Transit of Venus (June 2012)
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A Rare But Familiar Sight Venus transits are the rarest type of solar eclipse with over a hundred years elapsing between occurrences. They occur when the planet Venus passes directly in front of the Sun. A Venus transit occurred in 2004, and we traveled to South Africa to witness it. Because of the peculiar celestial geometry involved, Venus transits happen in pairs, with a second one occurring 8 years after the first one. Thinking about the Venus transit brought back good memories, so John planned a day off for the possibility of seeing a second one, a portion of which was to be visible from Baltimore. However, seeing a second one would require more luck than the first one because clear skies are much less likely in Maryland than in South Africa. On the night before the event, the prospects for clear weather in Maryland were dismal. However, we have found Clear Sky Charts to be a reliable predictor of clear skies in North America, and this web site predicted clear skies over Ocean City, Maryland. So, we hastily assembled our astrophotographic and toddler care gear for a last-minute road trip (Figs. 1 and 2). With the help of Google Maps, we chose a waterfront picnic area on Assateague Island as our observation site. The waterfront location would give us a clear view of the western horizon, an important consideration because the transit was to begin only a couple hours before sunset, when the Sun is relatively close to the horizon. The drive to Ocean City was completely surrounded by a sense of uncertainty because the sky was filled with large clouds. But when we arrived at our destination, the skies cleared almost miraculously, and we were able to observe and photograph most of the event (Figs. 3 and 4). The next Venus transit will occur in the year 2117 and will not be visible from most of the US. (  back to home page)
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 Fig. 1. Our observation site was Assateague Island National Seashore, located just south of Ocean City, Maryland.  Fig. 2. We cast long shadows because the Venus transit occurred in the hours before sunset. | |||
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 Fig. 5. Mark inspected our astrophotography setup.  Fig. 6. Sunset view of western horizon from our observation site. |
Equipment Details (optional reading, as usual) This was the first major trial of a new telescope for us, an Astro-Physics 5-inch apochromatic refractor (Fig. 5). Astro-Physics manufactures some of the best telescopes designed for amateur astronomers. These telescopes are in high demand because they are competitively priced but not mass-produced. On a whim, we got on the Astro-Physics waiting list back in 2003 when we first became serious about astrophotography, and our name came up 8 years later in 2011! Fig. 3 is the highest resolution solar image we have obtained so far, an example of the telescope's capabilities. The complete technical details of our outing appear below.
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