What is the Moon doing in July? |
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The Moon in July |
In general, we can tell what the Moon will look like, when it will be visible, and in what direction to look for it, just by working out how many days it is since New Moon. The details are here. But we can predict this more accurately by noticing that the Moon mimics, every month, the way the Sun behaves over the course of a whole year. Here is a schematic diagram of how the Moon behaves in July.
Immediately after New Moon, the crescent Moon is further south than the Sun, so it's hard to see. We have to wait several days after New, before we start to see the crescent Moon in the west after sunset. At this point the Moon behaves like the Sun in autumn, rising in the east and setting in the west. As it reaches First Quarter and continues to wax gibbous, it rises much later each day, and much further to the right. The time of moonset stays roughly constant, shortly after midnight, but the position shifts to the left. At Full, the Moon is well south, like the Sun in winter; it rises in the south-east and sets in the south-west. But the Moon soon starts to move northwards again, as it wanes towards Last Quarter. It continues to rise shortly after midnight, and the position of moonrise shifts to the left again. By the time it's a waning "crescent", the Moon is further north than the Sun, so we should be able to see it at dawn, until almost the date of New Moon itself. On any date, if you know how many
days it is since New Moon:
multiply that by twelve, and add it to the present date, to find out
roughly where the Moon will be in its cycle.
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