The Transits of Venus

Rating:
Summary: If You're Interested, Don't Miss It
Review: On June 8, 2004, I got up well before dawn and made my way to the school where I teach in Westchester County, New York. I met the astronomy teacher there--I teach physics and math-- and we proceeded to watch what we could of the transit of Venus, the passage of the planet Venus across the face of the sun. It dawned cloudy but we did manage to see the last half-hour or so and we got a number of excellent photographs of the event. It was a great morning--a chance to see a very rare astronomical event. I don't think I'll ever forget it.

Because of my experience, when I saw this book I couldn't resist taking a look. Sheehan & Westfall do a very good job at explaining the science of the transit, detailing views of the transit in maps & photographs, and in going through the history of the attempts at viewing and measuring the transit. Particularly interesting is their discussions of using the transit to measure the earth-sun distance and the number of voyages of exploration undertaken (including Captain Cook's) whose primary purpose was to find a good vantage from which to observe the transit.

Transits of Venus come in pairs separated by approximately 8 years. These pairs are then separated from each other by better than 100 years. Before 2004, the last transit was in 1882. After the transit of 2012, the next won't occur until 2117. Granted, this book is not going to hold any interest to anyone who is not interested in astronomy. But if observing the skies is something that fascinates you as it does me, read this book. Then put it on a shelf and pull it out again in 2012. Prepare yourself for the next transit because if you miss it next time, you won't get another chance. You'll have to leave the book for your grandchildren.

Rating:
Summary: Such an exquisitely rare event... such a great book
Review: William Sheehan is one of very few authors whose books I purchase as soon as they're published. Though not an historian of astronomy by profession, he is among the elite few who have contributed significantly to popular writings in that genre in the last 15 years or so. In taking on the topic of the transits of Venus, Sheehan, joined in this endeavor by John Westfall, has produced a magnificent volume that any amateur historian of astronomy will surely want to read.

As with all Sheehan efforts, Transits is meticulously researched and detailed, yet written in a lively and conversational tone that is a pleasure to read. Here will be found excellent scientific background: the nature of transits, the importance of transit observations in unlocking the value of the astronomical unit, etc. More importantly, to me, is the rich treatment of the history of transit observations. From Kepler's Rudolphine tables, where the first transits of Venus were accurately predicted, to the life and times of Jeremiah Horrocks, the short-lived English astronomer who first successfully observed one in 1639, to the massive international efforts of the 18th and 19th centuries, this work is filled with detail, photos, diagrams, and immensely satisfying story-telling. Here's an example of the detail and rich prose:

"The long wait for a transit of Venus finally ended at 3:06:22.3 PM Honolulu mean time, December 8 1874, when George Tupman became the first person in 105 years to see a transit of Venus. He had two advantages that gave him a head start: the Hawaiian stations were the closest in the world to the Delislean point of earliest ingress: and he was observing with a spectroscope that allowed him to spot Venus against the sun's inner atmosphere, the chromosphere, a full 39 seconds before it touched the visible solar limb."

Sheehan and Westfall's orientation is so decidedly historical that they make a surprising omission: There is no discussion of the reason for the curious spacing of Venus transits: a pair 8 years apart, followed by a gap of either 105 or 122 years, and then another pair 8 years apart. Perhaps this discussion, about which I think many readers would be curious, was omitted because it can be somewhat technical. More likely, they simply had to make some decisions on what to include and not include based on their particular slant.

At any rate, such an omission is more than balanced by what Sheehan and Westfall do include. I was overjoyed to read such exquisite detail about the observational and photographic instruments used to observe and measure the transits of 1874 and 1882. As far as I know, Sheehan and Westfall are the first authors to offer such thorough coverage in a popular work. There are also many photographs and drawings reproduced from this pair of transits, many more than I have ever seen in print before.

The much-anticipated Venus transit of June 2004 is fast approaching. Perhaps the rarity of this event makes it so compelling to me, as I'm sure it will to others as well. I can think of no better way to prepare than to purchase and read this excellent work.