On the weekend of 21st-23rd November 2014 the Horowhenua Astronomical Society hosted its second annual astrophotography get-together at Foxton beach, which is situated an hour and a half north of Wellington. The weekend promised to be a great event enabling like-minded people from all over New Zealand a chance to meet and discuss their favourite pastime.
Some of the attendees (Photo: Ian Cooper)
In the end it turned out to be even more successful than last year’s event with over 50 people attending from all over New Zealand – from as far away from Geraldine, Christchurch, Nelson, Auckland, New Plymouth, Wellington and Napier - making it a truly national event.
The purpose of the weekend was to facilitate learning through shared knowledge of all aspects of using digital cameras to photograph the night sky, whether to capture the beauty of the universe, undertake scientific observations or both. There were people present who are interested in all aspects of astrophotography, from deep sky objects, nightscapes, lunar, solar and aurorae to hunting for comets and supernovae. So there was something there for each participant to teach others about, and to learn for themselves too.
As guests arrived on the Friday afternoon it was obvious that the weather was not going to be kind that evening. Although it was not raining it was cloudy and very windy. However, many people set up their astrophotography gear anyway, next to the ‘imaging courtyard’, for point of conversation as well as in the vain chance that the sky might clear.
After the official opening, by the Horowhenua Astronomical Society president Stephen Chadwick, a slideshow of 150 different images, taken by 10 of the attendees, was presented on the big screen. This random selection revealed the great range of interests that astrophotographers have in New Zealand as well as what can be achieved with different equipment. The slideshow was followed by a group discussion, which provided an opportunity for each participant to explain how they had photographed and processed their images.
The Saturday programme was supposed to begin with a practical solar imaging workshop with George Ionas. Unfortunately the Sun was nowhere to be seen so instead the day began with the first of a series of talks. Bill Williams, Professor of Physics at Massey University, gave a talk entitled ‘Wasting Light’. He discussed the process by which CCD sensors capture photons and how optical aberrations can limit the acquisition of light that is so essential for imaging faint astronomical objects.
The second talk was given by Peter Aldous, from Geraldine on the South Island, as well as Robert McTauge, by live internet link, from Timaru. It was made possible with the assistance of the Gifford-Eiby Memorial Lectureship Scheme that is administered by the Royal Astronomical Society of New Zealand. The talk was about astronomical imaging using ‘Hyperstar’. This is a method that enables a Schmidt-Cassegrain telescope to be converted into a fast f/2 imaging system. They explained how it functioned and then gave examples of how much data could be captured in short periods of time. As Peter had brought all the equipment with him guests were able physically to see for themselves how the system works.
Perter Aldous and Robert McTauge (live via Skype on the screen) explaining the advantages of Hyperstar Imaging (Photo: Amit Kamble)
After lunch Stephen Chadwick introduced the audience to a piece of software called ‘CCDInspector’. He showed how it can be used to easily collimate a telescope with a camera in situ. He then explained what causes field curvature and how the software can be used in order to quickly determine the correct spacing between sensor and field flattener in order to achieve a nice flat field. Lastly, he showed how the software can monitor changes in focusing and seeing in real time.
Stephen Chadwick’s presentation on CCDInspector. (Photo: Edwin Rodley)
This was followed by the first processing workshop of the weekend, facilitated by Steve Lang. He introduced the processing software ‘PixInsight’ and went through all the steps necessary to move from unprocessed data to the final result using one of his images of the Eta Carinae Nebula.
Steve Lang processing the Eta Carinae Nebula at the PixInsight Workshop. (Photo: Jonathan Green)
The late afternoon session began with a theoretical presentation, given by physics lecturer Dr Steve Keen. His talk, ‘a beginners’ guide to ISO and exposure’, was aimed at dispelling myths about what the term ‘ISO’ actually means when used in the context of digital cameras and how manufacturers exploit misunderstandings for marketing purposes.
Jonathan Green presenting many of his wide field astronomical images (photo: Ian Cooper)
Jonathan Green then presented many of his inspirational nightscape photographs as well as wide field mosaics of the Milky Way. He showed what can be done with a DSLR on both a stationary tripod as well as on a small portable tracking mount. The Saturday afternoon session ended with the second processing workshop of the weekend, this time facilitated by Stephen Chadwick. He explained some of the processing techniques that can be utilised when using ‘Photoshop’.
The fish and chip supper then arrived, thanks to one of the best chippies in New Zealand – Mr Grumpy! The camp cat was delighted to help polish off any spare fish that was available.
The camp cat (photo: Edwin Rodley)
As night began to fall the weather was still looking very grim so it seemed unlikely that any practical imaging would be possible. But we still had some fascinating presentations ahead. Amit Kamble started the evening session explaining how he processes his fantastic nightscapes. He used a particular example of the Milky Way setting above a road to show all the steps necessary to turn a series of photographs into one extended panorama. This was followed by a talk by Peter Aldous on supernova hunting from a back yard using a CCD camera. Peter has discovered many supernovae over the years and he showed the steps needed to do this as well as the dedication necessary. He ended by explaining why he no longer undertakes this pastime and why he now prefers to capture the beauty of the universe using his ‘Hyperstar’ system.
As the skies were still not clear a few relaxing audio visual presentations were shown. Firstly, Jonathan Green showed a slide show of all the entries in the ‘Harry Williams Astrophotography Trophy’. This was followed by two videos of images taken by Stephen Chadwick. One was called ‘A journey along the southern Milky Way’ and the other ‘A trip around the Clouds of Magellan.’ These presented wide field shots of the Milky Way and the Clouds of Magellan respectively. By zooming in on each object it was possible to look in greater depth at many of the deep sky treasures that they hold.
At this point it was announced that the skies were clearing. Unfortunately the clouds were fast moving so as soon as one hole appeared another disappeared. However, this was just enough to tempt a few intrepid souls outside to set up their gear. It was quite frustrating though as just as an object was framed it disappeared again amongst the clouds. But, at last, one image was taken. At 9.30pm Adam Corbett managed to get an image of the Great Orion Nebula.
(M42 by Adam Corbett) Equipment: Modified Canon 6D, Celestron CGEM mount, Stellarvue 80mm refractor, 1x1min exposure unguided at ISO 1000.
Sunday began and again no solar imaging was possible. However we had a talk by Frank Andrews on how to get started in astrophotography using a DSLR. This was followed by the third processing workshop, this time led by George Ionas, on how to process solar images using ‘Registax’, ‘Microsoft ICE’ and ‘Photoshop’. His intention had been to use data acquired during the weekend but as this had not been possible he used some that, fortuitously, he had brought with him.
George Ionas leads a workshop on solar image processing (photo Edwin Rodley)
The weekend ended with a talk by Ian Cooper on photographing Aurora using many of his own images as examples.
Adam Corbett discusses his imaging set-up to other guests (left-right Andrew Drawneek, Amit Kamble, Adam Corbett (in front), Milind Ghandi, George Ionas, Simon Hills) (photo: Jonathan Green)
Although there had been very little practical imaging undertaken the weekend was a great success. The presentations were all informative and useful but most of all, as was obvious from the constant din of chatter throughout the building, people were learning from each other.
Here’s to the third astrophotography get-together next year.
Horowhenua Astronomical Society
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