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# homework1sol - Key for AST3018 HW 1 20 Points (Each...

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Key for AST3018 HW 1 20 Points (Each question worth 2 points) Leah Simon 24 Sept 2009 1. Right Ascension Declination Vernal Equinox 0h Summer Solstice 6h 23.5º Autumn Equinox 12h Winter Solstice 18h -23.5º 2. Simply use 90 − L + dec = alt where L is latitude, dec is declination (in degrees) and alt is altitude (in degrees). At the summer solstice the Sun is at its highest declination of 23.5º so we have 90º – 42º +23.5º = 71.5º. At the winter solstice the Sun is at its lowest declination of -23.5º so we have 90º – 42º -23.5º = 24.5º. 3. Stars that never set in the Northern Hemisphere have: 90 − L < dec < 90. Stars that never set in the Southern Hemisphere have: −90 < dec < −90 + L. A. Choose the star with the lowest declination, that is, the star furthest from the North Pole, and calculate where it will be circumpolar. 90 – L < 49º 19', so L > 40.7º B. Choose the star with the highest declination, that is the star closest to the North Pole, and calculate where it is visible: all the other stars will be higher in the sky (further above the horizon) than this star. - 90 - L < - 61º 45', so L =

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## This note was uploaded on 07/28/2011 for the course AST 3018 taught by Professor Lada during the Fall '08 term at University of Florida.

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homework1sol - Key for AST3018 HW 1 20 Points (Each...

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