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0 pointsdaeken9y ago0 comments

That's my thought. I counted about 12 seconds between initial explosion and the sound hitting the camera, which puts it at roughly 2.88km away.

Edit: Helps if I multiply properly. 12 seconds * 340m/s == 4080m.

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jychang9y ago

Ok, the Falcon 9 1.2 [1] is 70m tall [2], and the rocket fills up about 80% of the vertical frame [3].

Using the "Image = FL * Obj / distance" equation, we get:

.8 * 24mm = x * 70m/4080m

Where x is the focal length of the lens assuming a full frame camera.

This comes out to a x = 1119mm equivalent focal length. If you have a crop sensor, this isn't too hard to obtain. I'd be amused if the video was taken with a Canon EF 1200mm lens or something, but the probability of that is 0.

[1] https://en.wikipedia.org/wiki/Amos-6

[2] https://en.wikipedia.org/wiki/Falcon_9_Full_Thrust

[3] https://www.youtube.com/watch?v=_BgJEXQkjNQ#t=1m10s

tobz9y ago

Could be a teleconverter in the mix... or a Coolpix P900. :P

lucretian9y ago

i think you mean 4.1 km?

daekenOP9y ago

Yeah, I typoed the math -- used 240m/s rather than 340m/s for the speed of sound.

anigbrowl9y ago

15, 5k

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