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Parallax. Parallax. Point to a star that you think is close. Point to a star you think is far…. HOW did you know that???. Parallax animation. http://www.astronomy.ohio-state.edu/~pogge/Ast162/Movies/parallax.mov. Distance to star. Two things that affect parallax:
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Point to a star that you think is close. Point to a star you think is far… HOW did you know that???
Parallax animation http://www.astronomy.ohio-state.edu/~pogge/Ast162/Movies/parallax.mov
Distance to star Two things that affect parallax: 1. Distance to star 2. Baseline
Supplies to gather after reading background material • Meter Stick • Lined strip of paper • 2 ring stands • Clip • Blue paper with holes • 2 pieces of tape
Parallax The closer stars appear to shift relative to the background because of earth’s movement around the sun. Closer the star, greater the parallax! Larger the baseline, greater the parallax!
TRY THIS • Parallax online activity • http://astro.physics.uiowa.edu/ITU/labs/foundational-labs/parallax/parallax-puzzlers.html#previous-photo
0.7 Earth Moon 3000 miles How to find the distance to an object: Distance = d
* * * * * 0.7 Earth Moon 3000 miles d C. Finding the Distance to the Moon by Parallax • In this method, two observers simultaneously observe the Moon against the starry background from positions 6000 miles apart. The Moon’s position against the stars differs by 1.4.
* * * * * 0.7 Earth Moon 3000 miles d C. Finding the Distance to the Moon by Parallax • Observers are 6000 miles apart. • Moons position changes by 1.4 • sin (0.7) = 3000 miles / d • 0.0122 = 3000 miles / d • d= 3000 miles / 0.0122 • d= 246,000 miles
How to find the distance to Proxima Centauri: • Parallax Angle = 0.000214 degrees • Radius of our orbit = 9.3 x 107 miles • 1 lightyear = 5.9 x 1012 miles
If baseline is 1 AU … 1 ÷ ÷ d Distance p Parallax x