## APOD: Asteroid 2012 DA14 Passes the Earth (2013 Feb 17)

neufer
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### Re: APOD: Asteroid 2012 DA14 Passes the Earth (2013 Feb 17)

ta152h0 wrote:
There was a mention of a camera shake by one observer of the asteroid fly by. Is it possible to measure the distance of a background star by measuring the amplitude of the shake of a nearby object and compare the amplitute of the shake on a far away object and just bdo the math ? Couldn't be that simple , could it ?
This is called parallax and it generally involves the "shaking" of the Earth from side to side during its orbit around the sun.

Thankfully, the camera wasn't shaking quite that violently.
Art Neuendorffer

Chris Peterson
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### Re: APOD: Asteroid 2012 DA14 Passes the Earth (2013 Feb 17)

ta152h0 wrote:There was a mention of a camera shake by one observer of the asteroid fly by. Is it possible to measure the distance of a background star by measuring the amplitude of the shake of a nearby object and compare the amplitute of the shake on a far away object and just bdo the math ? Couldn't be that simple , could it ?
No, it couldn't be that simple. The amplitude of motion will be instrumentally identical for all the objects, since they are effectively point sources at infinity. Of course, if you were close enough to the foreground object, it might appear to have a different amplitude than the stars, but every star would seem to be the the same distance... infinity.

In essence, we do use "camera shake" to figure out how far away nearer stars are. We can measure parallax, but we "shake" the camera by imaging at diametrical points in Earth's orbit. In essence, we shake the camera with a 2 AU amplitude.
Chris

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Chris L Peterson
Cloudbait Observatory
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rstevenson
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