Venus. A planet that is nearly the twin of Earth is some respects, but also very different. Shrouded in clouds, it shines brightly in the morning or evening skies. Its atmosphere highly acidic, its surface temperature hundreds of degrees.

For the most part it isn't a very interesting imaging target. It's thick cloud cover results in a featureless white disc. (In fact, images taken in the near infrared can sometimes show a little bit of structure in the clouds... but you have to be into that kind of thing.) Occasionally, however, Venus can transit the Sun, and that provides an interesting imaging opportunity. Venus transits occur in pairs separated by eight years. The most recent ones were in 2004 and 2012. The 2004 event was not observable from Colorado. But I did capture images and video from the 2012 transit. The next pair will occur in 2117 and 2125. I probably won't get those!

5 June 2012. Normally, the weather conditions in central Colorado at this time of the year should be ideal for monitoring a transit. However, with global climate change starting to result in noticeable shifts of the regional climate, the monsoonal pattern is occurring earlier each year. In the days preceding the transit, thunderstorms developed by early afternoon. The day of the transit was mostly overcast, and remained that way until late afternoon, after the transit had begun.

In the hope of some clearing, I was prepared with several cameras. My Canon 300D was mounted on my 300mm SCT, with an off-axis white light filter (Baader film). Piggybacked on the scope was a Coronado PST solar telescope (hydrogen alpha) with a B&W video camera attached. Finally, I had a small Maksutov scope on a tripod with a white light filter for visually observing the event.

After first contact, some openings started appearing in the clouds, and I was able to collect some images. Nevertheless, clouds continued to be a problem until the Sun set, during mid-transit.

Gallery

Click on images to enlarge.