Sydney City Skywatchers

Sydney City Skywatchers is a friendly astronomy group for locals
2015 is the 120th anniversary of this active astronomy club once known as the BAA (British Astronomy Association). Meetings are held at 6:30pm mainly on the first Monday of the month at Sydney Observatory and include a guest speaker and astronomy-related presentations from members. Annual membership is $40 for lots of great benefits ($65 for family membership). Non-members are welcome to attend two meetings before deciding whether to become a member. There is a charge to cover the cost of a light supper – $2 for members; $5 for non-members. Bookings are not required. Meetings conclude around 8:30pm. You can join Sydney City Skywatchers on the evening or take home a membership form.


Monday 7th September

Topic: Determining the 3D structure of a giant molecular cloud: or How I learned to stop worrying and love the command line

Speaker: Anita Petzler, Honours candidate, Department of Astrophysics UNSW


A map of the Giant Molecular Cloud complex G333. © Anita Petzler 2015



While the two dimensional structure of astrophysical objects across the sky is easy to measure, determining structure in the third dimension along the line of sight is elusive. I am examining absorption and emission data of carbon monoxide, hydroxyl and atomic hydrogen from Mopra, ATCA and Parkes telescopes. I am using this data to distinguish foreground and background objects in the giant molecular cloud complex G333. To do this I am using several programs, notably kvis, miriad and kpvslice.

Speakers bio: 

As long as I can remember I’ve always loved Astronomy. I grew up in the dark ages of the pre-internet era, so as a kid I would actually sit and read encyclopedia entries on Astronomy and Physics. My goal has always been to get a PhD in Astrophysics and work in research. I completed my Bachelor of Science in Astrophysics at Monash University in 2005. I then completed a Graduate Diploma in Education in 2006 and have been teaching high school Science and Physics since then. Last year I went back to university, this time at UNSW to do Honours part time. This year I am completing the project component of Honours, working under Dr Maria Cunningham in the department of Astrophysics at UNSW. In my project I am attempting to determine the 3D structure of the giant molecular cloud complex G333.



Monday 3rd August 2015

Topic: Revealing magnetic activity in the coolest stellar objects

Speaker: Christene Lynch, postdoctoral research associate at the University of Sydney


Artist’s impression of the “super-aurorae” present at the magnetic poles of a radio emitting dwarf star. Hallinan et al NRAO/AUI/NSF

The discovery of intense, non-thermal radio emission from the lowest mass stars and brown
dwarfs implies the presence of strong magnetic fields. These fields are unexpected given the
fully convective interior and observed sharp decline in chromospheric Hα and coronal X-ray
emission for these objects (collectively called ultracool dwarfs). The exact mechanism for radio
emission from these sources is unclear, but the emission is likely due to a combination of the
cyclotron maser instability and the gyrosynchrotron process. Due to the small number of
detected sources and limited range of frequencies covered with current radio observations,
emission models are not well constrained. Radio surveys of ultracool dwarfs have found that
about 10% of these systems are radio luminous, with a current detection number at 15 sources.
We have conducted a large observational campaign to expand the current catalog of known
radio loud ultracool dwarfs and better characterize the frequency structure of the detected radio
emission. A portion of these observations were obtained using the new wideband receivers on
the Very Large Array and the Australian Telescope Compact Array, providing simultaneous
wideband frequency coverage not previously available. Additionally, we use the Murchison
Widefield Array to look for ultracool dwarfs at frequencies (154 MHz) not previously explored.
The results of this large campaign will be presented and we will summarize the prospects of
detecting ultracool dwarfs with other widefield radio surveys.

Speakers bio: Christene Lynch is a postdoctoral research associate at the University of Sydney. She earned her PhD at the University of Iowa characterising magnetic features in young stars using radio observations. She is currently working with the radio transient group within the ARC Centre of Excellence for All-sky Astrophysics (CAASTRO) to search for radio flares from stars using the newest low-frequecy, widefield radio telescopes.




Monday 6th July 2015

6.30 pm at Sydney Observatory in the Discovery Room

Topic: “Light Pollution:- Dimmer is Brighter”

Speaker: Michael Chapman


Sydney at night from the International Space Station. Image: Earth Science and Remote Sensing Unit, NASA Johnson Space Center.

As amateur astronomers we want to see the stars and the night sky.  Light pollution is about more than the night sky it’s also about your health and the health of our environment.  Light pollution effects humans and animals and insects and fish.  The answers are simple and straightforward.


Michael Chapman is the President of Sydney City Skywatchers and Secretary of Sydney Outdoor Lighting Improvement Society.

Michael is the President of Sydney City Skywatchers and Secretary of Sydney Outdoor Lighting Improvement Society.  As a long time amateur astronomy Michael is also actively involved with challenging light pollution.  Michael is a currently completing a Masters degree at Sydney University studying Illumination Design.

Also on the night… If it’s a clear sky we can set up some ‘scopes prior to the meeting and do some observing – lots of planets in the sky (Venus, Jupiter, Saturn).  If you bring a camera we can try some photography.

Monday 1st June 2015

6.30 pm at Sydney Observatory in the Discovery Room

Topic: A presentation of the film A Sidewalk Astronomer, Featuring John Dobson” – A film by Jeffrey Fox Jacobs
Speaker: Jeffrey Fox Jacobs. New York Amateur Astronomers Association


John Dobson’s life of public service was an inspiration to a great many people. The Sidewalk Astronomers continue to serve the public with large telescopes, providing free “star parties” and slide shows under dark skies and city lights, encouraging people to think and wonder about the Universe and give them a chance to see its beauty with their own eyes

Jeffrey Jacobs is President of Jacobs Entertainment Inc.  As a filmmaker, he produced and directed the documentary, “A Sidewalk Astronomer” featuring John Dobson, which had its international premiere at the Singapore Film Festival. He is a graduate of Brandeis University and received an M.F.A. from the Graduate School of Film and Television at UCLA. He has worked as an editor, production manager, and assistant director. He is presently the film buyer for  screens across the USA


The New Solar System presented by Kerrie Dougherty

Monday 13 April, 7:30pm – note change in start time

Image: NASA/H.Zell. NASA’s Advanced Composition Explorer (ACE) observes a wide array of particles that flow toward Earth from the sun to better understand the great space weather system that connects the sun to our planet.

Robotic planetary exploration has radically changed our understanding of the Solar System over the past 55 years. Join space specialist, author and curator Kerrie Dougherty on a voyage from the dawn of the Space Age to today, presenting the highlights of planetary exploration that have revealed new and important insights for our understanding of our neighbours in space.

120 Years of Astronomy Seminar – open to all 
Saturday 14 March 2015, 5pm to 8:30pm
Held at Sydney Observatory this is an opportunity to hear great speakers focus on the contributions of amateur astronomers.Cost: Celebratory Dinner ticket (see below) includes entry to the seminar held the following evening. Seminar only $10 (includes refreshments). Numbers are limited so reserve your seminar seat today by emailing: secretary@sydneycityskywatchers.asn.au5pm Introduction by Sydney City Skywatchers President, Mike Chapman
5:10pm Keynote presentation by Professor Wayne Orchiston
‘John Tebutt and the Formation of Sydney’s Earliest Astronomical Societies’
6:10pm Refreshments and discussion
6:30pm Sydney City Skywatcher presentations:
•  Monty Leventhal OAM, Steavenson Award ’22 years of Solar Observing’
•  Dr Nick Lomb, IMAgine Award, ‘Closing Encounters: the BAAs attempt to save Sydney Observatory’.
•  Toner Stevenson, PhD candidate  ‘Women in Amateur Astronomy’
•  Harry Roberts, Mike Kerr medal & McNiven Award ‘Astronomical Illustration’

8pm Concluding remarks
8:30pm Optional dinner at the Hero of Waterloo
(not included in seminar cost see website for menu and costs )

120 Years of Astronomy, celebratory Sydney City Skywatchers dinner
Friday 13 March 2015, 7-10pm.
Special guest presentation by Dr David Malin.
Founded in 1895, this is the 120th anniversary of this, the second oldest operating astronomical group in Australia and to celebrate there is a special dinner being held in the beautiful Sydney Observatory marquee. The evening includes canapes and main course, wine and sparkling water and musical interludes by the ‘Highly Irregular Orbits’ light music duo. It’s a unique way to celebrate a history of curious minds and astronomical observations. Tickets on sale now! Cost: $80 per person ($70 earlybird by 13 February). Members guests are welcome. Numbers are limited so email your booking by 5pm 11 March to:



6:30pm, Monday 2 MARCH, 2015
Professor Wayne Orchiston (National Astronomical Research Institute of Thailand) presents:
‘Joseph Ward and the Historic Cooke Refractor at the Wanganui Observatory, New Zealand’

Joseph Ward c 1921. Image source

Until quite recently, the historic 9.5-in Cooke refractor at the Ward Wanganui Observatory in the North Island city of Wanganui was the largest refracting telescope in New Zealand. Manufactured in 1859, this is an internationally-important telescope since it is a ‘type specimen’ (in zoological parlance) and features the first all-metal English equatorial mounting ever made. The telescope was used for serious research in England during the nineteenth century, and subsequently in New Zealand after it transferred ‘down under’ in 1902. The man responsible for bringing the telescope to New Zealand was Joseph Ward (1862–1927), who is a remarkable character. He not only discovered many new double stars with the Cooke telescope, but also made refractors and reflectors on a commercial basis. His largest telescope was a 20.5-in Newtonian reflector, which has an interesting history. Professor Orchiston will discuss the English and New Zealand histories of the historic Cooke refractor, and Ward’s bid to make astronomical telescopes more widely available throughout New Zealand at a reasonable price.

Sydney City Skywatchers are very grateful to the Donovan Astronomical Trust for helping fund Professor Orchiston’s visit to Sydney.

Bio: Wayne Orchiston was born in New Zealand, but grew up in Sydney. In 1959 he joined the NSW Branch of the British Astronomical Association, was elected to the Committee at the age of 16, and eventually served as President. Later he was elected an Honorary Life Member when the Branch closed and the Sydney City Skywatchers was formed. Wayne’s early observational interests were in sunspots, meteors, the planets and variable stars, but he also developed a passion for the history of Australian astronomy and particularly the achievements of the Branch’s first President, John Tebbutt of Windsor.

Wayne has B.A. Honours and Ph.D. degrees from the University of Sydney and formerly worked at the CSIRO’s Division of Radiophysics, Sydney Observatory (part-time), Victoria College (later Deakin University, in Melbourne), the National Observatory of New Zealand (as Director), the Anglo-Australian Observatory and the CSIRO’s Australia Telescope National Facility (in Sydney), and finally James Cook University (Townsville) before joining the National Astronomical Research Institute of Thailand (NARIT) a little over two years ago, where he is a Senior Researcher. He is co-founder and Editor of the Journal of Astronomical History and Heritage, and in 2013 the IAU named minor planet 48471 Orchiston after him.

6:30pm, 2 FEBRUARY, 2015
Craig Anderson, Doctoral Candidate, The University of Sydney. 
‘By unfair means: Wresting secrets from active galaxies using preposterously powerful radio telescopes and a little bit of voodoo’.

If you want a Universe that looks like ours 13.8 Billions years after a Big Bang, we now know that active galaxies are a crucial ingredient in the recipe. The energy released from actively feeding black holes is enormous. When this energy is fed back into material in the host galaxy itself, or even into the tenuous material surrounding the galaxy, it can have a profound effect on how these objects subsequently evolve. However, knowing that active galaxies have such an effect does not imply that these processes are well understood. We remain ignorant of many aspects of this basic picture, including (but not limited to) how the activity in these galaxies is triggered, how long it lasts, how the energy emitted by these processes is distributed back into the material in the universe, and how these processes have changed through cosmic time. In this talk I will discuss how an old, promising and slightly sneaky technique — the analysis of a phenomenon called Faraday rotation — is finally coming into its own with the firepower afforded by next generation radio telescopes. I will discuss what Faraday rotation is, why it is such a unique and powerful tool for studying active galaxies, some recent exciting results from the scientific literature, and the exciting science that we can look forward to in the next 10 years and beyond.

Cygnus A. Image courtesy of NRAO/AUI

Bio: Craig Anderson is a 33 year old PhD student working at the University of Sydney. Craig completed his bachelors degree in science in 2003. Following this, he worked for CSIRO in their Minerals division for 6 years, all the while cultivating a lifelong passion for both amateur and professional astronomy. In 2009 he returned to the University of Sydney to study honours level physics, and to undertake research into the processes that trigger the feeding of super-massive black holes in large galaxies. In 2010, he was awarded an Australian Laureate Scholarship to undertake a PhD under the supervision of Prof. Bryan Gaensler and Dr. Ilana Feain. Craig’s PhD thesis involves using one of Australia’s most powerful radio telescopes to study magnetic fields in the structures in and around galaxies containing super-massive black holes. When he’s not working on his research, Craig can be found at Sydney Observatory, eye glued to the eyepiece, indulging his obsession while helping others to make astronomy theirs.


W. J. MacDonnell's observatory in Mosman, c 1907

From left: William John Macdonnell, Mrs Macdonnell, Nathanial Basnett and G. D Hirst in front of Macdonnell’s private observatory in Mosman, c.1907. He was a leading member of the NSW branch of the British Astronomical Association – a forerunner of the Sydney City Skywatchers.