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Keeping comets & asteroids still

Comet C/2009 P1 (Garradd) - 2012 March 19 - 64 x 32s ISO6400

A modified stacking process keeps the comet or asteroid fixed while everything else moves past - no need to try to track the comet

Important to have regular intervals between shots to get smooth trails - here 32s exposures were initiated every 35s, using a Canon timer

This is a telescopic view. The trails here are not due to the Earth's rotation but because the comet moved in front of the stars.

The comet does not have a dust tail but the blue tail just visible is an ion tail: charged particles blown away by the solar wind. It therefore points away from the Sun, like all comet tails.

This image won me a Highly Commended in the 2012 Astrophotographer of the Year competition at Greenwhich.

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