PanBear
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PART 1:
July 2020: The Next Full Moon is the Buck Moon
By Gordon Johnston
Page Updated: June 30, 2020
July 2020
When is the Next Full Moon?
The next full Moon will be early Sunday morning, July 5, 2020, appearing opposite the Sun at 12:44 a.m. EDT. This will be a partial penumbral eclipse of the Moon, visible from most of North America.
The next full Moon is called the Buck Moon, Thunder Moon, Hay Moon, Mead Moon, Rose Moon, Guru Moon, and Dharma Day. There also will be a partial penumbral lunar eclipse.
The next full Moon will be just after midnight on Sunday morning, July 5, 2020, appearing opposite the Sun (in Earth-based longitude) at 12:44 a.m. EDT. The Moon will be close enough to opposite the Sun that its northern edge will pass through the partial shadow of the Earth — called a partial penumbral eclipse.
Although visible from the Americas, this slight dimming of part of the Moon should be difficult or impossible to notice without instrumentation. The Moon will appear full for about three days around the eclipse, from Friday evening into Monday morning, making this a full Moon weekend.
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 of what is now the northeastern United States 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.
Europeans called this full Moon the Hay Moon for the haymaking in June and July, and sometimes the Mead Moon (although this name and "Honey Moon" were also used for the previous full Moon). Mead is created by fermenting honey mixed with water, sometimes adding fruits, spices, grains, or hops.
Another European name is the Rose Moon, although some use this name for the previous full Moon. Some sources indicate the name "Rose Moon" comes from the roses that bloom in late June. Others report that the name comes from the color of the full Moon this time of year.
The orbit of the Moon around the Earth is almost in the same plane as the orbit of the Earth around the Sun (only about 5 degrees off). When the Sun appears highest in the sky near the summer solstice, the full Moon opposite the Sun appears low in the sky. For Europe's higher latitudes, the full Moon nearest the summer solstice shines through more atmosphere than at other times of the year, making it more likely to have a reddish color (for the same reasons that sunrises and sunsets are red).
For 2020, this full Moon in early July is closer to the summer solstice and will be lower in the sky than the full Moon in June. For the Washington, D.C. area, on the morning of July 5, 2020, the full Moon will reach only 26.2 degrees above the southern horizon at its highest for the night, about 1.5 degrees lower in the sky than the full Moon was in early June.
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. For Buddhists, this full Moon is Dharma Day, also known as Asalha Puha or Esala Poya. For Theravada Buddhism this is an important festival celebrating Buddha's first sermon.
In most 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 fifth 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 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 than 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 former bicycle commuter (before I retired from NASA), 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.
As usual, the wearing of suitably celebratory celestial attire is encouraged in honor of the full Moon. Be safe (especially during thunder storms), avoid starting wars, and take a moment to clear your mind.
More Skywatching
As for other celestial events between now and the full Moon after next:
As summer begins, the daily periods of sunlight begin to shorten. For the Washington, D.C. area (using the location of NASA Headquarters), on the day of the full Moon (Sunday, July 5, 2020) morning twilight will begin at 4:37 a.m., sunrise will be at 5:49 a.m, solar noon will be at 1:13 p.m. when the Sun reaches its maximum altitude of 73.8 degrees, sunset will be at 8:36 p.m., and evening twilight will end at 9:48 p.m. By the day of the full Moon after next (Monday, Aug. 3, 2020) morning twilight will begin at 5:06 a.m., sunrise will be at 6:11 a.m, solar noon will be at 1:14 p.m. when the Sun reaches its maximum altitude of 68.4 degrees, sunset will be at 8:17 p.m, and evening twilight will end at 9:22 p.m.
Jupiter and Saturn Watching
On the evening of July 4, 2020 (the evening before the full Moon after midnight on July 5), as evening twilight ends, the bright planet Jupiter and the fainter planet Saturn will appear in the east southeast, with Jupiter to the right about 6 degrees above the horizon and Saturn on the left about 3 degrees above the horizon. The bright star closest to appearing directly overhead will be Arcturus, appearing 64 degrees above the southwestern horizon. The three bright stars of the "Summer Triangle" will appear towards the east, with Vega appearing 55 degrees above the horizon in the east-northeast, Deneb about 35 degrees above the horizon to the lower left of Vega, and Altair in the east about 26 degrees above the horizon.
As the lunar cycle progresses, the background of stars and planets will appear to shift towards the west. This summer should be a great time for Jupiter and Saturn watching, especially with a backyard telescope. Jupiter will be at its closest and brightest for the year on July 14, 2020, while Saturn will be at its closest and brightest on July 20, 2020, (called "opposition" because they will be opposite the Earth from the Sun). Both will appear to shift towards the west over the summer 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. 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.
Comet Watching
We may have a naked eye comet visible in the evenings later in July 2020. However, we had two other promising comets this year [C/2019 Y4 (ATLAS) and C/2020 F8 (SWAN)] that both broke up as they got closer to the Sun and did not end up being visible.
This current comet, C/2020 F3 (NEOWISE), was discovered on March 27, 2020. It will make its closest approach to the Sun on July 3, passing closer to the Sun than Mercury. If (and this is a big if) it does not break up, in its current orbit it should make its closest pass by the Earth on July 23. For the Washington, D.C. area, we may be able to see it near its closest on July 22 after moonset (at 10:14 p.m. EDT), when it will be about 20 degrees above the horizon in the northwest, but before the comet sets in the north-northwest just after 1 a.m. on July 23, 2020.
This comet was discovered by NASA's Near Earth Object Wide-field Infrared Survey Explorer (NEOWISE). NEOWISE was launched as the WISE mission on Dec. 14, 2009, using stored liquid hydrogen to keep its long-wavelength and far infrared detectors cold for astronomy observations. After this stored cryogen ran out, it observed for four months using only its mid-wavelength infrared detectors. The spacecraft was put into hibernation in February 2011. In September 2013 it was revived to make observations in the mid-wavelength infrared looking for Near Earth Objects (NEOs). So far, NEOWISE has discovered 28 comets and 313 near Earth asteroids (NEAs), including 57 potentially hazardous asteroids (PHAs) that might someday make threatening close approaches to the Earth.
By the evening of the full Moon after next on Aug. 3, 2020, as evening twilight ends (at 9:22 p.m. EDT for the Washington, D.C. area), the bright planet Jupiter and the fainter planet Saturn will appear in the southeast, with Jupiter to the right about 19 degrees above the horizon and Saturn on the left about 18 degrees above the horizon. The bright star appearing closest to overhead will be Vega, the brightest of the stars of the "Summer Triangle," appearing 72 degrees above the eastern horizon. The other bright stars of the "Summer Triangle" are Deneb, which will appear about 50 degrees above the horizon in the east-northeast, and Altair, which will appear about 43 degrees above the horizon in the east-southeast.
On the morning of the full Moon on Sunday, July 5, 2020, as morning twilight begins (at 4:37 a.m. EDT for the Washington, D.C. area), four visible planets will be above the horizon (Neptune and Pluto will also be above the horizon but are not visible without a telescope). Venus will be the brightest, appearing about 11 degrees above the horizon in the east-southeast near the bright star Aldebaran. Next in brightness will be Jupiter appearing about 18 degrees above the horizon in the southwest. Saturn (the faintest of the four) will appear to the upper left of Jupiter at about 23 degrees above the horizon. Mars, third in brightness, will appear about 42 degrees above the horizon in the southeast.
Venus and Mercury Watching
Wednesday morning, July 8, 2020, will be when the brightest of the planets, Venus, reaches its greatest brilliancy (a geometric approximation of its greatest brightness). The bright star appearing to the lower left of Venus will be Aldebaran. Also around July 8, 2020 (depending upon viewing conditions), the planet Mercury should begin emerging from the glow of dawn about 30 minutes before sunrise, appearing low on the horizon in the east-northeast. Venus and Aldebaran will appear at their closest to each other on the morning of Sunday, July 12, 2020, about 1 degree apart. Starting the morning of Thursday, July 16, 2020, the planet Mercury will be above the horizon at the time morning twilight begins (at least for the Washington, D.C. area), making all five of the naked eye planets visible (if you have a clear view of Mercury on the horizon in the east-northeast and Jupiter and Saturn on the horizon in the southwest). Mercury will appear at its highest above the horizon at the time morning twilight begins on the morning of Sunday, July 26, 2020 (3.5 degrees above the horizon in the east-northeast for the Washington, D.C. area), after which Mercury will begin shifting towards the glow of dawn again. Monday, July 27, 2020, will be the last morning that Jupiter will be above the horizon at the time morning twilight begins (for the D.C. area, at least).
By the morning of the full Moon after next on Monday, Aug. 3, 2020, as morning twilight begins (at 5:06 a.m. for the Washington, D.C. area), the brightest of the visible planets, Venus, will appear about 25 degrees above the horizon in the east. Jupiter will have already set, so next in brightness will be Mars, appearing 54 degrees above the horizon in the south-southeast. Almost as bright as Mars, Mercury will appear only about 1 degree above the horizon in the east-northeast. The faintest of the visible planets, Saturn, will just be setting in the west-southwest, and this will be the last morning that Saturn will be above the horizon at the time morning twilight begins.
Meteor Showers
If you happen to find yourself in a place with clear, dark skies, away from city lights, especially if the Moon has already set and it is after midnight but before the sky starts to show any sign of dawn, keep a look out for meteors. Last month I mentioned the June Bootids, which peaked on June 27 and are expected to end by July 2, so I won't write much more here.
The Southern Delta-Aquariids are expected to be active from around July 12 to Aug. 23, peaking on July 27, 2020. Under ideal conditions (a clear, dark night in the southern hemisphere) near this peak you might be able to see 25 meteors per hour, although fewer meteors are expected be visible for us in the northern hemisphere. The best time to look should be on Monday morning, July 27, 2020, after moonset (12:20 a.m. EDT for the Washington, D.C. area) and before any sign of dawn (before about 4:17 a.m.), but only if the weather is clear with no clouds or high hazes, you can find a place that has a clear view of a wide expanse of the sky especially towards the south, and it is a place that is far from any light sources or urban light pollution.
If you do go out looking for meteors, be sure to give your eyes plenty of time to adapt to the dark. The rod cells in your eyes are more sensitive to low light levels but play little role in color vision. Your color-sensing cone cells are concentrated near the center of your view with more of the rod cells on the edge of your view. Since some meteors are faint, you will tend to see more meteors from the "corner of your eye" (which is why you need a view of a large part of the sky). Your color vision (cone cells) will adapt to darkness in about 10 minutes, but your more sensitive night vision will continue to improve for an hour or more (with most of the improvement in the first 35 to 45 minutes). The more sensitive your eyes are, the more chance you have of seeing meteors. Even a short exposure to light (from passing car headlights, etc.) will start the adaptation over again (so no turning on a light or your cell phone to check what time it is).
The Perseids are expected to be active from July 17 to Aug. 24, peaking on Aug. 12, 2020. Since this peak will be after the full Moon after next, I'll write more next month.
Even though they are not usually visible, I include in these Moon missives information about Near Earth Objects (mostly asteroids) that may pass the Earth within 5 lunar distances, because I find it interesting that we have discovered so many. Early on Monday morning, June 29, 2020, at 12:09 a.m. EDT (2020-Jun-29 04:09 UTC), Near Earth Object (2020 JX1), between 46 and 103 meters (152 to 339 feet) across, will pass the Earth at 3.3 lunar distances, traveling at 5.00 kilometers per second (11,180 miles per hour).
July 1, 2020
On Wednesday afternoon, July 1, 2020, at 4:27 p.m. EDT (2020-Jul-01 20:27 UTC), Near Earth Object (2020 MK3), between 18 and 41 meters (60 to 135 feet) across, will pass the Earth at 1.8 lunar distances, traveling at 8.35 kilometers per second (18,670 miles per hour).
July 2, 2020
On Thursday night, July 2, 2020, the bright star Antares will appear to the lower right of the waxing nearly-full Moon.
July 4, 2002
Saturday morning, July 4, 2020, the Earth will be at aphelion, its farthest from the Sun in its year-long orbit. The Earth will be 3.4% farther from the Sun than it was at perihelion in early January. Since light intensity drops off as the square of the distance from the light source, the sunlight reaching the Earth at aphelion will be about 6.5% less bright than sunlight reaching the Earth at perihelion.
July 5, 2020
As mentioned above, the next full Moon will be early Sunday morning, July 5, 2020, appearing opposite the Sun at 12:44 a.m. EDT. This will be a partial penumbral eclipse of the Moon, visible from most of North America, but the slight reduction in brightness on part of the Moon will be difficult to notice with the human eye. The Moon will start to enter the partial shadow on Saturday night, July 4, 2020, at 11:07 p.m. EDT. On Sunday morning at 12:30 a.m. (the peak of the eclipse) about 35 percent of the Moon will be in the partial shadow. The Moon will finish exiting the partial shadow of the Earth at 1:52 a.m.
On Sunday night into Monday morning, July 5 to 6, 2020, the full Moon and the planets Jupiter and Saturn will form a triangle. The Moon will appear in the southeast at about 3 degrees above the horizon as evening twilight ends, with Jupiter above the Moon and Saturn to the left of the Moon. The Moon will reach its highest in the sky for the night on Monday morning (at 2:11 a.m. EDT for the Washington, D.C. area), with Jupiter to the right and Saturn above, and the Moon will be about 19 degrees above the horizon in the southwest as morning twilight begins (at 4:38 a.m. EDT).
July 8, 2020
Wednesday morning, July 8, 2020, will be when the brightest of the planets, Venus, will reach its greatest brilliancy (a geometric approximation of its greatest brightness) for this apparition. The bright star appearing to the lower left of Venus will be Aldebaran. For the Washington, D.C. area, Venus will rise in the east-northeast at 3:29 a.m. EDT, Aldebaran will rise around 3:40 a.m., morning twilight will begin around 4:40 a.m., but Venus should be bright enough to remain visible well into dawn. Since Venus will be near aphelion (its farthest from the Sun in its orbit), Venus will not be as bright this apparition as it can be in other apparitions.
Also Wednesday morning (depending upon viewing conditions), the planet Mercury should begin emerging from the glow of dawn about 30 minutes before sunrise, appearing low on the horizon in the east-northeast (rising at 5:21 a.m. EDT for the Washington, D.C. area). Mercury passed between the Earth and the Sun on June 30, 2020.
July 2020: The Next Full Moon is the Buck Moon
By Gordon Johnston
Page Updated: June 30, 2020
July 2020
When is the Next Full Moon?
The next full Moon will be early Sunday morning, July 5, 2020, appearing opposite the Sun at 12:44 a.m. EDT. This will be a partial penumbral eclipse of the Moon, visible from most of North America.
The next full Moon is called the Buck Moon, Thunder Moon, Hay Moon, Mead Moon, Rose Moon, Guru Moon, and Dharma Day. There also will be a partial penumbral lunar eclipse.
The next full Moon will be just after midnight on Sunday morning, July 5, 2020, appearing opposite the Sun (in Earth-based longitude) at 12:44 a.m. EDT. The Moon will be close enough to opposite the Sun that its northern edge will pass through the partial shadow of the Earth — called a partial penumbral eclipse.
Although visible from the Americas, this slight dimming of part of the Moon should be difficult or impossible to notice without instrumentation. The Moon will appear full for about three days around the eclipse, from Friday evening into Monday morning, making this a full Moon weekend.
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 of what is now the northeastern United States 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.
Europeans called this full Moon the Hay Moon for the haymaking in June and July, and sometimes the Mead Moon (although this name and "Honey Moon" were also used for the previous full Moon). Mead is created by fermenting honey mixed with water, sometimes adding fruits, spices, grains, or hops.
Another European name is the Rose Moon, although some use this name for the previous full Moon. Some sources indicate the name "Rose Moon" comes from the roses that bloom in late June. Others report that the name comes from the color of the full Moon this time of year.
The orbit of the Moon around the Earth is almost in the same plane as the orbit of the Earth around the Sun (only about 5 degrees off). When the Sun appears highest in the sky near the summer solstice, the full Moon opposite the Sun appears low in the sky. For Europe's higher latitudes, the full Moon nearest the summer solstice shines through more atmosphere than at other times of the year, making it more likely to have a reddish color (for the same reasons that sunrises and sunsets are red).
For 2020, this full Moon in early July is closer to the summer solstice and will be lower in the sky than the full Moon in June. For the Washington, D.C. area, on the morning of July 5, 2020, the full Moon will reach only 26.2 degrees above the southern horizon at its highest for the night, about 1.5 degrees lower in the sky than the full Moon was in early June.
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. For Buddhists, this full Moon is Dharma Day, also known as Asalha Puha or Esala Poya. For Theravada Buddhism this is an important festival celebrating Buddha's first sermon.
In most 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 fifth 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 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 than 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 former bicycle commuter (before I retired from NASA), 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.
As usual, the wearing of suitably celebratory celestial attire is encouraged in honor of the full Moon. Be safe (especially during thunder storms), avoid starting wars, and take a moment to clear your mind.
More Skywatching
As for other celestial events between now and the full Moon after next:
As summer begins, the daily periods of sunlight begin to shorten. For the Washington, D.C. area (using the location of NASA Headquarters), on the day of the full Moon (Sunday, July 5, 2020) morning twilight will begin at 4:37 a.m., sunrise will be at 5:49 a.m, solar noon will be at 1:13 p.m. when the Sun reaches its maximum altitude of 73.8 degrees, sunset will be at 8:36 p.m., and evening twilight will end at 9:48 p.m. By the day of the full Moon after next (Monday, Aug. 3, 2020) morning twilight will begin at 5:06 a.m., sunrise will be at 6:11 a.m, solar noon will be at 1:14 p.m. when the Sun reaches its maximum altitude of 68.4 degrees, sunset will be at 8:17 p.m, and evening twilight will end at 9:22 p.m.
Jupiter and Saturn Watching
On the evening of July 4, 2020 (the evening before the full Moon after midnight on July 5), as evening twilight ends, the bright planet Jupiter and the fainter planet Saturn will appear in the east southeast, with Jupiter to the right about 6 degrees above the horizon and Saturn on the left about 3 degrees above the horizon. The bright star closest to appearing directly overhead will be Arcturus, appearing 64 degrees above the southwestern horizon. The three bright stars of the "Summer Triangle" will appear towards the east, with Vega appearing 55 degrees above the horizon in the east-northeast, Deneb about 35 degrees above the horizon to the lower left of Vega, and Altair in the east about 26 degrees above the horizon.
As the lunar cycle progresses, the background of stars and planets will appear to shift towards the west. This summer should be a great time for Jupiter and Saturn watching, especially with a backyard telescope. Jupiter will be at its closest and brightest for the year on July 14, 2020, while Saturn will be at its closest and brightest on July 20, 2020, (called "opposition" because they will be opposite the Earth from the Sun). Both will appear to shift towards the west over the summer 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. 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.
Comet Watching
We may have a naked eye comet visible in the evenings later in July 2020. However, we had two other promising comets this year [C/2019 Y4 (ATLAS) and C/2020 F8 (SWAN)] that both broke up as they got closer to the Sun and did not end up being visible.
This current comet, C/2020 F3 (NEOWISE), was discovered on March 27, 2020. It will make its closest approach to the Sun on July 3, passing closer to the Sun than Mercury. If (and this is a big if) it does not break up, in its current orbit it should make its closest pass by the Earth on July 23. For the Washington, D.C. area, we may be able to see it near its closest on July 22 after moonset (at 10:14 p.m. EDT), when it will be about 20 degrees above the horizon in the northwest, but before the comet sets in the north-northwest just after 1 a.m. on July 23, 2020.
This comet was discovered by NASA's Near Earth Object Wide-field Infrared Survey Explorer (NEOWISE). NEOWISE was launched as the WISE mission on Dec. 14, 2009, using stored liquid hydrogen to keep its long-wavelength and far infrared detectors cold for astronomy observations. After this stored cryogen ran out, it observed for four months using only its mid-wavelength infrared detectors. The spacecraft was put into hibernation in February 2011. In September 2013 it was revived to make observations in the mid-wavelength infrared looking for Near Earth Objects (NEOs). So far, NEOWISE has discovered 28 comets and 313 near Earth asteroids (NEAs), including 57 potentially hazardous asteroids (PHAs) that might someday make threatening close approaches to the Earth.
By the evening of the full Moon after next on Aug. 3, 2020, as evening twilight ends (at 9:22 p.m. EDT for the Washington, D.C. area), the bright planet Jupiter and the fainter planet Saturn will appear in the southeast, with Jupiter to the right about 19 degrees above the horizon and Saturn on the left about 18 degrees above the horizon. The bright star appearing closest to overhead will be Vega, the brightest of the stars of the "Summer Triangle," appearing 72 degrees above the eastern horizon. The other bright stars of the "Summer Triangle" are Deneb, which will appear about 50 degrees above the horizon in the east-northeast, and Altair, which will appear about 43 degrees above the horizon in the east-southeast.
On the morning of the full Moon on Sunday, July 5, 2020, as morning twilight begins (at 4:37 a.m. EDT for the Washington, D.C. area), four visible planets will be above the horizon (Neptune and Pluto will also be above the horizon but are not visible without a telescope). Venus will be the brightest, appearing about 11 degrees above the horizon in the east-southeast near the bright star Aldebaran. Next in brightness will be Jupiter appearing about 18 degrees above the horizon in the southwest. Saturn (the faintest of the four) will appear to the upper left of Jupiter at about 23 degrees above the horizon. Mars, third in brightness, will appear about 42 degrees above the horizon in the southeast.
Venus and Mercury Watching
Wednesday morning, July 8, 2020, will be when the brightest of the planets, Venus, reaches its greatest brilliancy (a geometric approximation of its greatest brightness). The bright star appearing to the lower left of Venus will be Aldebaran. Also around July 8, 2020 (depending upon viewing conditions), the planet Mercury should begin emerging from the glow of dawn about 30 minutes before sunrise, appearing low on the horizon in the east-northeast. Venus and Aldebaran will appear at their closest to each other on the morning of Sunday, July 12, 2020, about 1 degree apart. Starting the morning of Thursday, July 16, 2020, the planet Mercury will be above the horizon at the time morning twilight begins (at least for the Washington, D.C. area), making all five of the naked eye planets visible (if you have a clear view of Mercury on the horizon in the east-northeast and Jupiter and Saturn on the horizon in the southwest). Mercury will appear at its highest above the horizon at the time morning twilight begins on the morning of Sunday, July 26, 2020 (3.5 degrees above the horizon in the east-northeast for the Washington, D.C. area), after which Mercury will begin shifting towards the glow of dawn again. Monday, July 27, 2020, will be the last morning that Jupiter will be above the horizon at the time morning twilight begins (for the D.C. area, at least).
By the morning of the full Moon after next on Monday, Aug. 3, 2020, as morning twilight begins (at 5:06 a.m. for the Washington, D.C. area), the brightest of the visible planets, Venus, will appear about 25 degrees above the horizon in the east. Jupiter will have already set, so next in brightness will be Mars, appearing 54 degrees above the horizon in the south-southeast. Almost as bright as Mars, Mercury will appear only about 1 degree above the horizon in the east-northeast. The faintest of the visible planets, Saturn, will just be setting in the west-southwest, and this will be the last morning that Saturn will be above the horizon at the time morning twilight begins.
Meteor Showers
If you happen to find yourself in a place with clear, dark skies, away from city lights, especially if the Moon has already set and it is after midnight but before the sky starts to show any sign of dawn, keep a look out for meteors. Last month I mentioned the June Bootids, which peaked on June 27 and are expected to end by July 2, so I won't write much more here.
The Southern Delta-Aquariids are expected to be active from around July 12 to Aug. 23, peaking on July 27, 2020. Under ideal conditions (a clear, dark night in the southern hemisphere) near this peak you might be able to see 25 meteors per hour, although fewer meteors are expected be visible for us in the northern hemisphere. The best time to look should be on Monday morning, July 27, 2020, after moonset (12:20 a.m. EDT for the Washington, D.C. area) and before any sign of dawn (before about 4:17 a.m.), but only if the weather is clear with no clouds or high hazes, you can find a place that has a clear view of a wide expanse of the sky especially towards the south, and it is a place that is far from any light sources or urban light pollution.
If you do go out looking for meteors, be sure to give your eyes plenty of time to adapt to the dark. The rod cells in your eyes are more sensitive to low light levels but play little role in color vision. Your color-sensing cone cells are concentrated near the center of your view with more of the rod cells on the edge of your view. Since some meteors are faint, you will tend to see more meteors from the "corner of your eye" (which is why you need a view of a large part of the sky). Your color vision (cone cells) will adapt to darkness in about 10 minutes, but your more sensitive night vision will continue to improve for an hour or more (with most of the improvement in the first 35 to 45 minutes). The more sensitive your eyes are, the more chance you have of seeing meteors. Even a short exposure to light (from passing car headlights, etc.) will start the adaptation over again (so no turning on a light or your cell phone to check what time it is).
The Perseids are expected to be active from July 17 to Aug. 24, peaking on Aug. 12, 2020. Since this peak will be after the full Moon after next, I'll write more next month.
Even though they are not usually visible, I include in these Moon missives information about Near Earth Objects (mostly asteroids) that may pass the Earth within 5 lunar distances, because I find it interesting that we have discovered so many. Early on Monday morning, June 29, 2020, at 12:09 a.m. EDT (2020-Jun-29 04:09 UTC), Near Earth Object (2020 JX1), between 46 and 103 meters (152 to 339 feet) across, will pass the Earth at 3.3 lunar distances, traveling at 5.00 kilometers per second (11,180 miles per hour).
July 1, 2020
On Wednesday afternoon, July 1, 2020, at 4:27 p.m. EDT (2020-Jul-01 20:27 UTC), Near Earth Object (2020 MK3), between 18 and 41 meters (60 to 135 feet) across, will pass the Earth at 1.8 lunar distances, traveling at 8.35 kilometers per second (18,670 miles per hour).
July 2, 2020
On Thursday night, July 2, 2020, the bright star Antares will appear to the lower right of the waxing nearly-full Moon.
July 4, 2002
Saturday morning, July 4, 2020, the Earth will be at aphelion, its farthest from the Sun in its year-long orbit. The Earth will be 3.4% farther from the Sun than it was at perihelion in early January. Since light intensity drops off as the square of the distance from the light source, the sunlight reaching the Earth at aphelion will be about 6.5% less bright than sunlight reaching the Earth at perihelion.
July 5, 2020
As mentioned above, the next full Moon will be early Sunday morning, July 5, 2020, appearing opposite the Sun at 12:44 a.m. EDT. This will be a partial penumbral eclipse of the Moon, visible from most of North America, but the slight reduction in brightness on part of the Moon will be difficult to notice with the human eye. The Moon will start to enter the partial shadow on Saturday night, July 4, 2020, at 11:07 p.m. EDT. On Sunday morning at 12:30 a.m. (the peak of the eclipse) about 35 percent of the Moon will be in the partial shadow. The Moon will finish exiting the partial shadow of the Earth at 1:52 a.m.
On Sunday night into Monday morning, July 5 to 6, 2020, the full Moon and the planets Jupiter and Saturn will form a triangle. The Moon will appear in the southeast at about 3 degrees above the horizon as evening twilight ends, with Jupiter above the Moon and Saturn to the left of the Moon. The Moon will reach its highest in the sky for the night on Monday morning (at 2:11 a.m. EDT for the Washington, D.C. area), with Jupiter to the right and Saturn above, and the Moon will be about 19 degrees above the horizon in the southwest as morning twilight begins (at 4:38 a.m. EDT).
July 8, 2020
Wednesday morning, July 8, 2020, will be when the brightest of the planets, Venus, will reach its greatest brilliancy (a geometric approximation of its greatest brightness) for this apparition. The bright star appearing to the lower left of Venus will be Aldebaran. For the Washington, D.C. area, Venus will rise in the east-northeast at 3:29 a.m. EDT, Aldebaran will rise around 3:40 a.m., morning twilight will begin around 4:40 a.m., but Venus should be bright enough to remain visible well into dawn. Since Venus will be near aphelion (its farthest from the Sun in its orbit), Venus will not be as bright this apparition as it can be in other apparitions.
Also Wednesday morning (depending upon viewing conditions), the planet Mercury should begin emerging from the glow of dawn about 30 minutes before sunrise, appearing low on the horizon in the east-northeast (rising at 5:21 a.m. EDT for the Washington, D.C. area). Mercury passed between the Earth and the Sun on June 30, 2020.