Here’s the kind of movie (javascript) I usually look at, or sometimes make. This one shows yesterday’s partial eclipse of the sun as seen from space with an ultraviolet telescope.
A bit hard to grasp, but I take it that’s the moon swingin’ by … ? Why the pan up and back down?
And how’d the other guy calculate that exposure? Never mind how’d he get all those cows to stand still enough so his tripod didn’t minutely shake such that he was actually able resolve the parallel wings of what I imagine to be the solar arrays … ? Amazing photograph! Thanks!
The reason the picture “pans” up is that the dark area of the moon’s disk moving across the sun (Yes, that’s the moon!) confuses the sun sensors that the instrument uses to keep pointing at the sun. (Several years ago another solar satellite telescope lost its pointing system altogether during an eclipse. The pointing system got so confused it shot off the solar direction a long ways and the solar panels failed permanently.)
The ISS picture taken with a little earth-based telescope was a tour de force, wasn’t it! Yes, those wings are the solar panels. Getting the exposure right isn’t too hard. You just bracket the exposure over and over until you can see sunspots or the solar granulation. And later you can use that same exposure again for pictures like this one because the sun doesn’t ever change brightness by more than 0.1%.
The picture is not a time exposure–only a fraction of a second, even with a dark solar filter on the ‘scope.
Comment by rakkity — September 22, 2006 @ 10:07 am
I must be living under a rock. I didn’t even know that happened yesterday. Thanks for the 411.
Jen, don’t feel bad. First find out from where on earth the eclipse was visible … I think it was the southern Atlantic Ocean.
Comment by Jennifer — September 22, 2006 @ 6:24 pm
Ohmigod! I didn’t scroll down the first time. That’s unbelievable. No, I mean … really impressive (because the photos, plus Lew standing looking over my shoulder at it saying that’s really some pretty cool equipment, make it completely believable). It took me three reads to take it even partially in. (I was trying to understand why timing the photo was so important. Duh.)
Adam, I think the cows could stand still for 1/8000th second. Thanks so much for asking a question which made rakkity answer which made me re-read.
Comment by Jennifer — September 22, 2006 @ 6:43 pm
Rakkity, do you do this for business or pleasure? Fascinating! I for one would love to see more.
A bit hard to grasp, but I take it that’s the moon swingin’ by … ? Why the pan up and back down?
And how’d the other guy calculate that exposure? Never mind how’d he get all those cows to stand still enough so his tripod didn’t minutely shake such that he was actually able resolve the parallel wings of what I imagine to be the solar arrays … ? Amazing photograph! Thanks!
Comment by el kib — September 22, 2006 @ 7:14 am
The reason the picture “pans” up is that the dark area of the moon’s disk moving across the sun (Yes, that’s the moon!) confuses the sun sensors that the instrument uses to keep pointing at the sun. (Several years ago another solar satellite telescope lost its pointing system altogether during an eclipse. The pointing system got so confused it shot off the solar direction a long ways and the solar panels failed permanently.)
The ISS picture taken with a little earth-based telescope was a tour de force, wasn’t it! Yes, those wings are the solar panels. Getting the exposure right isn’t too hard. You just bracket the exposure over and over until you can see sunspots or the solar granulation. And later you can use that same exposure again for pictures like this one because the sun doesn’t ever change brightness by more than 0.1%.
The picture is not a time exposure–only a fraction of a second, even with a dark solar filter on the ‘scope.
Comment by rakkity — September 22, 2006 @ 10:07 am
I must be living under a rock. I didn’t even know that happened yesterday. Thanks for the 411.
Comment by Jen — September 22, 2006 @ 10:08 am
I’m glad you asked Adam.
Comment by michael — September 22, 2006 @ 6:09 pm
Jen, don’t feel bad. First find out from where on earth the eclipse was visible … I think it was the southern Atlantic Ocean.
Comment by Jennifer — September 22, 2006 @ 6:24 pm
Ohmigod! I didn’t scroll down the first time. That’s unbelievable. No, I mean … really impressive (because the photos, plus Lew standing looking over my shoulder at it saying that’s really some pretty cool equipment, make it completely believable). It took me three reads to take it even partially in. (I was trying to understand why timing the photo was so important. Duh.)
Adam, I think the cows could stand still for 1/8000th second. Thanks so much for asking a question which made rakkity answer which made me re-read.
Comment by Jennifer — September 22, 2006 @ 6:43 pm
Rakkity, do you do this for business or pleasure? Fascinating! I for one would love to see more.
Comment by Jen — September 24, 2006 @ 10:09 am
Business and pleasure! But next January when I retire to where the skies are not cloudy all night (Colorado), it’ll be just pleasure.
Comment by rakkity — September 25, 2006 @ 11:00 am