates for election to the Committee for
the year ending June 2012 – read more on page 8
Venue: Telescope Lecture Room, JHB Observatory, 18a Gill St, Observatory
Starting time: 7:30pm
Saturday, 23 July 2011 (RSVP by 15 July)
ESSA/ASSA/ATM Star party - Exploration Society of Southern Africa (ESSA),
Astronomical Society of Southern Africa (ASSA), Amateur Telescope Makers (ATM)
Venue: Paul's farm, Magaliesburg, +/- 2 hour drive from Joburg or Pretoria
(detailed directions and instructions will be sent by e-mail closer to the time)
Time: it is advisable to arrive at about 15h00
Cost: R30 for ESSA/ASSA/ATM members, R50 for non-members (children and
people bringing telescopes free)
Accommodation: camping available for diehards at R20 for the night
Viewing opportunity: ASSA Jhb will be taking the 12" Meade to the event and
members will have a chance so see how it performs under a dark sky
RSVP: by 15 July, Simon Donally: donallys2@yahoo.fr
Thursday, 28 July 2011
Science in Science Fiction? Are Sci-Fi Futures far-fetched fantasy or feasible fact?
Venue: Auditorium, Sci-Bono Discovery Centre, Miriam Makeba Street
between Jeppe & President, Newtown, Joburg (secure lit parking available)
Time: 6:30 for 7:00 pm
RSVP: speaktoascientist@sci-bono.co.za
Contact: Refilwe Pico (011 639 8448) for more information
Friday 29 to Sunday 31 July 2011
West Rand Astronomy Club Annual Star Party: all are welcome
Venue: Mountain Sanctuary Park, Magaliesberg (private nature reserve, about
120km north-west of Johannesburg and 90km west of Pretoria)
Accommodation: options are chalets, log cabins or camping - telescopes will
be set up in an open field between campsites 14 & 16
Bookings: please contact Mountain Sanctuary Park @ Tel: (014) 534-0114
(08H00-17H00, 7 Days a week), e-mail: owen@mountain-sanctuary.co.za, web:
www.mountain-sanctuary.co.za
Contact: Kenny Neville on 082 335 1983, email: kenny@wrac.org.za
Program & further details: visit www.wrac.org.za
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Monday 3 to Friday 7 October 2011
62nd International Astronautical Congress
Venue: Cape Town International Convention Centre
Visit: http://iac2011.com for more information
ASSA JHB AGM: Notice of Meeting – 13 July 2011
The Annual General Meeting of Members of the ASSA Johannesburg Centre will be
held in the Telescope Lecture Room at the Johannesburg Observatory on
Wednesday 13 th July 2011, commencing at 7:30 pm.
Agenda
1. Notice of meeting.
2. Welcome
3. Attendance / Apologies.
4. Confirmation of the previous minutes.
5. Office Bearers’ reports for the year ended 30th June 2011:
5.1. Chairman’s report, Gary Els.
5.2. Treasurer's report, Heather Dalgleish.
5.3. Membership Secretary and Librarian’s report, Alec Jamieson.
5.4. Curator of Instruments report, Gary Els in the absence of Michael Robins.
5.5. Observing report, Eric Brindeau.
5.6. Astro-photography, Gary Els.
6. Awards and prize giving.
7. General.
8. Final nominations for the election of Committee members.
9. Voting.
10. Results of the Committee election.
11. Closure.
12. Snacks and refreshments during vote counting.
ASSA JHB Committee Election: Call for Nominations
By Alec Jamieson
Election of the 2011/2012 committee will take place at the Annual General Meeting to
be held on 13th July 2011, and nominations of candidates for election to the committee
are requested.
Nominations must be in writing, and received by the Secretary by 11th July 2011:
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by hand;
or by post to P. O. Box 412323, Craighall, 2024;
or by e-mail to alec.jamieson@telkomsa.net ;
or by fax to 011 886 7288. Note: this is a manual fax, please phone first.
Late nominations will be accepted at the AGM at the discretion of the Electoral Officer
and the names of late nominees will not appear on the voting form.
There is no prescribed nomination form. For guidance, a typical nomination would take
the form shown below.
I, ............................................. nominate ......................................... for election to the
Name printed Name printed
2011/2012 ASSA Johannesburg Centre Committee.
Seconded .................................... ................................................. ..............................
Name printed Signature Date
Accepted .................................... ................................................. ..............................
Name printed Signature Date
For a nomination to be valid, all names appearing on a nomination must be names of
members in good standing with the Centre.
In the case of e-mail nominations, the Secretary will confirm the nominations
telephonically, using telephone numbers recorded in the membership database.
To encourage wider participation in the committee, more than the minimum 7 members
may be elected. A committee must consist of at least a chairman, vice-chairman,
secretary, treasurer and 3 other members. The newly elected committee chooses the
chairman by consensus, and thereafter the chairman leads the discussion in the
allocation of other responsibilities. For this reason it is not possible to nominate candidates
for election to a particular position on the committee.
New ideas are vital to any organisation, so recently joined members should not feel
excluded from participating in the ASSA Jhb Centre Committee.
Alec Jamieson, Secretary.
New Members
The Committee would like to welcome the following new members to the ASSA
Johannesburg Centre:
Member No Name
1201 Norman Leibowitz
1202 Kerry McArthur
page 9

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M41 – Your Best Friend
By Magda Streicher
Canis Major is a special constellation because of its shape and the impression it creates
for a star-lover. It houses bright and outstanding objects and, of course, the brightest star,
Sirius.
NGC 2287, also known as Messier 41, appears to be hiding itself under the belly of the
doglike figure, like a bunch of fleas, about 4º south of Sirius. This beautiful cluster of
approximately 100 stars, which can be seen with the naked eye and partly resolved
using binoculars, is moving away from us at about 34 km per second and is said to be
about 24 light years across and 2 300 light years away.
This is one of the few deep sky objects to have been recorded by the ancients: it was
mentioned by Aristotle in 325 BC. It is one of the delights of the sky, with the grouping
reminding me of a lovely flower opening its petals in clear curls and curved lines. Two
rust-coloured stars, magnitude 6.8 and 7.3, remind me of pollen threads flowing out of a
central crown consisting of a semi-circle of bright members. A swarm of faint stars covers
the cluster like powder dust with a few dark patches between chains of faint stars. The
magnitude 6 star 12 Canis Majoris shares the field of view towards the south-east.
M41 – Like a flower opening its petals in clear curls and curved lines (Sketch: Magda Streicher)
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Name Object RA: DEC: Magnitude Size
M41 Open Cluster 06h41m.2 -20 o 44’52” 4.5 38.0’
It is easy to make friends with fellow astronomers, as they are usually friendly and
winsome people. Eric Brindeau, who was so helpful to me and did such an outstanding
job at Canopus, became such a friend. Although, sadly, he will be leaving his position at
the end of June, he remains a friend to me and to everyone else at Canopus.
— Thanks Magda! Your articles have inspired me to find new and exciting objects. I wait
in anticipation for your forthcoming book — Editor
Magda Streicher
magdalena@mweb.co.za
Magda—a past President of ASSA—is a passionate deep-sky observer and views
from excellent, dark skies on a farm close to the Zimbabwe border. Her fascination
in the stars goes back to childhood and over the past 15 years has contributed
greatly to visual astronomy in SA, helping to motivate others to observe and record
deep-sky objects. Using 12” and 16” Schmidt-Cassegrain telescopes, she hunts
down and sketches these faint fuzzies, sharing her interest through regular talks and
articles. She contributes to various deep sky sections in SA as well as publications
like Canopus and Deep Sky Delights, her regular deep sky column in MNASSA
(Monthly Notes of the Astronomical Society of SA). Magda is currently working on
her book “Astronomy Delights”, which she plans to finish towards the end of year.
Satellite Phone Dish to be Turned into Telescope
Submitted by Eric Brindeau
http://www.irishtimes.com/newspaper/ireland/2011/0510/1224296602827.html
The Irish Times - Tuesday, May 10, 2011: A 32-metre satellite dish originally used in the
1980s to take transatlantic calls from Europe to the US is to be reborn as a deep
space radio telescope.
The huge dish was originally constructed in Co Cork in 1984 but was retired in the
mid-1990s when new fibre-optic transatlantic cables were laid.
There are only a handful of these dishes remaining globally, many of which have
fallen into disrepair.
Right: Arek Pilat, a satellite engineer at Elfordstown
Earthstation, Midleton, Co Cork, with the former
telephone satellite dish which is to become a deep
space radio telescope available to students for
educational purposes.
Photograph: Gerard McCarthy (Irish Times)
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Yesterday at Elfordstown Earthstation, Midleton, Co Cork, Minister of State for
Research and Innovation Seán Sherlock announced a partnership between the
National Space Centre and Cork Institute of Technology (CIT) which will see the dish
start a new life as a telescope. The telescope will be capable of detecting a host of
cosmic phenomena including the emission of giant, slow moving hydrogen clouds,
the violent explosions of stars, eruptions of the solar surface and storms on Jupiter.
It will be the only 32m radio telescope available to primary students for educational
purposes in Europe.
Phase one of the project will see the telescope operational by the end of this
summer, with feeds available in September via the internet to primary and post
primary schools.
Phase two will occur in 2012 and will involve the refurbishment of the dish to enable it
to turn as it originally did and the installation of sensors and new receivers. The
project will be co-ordinated and operated by CIT under Dr Niall Smith, head of
research, and Blackrock Castle Observatory.
Dr Smith said this project will see a €10 million radio telescope brought back to life for
less than €10,000 thanks to the partnership between the National Space Centre and
CIT.
“It’s a great example of using world-class infrastructure in the most cost-effective
way to reach out into the community and to embed our growing scientific heritage
alongside our world-renowned culture.
“It will excite students in schools who will get to listen in on the radio signals from outer
space.
“It will be a test bed for engineering and science projects from primary through to
PhD.” The project will benefit education and skills training, and research and
development and provide incomparable hands-on training and research
opportunities for students from primary through to PhD level.
Mr Sherlock said the National Space Centre is already active in European Space
Agency (ESA) programmes including the Galileo Satellite Navigation Programmes.
“Ireland’s ESA membership has contributed to the development of a highly
knowledge-intensive industry sector with over 60 Irish technology companies having
secured ESA contracts worth over € 60 million since 2000.
“We expect this number to grow significantly in 2011,” the Minister added.
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ASSA JHB Dark Sky Weekend: 27-29 May 2011
By Antonio De Franca (Pretoria Centre member)
The Suikerbos Nature Reserve is situated in the Vredefort Dome area approximately 22km
southeast of Potchefstroom, near Venterskroon. This splendid area is declared a World
Heritage Site and it boasts a number of interesting treasures e.g. wildlife, bird life, fauna &
flora and a rich geological history. This area is mountainous and picturesque with
minimal light pollution.
Attending the ASSA weekend (from left to right): Sue & Alec Jemieson, Tony De Franca, Trevor Gould,
Tracey Benadie, Lee Herbst, Gary Els and Melvyn Hannibal.
page 14
Observing conditions were
considered ideal, clear and
although bitterly cold on the first
night, it proved to be one of the
finest night skies seen in a long
time. Those who attended were
mostly from the Joburg Centre
and needless to say they were a
friendly and helpful bunch of
amateur astronomers to say the
least. Four telescopes were set
up including the enormous and
impressive Meade LX200 12 inch
Schmidt Cassegrain telescope.
Above: although bitterly cold on the first night, observing conditions were considered ideal

Alec Jamieson and Melvyn Hannibal did the duty of erecting
the magnificent telescope on to its large tripod. Gary Els,
Chairman of the Johannesburg Centre also attended the
event. His enthusiasm for astro-photography brought some
more interest to the evening’s business. Spectacular photos
were taken of NGC 5139 or Omega Centauri, M17 or “Swan
nebula”, NGC 2070 commonly known as the “Tarantula
nebula” in the Large Megellanic Cloud (LMC), NGC 4755 or
“Jewel box” in Crux, only to mention a few of these gems.
Gary and Antonio photographed the Milky Way without the
aid of a telescope. These images were equally impressive: by
using a standard 18-55mm lens, wide aperture, high ISO
setting (3200 to 6400) and 5 to 40 second exposures produced
stunning results of the “heavens above”.
canopus july 2011
Above: Alec Jamieson setting up the 12” Meade
Portrait of The Milky Way: Nikon D60 camera, 18-55mm lens, 30 sec exposure
Further observations included Saturn, M4 globular cluster in Scorpius, NGC 5822 open
cluster in the constellation of Lupus the Wolf, M44 “Beehive open cluster” in Cancer and
a few more.
Saturday morning was welcomed by a proposal to visit a geological site in an
abandoned granite quarry near Venterskroon.
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Trevor expertly explained
how granite rock was
impacted by the
meteorite to form a black
crystallised molten rock
called “pseudotachylite”.
This rock was caused by
high impact pressure on
the existing granite and it
took millions of years to
cool down to its current
state.
Right: Trevor Gould describing
the geology after the meteorite
impact 2000 million years ago
The Vredefort Dome was a result of a meteorite impact. This occurred approximately
2000 million years ago and the damage caused when the meteorite collided in this
region was massive. The size of the meteorite was about 10km wide. The speed of this
meteorite was so fast that it exploded when it hit the ground. It blasted a mammoth
crater. This meteorite made a crater of about 300km in diameter and approximately
5km deep. This is the largest and oldest meteorite impact known according to
geologists.
In conclusion the outing was entertaining and fun with plenty jokes and laughter despite
the low turnout. A special thanks to the members of the Johannesburg Centre who
hosted the event, it was certainly a prelude to the next exciting astronomy event.
SA Astronomers Find Evidence for Planetary System
Submitted by Sharon Tait
http://www.saao.ac.za/no_cache/public-info/news/news/article/199/
page 16
Astronomers in South Africa find evidence for a strange new
planetary system
14 June 2011: Drs. Stephen Potter and Encarni Romero-Colmenero from the South
African Astronomical Observatory (SAAO) and collaborators have found evidence
for the existence of an extraordinary planetary system where two giant planets are
orbiting a close pair of “suns”.
If confirmed, this will be an example of a very strange planetary system, given the nature
of the stellar pair. The two stars, referred to as a white dwarf and a red dwarf, are each
smaller than our Sun and are so close that they take only a couple of hours to orbit each
other. The pair of them would actually fit comfortably within our Sun! By chance, the
system is oriented in such a way that the stars appear to eclipse each other once every
orbit as viewed from Earth. Dr. Potter and his collaborators noticed that the eclipses were

canopus july 2011
not occurring on time, but were sometimes too early or too late. This led them to
hypothesize the presence of two giant planets whose gravitational effect would cause
the stars' orbit to wobble and consequently slightly alter the measured time between
eclipses. The astronomers were also able to infer that the masses of the two planets must
be at least 6 and 8 times that of Jupiter and take 16 and 5 years respectively to orbit the
two stars. The system is too far away from us to be imaged directly.
Artist impression (Credit: http://www.saao.ac.za/typo3temp/pics/9f2c961304.jpg)
This binary star system (known as UZ For) would be an extremely inhospitable
environment. Due to their close proximity, the gravity of the white dwarf is constantly
“stealing” material from the surface of the red dwarf in a continuous stream. This
stream crashes onto the white dwarf where it gets super-heated to millions of
degrees and subsequently floods the entire planetary system with enormous
amounts of deadly X-rays.
This discovery was made possible by new SAAO and Southern African Large
Telescope (SALT) observations combined with archival data spanning 27 years,
gathered from multiple observatories and satellites.
A Big Surprise from the Edge of the Solar System
Submitted by Lerika Cross
June 9, 2011: NASA's Voyager probes are truly going where no one has gone before.
Gliding silently toward the stars, 9 billion miles from Earth, they are beaming back news
from the most distant, unexplored reaches of the solar system.
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Mission scientists say the probes have just sent back some very big news in deed. It's
bubbly out there.
page 18
Old view (Credit: http://science.nasa.gov/media/medialibrary/2011/06/09/oldview.jpg)
New view (Credit: http://science.nasa.gov/media/medialibrary/2011/06/09/newview.jpg)
Old and new views of the heliosheath. Red and blue spirals are the gracefully curving magnetic
field lines of orthodox models. New data from Voyager add a magnetic froth to the mix.

canopus july 2011
“The Voyager probes appear to have entered a strange realm of frothy magnetic
bubbles,” says astronomer Merav Opher of Boston University. “This is very surprising.”
According to computer models, the bubbles are large, about 100 million miles wide, so it
would take the speedy probes weeks to cross just one of them. Voyager 1 entered the
“foam-zone” around 2007, and Voyager 2 followed about a year later. At first
researchers didn't understand what the Voyagers were sensing—but now they have a
good idea.
“The sun’s magnetic field extends all the way to the edge of the solar system,” explains
Opher. “Because the sun spins, its magnetic field becomes twisted and wrinkled, a bit
like a ballerina’s skirt. Far, far away from the sun, where the Voyagers are now, the folds
of the skirt bunch up.”
When a magnetic field gets severely folded like this, interesting things can happen. Lines
of magnetic force criss-cross and “reconnect”. (Magnetic reconnection is the same
energetic process underlying solar flares.) The crowded folds of the skirt reorganize
themselves, sometimes explosively, into foamy magnetic bubbles.
“We never expected to find such a foam at the edge of the solar system, but there it is!”
says Opher’s colleague, University of Maryland physicist Jim Drake.
Theories dating back to the 1950s had predicted a very different scenario: The distant
magnetic field of the sun was supposed to curve around in relatively graceful arcs,
eventually folding back to rejoin the sun. The actual bubbles appear to be selfcontained
and substantially disconnected from the broader solar magnetic field.
Energetic particle sensor readings suggest that the Voyagers are occasionally dipping in
and out of the foam—so there might be regions where the old ideas still hold. But there is
no question that old models alone cannot explain what the Voyagers have found.
Says Drake: “We are still trying to wrap our minds around the implications of these
findings.”
The structure of the sun’s distant magnetic field—foam vs. no-foam—is of acute scientific
importance because it defines how we interact with the rest of the galaxy. Researchers
call the region where the Voyagers are now “the heliosheath.” It is essentially the border
crossing between the Solar System and the rest of the Milky Way. Lots of things try to get
across—interstellar clouds, knots of galactic magnetism, cosmic rays and so on. Will these
intruders encounter a riot of bubbly magnetism (the new view) or graceful lines of
magnetic force leading back to the sun (the old view)?
The case of cosmic rays is illustrative. Galactic cosmic rays are subatomic particles
accelerated to near-light speed by distant black holes and supernova explosions. When
these microscopic cannonballs try to enter the solar system, they have to fight through
the sun’s magnetic field to reach the inner planets.
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“The magnetic bubbles could be our first line of defense against cosmic rays,” points out
Opher. “We haven’t figured out yet if this is a good thing or not.”
On one hand, the bubbles would seem to be a very porous shield, allowing many
cosmic rays through the gaps. On the other hand, cosmic rays could get trapped inside
the bubbles, which would make the froth a very good shield indeed.
“We’ll probably discover which is correct as the Voyagers proceed deeper into the
froth and learn more about its organization1,” says Opher. “This is just the beginning,
and I predict more surprises ahead.”
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Credit: www.lab-initio.com/thumbnail/nz058B.jpg

Sharon’s APOM
Sharon Tait shares with us her favourite Astronomy Picture of the Month.
canopus july 2011
Photo credit: http://www.nasa.gov/multimedia/imagegallery/image_feature_1914.html
The View from Up Top
A low pressure system in the eastern North Pacific Ocean is featured in this image
photographed on Mar. 20, 2011 by an Expedition 27 crew member in the Cupola of
the International Space Station. Just under ten feet in diameter, the Cupola
accommodates two crew members and portable workstations that can control
station and robotic activities. The multi-directional view allows the crew to monitor
spacewalks and docking operations, as well as provide a spectacular view of Earth
and other celestial objects as evidenced in this image.
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Credit: www.lab-initio.com/thumbnail/nz398.jpg
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canopus july 2011
The Sky this Month
Data provided by Brian Fraser
Site location: lat. 26.0 deg S long. 28.0 deg E local time – UT = +2.0 hrs.
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Local time of Rise and Set
Date Sun Mercury Venus Mars Jupiter Saturn Uranus
Rise Set Rise Set Rise Set Rise Set Rise Set Rise Set Rise Set
Jul 5 6 57 17 30 8 28 19 8 6 9 16 37 4 34 15 8 1 54 13 11 11 56 0 11 23 34 11 37
Jul 10 6 57 17 32 8 32 19 24 6 16 16 44 4 30 15 2 1 38 12 54 11 37 23 52 23 15 11 17
Jul 15 6 56 17 34 8 31 19 35 6 23 16 51 4 27 14 56 1 21 12 36 11 17 23 33 22 55 10 57
Jul 20 6 55 17 37 8 26 19 40 6 28 16 59 4 23 14 51 1 4 12 19 10 58 23 15 22 35 10 37
Jul 25 6 52 17 39 8 16 19 40 6 33 17 8 4 18 14 45 0 47 12 1 10 39 22 57 22 15 10 18
Jul 30 6 50 17 42 8 0 19 33 6 37 17 17 4 14 14 40 0 30 11 43 10 21 22 38 21 55 9 58
Aug 4 6 47 17 44 7 39 19 16 6 39 17 26 4 9 14 35 0 12 11 25 10 2 22 20 21 35 9 38
Aug 9 6 43 17 47 7 13 18 51 6 41 17 35 4 4 14 29 23 54 11 6 9 43 22 2 21 14 9 17
Aug 14 6 39 17 49 6 42 18 16 6 42 17 44 3 58 14 24 23 36 10 47 9 25 21 44 20 54 8 57
Aug 19 6 35 17 51 6 11 17 37 6 43 17 53 3 53 14 19 23 17 10 28 9 6 21 27 20 34 8 37
Aug 24 6 30 17 54 5 45 17 3 6 42 18 1 3 46 14 14 22 58 10 9 8 48 21 9 20 13 8 17
Aug 29 6 25 17 56 5 30 16 41 6 41 18 10 3 40 14 9 22 38 9 50 8 30 20 52 19 53 7 57
Diary of Astronomical Phenomena 2011
July
d h d h
1 8 NEW MOON Eclipse 15 6 FULL MOON
2 23 Mercury 4.9N of Moon 18 6 Neptune 5.3S of Moon
4 18 Earth at aphelion 20 2 Mercury greatest elong E(27)
5 1 Regulus 5.3N of Moon 21 1 Uranus 5.8S of Moon
5 3 Mars 5.4N of Aldebaran 21 22 Moon at apogee
7 13 Moon at perigee 23 5 LAST QUARTER
8 6 FIRST QUARTER 23 21 Jupiter 4.9S of Moon
8 20 Spica 2.4N of Moon 27 2 Moon furthest North (23.3)
10 8 Uranus stationary 27 16 Mars 0.5N of Moon Occn
12 2 Antares 3.4S of Moon 28 23 Mercury 3.1S of Regulus
12 17 Moon furthest South (-23.4) 30 9 Venus 4.1N of Moon
14 0 Pluto 3.3N of Moon 30 18 NEW MOON
August
d h d h
1 8 Regulus 5.2N of Moon 17 8 Uranus 5.7S of Moon
1 10 Mercury 1.3N of Moon 18 15 Moon at apogee
2 6 Mercury stationary 20 9 Jupiter 4.7S of Moon
2 21 Moon at perigee 21 21 LAST QUARTER
5 1 Spica 2.3N of Moon 21 22 Venus 0.9N of Regulus
6 11 FIRST QUARTER 22 23 Neptune at opposition
8 4 Mercury 5.0S of Regulus 23 11 Moon furthest North (23.1)
8 8 Antares 3.5S of Moon 25 12 Mars 2.7N of Moon
8 23 Moon furthest South (-23.2) 26 1 Mercury stationary
10 6 Pluto 3.2N of Moon 28 0 Mercury 2.4N of Moon
13 19 FULL MOON 28 18 Regulus 5.1N of Moon
14 12 Neptune 5.2S of Moon 29 3 NEW MOON
16 12 Venus superior conjunction 30 17 Jupiter stationary
16 23 Mercury 5.9S of Venus 30 18 Moon at perigee
17 1 Mercury inferior conjunction

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canopus july 2011