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    Re: An assumption about the moon
    From: Frank Reed
    Date: 2010 Feb 17, 17:12 -0800

    Here's my take on your question:

    The Moon's path during any one night can be related to the seasons for a specific phase of the Moon. The most important case is the Full Moon phase. Naturally, on the night when the Moon is full, it is close to 180 degrees from the Sun. The Moon travels around the Earth in an orbit which is inclined only about 5 degrees with respect to the ecliptic so when it's full, it's fairly close to the spot in the heavens where the Sun would be in exactly the opposite season (in other words, six months earlier/later).

    So let's say it's early winter, around the winter solstice, in middle latitudes in the northern hemisphere. The Full Moon rises well to the north of east around sunset in the late afternoon, climbs to a high altitude on the meridian around midnight, and then sets well to the north of west around sunrise in the morning. This is just the same path that the Sun would take through the sky in the summer. That high moon near midnight is bright and casts short shadows. It leads to a certain "stark" appearance on winter nights.

    In early summer, it's reversed. The Full Moon then mimics the December Sun. It rises well south of east, arcs low in the south reaching an altitude about 47 degrees lower (on average) than its early winter appearance, and sets well to the south of west. Note that the total time the Moon is in the sky is also comparable to the Sun's total time six months later: short winter days imply short summer appearances for the Full Moon. The low moon near midnight, especially with the humidity and haze of early summer is rather subdued in brightness and casts long shadows leading to more gentle lighting on early summer nights.

    The above description also works in the southern hemisphere if you swap north for south at the right places.

    For First Quarter and Last Quarter you could work out similar rules. The path of the First Quarter Moon corresponds to the path of the Sun three months later than the current date, and so on.


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