Lunar eclipse time lapse

Bad Astronomy
The entire universe in blog form
Dec. 12 2011 6:26 PM

Lunar eclipse time lapse

I missed the lunar eclipse on Saturday morning, but a whole bunch of people got up to see it (click that link and scroll down to the comments; lots of folks link to their pictures). That includes photographer Jeffrey Sullivan, who took a sequence of pictures of the Moon from San Francisco, and put together this extremely cool time lapse animation covering ten minutes of the eclipse:

Phil Plait Phil Plait

Phil Plait writes Slate’s Bad Astronomy blog and is an astronomer, public speaker, science evangelizer, and author of Death From the Skies!  

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How amazing is that? It's no coincidence he got the Moon to pass right behind the narrow pyramid of the Transamerica Building like that. According to the description on the YouTube page, he used some software to find the position of the Moon at various times, including the altitude (its distance above the horizon). Knowing the height of the building, he could then figure out how far away he had to be for the top of the building to be at that same altitude (it's just a bit of trig). Then it was just a matter of finding a good spot using Google Earth -- of course, accuracy is an issue. If the Moon was only 20 degrees off the horizon, then, given the 260 meter height of the building he had to be within about 10 meters of the right spot (about 715 meters from the building) or the Moon would miss. The lower the Moon, the less accurate he needed to be. Still. Nicely done.

When I was younger, dragging my telescope to the end of my driveway to observe the sky, I used to do calculations like that, and it would take forever. I had to look stuff up in tables, interpolate between entries, do all kinds of math -- only to find out that somewhere along the line I dropped a 2 someplace and messed it all up. I would've cheerfully killed for access to the kind of software we have today.

It's easy to be jaded with the privilege we have now. Animations like this one from Jeffrey drive home how amazing our tools have become.