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BAA Gallery Transit of Venus 2012
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Lyrup, South Australia by Ray Johnson


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About this observation
Ray Johnson
Time of observation
25/07/2012 - 10:04
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This image was taken on 2012-6-6 at 0135UT from Lyrup in South Australia. The equipment used was: 80mm Celestron achro on GSO SV1 mount, Celestron solar filter (white light) + Astronomik green filter and QHY5 colour camera Exposures were 25ms and the disk was imaged over 4 panels with 100 frames recorded for each. ~60/100 frames in each panel were stacked and sharpened in Registax6, with flats to control fixed pattern noise, and the composite was assembled and coloured in theGIMP2. The final image has been resampled by a factor of 0.5 to meet website requirements. The weather was nearly perfect for almost the whole transit, and images were taken every half hour for much of it. I deliberately chose not to find out the exact time of first contact and observed visually for the first half hour or so, in order to partially recreate the excitement that early astronomers must have felt when observing this rare phenomenon. The sight of the planet moving onto the disk as the sun rose above the horizon was spellbinding. Technical comments: the green filter was selected to get the best out of both the achro scope and the colour camera, and to reduce the effects of atmospheric dispersion the combination worked well. The QHY5 was used because it has 1.3mpixels and the whole disk could be covered at fairly high resolution with 4 sub-images. The low end SV1 mount was fitted with a battery powered RA drive, resulting in a very lightweight and self contained system that could be rapidly transported to a new site if clouds interfered as it turned out this was not an issue.
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