That black dot called Venus

June 7, 2012

By David Gray

The alarm woke me at 6am so that I could catch the sun as it rose slowly above the buildings to the east. But this was no ordinary sunrise. This was the morning when the sun had a black dot slowly moving across it, and that black dot was the planet Venus.


Photographing the ‘Transit of Venus’ as it is known, was something that I was not at all familiar with. For a start, the total time would be around 6 hours. This was extremely slow in comparison to the eclipses I had previously photographed, with ‘totality’ (when the moon completely covers the sun) lasting on each occasion just 11 and 90 seconds. These celestial events, of course, involved the sun and the moon, but this one amazingly would involve a planet. The difficulty of this was that the sun would remain at its normal brightness the entire time.

So, I figured this could be dealt with in two ways. As the transit began in Beijing at sunrise, it would be possible to photograph it just as it appeared above the horizon due mainly, believe it or not, to the pollution that blankets Beijing on any normal day. This would reduce the brightness of the sun enough to allow direct viewing and thus making a photograph possible without the need for any filters. So I awoke at 6am, walked onto my balcony, and to my surprise, could not even see the sun. The haze was so thick in the morning, that the sun was totally obscured. So I waited. 6.30am came and still nothing. 7am rolled on with the sky completely lit up but still with no sun visible. Then at 7.30am, I could just make out a small circle of red peeking through the grey. I grabbed my 400mm lens, added a 1.4x converter, and took some frames. At first I didn’t see anything, but when I magnified the image on the back of my camera, there it was, a black dot that was very obviously not the same as the 3 sun spots also visible.

This was all well and good, but I had to show that it was moving, and that it wasn’t just a stationary object. However this meant that when I needed to next photograph the sun, it would be extremely bright, thus requiring some sort of filter. Previously when photographing eclipses, I had obtained special foil that I used to cover the front of my lens which enabled a picture to be taken. But sadly, since my last eclipse more than three years ago, I could not find it. So, I remembered an old trick that I had seen someone doing in the Australian outback a decade ago – looking through a medical x-ray sheet. I remembered that when I moved to China nearly five years ago, I had to have a lung x-ray to pass the medical examination. So I looked through my desk, and found them still sealed after the doctor had examined them all those years ago. About an hour or so after my previous picture, I placed the x-ray over the front of my lens, moving it around slightly until the sun was just a bright circle, I took a few frames with varying exposures. I put the images into my laptop and to my delight, they once again showed Venus, and slightly further along the suns’ face.

Knowing that this worked, I was hoping to take a picture every hour until it was over. But to my dismay and disappointment, clouds rolled in shortly after my previous picture, and it was not possible to see the transit anymore.

In the end, I was pleased that I had not only managed to get a picture of this extremely rare event, but the fact that I could say I had seen it was very satisfying, especially considering it would not occur again until 2117 – another 105 years. So, doubtful we will make it for THAT viewing.

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