August full moon guide 2023: The Full Sturgeon Moon makes a close pass to Saturn (Image Credit: Space.com)
The Full Sturgeon moon will come up on the evening of Aug. 1, at 2:32 p.m. Eastern Time (1832 UTC), and it will be a “supermoon” as it happens just a day before the moon is closest to Earth; two days later, on Aug. 3, the just-past-full moon will make a close pass to Saturn.
The full moon won’t have risen yet for observers on the U.S. eastern seaboard; the moon sets the morning of Aug. 1 at 5:12 a.m. Eastern Time and rises at 8:43 p.m. local time in New York City. Lunar phases are measured from the position of the moon relative to the Earth; a full moon happens when the moon is exactly on the opposite side of Earth from the sun. That means the hour of the full moon differs by time zone: the moon reaches full phase at 11:32 a.m. in Los Angeles, 7:32 p.m. in London, and 8:32 p.m. in Paris.
In all three cities the moon becomes full while it is still below the horizon (it rises in London at 9:23 p.m. local time and in Paris at 10:00 p.m.) One has to go as far east as Athens, Greece to see the moon rise before the full phase happens (moonrise there is at 8:53 p.m. while the moon gets full at 9:32 p.m.). In some areas the full moon occurs as late as Aug. 2; for example, in Tokyo the full moon is at 3:32 a.m. local time; the moon sets there at 4:47 a.m.
Moonrise times are affected by both latitude and time zone; given the moon’s position against the background stars, it tends to rise later as one goes north; below the equator rising times will be earlier. So while the current time New York City and San Juan, Puerto Rico is the same (because New York City observes Daylight Savings Time), the moon rises in New York at 8:43 p.m. on Aug. 1, in San Juan it rises at 7:20 p.m. Further south it rises even earlier; in Santiago, Chile the moon rises at 6:02 p.m.
Within the same time zone, even at the same latitude, there will be differences because the time in a zone is set so that the hour is the same across a wide range of longitudes, but the actual local time as measured by the sun and stars will differ slightly between the eastern side and western side of the zone. For example, the moon rises at 9:38 p.m. local time in Grand Rapids, Michigan, which is on the western side of the Eastern Time Zone, while in Nantucket, Massachusetts, which is on the eastern side, the moon rises at 8:29 p.m., even though both are at about 42 degrees north.
The August full moon will appear slightly larger than normal; this is called a “supermoon,” though it’s not a real astronomical term. Supermoons are when the full moon coincides with the moon being at the point in its orbit closest to Earth, called perigee. This happens because the lunar orbit isn’t a perfect circle, though it is close. At its closest, the moon is 226,000 miles (363,300 kilometers) from the center of the Earth; at its farthest it is 253,000 miles (405,500 kilometers).
As a result, sometimes the full moon appears larger in the sky but the difference is small, only about 10 to 11 percent; most people don’t notice. Such full moons don’t occur every month (or more accurately, every 28.5 days) because the major axis, or longer dimension, of the moon’s orbit doesn’t stay pointed in the same direction relative to the Earth; it slowly rotates so that supermoons happen three to four times per year. Perigee for this full moon actually happens a day after the full moon (at least for Western Hemisphere observers); it is at 1:52 p.m. Eastern Time on Aug. 2.
On Aug. 3 the moon will make a close pass to Saturn. The two will be in conjunction (sharing the same celestial longitude) at 6:25 a.m. Eastern Time according to In-the-Sky.org. The moon will be about two and a half degrees to the south of Saturn, so it will look (from New York City) as though it is below and slightly to the left of the planet; but sunrise is at 5:53 a.m.
Spotting the planet near the moon will be tricky as by that time the sky is bright enough to wash out the planet – though it can still be seen with a telescope. About an hour and a half later at 8:03 the moon makes its closest approach, about 2 degrees away from Saturn, but from New York City it will be not only daylight but very nearly set – the planet sets at 8:05 a.m. local time.
To catch the conjunction and close approach while it is still night, one has to move south and west. From Miami, the conjunction is still at 6:25 a.m. but sunrise isn’t until 6:48 a.m. The moon and Saturn will both be about 27 degrees above the southwestern horizon, and the sky will be getting light but Saturn should still be just naked-eye visible. From Los Angeles it’s even easier, as the conjunction is at 3:25 a.m. and the moon will be a full 40 degrees high in the south, with Saturn appearing above it. In the Southern Hemisphere, in Santiago, Chile, sunrise is at 7:33 a.m., an hour after the conjunction (which is at 6:25 a.m. local time). From the Southern Hemisphere the sky looks “reversed” – so the moon will appear to be to the left of Saturn.
The full moon will share the sky with most of the naked-eye planets. Venus will get lost in the solar glare as the sun goes down; bright as it is, the planet will be so close to the sun that it will be basically invisible. Mercury, on the other hand, is becoming more visible; the planet reaches its greatest eastern elongation – the furthest east of the sun that it gets — on Aug. 9, so by Aug. 1 it is starting to get into a better position in the evening sky. Even so, it is still only 12 degrees high at sunset (8:11 p.m. local time) in New York, and only about 6 degrees high a half hour after sunset. Mars is a bit higher than Mercury, and while it is easier to spot it is still going to be against a not-quite-dark sky; a half hour after sunset it is only 11 degrees high in the west.
Jupiter, meanwhile, rises just after midnight (12:05 a.m. on Aug. 2) and by that point the moon will be about 26 degrees high low in the south; As noted the moon is making a close pass to Saturn just a day after it is full, in the days leading up to the conjunction and on the night of the full moon one can watch the moon approach he ringed planet – the moon moves relatively fast against the background stars, about one of its own diameters every hour. So one can see the moon get closer to Saturn over the course of the night.
August full moon culture
The August full moon, per the Farmer’s Almanac, is called the Full Sturgeon moon because the sturgeons are more easily caught in August and early September. Sturgeons are native to both Europe and the Americas; the name (for the moon, not the fish) likely came from both colonists and Algonquin-speaking people in northeastern North America. In the Pacific Northwest the Tlingit called it the “berries ripe on mountain” (Sha-ha-yi), while the Haida called it the “Salmon moon” (Chiín Kungáay).
The Chinese lunar calendar lunation containing the Aug. 1 full moon the sixth month, called Héyuè (荷月) or Lotus month. The Chinese lunar month differs from the Gregorian calendar because the length of a lunar month is less than 30 days – and the lunar calendar thus “loses” about 11 days every year. The Chinese New Year, for example, was in February 2023. Periodically the Chinese calendar adds what is called an intercalary month, to make sure that the lunar calendar isn’t too far out of step with the seasons.
This full moon falls in the 14th day of the month of Av on the Hebrew calendar, and the day afterwards is called Tu’Bav, which is considered auspicious for weddings, and is akin to Valentine’s Day for many modern Jews.
The Māori of New Zealand described the lunar months in August as Here-turi-kōkā: “The scorching effect of fire is seen on the knees of man,” reflecting the fact that in New Zealand, August is one of the colder months of the year. The day of the full moon was called Rākau-nui, according to the Encyclopedia of New Zealand.
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