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    Re: Sun and moon at the North Pole.
    From: Brad Morris
    Date: 2019 Jan 29, 16:48 -0800

    The only object that shows phases WITHOUT a telescope or other magnifying optics is the moon.

    Venus shows phases, but they require a telescope to see.  The maximum size of Venus, 1'6", is just above the minimum angular resolution of the human eye, at 1'.  Of course, Venus also gets smaller as the phases change   It is said that the phases of Venus were discovered by Galileo Galelei when using his telescopes. 

    Mercury also shows phases, but once again, to see them, a telescope or other magnifying optics are required.  Mercury varies an apparent diameter from 4.5 to 13 arcseconds.  Compare them to the diameter of the sun, ~32 arcminutes, or 1920 arcseconds.  We can clearly eliminate Mercury from contention in "Hideaway", as it is entirely out of scale to the sun (minimum 3 orders of magnitude!), just as Frank has already determined for Venus.

    In answer to the question: At what latitude(s) does the moon have horizontal horns, as displayed in "Hideaway"?  The closer to your true zenith, the more parallel to the horizon the horns of the moon appear.  The moon can be at your zenith when its declination matches your latitude, at your meridian crossing. The maximum declination of the moon is roughly 28.5 degrees.  So you cannot be anywhere near the North Pole.  You MUST be at a latitude less than or equal to 28.58 degrees and, of course, match the declination of the moon.  The moon will be, for an instant, perfectly at your zenith and then perfectly horn horizontal. 

    Santa, an imaginary elf, is going to be very disappointed to never observe an imaginary view like Hideaway!

       
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