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Halley's Comet on December 9, 1985

auteur: Anglo-Australian Observatory/David Malin Images/Novapix

référence: a-com03-00015

Image Size 300 DPI: 51 * 40 cm

Almost all the colour pictures from the AAT are made by combining three black and white photographs taken in red, blue and green light. Most of the objects are very distant and plates taken years apart show little change; however Halley's Comet moved rapidly through the solar system towards the sun and as the telescope followed its motion the background stars were recorded as coloured streaks, their length corresponding to the exposure times, (15, 15 and 20 minutes). The diffuse coma is tinged blue by the action of sunlight on gases evaporated from the icy nucleus, leaving behind tiny dust grains as a faint yellow tail shining by reflected sunlight.  

Keywords for this photo:

1985 - AAO - ASTRONOMY - COMET - HALLEY - POSTER - SIDING SPRING - STAR - WATER -