In astronomical terms, “once in a lifetime” conjures images of a rare celestial event, such as a total eclipse of the sun or moon. While they are indeed few and far between, the phrase is applicable in the sense that the opportunity for the average person to be able to actually see our star blocked out by the moon passing directly in front of it is indeed “once in a lifetime”: the path of totality, or the moon’s ultra-narrow shadow, only falls close to where a person lives at one point in his or her life. Only affluent people, with money AND time on their hands, can travel halfway around the world to observe one, to get inside that narrow “cone” of totality.
But when it comes to a transit of an inner planet such as Mercury or Venus (think of them as mini-eclipses), it really is a once-in-a-lifetime experience…especially in the case of the latter. The relatively recent transit of Venus crossing over the face of our sun happened in June 2012. And Yours Truly was able to see it, and even captured the image!
Venus, of course, passes between Earth and the Sun quite often, as does Mercury and our own moon. But since planets have different orbital planes, most of the time they seem to go just above or just below our daytime star.
Venus transits only occur twice a century. Nobody will be alive to see the next one: December 11, 2117…but if you missed the above-mentioned one, plenty of folks took lots of pictures, including Moi:
I happened to be living in Southeastern Tennessee in June 2012. The transit began for us late in the afternoon, so I was able to observe the first hour or so before the sun went behind some nearby trees. Here’s another, closer image:
There were two reasons I used a white cardboard surface to see the image: not only for the sake of a simple, casual shot, but also to avoid going blind from attempting to observe the transit directly through the telescope (never, NEVER look a the Sun through a telescope, or you will wear that image on your retinas for the rest of your life…and be blind).
The coolest thing about this event was that I knew precisely when it would begin. I was watching the projected image of the Sun on the back of a spiral notebook…waited…waited…and then a “bite” occurred, right on schedule, on one side of the Sun’s disk! I was transfixed. It slowly emerged as a distinct, well-defined ball. Lots of folks took far better pictures of this transit, but I think my uber-casual shot lends a unique perspective!
Here is a link to a few “serious” shots, taken by amateur photographers:
When I say “amateur” shots, by that I mean these intrepid folks make no more of a living than I do with their photography…but they have far more sophisticated (and expensive) gear than I possess.
Now take a look at the next shot: Venus again, but taken three weeks after the transit date…when the planet had moved enough in its orbit to become the morning star once again:
To the extent you’re able, try to enjoy rare celestial events such as a transit. The next one of Mercury (and its last for a few decades) will occur on May 9, 2016.
Maybe, just maybe, the weather will cooperate!