The Full Buck Moon will be joined by four planets in the night sky this month.
The July full moon, also known as the Full Buck Moon or Thunder Moon, occurs in the morning on July 3, at 7:39 a.m. Eastern Time according to the U.S. Naval Observatory. The moon will have set for East Coast observers by then (moonset is at 5:06 a.m. that day). A
A day later on July 4, the moon will be at perigee, when it is closest to Earth, so the just-past-full moon will appear slightly larger than normal as the first of four supermoons in a row this summer (though it will take a keen observer to see the effect). Three days later the moon will make a close approach to the ringed planet Saturn.
A full moon means that the moon is on the opposite side of the sun from Earth, and as such is fully illuminated. If you were standing on the moon at the right longitude it would be noontime – the sun would be directly overhead at the moon's equator, and as high as it ever gets in the sky as one moves north or south. Lunar days are about 14 days long, as the moon always keeps the same face towards Earth.
The timing of a full moon depends on one's time zone since the phase of the moon depends on the moon's position rather than that of the observer; the "official" full moon won't be visible most of the day to people in the Eastern U.S., but in Los Angeles, for example, the full moon will be at 4:39 a.m. and the moon doesn't set until 5:38 a.m. local time.
As one moves further west it gets earlier; residents of Hawaii will see the full moon at 2:39 a.m., well before it sets at 6:01 a.m. (in Honolulu). In cities such as Tokyo, the full moon is at 8:39 p.m. on July 4 and moonrise is at 8:11 p.m. local time.
If you're looking to snap photos of the moon and the night sky in general, check out our guide on how to photograph the moon, as well as our best cameras for astrophotography and best lenses for astrophotography.
Saturn conjunction and visible planets
On the night of the full moon, just after sunset (8:31 p.m. in New York), Venus, and Mars will be in the west. Saturn rises later, just before midnight in mid-northern latitudes, followed by Jupiter in the wee hours of the morning. Mercury is basically lost in the solar glare as it rises just after sunrise at 5:37 a.m. (sunrise is at 5:29 a.m.) and sets at 8:50 p.m., which is only 19 minutes after sunset; the planet is less than 3 degrees above the horizon at that point.
Venus will be a bright evening star, setting at 10:41 p.m. local time in New York. A good exercise is to see how soon after sunset you can spot it; the planet, which is at magnitude -4.4, is usually the very first "star" that is visible to the eye in the evening (Venus is the brightest object in the sky after the moon). In New York City (and other mid-northern latitude cities such as Chicago, Denver or San Francisco) Look for Venus in the west, about 23 degrees high. Right near Venus is Mars, which will be to the left and just above Venus for Northern Hemisphere sky watchers. Mars has a distinct red-orange hue (hence the epithet "Red Planet") and is easily recognizable. It will probably start to show itself by about 9 p.m. Mars will set just after Venus does, at 10:56 p.m. Venus and Mars are both in the constellation Leo the Lion.
One way to know that you are looking at planets, and not stars, is that stars will sometimes twinkle, but planets shine with a steadier light; the reason is that however small it is, a planet shows a disc; even through binoculars it's apparent. Stars, on the other hand, are basically point sources of light; the movement of air distorts the light they send to our eyes more.
Later that night, Saturn comes up, at 11:19 p.m. Saturn is in the constellation Aquarius and stands out as Aquarius is a faint group of stars, for mid-northern latitudes it will be in the southeast as it rises. Jupiter follows at 1:47 a.m. on July 4, it will be just north of east as it clears the horizon.
On July 6 the moon will share the same right ascension (or celestial longitude) as Saturn, a condition called a conjunction. The moon will pass 2.67 degrees south of Saturn at 11:09 p.m., just as the pair rises in New York, which will mean from mid-northern latitudes the moon will appear to be to the right and below Saturn, according to In-the-Sky.org. Just after midnight (July 7), the moon will get closer, about 2 and a half degrees, at 12;59 a.m. and it will look as though it is just below Saturn. As the night progresses the moon will appear to move to the left (eastwards); it moves approximately one of its own diameters against the background stars every hour.
For Southern Hemisphere sky watchers the moon and planets will look a bit different; the sky is "upside down" and it is wintertime, so the nights are longer. For example, in Santiago, Chile, the sun sets at 5:46 p.m. on July 3, and the full moon occurs at 7:39 p.m. – the moon rises there at 5:57 p.m. At sunset, Venus is a full 33 degrees high in the northwest; it starts to become visible by about 6 p.m. local time. Soon after that, by about 6:30 p.m., Venus is still 26 degrees above the horizon and Mars is to the right and about three degrees above Venus. Venus sets at 9:01 p.m. local time and Mars at 9:16 p.m. Saturn rises at 10:03 p.m., and Jupiter at 3:00 a.m. Saturn and the moon will both be quite high in the sky; at 1:35 a.m. local time on July 4 the moon will be 83 degrees above the northern horizon, nearly at the zenith. Saturn will be about 67 degrees high when it crosses the local meridian at about 4:31 a.m.
In the Southern Hemisphere, the conjunction between the moon and Saturn will look rather different; since the moon will pass to the south of Saturn as the pair rises the moon will be to the right of the planet; as the two progress across the sky the moon will appear to move slightly downward relative to Saturn. The time of conjunction will be the same 11:09 p.m. local time and the close approach will be at 12:59 a.m.
Stars and constellations joining the Buck Moon
In July, the summer constellations are ascendant; from mid-northern latitudes the Summer Triangle is high in the east by 10 p.m. The Summer Triangle is an asterism (a group that isn't an official constellation) made up of three bright stars: Vega, Deneb, and Altair, with Vega rising first, followed by Deneb. Both rise in the afternoon, so by the time the sky is dark they are above the horizon; the same is true of Altair, which rises about an hour before sunset. The three stars form a rough right triangle with Deneb at the 90 degree angle. Vega is the highest of the three, with Deneb appearing below it, and to the right of both (southwards) is Altair. Vega is the brightest star in Lyra, the Lyre, the instrument of Orpheus. Deneb is the tail of Cygnus the Swan, and Altair is the eye of Aquila, the Eagle.
Looking to the right of the Summer Triangle and facing north, at 10 p.m. the Big Dipper is to the left (west) of the celestial pole, it faces downwards with the stars of the bowl towards the horizon and the handle pointing "up". Using the "pointers" on the bowl (these will be the stars closest to the horizon) one can find Polaris, the Pole star, and if one keeps going one hits Cassiopeia, the legendary queen of Ethiopia and mother of Andromeda. Cassiopeia forms a "W" shape.
Going back to the Big Dipper – itself an asterism that is part of the much larger Ursa Major, the Great Bear – one can use the handle to "arc to Arcturus" the brightest star in Bootes, the Herdsman. Arcturus is recognizable because it is a slightly orange color. Above Arcturus one can sometimes spot a circle of fainter stars, this is usually drawn as Bootes' head. To the right is a bright curve of stars that is the Northern Crown, the Corona Borealis.
If one turns exactly opposite from Polaris, and looks due south, by 10 p.m. one can see a bright reddish star about 22 degrees above the horizon. This is Antares, the heart of Scorpius, the Scorpion. Even with the full moon nearby (to the left, just above the southeastern horizon) it is easy to see.
In the Southern Hemisphere, the Southern Cross and Centaurus will be high in the southwest by 10 p.m., with the four stars of the Cross below Rigil Kentaurus, otherwise known as Alpha Centauri. High in the sky, almost at the zenith, is Antares. In the east, just to the right of Saturn, is Fomalhaut, the brightest star in the Southern Fish, Piscis Austrinus.
How the Buck Moon got its name
Native American peoples had different names for July's Full Buck Moon; the name "Thunder moon" and others from the Old Farmer's Almanac reflect that in the Northern Hemisphere it is summer, the weather tends to be hot, and thunderstorms are more common. But that name came from Native people in what is now the eastern United States; even in North America there were differences between nations. According to the Ontario Native Literacy Coalition the Anishinaabe called it the Raspberry moon, while Cree called it the Feather Molting moon, as some birds start to molt in the summer. Further south, the Cherokee call the July lunation in their traditional calendar the Ripe Corn moon.
In the Jewish Calendar, July 6, which is the 17th of the Hebrew month Tammuz, and three days after the full moon, marks the beginning of "The Three Weeks" – a period of mourning for the loss of the Second Temple in 69 CE. The 17th of Tammuz is for some observant Jews a fast day. For Muslims, the July lunation marks the last month of the year before the Islamic New Year on July 19.
The Māori of New Zealand used a lunar calendar called the maramataka which measured months between successive new moons. The June-to-July lunar month (which this year spans the new moons from June 21 to July 20) is called Hōngongoi, or "man is now extremely cold and kindles fires before which he basks." according to the Encyclopedia of New Zealand. This lunar month was, to the Māori, the second month of the year.
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