Silhouette of an elk in front of a large Moon.

A setting Moon and elk at Mammoth Hot Springs in Yellowstone National Park in March 2015. Credit: National Park Service/Neal Herbert | › Full image and caption

July 2019

When is the Next Full Moon?

The next full Moon will be on Tuesday afternoon, July 16, 2019, appearing "opposite" the Sun (in Earth-based longitude) at 5:38 PM EDT. The Moon will appear full for about three days around this time, from Monday night through Thursday morning.

The Next Full Moon is the Buck Moon, the Thunder Moon, and the Guru Moon.

The next full Moon will be on Tuesday afternoon, July 16, 2019, appearing "opposite" the Sun (in Earth-based longitude) at 5:38 PM EDT. The Moon will appear full for about three days around this time, from Monday night through Thursday morning.

The Maine Farmer's Almanac first published "Indian" names for the full Moons in the 1930's. According to this almanac, as the full Moon in July and the first full Moon of Summer, the Algonquin tribes in what is now the Eastern USA called this full Moon the Buck Moon. Early Summer is normally when the new antlers of buck deer push out of their foreheads in coatings of velvety fur. They also called this the Thunder Moon because of early Summer's frequent thunderstorms.

As usual, the wearing of suitably celebratory celestial attire is encouraged in honor of the full Moon.

For Hindus this is the Guru Full Moon (Guru Purnima) and is celebrated as a time for clearing the mind and honoring the guru or spiritual master.

In lunisolar calendars the months change with the new Moon and full Moons fall in the middle of the lunar months. This full Moon is the middle of the sixth month of the Chinese calendar and Tammuz in the Hebrew calendar. In the Islamic calendar the months start with the first sighting of the waxing crescent Moon a few days after the New Moon. This full Moon is near the middle of Dhu al-Qidah, one of the four sacred months during which warfare is prohibited.

Since this is the Thunder Moon, a quick note on lightning safety. Most of the lightning that strikes the ground arcs from the negatively charged bottom of the storm to the ground underneath the storm. Much rarer is positive lightning, which arcs from the top of a thunderstorm to strike the ground up to eight miles away. Positive lightning can sometimes strike areas where the sky is clear (hence the term "bolt out of the blue"). Because it arcs across a greater distance it tends to be 5 to 10 times more powerful that regular ground strikes. Because it can strike dry areas outside of the storm, positive lightning tends to start more fires than negative lightning. Although positive lightning is rare (less than 5% of all lightning strikes), the lack of warning combined with its greater power tends to make it more lethal. A good rule to follow is, if you can hear the thunder, you can be struck by the lightning. As a bicycle commuter, I am well aware that the inch or so of rubber tire between my metal bicycle and the ground will make little difference to a bolt that can arc across miles of air from the top of a thunderstorm to where I am riding. Stay safe!

As usual, the wearing of suitably celebratory celestial attire is encouraged in honor of the full Moon. Be safe (especially during thunder storms), don't start any wars if you can avoid it, and take a moment to clear you mind.

More Skywatching

As for other celestial events between now and the full Moon after next:

As summer continues, the daily periods of sunlight have passed their longest and are shortening again. For Washington, DC, the daylight period of the day of the full Moon, Tuesday, July 16, 2019, will last 14 hours, 36 minutes, 31 seconds. Morning twilight will begin at 4:46 AM EDT, sunrise will be at 5:56 AM, the Sun will reach a maximum altitude of 72.4 degrees at 1:14 PM, sunset will be at 8:32 PM, and evening twilight will end at 9:42 PM. 30 days later, the daylight period on the day of the full Moon after next, Thursday, August 15, 2019, will be 55 minutes shorter, lasting 13 hours, 41 minutes, 42 seconds. Morning twilight will begin at 5:15 AM, sunrise will be at 6:22 AM, the Sun will reach a maximum altitude of 65.1 degrees at 1:12 PM, sunset will be at 8:03 PM, and evening twilight will end at 9:06 PM.

On the evening of the full Moon on July 16, 2019, as evening twilight ends, the brightest planet in the sky will be Jupiter, appearing in the south-southeast at about 28 degrees above the horizon. Jupiter remains near its brightest, having been at its closest and brightest for the year on June 10, 2019. The planet Saturn will appear near its brightest for the year in the southeast at about 16 degrees above the horizon, having been at its closest and brightest the week before, on July 9, 2019. The planet Mars will have already set, but might still be visible on the horizon in the west-northwest about 30 minutes after sunset. The Summer Triangle will appear high in the east with Vega 62 degrees above the horizon. The "Summer Triangle" is made up of Vega, the brightest star in the constellation Lyra the Harp; Deneb, the brightest star in the constellation Cygnus the Swan; and Altair, the brightest star in the constellation Aquila the Eagle. Over the following evenings these planets and the background of stars will all appear to shift towards the west, with Mercury becoming lost in the glow of sunset. By the evening of the full Moon after next, August 15, 2019, Jupiter will appear in the south-southwest at about 28 degrees above the horizon, Saturn will appear in the south-southeast at about 25 degrees above the horizon, and the star Vega will appear nearly overhead, at about 78 degrees above the eastern horizon.

On the morning of the full Moon on July 16, 2019, as morning twilight begins, Jupiter will have already set and Saturn will appear low in the southwest at about 7 degrees above the horizon (appearing quite near the full Moon). The "Summer Triangle" will appear high in the west. The bright planet Venus will not rise until about 40 minutes before sunrise and will become more and more difficult to see in the east-northeast over the following mornings. Towards the end of July, the planet Mercury will be rapidly emerging from the glow of dawn in the east-northeast, having passed between the Earth and the Sun on July, 21, and will begin to be visible above the horizon at the time morning twilight begins in early August. By the morning of the full Moon on August 15, 2019, as morning twilight begins, the only planet visible in the sky will be Mercury, appearing about 4 degrees above the horizon in the east-northeast. The "Summer Triangle" will appear low in the west-northwest.

Jupiter and Saturn Watching

This summer should be a great time for Jupiter and Saturn watching, especially with a backyard telescope. Jupiter was at its closest and brightest for the year on June 10 and Saturn on July 9, 2019 (called "opposition" because they are opposite the Earth from the Sun, effectively a "full Jupiter" and a "full Saturn"). Both will appear to shift towards the west over the coming months, making them visible earlier in the evening sky (and friendlier for backyard stargazing, especially if you have young ones with earlier bed times). With clear skies and a small telescope you should be able to see Jupiter's four bright moons, Ganymede, Callisto, Europa, and Io, shifting positions noticeably in the course of an evening. Galileo was the first person known to point the newly developed telescope at Jupiter, and he immediately noticed these moons that we now call the Galilean moons. For Saturn, you should be able to see the brightly illuminated rings as well as the motions of Saturn's moons, particularly the largest moon, Titan. Galileo also observed Saturn, but at the time the rings were edge on, so he did not see them.

Meteor Showers

There will be several meteor showers that should be active from now into August. If you happen to be out in an area with dark skies and no Moon on a clear night after midnight, you just might see some meteors.

The Alpha Capricornids should be active until August 11. This shower typically produces only about 1 to 3 meteors per hour, but I mention it because it has a fairly broad peak between July 25 and 30, and occasionally produces bright fireballs. Although most meteor showers are best viewed around 3 AM (in Daylight Savings Time), this shower tends to peak a little after midnight (and the waning Moon will interfere later in the mornings). These meteors are thought to be caused by dust from the comet 169P/NEAT that enters our atmosphere at a relatively "slow" 22 kilometers per second (49,000 miles per hour).

The Southern Delta Aquariids should be active from through August 23, peaking around July 28. This shower is best seen from the southern hemisphere, where under ideal conditions you might be able to see about 20 meters per hour, but for the northern hemisphere the predictions are far less. There are reports that this shower occasionally produces short but intense outbursts of meteors, but these are unpredictable. This meteor shower usually produces faint meteors without persistent trails, and rarely produces fireballs. The best time to look should be after midnight but before moonrise. The Delta Aquarids are probably caused by dust from the the short period comet 96P/Machholz or from the breakup of what are now the Marsden and Kracht Sungrazing comets that enter our atmosphere at 41 kilometers per second (92,000 miles per hour).

The Perseids are often one of the best meteor showers of the year, but moonlight will interfere this year. The Perseids should be active from around July 17 to August 24, peaking around the morning of August 13. With the full Moon on August 15 this year, moonlight will interfere with viewing, especially on and after the peak. The Perseid meteors are caused by dust from the comet 109P/Swift-Tuttle that enters our atmosphere at 58 kilometers per second (130,000 miles per hour).

July 12, 2019

Even though they are not visible usually, I include in these Moon missives information about Near Earth Objects (mostly asteroids) that pass the Earth within about 20 lunar distances, because I find it interesting that we have discovered so many. On Friday afternoon, July 12, 2019, at 2:16 PM EDT (2019-Jul-12 18:16 UTC), Near Earth Object (2016 NJ33), between 24 and 54 meters (80 to 178 feet) in size, will pass the Earth at 14.9 lunar distances, traveling at 4.48 kilometers per second (10,016 miles per hour).

July 13, 2019

On Saturday night, July 13, 2019, at 10:06 PM EDT (2019-Jul-14 02:06 UTC), Near Earth Object (2019 NQ5), between 25 and 57 meters (83 to 186 feet) in size, will pass the Earth at between 11.4 and 11.5 lunar distances (nominally 11.4), traveling at 9.90 kilometers per second (22,145 miles per hour).

On Saturday night into Sunday morning, July 13 to 14, 2019, the bright planet Jupiter will appear to the right of the waxing, gibbous, nearly full Moon. For the Washington, DC area, evening twilight will end at 9:44 PM, the Moon will reach its highest in the sky for the night at 10:56 PM, and Jupiter will set in the west-southwest on Sunday morning at 3:25 AM EDT.

July 14, 2019

On Sunday morning July 14, 2019, at 7:33 AM EDT (2019-Jul-14 11:33 UTC), Near Earth Object (2019 NR3), between 15 and 33 meters (48 to 107 feet) in size, will pass the Earth at between 16.7 and 16.8 lunar distances (nominally 16.7), traveling at 4.80 kilometers per second (10,748 miles per hour).

July 15, 2019

On Monday evening into Tuesday morning, July 15 to 16, 2019, the bright planet Saturn will appear near the full Moon. For the Washington, DC area, evening twilight will end at 9:43 PM, the Moon will reach its highest in the sky for the night on Tuesday at 12:40 AM, and the pair will be about 7 degrees above the southwestern horizon as morning twilight begins at 4:46 AM EDT. From much of the southern Pacific and parts of South America the Moon will actually pass in front of Saturn and block Saturn from view.

July 16, 2019: Full Moon

As mentioned above, the next full Moon will be on Tuesday afternoon, July 16, 2019, at 5:31 PM EDT. Although not visible from nearly all of North America, this will be a partial eclipse of the Moon, with the full shadow of the Earth (called the umbra) falling on about two-thirds of the Moon at the peak of the eclipse.

July 17, 2019

On Wednesday afternoon, July 17, 2019, at 1:09 PM EDT (2019-Jul-17 17:09 UTC with 1 minute uncertainty), Near Earth Object (2019 NF1), between 44 and 99 meters (145 to 324 feet) in size, will pass the Earth at between 19.0 and 19.4 lunar distances (nominally 19.2), traveling at 10.04 kilometers per second (22,468 miles per hour).

July 19, 2019

On Friday afternoon, July 19, 2019, at about 3:53 PM EDT (2019-Jul-19 19:53 UTC with 18 minutes uncertainty), Near Earth Object (2019 NJ2), between 28 and 62 meters (91 to 204 feet) in size, will pass the Earth at between 13.1 and 13.5 lunar distances (nominally 13.3), traveling at 13.46 kilometers per second (30,118 miles per hour).

July 20, 2019

Saturday evening, July 20, 2019, at 8:01 PM EDT, the Moon will be at apogee, its farthest from the Earth for this orbit.

July 21, 2019

Sunday morning, July 21, 2019, will be when the planet Mercury passes between the Earth and the Sun (called inferior conjunction), lost from view in the glow of the Sun as it moves from the evening sky to the morning sky.

July 24, 2019

On Wednesday morning July 24, 2019, sometime around 1:21 AM EDT (2019-Jul-24 05:21 UTC with 2 hours, 4 minutes uncertainty), Near Earth Object (2015 HM10), between 51 and 113 meters (166 to 372 feet) in size, will pass the Earth at between 12.0 and 12.3 lunar distances (nominally 12.2), traveling at 9.50 kilometers per second (21,256 miles per hour).

Wednesday evening, July 24, 2019, the waning Moon will appear half-full as it reaches its last quarter at 9:18 PM EDT.

July 26, 2019

On Friday morning, July 26, 2019, at 11:04 AM EDT (2019-Jul-26 15:04 UTC), Near Earth Object (2010 PK9), between 135 and 151 meters (443 to 495 feet) in size, will pass the Earth at 8.2 lunar distances, traveling at 16.49 kilometers per second (36,889 miles per hour).

July 27, 2019

On Saturday morning, July 27, 2019, the bright star Aldebaran will appear to the lower left of the waning crescent Moon.

By Sunday morning, July 28, 2019, the Moon will have shifted so that Aldebaran will appear to the upper right of the Moon.

On Saturday evening, July 27, 2019, at about 6:10 PM EDT (2019-Jul-27 22:10 UTC with 4 minutes uncertainty), Near Earth Object (2019 NT1), between 11 and 25 meters (36 to 81 feet) in size, will pass the Earth at between 18.7 and 19.2 lunar distances (nominally 19.0), traveling at 3.69 kilometers per second (8,256 miles per hour).

July 28, 2019

As mentioned above, Sunday morning, July 28, 2019, should be the peak of the Southern Delta Aquariids meteor shower. The best time to look should be after midnight but before moonrise (at 2:29 AM EDT for the Washington, DC area).

On Sunday night, July 28, 2019, at about 9:26 PM EDT (2019-Jul-29 01:26 UTC with 13 minutes uncertainty), Near Earth Object (2019 NN4), between 21 and 47 meters (69 to 155 feet) in size, will pass the Earth at 6.6 lunar distances, traveling at 3.78 kilometers per second (8,460 miles per hour).

July 31, 2019

Wednesday night, July 31, 2019, at 11:12 PM EDT, will be the new Moon, when the Moon passes between the Earth and the Sun and will not be visible from the Earth. The day of or the day after the New Moon marks the start of the new month for most lunisolar calendars. Sundown on August 1 marks the start of Av in the Hebrew calendar. The seventh month of the Chinese calendar starts on Thursday, August 1 (at midnight in China's time zone, which is 12 hours ahead of EDT).

Aug. 2, 2019

Friday morning, August 2, 2019, at 3:08 AM EDT, the Moon will be at perigee, its closest to the Earth for this orbit.

In the Islamic calendar the months start with the first sighting of the waxing crescent Moon after the New Moon. Friday evening, August 2, 2019, will probably mark the beginning of Dhu al-Hijjah, the twelfth and final month of the Islamic year, a sacred month, the month of the Hajj. Making the Hajj or pilgrimage to Mecca at least once in your life is one of the Five Pillars of Islam.

Aug. 5, 2019

On Monday evening, August 5, 2019, the bright star to the lower left of the waxing crescent Moon will be Spica.

Aug. 7, 2019

Wednesday afternoon, August 7, 2019, the waxing Moon will appear half-full as it reaches its first quarter at 1:31 PM EDT.

Wednesday, August 7, 2019, will be the seventh day of the seventh month of the Chinese calendar, sometimes called the Chinese Valentine's Day. The seventh night of the seventh month is known as the double seventh festival, Qixi in China, Chilseok in Korea, and Thất Tịch in Vietnam. There are many variations on the legend, but basically, the bright star Vega symbolizes the weaver girl and the bright star Altair symbolizes the cowherd. They fall in love and neglect their duties, so the Goddess of Heaven puts a wide river in the sky, the Milky Way, to keep them apart. They are allowed to meet only one night a year, on the seventh night of the seventh month, when the bright star Deneb forms a bridge across the Milky Way. In some versions of the legend, the bridge is formed by magpies, so this is sometimes called the Magpie Festival. The Japanese Tanabata or the Star Festival is related, but is no longer tied to the lunisolar date (it is now celebrated on July 7th, the double sevenths in the Gregorian Calendar).

Aug. 9, 2019

On Friday evening into early Saturday morning, August 9 to 10, 2019, the bright planet Jupiter will appear to the lower right of the waxing gibbous Moon, with the bright star Antares appearing further to the lower right.

Aug. 10, 2019

On Saturday morning, August 10, 2019, at about 3:22 AM EDT (2019-Aug-10 07:22 UTC with 8 minutes uncertainty), Near Earth Object (2006 QQ23), between 254 and 568 meters (833 to 1,862 feet) in size, will pass the Earth at 19.4 lunar distances, traveling at 4.67 kilometers per second (10,447 miles per hour).

Aug. 11, 2019

On Sunday night, August 11, 2019, at 8:14 PM EDT (2019-Aug-12 00:14 UTC), Near Earth Object 454094 (2013 BZ45), between 114 and 220 meters (374 to 722 feet) in size, will pass the Earth at 16.9 lunar distances, traveling at 8.16 kilometers per second (18,263 miles per hour).

On Sunday evening into Monday morning, August 11 to 12, 2019, the bright planet Saturn will appear to the right of the waxing gibbous Moon, shifting closer together as the night progresses until moonset (at 3:28 AM EDT for the Washington, DC area).

Aug. 12, 2019

On Monday morning, August 12, 2019, for the Washington, DC area and similar latitudes at least, the planet Mercury will appear at its highest above the horizon at the time morning twilight begins, about 4.5 degrees in the east-northeast. Mercury was at its greatest angular separation from the Sun for this apparition a few days before, on August 9, 2019.

Throughout this period, the bright star Antares will appear to the lower right of the bright planet Jupiter. They will appear at their closest, less than 7 degrees apart, on Monday night, August 12, 2019.

Aug. 13, 2019: Perseid Meteors

As mentioned above, the Perseid meteor shower should peak the morning of Tuesday, August 13, 2019. The best time to look should be the narrow window between moonset and when the sky begins to lighten with dawn. For the Washington, DC area, moonset will be at 4:21 AM and morning twilight will begin at 5:16 AM EDT.

Aug. 14, 2019

Wednesday morning, August 14, 2019, will be when the planet Venus passes on the far side of the Sun as seen from Earth (called superior conjunction), shifting from the morning to the evening sky. Venus will begin to emerge from the glow of sunset in late September 2019.

Aug. 15, 2019: The full Moon After Next

The Full Moon after next will be on Thursday morning, August 15, 2019, at 8:29 AM EDT.

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