"ttyymmnn" (ttyymmnn)
05/13/2016 at 09:19 • Filed to: spacelopnik
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"ttyymmnn" (ttyymmnn)
05/13/2016 at 09:19 • Filed to: spacelopnik | 5
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NASA explanation: !!!error: Indecipherable SUB-paragraph formatting!!! are relatively rare. Monday’s leisurely 7.5 hour long event was only the 2nd of 14 Mercury transits in the 21st century. If you’re willing to travel, !!!error: Indecipherable SUB-paragraph formatting!!! can be more frequent though, and much quicker. !!!error: Indecipherable SUB-paragraph formatting!!! was taken from a well-chosen location in Philadelphia, USA. It follows the space station, moving from upper right to lower left, as it crossed the Sun’s disk in 0.6 seconds. !!!error: Indecipherable SUB-paragraph formatting!!! is included as the small, round, almost stationary silhouette just below center. In apparent size, the International Space Station looms larger !!!error: Indecipherable SUB-paragraph formatting!!! , about 450 kilometers from Philadelphia. Mercury was about 84 million kilometers away. ( Editor’s note: !!!error: Indecipherable SUB-paragraph formatting!!! includes another double transit, Mercury and a Pilatus PC12 aircraft. Even quicker than the ISS to cross the Sun, the aircraft was about 1 kilometer away.)
http://apod.nasa.gov/apod/ap160513.…
OPPOsaurus WRX
> ttyymmnn
05/13/2016 at 09:32 |
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its really cool how you can see the heat / disturbance of the air following the plane
You can tell a Finn but you can't tell him much
> ttyymmnn
05/13/2016 at 14:44 |
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It is crazy that the plane propellers show no apparent movement during the transit. It seems like they should show some movement unless they were perfectly synced with the shutter speed and the chances of that seem infinitesimally small.
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ttyymmnn
> You can tell a Finn but you can't tell him much
05/13/2016 at 14:51 |
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I do a lot of aviation photography, and you need a pretty slow shutter to blur a propeller, really nothing much faster than 1/200 sec. Any faster than that and you freeze the prop. I'd be interested to know exactly how he got those shots. To have even three frames of airplane means he was using a pretty fast shutter, or that these are single frames from a video, which I think is more likely.
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You can tell a Finn but you can't tell him much
> ttyymmnn
05/13/2016 at 15:54 |
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Its not that it is frozen in the frames, but the position of the propeller relative to the aircraft is constant. In the distance the plane travels the propeller would probably have made a couple revolutions, so each frame should have the propeller frozen in a slightly different orientation unless the shutter was synchronized to the propeller speed or some multiple / fraction of the speed.
Think of using a strobe tach to check the rotational speed of something. Each time it flashes your eye sees a frozen image of where things were when the light flashed. If the light is perfectly synced to the rotational speed, the object you’re looking at will appear to be still. If the light isn’t perfectly synced the object will appear to be slowly rotating or showing up in random positions when the strobe flashes.
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ttyymmnn
> You can tell a Finn but you can't tell him much
05/13/2016 at 15:58 |
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Like an old timing light, yes. I noticed the prop position, but I didn't stop to think about it.