Skywatching Tips for July

Venus is joined by Mars in the July twilight. And 'tis the season for enjoying the Milky Way core!

July Highlights

  • July 28: The bright planet Jupiter will appear above the horizon in the east-southeast.
  • July 29: Mars and the bright star Regulus will appear near each other low on the west-northwestern horizon.
  • July 31: The waning Moon will appear half-full.

VenusMars_July12.jpg
Venus and Mars appear close in the night sky in mid-July. Credit: NASA/JPL-Caltech

Sunsets in July come with an added bonus: a brilliant gem low in the western sky, calling to us to come and explore its many mysteries. This is the planet, Venus. It's our cosmic next-door neighbor – that is, the planet with the closest orbit to the orbit of Earth.

It's also often thought of as Earth's sister planet, given that it's also a rocky world of the same size, though Venus developed into a hellishly hot world, where Earth became the cool, blue planet we know and love.

Venus is sometimes referred to as "the Morning Star," or "the Evening Star," depending on whether it's visible around sunrise or sunset. This month, it's the latter, and you'll find Venus low in the west together with a faint planet Mars beginning about half an hour after sunset. In fact, Venus and Mars recently had a close conjunction on July 12th, when they appeared only a finger's width apart.

Venus Mars and Moon
On July 12, Venus and Mars were a mere half-degree apart, or about the width of an index finger at arm's length. Credit: NASA/JPL-Caltech

In June, NASA announced that two new space missions would be heading to Venus beginning later in the decade. VERITAS and DAVINCI will investigate the planet's surface and atmosphere, returning incredible images, maps, and other data, likely rewriting our understanding of how Earth's sister planet became so inhospitable, along with how it might still be active today. They'll be joined by the European spacecraft EnVision, for what's sure to be an exciting new chapter in solar system exploration.


July is also one of the best times of year to enjoy the magical sight that is the Milky Way. This is our view of our spiral galaxy, seen edge on, from within. Now, some part of the Milky Way is visible in the night sky any time of year, but the galaxy's bright, complex core is only observable during certain months. Earlier in the season, you have to wait until the wee hours of the morning for the core to rise in the sky. But in June and July, the core has already risen by the time it's fully dark, and can be seen fairly well until around 2 a.m. when it starts to set.

MilkyWayFinding_July2021.jpg
In June and July, the bright, complex Milky Way core has already risen in the sky by the time it's truly dark out. Credit: NASA/JPL-Caltech

Now, the Milky Way is faint, and to see it, you'll need to find your way out to fairly dark skies, but as long as you're below about 55 degrees north latitude, you should be able to observe the Milky Way core under dark skies. (Southern Hemisphere observers have it even better, as the core appears much higher overhead there.)

MilkyWayViewingCalendar_July2021.jpg
Calendar showing the best and worst times of July 2021 to observe the Milky Way. Bottom line: Milky Way chasers need to avoid the full moon and the brightness it brings. Credit: NASA/JPL-Caltech

One super important tip is to avoid the full moon and the days close to it since a bright Moon overwhelms the faint glow of the Milky Way. The three or four nights around the new moon are best, but the week before and after is also okay – you just have to note when the Moon will be rising or setting. There are a variety of great apps and websites to help you find dark skies and figure out when and where to look. So here's hoping you get out there and experience one of the most fantastic sights the sky has to offer.


Phases of the Moon

Current Moon Phase
Use this tool to see the current Moon phase and to plan ahead for other Moon views. Credit: NASA
Daily Guide

Daily Guide

July 28

Wednesday evening, July 28, 2021, the bright planet Jupiter will appear above the horizon in the east-southeast. It's the last evening the bright star Regulus will appear above the horizon in the west-northwest as evening twilight ends at 7:30 p.m. EDT.

July 29

Thursday, July 29, 2021, will be the evening when the planet Mars and the bright star Regulus will appear nearest each other low on the west-northwestern horizon. Regulus will set shortly before evening twilight ends and Mars will set shortly after evening twilight ends (at least for Washington, and similar latitudes).

July 30

Friday evening, July 30, 2021, will be the last evening the planet Mars will be above the horizon in the west-northwest as evening twilight ends.

July 31

Saturday morning, July 31, 2021, the waning Moon will appear half-full as it reaches its last quarter at 9:16 a.m. EDT.


August 1

Sunday, Aug. 1, 2021, is about halfway between the summer solstice and the Northern Hemisphere autumn equinox. We currently divide the year into four seasons based upon the solstices and equinoxes, with our summer ending on the equinox in September. This approximates summer as the quarter of the year with the warmest temperatures. Much of pre-Christian northern Europe celebrated "cross-quarter days" halfway between the solstices and equinoxes, and divided the seasons on these days. Using this definition, summer was the quarter of the year with the longest daily periods of daylight, with summer ending with Lughnasadh, traditionally celebrated on Aug. 1.

The planet Mercury will be passing on the far side of the Sun as seen from the Earth, called superior conjunction. Because Mercury orbits inside of the orbit of Earth, Mercury will be shifting from the morning sky to the evening sky and will begin emerging from the glow of the dusk on the western horizon on or after Aug. 9 (depending upon viewing conditions).

August 2

Early Monday morning, Aug. 2, 2021, the planet Saturn will appear opposite the Sun as seen from the Earth (called "opposition"). Saturn will be at its closest and brightest for the year, effectively a "full Saturn," rising around sunset and setting around sunrise. With clear skies and a backyard telescope, you should be able to see the rings of Saturn and its largest moon, Titan.

At 3:36 a.m. EDT on Monday, the Moon will be at apogee, its farthest from the Earth for this orbit.

August 3

On Tuesday morning, Aug. 3, 2021, the bright star Aldebaran will appear about 6 degrees to the right of the waning crescent Moon.

August 6

On Friday morning, Aug. 6, 2021, the bright star Pollux will appear to the lower left of the thin waning crescent Moon.

August 8

Sunday morning, Aug. 8, 2021, at 9:50 a.m. 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. The seventh month of the Chinese calendar starts on Sunday, Aug. 8, 2021 (at midnight in China's time zone, which is 12 hours ahead of EDT). Sundown marks the start of Elul in the Hebrew calendar. Elul is a time of preparation for the High Holy Days of Rosh Hashanah and Yom Kippur. Customs include granting and asking others for forgiveness as well as beginning or ending all letters with the wish that the recipient will have a good year.

In the Islamic calendar, the months traditionally start with the first sighting of the waxing crescent Moon. Many Muslim communities now follow the Umm al-Qura Calendar of Saudi Arabia, which uses astronomical calculations to start months in a more predictable way. Using this calendar, sundown on Aug. 8, 2021, will probably mark the beginning of Muharram. Muharram is the first month of the Islamic year and one of the four sacred months during which warfare is forbidden.

August 9

Monday evening, Aug. 9, 2021, will be the first evening that the planet Mercury will appear above the horizon in the west-northwest about 30 minutes after sunset (an approximation of when it will begin being visible in the glow of dusk). For this apparition, Mercury will remain low and not appear above the horizon as evening twilight ends.

Before evening twilight ends on Monday, you might be able to see the waxing crescent Moon low in the west-northwest with the planet Mars to the lower left of the Moon. Mars will set first about 9 minutes before evening twilight ends at 9:05 p.m. EDT, evening twilight will end at 9:14, and the Moon will set about 3 minutes later at 9:17 p.m. Mars will be nearing the opposite side of the Sun from us, appearing near its farthest and faintest, so it may be difficult to see in the glow of dusk without binoculars or a telescope.

August 10

Tuesday evening, Aug. 10, 2021, the bright planet Venus will appear in the west to the left of the waxing crescent Moon. They will be about 5 degrees above the horizon as evening twilight ends at 5:12 p.m. EDT, Venus will set first at 9:42 p.m., and the Moon will set about 4 minutes after Venus.

By Wednesday evening, Aug. 11, 2021, the Moon will have shifted such that the bright planet Venus will appear to the lower right of the waxing crescent Moon. Venus will set first at 9:41 p.m. EDT.

August 12

The Perseid meteor shower is expected to peak on (or after) Thursday afternoon, Aug. 12, 2021 (when we can't see these meteors). Since this shower tends to have a broad peak you may be able to see meteors in either the early morning before or after this expected peak. The night before the expected peak, if the skies are clear and you are in a dark place, try looking for meteors between moonset (10:13 p.m. EDT) Wednesday night, Aug. 11, and the first signs of dawn (about 4:39 a.m.) Thursday morning, Aug. 12.

The night after the expected peak of the Perseid meteor shower, try looking for meteors between moonset (10:40 p.m. EDT) Thursday night, Aug. 12, and the first signs of dawn (about 4:40 a.m.) Friday morning, Aug. 13, 2021.

August 13

Friday evening, Aug. 13, 2021, the bright star Spica will appear to the lower right of the waxing crescent Moon.

August 14

Saturday morning, Aug. 14, 2021, will be the last morning that the planet Saturn will appear above the horizon at the time morning twilight begins.

Sometime during the morning to early afternoon on Aug. 14 (2021-Aug-14 14:35 UTC with 4 hours, 10 minutes uncertainty), Near-Earth Object (2016 BQ), between 38 to 85 feet (12 and 26 meters) across, will pass the Earth at between 4.3 and 4.6 lunar distances (nominally 4.4), traveling at 10,500 miles per hour (4.70 kilometers per second).

August 15

On Sunday, Aug. 15, 2021, the Moon will appear half-full as it reaches its first quarter at 11:20 a.m. EDT.

August 16

Monday evening, Aug. 16, until Antares sets just after midnight Tuesday morning, Aug. 17, 2021, the bright star Antares will appear to the lower right of the waxing gibbous Moon.

August 17

Tuesday morning, Aug. 17, 2021, at 5:16 a.m. EDT, the Moon will be at perigee, its closest to the Earth for this orbit.

August 18

Before evening twilight ends on Wednesday, Aug. 18, 2021, you might be able to see the planets Mercury and Mars appearing only 0.14 degrees (or about a quarter of the apparent diameter of the Moon) apart from each other. To see them you will need a clear view to the horizon low and slightly to the north (right) of due west. They will only be about 2.5 degrees above the horizon about 30 minutes after sunset (8:28 p.m. EDT) and Mercury will set first about 15 minutes later (8:43 p.m.), with evening twilight ending 17 minutes after that (9 p.m.). Mercury will appear substantially brighter than Mars (which may be hard to see in the glow of dusk). In addition, the bright planet Venus will appear about 20 degrees to the upper left of Mercury and Mars.

August 19

Thursday afternoon, Aug. 19, 2021, the planet Jupiter will appear opposite the Sun as seen from the Earth (called "opposition"). Jupiter will be at its closest and brightest for the year, effectively a "full Jupiter," rising around sunset and setting around sunrise. With clear skies and a backyard telescope, you should be able to see Jupiter's four bright moons, Ganymede, Callisto, Europa, and Io, shifting positions noticeably over the course of an evening.

August 20 to 21

Friday evening into Saturday morning, Aug. 20 to 21, 2021, the planet Saturn will appear near the waxing full Moon. Saturn will appear about 5 degrees above the Moon as evening twilight ends and will appear to move clockwise around the Moon until Saturn sets in the west-southwest Saturday morning (at 4:54 a.m. EDT).

Saturday evening into Sunday morning, the bright planet Jupiter will appear near the full Moon. Jupiter will appear about 6 degrees to the upper left of the Moon as evening twilight ends and will appear to shift clockwise around the Moon as the night progresses. The Moon will reach its highest in the sky for the night early on Sunday morning at 1:04 a.m. EDT when Jupiter will appear above the Moon, and Jupiter will appear to the upper right of the Moon as morning twilight begins at 5:27 a.m.

The next full Moon will be on Sunday morning, Aug. 22, 2021, at 8:02 a.m. EDT. The Moon will appear full for about 3 days around this time, from Friday night through Monday morning, making this a full Moon weekend. ​

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Additional Resources

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