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Message: <blockquote data-quote="Mark9473" data-source="post: 4060695" data-attributes="member: 106929">To me, a ghost image is a fainter version of something bright in the view but it keeps the same shape and some of its details. Pretty easy to identify at night when looking at the Moon and everything else is just black sky - the ghost is then a fainter image of the Moon. A not too close streetlight works too.Depending on the size of the ghost Moon you can identify if it comes from a flat surface (no magnification difference) or a curved surface (smaller or larger); depending on how it moves you might identify if it is internal to the instrument or if it is a reflection between your eye and the eye lens.</blockquote>