Talk

Do you get frustrated when you finally get a calm, clear night and there are no occultations predicted? I know I do. I recently came across something we could do in those circumstances that uses our existing occultation equipment and is in a related area of astronomy - measuring the position angle and separation of 'wide' double stars. This talk will give a brief introduction to the subject - why, what and who (why do it, what do you do, and who do you send the results to).

This presentation will describe my recent 'adventures' in 3D printing a few parts for a telescope accessory when I found the commercially available part did not fit. Based on my brief experience in this, I will outline the various pros and cons that I've found. I will also have a few of my failures available for the audience to inspect.

The standard method for measuring and correcting for extinction by the Earth's atmosphere is well known. However it requires 'photometric' conditions, i.e. the extinction must be constant across the entire sky and for the whole night. Due to our maritime climate, these conditions are very rare in New Zealand (and I expect it is similar in Australia but the audience is sure to tell me if I'm wrong). Approximately 30 years ago, the Vilnius Observatory developed another, little known, method for measuring and correcting extinction that can cope better with less that photometric conditions. This presentation will describe this method, which I hope will allow us to reduce the systematic error in our results that comes from applying incorrect extinction coefficients.

Colour photometry as a simple alternative to spectra was introduced with the development of filtered photoelectric photometry in the 1950s. It is cruder in some ways and relies heavily upon empirical relationships. However, it is quicker and simpler than spectra and can reach much fainter magnitudes. This presentation initially explains what it is and how it has been used, with a variety of practical examples. It then discusses observational possibilities in a range of astrophysical aspects of stars which show evolutionary or other changes in their light and colour curves.

In 2012, the 30-inch telescope at the Linden Observatory was essentially idle and, literally, collecting dust. Famed supernova hunter and Linden Trustee, Bob Evans, remarked: “the 30-inch telescope needs somebody to love it and to use it”. WSAAG had the expertise and the manpower. In any case, we have had a long-standing, productive relationship with the Linden Trust and Bob was confident that we could look after the telescope. So, WSAAG became caretakers of the telescope. The 30-inch would require a lot of attention to make it practical and safe to use.

Essentially, it had been just manually operated and a visual observer's tool. Our goal was to turn it into a goto/tracking telescope for visual use and one that was also capable of producing reliable video for events such as occultations. As a manually-operated big Dobsonian, it was never intended to be an imaging scope. After 18 years or so, the 30-inch primary mirror was also in dire need of a re-coat and the secondary mirror was in poor condition. Re-coating of the primary and replacement of the secondary would bring the scope closer to its full potential.

This is the story of the upgrade of the 30-inch telescope, the problems presented, the compromises and the solutions and how WSAAG members, with the support of the Linden Trust, have made this into one of the best telescopes around for use by amateur (or professional) astronomers.

Anyone who spends time doing astronomy outreach begins to notice that some questions get repeated. "How far can this telescope see?" is a common one, as well as "what magnification is this?" Some of the most commonly-heard questions will be addressed in this talk, as well as some of the craziest! Bring along your own experience to share, or perhaps find the answer to something that's been puzzling you for a while.

In this presentation, David will talk about IOTA, some of its history, and how they currently observe occultations. He will describe how he has worked with Australian observers to develop new equipment and methods, especially for multi-station deployments, and will discuss the subsequent results from his observations during his and his wife’s year of astro-tourism while in Australia. He will predict how the precision astrometric data from ESA’s Gaia mission, with the first release later this year, will make our efforts more productive and open new opportunities for occultation observers, similar to, but more far-reaching than, the revolution for asteroidal occultations that resulted in 1997 when the results from ESA’s earlier HIPPARCOS space astrometry mission were released.In this presentation, David will talk about IOTA, some of its history, and how they currently observe occultations. He will describe how he has worked with Australian observers to develop new equipment and methods, especially for multi-station deployments, and will discuss the subsequent results from his observations during his and his wife’s year of astro-tourism while in Australia. He will predict how the precision astrometric data from ESA’s Gaia mission, with the first release later this year, will make our efforts more productive and open new opportunities for occultation observers, similar to, but more far-reaching than, the revolution for asteroidal occultations that resulted in 1997 when the results from ESA’s earlier HIPPARCOS space astrometry mission were released.

Of all the night sky, no fields are so rich or challenging to observe than the Large and Small Magellanic Clouds. What follows are some highlights of historical observations of these fields, along with recent visual variable star estimates of selected stars. The first research article mentioning the Clouds available here was published in 1774, after Neville Maskelyne’s trip to the island of St. Helena in the South Atlantic. 60 years later the really pivotal work was undertaken by John Herschel from the Cape of Good Hope in South Africa. In fact, in my opinion Herschel’s chart of the Large Magellanic Cloud published in 1847 is of more practical use than some high profile modern charts of the area. Several stars in the current observing program can be found on this chart. Recent observations focus on what has been done from Linden Observatory west of Sydney, but other people’s work is introduced as much as possible. An unexpected result of writing this talk is that a much more useful observing program of these two galaxies is in place today than existed before.

Scientifically useful spectroscopy by amateurs, which generally means medium/high resolution spectra taken with a slit spectrograph, has been well established in Europe for at least ten years but in the southern hemisphere, mainly Australia, it has only had a couple of active participants until recently. Increased internet coverage, the availability of more cost-effective instruments and a recent online collaborative ring (SASER) has seen a growth in southern participants and valuable pro-am collaborations leading to co-authored papers in leading international journals. This presentation will review the current situation and what is needed by those wishing to get on board the observational astrophysics train.

In March 2016, I will travel to the Indonesian island of Sulawesi to do some scuba diving. All going well, I will then travel to the city of Palu in central Sulawesi to observe and photograph the 2016 total solar eclipse. Will I break my recent run of three clouded out eclipses? Will the organisers of the Palu expedition overcome the logistical and geographical problems and find a cloud-free location in the equatorial jungle of Sulawesi? Will all of my equipment work this time? You will have to attend this talk to find out the answers to these questions.