Lunar eclipse time lapse

By Phil Plait | December 12, 2011 6:26 pm

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:

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.

CATEGORIZED UNDER: Astronomy, Cool stuff, Pretty pictures

Comments (16)

  1. Wzrd1

    I’ll be honest, I slept in, as I knew it was an impossibility and hoax, due to an odd effect of physics.
    Simply put, it’s against the natural laws of the universe.
    You see, it’s utterly impossible for any astronomic phenomena to occur AND the sky be clear where I live. Utterly impossible.
    I’ve got 5 sigma statistics on that peculiar effect.

    On other news, LHC is looking to acquire 5 sigma level certainty in their data sets on the Higgs boson. So far, it seems promising.
    Of course, I have 6 sigma certainty that I can’t observe the LHC facility, due to the mass of our flat Earth curving space-time to the point that the Earth appears round. (Phil, consider the math, if you don’t get a case of the giggles, I’m at a loss as to why. A singular loss…) 😉
    Hey, when one has to play the Luddite card, be ludicrous! 😀

    But, I’m nearly serious in the first part of my comment. Whenever anything interesting is happening in the sky, it’s cloudy here. :(
    PLUS light pollution that makes one think we had a GRB 20 LY away…

  2. Legion

    What was that point of light just to the bottom left of it?

  3. Messier Tidy Upper

    @^ Legion : I’m pretty sure it was a star or planet but not sure which one. (Jupiter was very close a few nights ago.) There’s actually a couple of stars &/or wandering stars present in that clip. It should be possible to replicate the scene using a planetarium program of some sort to find out which object exactly but haven’t done that myself for this.

    Stayed up to see the lunar eclipse – midnight~ish my local time – but got clouded out. Caught the occassional glimpse through gaps in clouds but, sadly, only the *very* occassional glimpse. :-(

  4. Messier Tidy Upper

    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.

    Ramen to that! So very true.

    Thanks to a lot of very intelligent, hard-working people for that – Thanks science! :-)

  5. Here’s another SF time-lapse — my friends and I used math and science to determine that the eclipsed moon would pass right behind Sutro Tower as seen from the top of Bernal Heights.

  6. dcsohl

    My research indicates that the point of light below and to the left of the moon is Aldebaran.

  7. To add a bit more detail to my original description:

    I timed the moon – tower conjunction to coincide with the arrival of the total eclipse at 6:06 (thanks to NASA for that prediction).

    The moon angles were determined using the software The Photographer’s Ephemeris (which has a lot of credits for the formulas listed in the About section). This software runs on Google Earth and is free for desktops (Windows, Mac OS X), and available via a nominal fee for Android (2.2+) and Apple iOS (iPhone, iPad, iPod Touch) devices.

    I slightly glossed over some of the building height and viewing distance calculations, since I actually had to consider and add the elevation of the base of the building, add the building height, then subtract the elevation of my ultimate viewing position to get a more accurate figure for the height of the top of the building.

    The rest was math… and of course a little luck, as any inaccuracies in my assumptions apparently cancelled each other out.

  8. I had to take my friend’s dog out and got to see part of it (otherwise I’d have cheerfully slept through it, lol). Very clear night, it was lovely.

  9. Mike

    So for some reason I apparently know nothing about lunar eclipses. Why is it that we can actually see the moon during them, despite the moon lying completely in the umbral shadow of the Earth?

  10. Mike,

    The red light illuminating the moon comes from the outline of the earth, the sun-lit atmosphere, where the combined sunrises and sunsets of the entire planet reflect a just enough light to to the moon to provide a red-tinted image of the moon back to us.

    Too bad we don’t have a photo of the earth, taken from the moon during a total lunar eclipse! If NASA ever sends such an expedition, I call “shotgun” for an astrophotography ride-along on that one!

  11. Ilkka

    Gave me a good chuckle when I saw this in my RSS reader: the embedded ad was for a 2012 psychic reading.

  12. Shahaad

    I have to disagree with 8.   dcsohl. There are 3 stars visible in the time lapse, just below and left is Iota (102) Tau, further left is HR 1633, and above left is 105 Tau (ref Uranometria 2000 and SkySafari Pro). The moon at the time of eclipse had an apparent size of 30 arcmin. Aldebaran was 8.5 degrees south (17 moon diameters away!), and just 3 degrees above the horizon at the time of the eclipse. If I had to hazard a guess, I’d bet those three stars weren’t naked eye visible in light polluted San Fran, but through the camera, they were!

  13. Matt B.

    “…only to find out that somewhere along the line I dropped a 2 someplace and messed it all up.”

    It’s okay, Bender Phil, there’s no such thing as 2.


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