Skip to main content

The brightest planets in August's night sky: How to see them (and when)

Step outside anytime this month just before the stroke of midnight and you’ll be able to see three bright naked-eye planets.  Jupiter and Saturn are near their highest point in the southern sky, while Mars begins to ascend the eastern sky. If you’re an early riser and head out about an hour before sunrise during the first week of August you’ll have a chance at seeing five bright planets at the same time: Mercury, low in the east-northeast; brilliant Venus, higher up to the upper right of Mercury; Mars high and almost due south, while Jupiter and Saturn approach their setting in the west-southwest.

Mercury will disappear by the second week of August.  

A telescope will reveal the cloud bands on Jupiter as well as its four big moons, Saturn’s beautiful rings, the disk of Mars which will appear to slowly swell as it continues to approach Earth and Venus goes from a crescent to gibbous phase, appearing like a half moon at midmonth.  

In our schedule, remember that when measuring the angular separation between two celestial objects, your clenched fist held at arm’s length measures roughly 10-degrees.  Here, we present a schedule below which provides some of the best planet viewing times as well directing you as to where to look to see them.

Mercury 

During the first week of August, Mercury will be visible very low in the eastern pre-dawn sky as a magnitude -0.9 object. Viewed in a telescope during that time, the planet will exhibit a waxing gibbous phase and a diminishing apparent disk size. It will be descending sunward, and will disappear into the sun's glow well before it reaches superior conjunction on Aug. 17. Mercury will re-appear low in the western sky after sunset for the final week of the month. This time, the planet will show a waning, nearly fully-illuminated phase, and a disk size of approximately 5 arc-seconds. (Image credit: Starry Night)

Mercury – is still visible before sunrise as August begins, but it quickly drops of sight and reaches superior conjunction with the sun on August 17th.

Venus

During August, Venus will shine very brightly in the eastern pre-dawn sky. For the first half of the month, it will move prograde east through the stars of eastern Taurus and then through northern Orion. On Aug. 13, Venus will reach its greatest separation, 46 degrees west of the sun, as it crosses into Gemini, where it will remain until early September. The planet will diminish slightly in visual brightness during August. Viewed in a telescope, Venus will exhibit a half-illuminated phase, and its apparent disk diameter will shrink from 27 to 20 arc-seconds. On Aug. 15, a pretty, waning crescent moon will take up a position 3.5 degrees to the celestial north of Venus, setting up a nice photo opportunity. (Image credit: Starry Night)

Venus – rises about the same time all August: around 2:40 a.m. local daylight time.  It accomplishes this by racing eastward against the westward seasonal progression of the constellations, starting the month 2° from Zeta Tauri and ending in eastern Gemini near Cancer.  On the morning of August 12th, Perseid watchers will find Venus is at greatest elongation, 46° from the sun, and it will be fascinating to observe in a telescope within a few days of this date, appearing exactly half-lit in telescopes – though not necessarily on the 12th itself. Venus glows less than 4° to the lower right of a slender crescent moon on the morning of the 15th. 

Mars

august 2020 night sky mars

During August, Mars will shine prominently among the modest stars of Pisces in the late evening and overnight sky as the Earth continues to overtake the reddish planet. Visually, Mars will nearly double in brightness during August — from magnitude -1.1 on Aug. 1 to magnitude –1.8 on the 31st. Meanwhile, its apparent disk size will grow from 14.5 to 19 arc-seconds. On Saturday night, Aug. 8, the waning last quarter moon will pass only two finger widths to the lower right (or 2.3 degrees to the celestial southwest of) Mars. They will not set in the west until mid-morning on Sunday — offering a chance to see Mars in the morning daytime sky using binoculars and backyard telescopes, by using the moon as a reference. (Image credit: Starry Night)

Mars – is rising earlier every week and becoming dazzling!  At the beginning of August, it comes up soon after 11 p.m. local daylight time, and by the 31st it rises around 9:30 p.m. Mars is gradually slowing in its nightly eastward progression in the southeast corner of Pisces the Fishes.  Drawing ever nearer, Mars doubles in brightness during August, surpassing Sirius on August 21st and reaching magnitude -1.8 by month’s end.  By the end of August its disk will have swelled to about 40% of Jupiter’s, which may still look pretty small in a telescope but is enormous compared to how Mars usually appears.  Set your alarm clock so you can be out about 4:30 a.m. local daylight time. Mars is best during the first light of dawn when it is high in the south.  On August 8th, in the hour before midnight, you’ll see the waning gibbous moon ascending the eastern sky, accompanied by brilliant Mars situated about 2½° to the moon’s upper left.  As the night wears on, watch how the moon appears to draw closer to the red planet.  They will appear closest during the predawn hours, separated then by about a degree.

Jupiter

august 2020 night sky jupiter

During August, Jupiter will already be shining low in the southeast when the evening sky begins to darken. Recently past opposition, the planet will be a fine observing target all night long as it moves retrograde westward through the stars of northeastern Sagittarius — and only 8 degrees to the west of dimmer Saturn. During August, Jupiter will decrease slightly in brightness (from magnitude -2.71 to -2.55) and in apparent disk size (from 47 to 44 arc-seconds). On Aug. 1 the nearly full moon will sit to the celestial south of Jupiter and Saturn — a grouping that will make a beautiful wide field image. The tableau will repeat on Aug. 28. Commencing at 10:30 p.m. EDT on Friday evening, Aug. 14 (or 02:30 GMT on Saturday, Aug. 15), observers in the Central Time zone, and east of there, can watch Ganymede's round, black shadow and the Great Red Spot travel across Jupiter's northern and southern hemispheres, respectively. Commencing at 12:06 a.m. EDT (or 04:06 GMT) on Saturday, Aug. 15, observers in the Americas can witness a rare double shadow transit when Io's and Ganymede's shadows cross Jupiter accompanied by the Great Red Spot! On Saturday, Aug. 22, observers in the western half of North America can watch the shadows of Io and Ganymede transit Jupiter together starting at 1:32 a.m. EDT (or 06:32 GMT).  (Image credit: Starry Night)

Jupiter – shines in eastern Sagittarius and was at opposition on July 14th, so in August it’s already visible in the southeast at dusk and sets before dawn.  This giant world still glares at magnitude -2.7.  Its large disk is best observed when the planet is highest in the sky: around 11:30 p.m. local daylight time at the start of August, and 9:30 p.m. by month’s end.  On the evening of August 1st, Jupiter can be readily found about 3° to the upper right of the moon. The moon has a second encounter with Jupiter this month, passing about 2° below it as darkness falls on the evening of the 28th.  

Saturn

After its recent opposition, Saturn will be well-positioned for observing all night during August while it moves retrograde (westward) through the stars of northeastern Sagittarius. The planet will also remain just 8 degrees to the east of Jupiter, which will outshine Saturn by a factor of 10 — delaying the dimmer planet's appearance, low the southeastern sky, until well after sunset. The rings, and many of Saturn's moons, are easily visible in backyard telescopes. During August, Saturn will diminish slightly in brightness and apparent size. On Aug. 1 the nearly full moon will sit just to the celestial south of Jupiter and Saturn — a grouping that will make a beautiful wide field image. The tableau will repeat on Aug. 28 — and then the gibbous moon will shift to sit 6 degrees southeast of Saturn the following night.  (Image credit: Starry Night)

Saturn – shines in the south-southeast during evening hours and like Jupiter, is also in eastern Sagittarius. And with all due respect to Venus, Mars and Jupiter, many would say unequivocally that Saturn is also the most beautiful planet. It never fails to elicit a gasp from someone shown it for the first time through a reasonably good telescope. The ringed-planet design has so thoroughly imbued our popular culture that many people are amazed to see that such an object actually exists!  The famous rings are now tilted 21½° from edge on, a value that will gradually close to zero by 2025.  A cloud belt or two may be detectable on the ball of Saturn itself, and possibly an elusive bit of detail if you have a high-resolution telescope and some luck. And any telescope that shows Saturn’s rings will also show Titan, its largest satellite.  Titan always appears within four ring-lengths of the planet.  It’s that far west of Saturn on August 13th and 29th, and about the same distance east on the 5th and 21st. On August 1st, Saturn is 6° to the moon’s upper left. Then, the moon will slide past Saturn during the midday hours on the 29th.  By that evening, you’ll find the ringed world 5° to the moon’s upper right.   

Space Launch Calendar 2019: Sky Events, Missions & More  

Joe Rao serves as an instructor and guest lecturer at New York's Hayden Planetarium. He writes about astronomy for Natural History magazine, the Farmers' Almanac and other publications in New York's lower Hudson Valley. Follow us on Twitter @Spacedotcom and on Facebook

All About Space Holiday 2019

Need more space? Subscribe to our sister title "All About Space" Magazine for the latest amazing news from the final frontier! (Image credit: All About Space)

Join our Space Forums to keep talking space on the latest missions, night sky and more! And if you have a news tip, correction or comment, let us know at: community@space.com.

  • rod
    Good to see in the report Starry Night used for some charts. I use and enjoy very much in my stargazing as well as planet observations and asteroid tracking like 4 Vesta in Cetus now, moving retrograde. In my observation log (MS ACCESS DB), I load up views of the sky from Starry Night into my log entry along with various ephemeris generated that I import into Excel - works very well.
    Reply