Recent content by IzzaddinR

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    Undergrad If I know the Solar Hour Angle at sunrise, can I calculate twilight by simply -

    Hi dacruick, Thanks for your quick reply. What I'm trying to calculate is the time that twilight (sun = 18 degr below horizon) starts, or more generally speaking; I'm trying to calculate the time of day by a given altitude of the sun. I've been browsing the web and found this...
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    Undergrad If I know the Solar Hour Angle at sunrise, can I calculate twilight by simply -

    At time T(sunrise) the SHA = -81.361029147899785, which makes frac. hours to noon (SHA / 15.0). Is calculating the time of astronomical twilight to noon as simple as (SHA - 18) / 15.0?