OT: Astronomical Quiz difia

From: Jeff Umbarger (jumbarger2000@yahoo.com)
Date: Tue Apr 19 2005 - 19:19:21 EDT

  • Next message: Tim Rogers: "Re: Astronomical Quiz difia"

    Hey All,
         So, watching satellites the other night I came up
    a with an idea that I believe is correct, but I want
    to bounce if off others in the group to see if I'm on
    the right path. There is a point in the stellar field
    (that is described with coordinates Right Ascension
    and Declination), that when observed from directly
    below on the earth's surface, can never be seen in
    complete darkness. You can either name the RA and Dec
    or the name of the constellation. Please respond back
    to me and not to the group. I'll post the answer if
    enough folks are interested.
         And now a slightly more on thread notion: I
    learned of a formula that tells when an observers
    Civil Twilight (when the Sun is 6 degrees below the
    horizon) is shortest during the year (when Civil
    Twilight follows Sunset in the shortest amount of
    time) based on the observer's latitude. The formula
    is:
    The date in March = March 21 - 1.0146 *
    arcsin(0.1427*sin(theta))
    
         where theta = the observer's latitude.
    
    This, of course, is the shortest visual satellite
    observing night of the year - on average. This formula
    came from a magazine called The Bent, put out by Tau
    Beta Pi - an engineering honor society.
    
         Regards,
              Jeff Umbarger
              Plano, TX USA
    
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