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Old 06-14-2019, 12:44 PM
brossa is offline
Join Date: Feb 2005
Posts: 1,141
I will argue that you can't determine hemisphere by whether the shadow is to the north or south of the bottle; instead you can determine whether you are north or south of whichever latitude line has the noon sun directly overhead for that date. There may be a more elegant way of putting that. This line of latitude varies from the Tropic of Capricorn to the Tropic of Cancer depending on the date. So, on June 21st (summer solstice) if the shadow at noon is pointing south, the most that you can say is that your latitude is somewhere between ~23.5 deg North, and 66.5 deg South (any further South on that date and the Sun wouldn't ever rise). But on December 22nd, if the noon shadow was pointing South, you would say that you were between ~23.5 deg South and 66.5 deg S (again, any farther South and the Sun wouldn't have ever set).

Those of us who live in the mid- or- high-latitudes get used to the Sun always moving across the same half of the sky, year-round. But in the Tropics, sometimes it's in the North and sometimes it's in the South.

Further quibble: there's nothing in the original question to prove that it isn't near the equinoxes; there are plenty of places in the world where it could be snowy around the vernal or autumnal equinoxes. Youtube example.

Last edited by brossa; 06-14-2019 at 12:45 PM.