The Moon and the stars near it on the sky appear to travel westward (as shown here, to the right) across the sky by one Moon diameter about every two minutes due to the rotation of the Earth. Because the Moon is also orbiting the Earth, it appears to move across the sky slightly slower than the stars, moving eastward by its diameter against the background of the stars about every 71 minutes. Both of these two motions are visible in this composite photo of the Moon occulting Venus. The images were taken 1 minute apart and are arranged as they would appear on the sky, starting on the left. During the sequence, the waning crescent Moon and Venus set towards the horizon (to the lower right) while the Moon inches slightly to the left relative to Venus, ultimately hiding Venus. Composite of 6 images, each 1/15,000 second at ASA 800, taken one minute apart starting at 12:37 p.m. EST on 2015-12-07 using a Canon 5D III through an Astro-Physics 155mm refractor at f13.3 from northern New Jersey. To correct for atmospheric turbulence, each image of the Moon and of Venus has been partially blended with a composite formed from a stack of 5 selected sharp images taken during the sequence.
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