Tuesday, June 5, 2012

2012 Transit of Venus

This image is of the 2012 transit of Venus. Made at 6:05 PM with a Pentax K-r, a Takumar-A 2x tele-converter, a Sigma 100-300mm 1:4.5-6.7 DL lens, and a solar filter made from a sheet of Seymour Solar Optical Thin Film. The image was made on the side of Highway 63 between Fort McMurray and Edmonton. This was taken at ISO 100 with an aperture of f/11 and an equivalent focal length of 900mm. Some sun spots are also visible. The darker parts on the lower right are caused by passing clouds.

I really lucked out in making this image, as is described below.

Transit of Venus, 2012

I had spent a few days working north of Fort McMurray, with the expectation of being back in Edmonton near the beginning of the transit. I brought my gear with me in the field to be sure I had it, should I get stuck staying in camp for an extra day.

By Monday evening, it was obvious that things where not shaping up well weather-wise: the weatheroffice.gc.ca cloud forecast indicated that most of the province would be covered with clouds and that I would need to travel an hour or more south of Edmonton to find clear skies.

As it turned out, we spent longer at a site on Tuesday morning than intended (the morning of the transit). New ETA in Edmonton: 7:30 PM (i.e., about 70% of the way through the portion of the transit that would be visible from Edmonton before the sun set). This would not leave much time for me to drive to Camrose – the closest location that the Clear Sky Charts indicated would be, well… clear.

A couple of hours into our drive home, I knew I would not make it to Camrose, or even Wetaskiwin, before the sun set. Then, I noticed something I had not seen all day: a shadow (to be specific, it was the shadow of a llama in a ranchers field beside the highway… ok, ok… it might have been an alpaca). We drove for another 5 minutes as the sun slowly poked its head fully out of the clouds. I hesitated stopping for a moment, as my colleague Tim still had a long drive ahead of him to Banff after letting me off in Edmonton. But then I came to my senses and pulled off the highway into a small driveway so we could do some observing and take some photos (apologies to Tim and Julien – who’s ETA in Banff, when I last saw them, was about 2 AM).

Tim and I spent about 25 minutes looking through my solar viewer (shade 14 welding glass in a piece of cardboard) and taking photos. I helped Tim tape my solar filter onto the front of his camera lens so he could get a couple of shots too. Then the clouds rolled back in – this time for good.

To sum up: I saw only about half an hour of sunlight all day, and it conveniently happened to occur both during the transit, and more importantly, while I was in control of the vehicle :)