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    Re: Lunar mechanics and Double Alts.
    From: Herbert Prinz
    Date: 2003 Apr 30, 13:39 +0000

    Fred Hebard wrote:
    
    >
    > The moon's declination changes radically from day to day, so the
    > ecliptic is only a first approximation as to the best location for a
    > star.  You could pick Regulus, which is smack dab on the ecliptic, and
    > still have it be 35 degrees of declination out of the moon's orbit.
    
    Hello Fred,
    
    Something is amiss here. If a point falls on a given line, it does so
    regardless of the co-ordinate system. The ecliptic is fixed in the
    horizontal (RA/Dec) system (ignoring minor and secular effects). Yes, the
    declination of the Moon does change; but that's because the Moon follows
    the ecliptic. Regulus does not change its ecliptic latitude of half a
    degree, nor does the Moon change its own by more than 5 deg. If the Moon's
    orbit were not inclined 5 deg w.r.t. the ecliptic, it would come within a
    distance of Regulus equal to the size of its own semidiameter every single
    month.
    
    Best regards
    
    Herbert Prinz
    
    
    

       
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