Skylights: August 2025

Sun

The last sunset in the 8:00pm hour occurs at 8:01pm on the 3rd. We won’t see 8:00pm sunsets again until May 17, 2026.

The Sun begins its annual 37-day trek through Leo on the 10th. The following day, the 11th, gives us our last day with at least 14 hours of daylight. The length of daylight will not be greater than 14 hours again until May 1.

The Sun crosses the line of declination halfway between solstice and equinox (+12° 43’ 09”) on the 19th, and on the 21st, the Sun rises before 6:00am for the last time until April 19. 

Moon

The Moon is first quarter at 6:41am on the 1st, in Virgo. On the third, the 74% waxing gibbous Moon pairs with Antares, just 1.1° to its north.

The Moon reaches its most southerly declination, -28.5°, on the 5th. Note how it bisects the Teapot asterism of Sagittarius, whereas the line of the ecliptic is well north of it. On the evening of the 5th, find magnitude 2.7 Kaus Media (delta Sagitarii) just 0.4° south of the Moon.

The Moon is full at 3:55am on the 9th. The Sturgeon Moon rises on the previous evening at 7:55pm, just one minute after sunset. It sets at 5:50am on the 9th, two minutes past sunrise.

The waning gibbous Moon and Saturn, separated by 9.0° rise together at about 9:30pm on the 12th.

The Moon is last quarter at 1:12am on the 16th, just a few degrees west of the Pleiades cluster in Taurus.  When watching the Moon rise just after 1:00am on the 18th, you may notice a fairly bright star floating 0.6° to its north. This is magnitude 1.7 Elnath (beta Tauri), a class B blue giant star that lies 130 light years away, and the 25th brightest star in the sky. It is notable that this star is over 5° from the ecliptic, indicating that the Moon is at its most northerly declination for this month.

The waning crescent joins Jupiter and Venus in the morning sky, appearing 8° above (northwest of) Venus on the 19th, and 4.0° north of Jupiter on the 20th.

Try to spot the very old, 0.7% illuminated Moon before sunrise on the 22nd. When it rises at 5:05am it will be just 21 hours from its new phase, which occurs at 2:06am on the 23rd.

The Moon is new at 2:06am on the 23rd, marking the beginning of Lunation 1269.

Back in the evening sky, the waxing crescent Moon passes Mars on the 26th, is 5.1° to the left of Spica, in Virgo, on the 27th, and reaches its first quarter, in Scorpius, at 2:25am on the 31st.

Mercury

Mercury, which passed inferior conjunction on the last day of July, comes into view in the morning sky during the second week of August. By the 11th, Mercury rises an hour before sunrise. With a telescope, Mercury appears as a widening crescent.

It rises at its earliest at 4:26am on the 19th, when it will be at its greatest elongation, 18.6° west of the Sun. Use binoculars or a telescope on the 19th to find the Beehive cluster, M44, 1.8° north of Mercury.

On the 27th and 28th, Mercury, Venus, and Jupiter are equally spaced about 15° apart.

Venus

Venus begins the month located within the same binocular field of view of the open cluster M35, from which it will be just 2.4° south-southeast of on the 2nd. 

Venus draws closer to Jupiter in Gemini over the first week and a half of August. On the 11th, they are positioned almost horizontally, and rise less than a minute apart, at 2:54am.

The pair are at their closest, just 0.9° apart on the 12th, with Venus to the south of the giant planet. 

When the two brightest planets come together in the sky, it is a good time to compare the differences of brightness and size of the planetary pair. 

Venus, at magnitude -3.9, is 6.4 times brighter than Jupiter, at magnitude -1.9. Even at seven times Venus’ distance of 0.723 au, Jupiter’s apparent size dwarfs the inner planet by two and a half times. 

The pair is closest on the morning of the 12th, at just 0.9° separation. On the 13th, Venus is directly below Jupiter, which would make for an interesting event to watch the pair of bright planets rising eight minutes apart, beginning at 2:48am.

Venus gains distance from Jupiter at nearly 1° per day. On the 17th, the pair form a conspicuous arrangement with their nearby stars. They form a trapezoid with the twin stars Castor and Pollux, and together those four objects form the bowl of an elongated and reverse dipper asterism with the stars Betelgeuse and Rigel of Orion to their southwest.

On the 19th, the 16.9% waning crescent Moon appears above Jupiter and Venus.

Venus crosses the line between Pollux and Sirius on the 19th. As we’re now into what are known as the Dog Days, this is a helpful guide on locating Sirius low in the southeast before dawn.

Two days later, on the 21st, Venus crosses the line connecting Pollux and Procyon, marking its exit from the Winter Hexagon asterism. On the 25th, Venus lies on the line extending southeast from Castor through Pollux.

At the end of August, the entire Winter Hexagon asterism can be seen in the eastern sky before dawn. As the sky’s most conspicuous collection of bright stars is bisected by the ecliptic, it is interesting to watch the nightly motions of the bright planets through it, and how they seem to reconfigure the recognizable patterns. Both Venus and Jupiter are presently doing this, with the former making the biggest strides of just over 1° per day. 

A notable alignment can be seen on the morning of the 27th, when Venus lies along a line extended from the southeastern segment of the hexagon, from Sirius and through Procyon.

The brilliant planet is 1.2° south of the Beehive cluster, M44, in Cancer on the morning of September 1st.

Mars

Mars continues to move lower in the sky each evening, in western Virgo.

Be sure to turn your telescope or binoculars to it on the 2nd, when it will be just 0.1° south of the magnitude 3.6 star Zavijava (beta Virginis). Now over 2 au from Earth, Mars no longer shows any discernible details on its tiny 4.4 arcsecond disk.

The 13.6% waxing crescent Moon is 5.5° south-southeast of Mars, appearing to its left, on the 26th. The Red Planet, now dimmed to magnitude 1.6, departs the evening sky before the end of astronomical twilight. This effectively marks the end of Mars observing season.

Jupiter

Located in Gemini, Jupiter is now rising before the onset of astronomical twilight. 

Venus approaches the giant planet each morning until the 12th, when the pair are just 0.9° apart.

The 16.9° waning crescent Moon appears 8° above Jupiter on the 19th.

Jupiter rises in the east-northeastern sky before 2:30am, in Gemini. The waning crescent Moon is nearby on the 19th and 20th. Jupiter crosses the line connecting Betelgeuse and Pollux on the 25th.

Jupiter is now rising at about 2:00am, in Gemini.

Moving eastward at 0.2° per day, Jupiter spends a few days around the 26th along the line between Betelgeuse and Pollux.

Saturn

Starting on the 11th, and for the first time since January, there is no time during the night when there are no naked-eye planets visible.

Saturn spends another month with Neptune, and the pair in Pisces are now rising into the evening sky early enough to get some good viewing in before midnight.

Focusing on Saturn, our most favorable Titan shadow transit yet occurs on the 3rd. Begin watching the northwestern limb of the planet at about 2:00am. You should begin to see the notch created by the shadow of Saturn’s largest moon beginning at about 2:10am. The full disk of the shadow, which is just under 1 arcsecond in size, will be visible about 15 minutes later, and viewing improves as the shadow moves towards the planet’s central meridian as the planet itself crosses our local meridian, before the onset of twilight.

August’s second Titan shadow transit can be seen on the 19th, beginning just after 1:30am.

Notice that Saturn’s ring plane angle is now just 3.3°, and will continue to become more narrow until November 24, when it will be just 0.5°. With opposition being just under a month away, and having a bit less light coming from the planet’s rings, now is a good time to observe the planet’s innermost moons.

Tethys, Dione, and Rhea can be seen relatively easily on a dark, transparent night using a telescope as small as 6 inches, but Mimas and Enceladus can be a bit more of a challenge, due to their smaller size making them dimmer, plus their proximity to the planet.

We’ll start with Enceladus, which at 500 kilometers is comparatively small, but is also one of the brightest objects in the solar system, as its surface is covered with ice. At its closest, over the next few weeks, it shines at magnitude 11.8, and extends to a maximum elongation of 39 arcseconds on either side of Saturn, which occurs twice during its 33-hour orbit.

Mimas, with an orbital period of just under 23 hours, shines at magnitude 12.9, and has an elongation of as much as 30 arcseconds from Saturn. A 10-inch telescope with high magnification on a steady night should reveal the 400-kilometer moon, or use a well-calibrated planetary imaging setup.

Uranus

Uranus moves into the evening sky, rising before midnight, beginning on the 11th. The seventh planet is conveniently located 4.3° south-southeast of the Pleiades cluster in Taurus. At magnitude 5.7 and at a distance of 19.6 au, the pale blue-green orb can be seen in the same binocular field of view as the Pleiades cluster.

Neptune

Neptune rises with Saturn, at 10:30pm. At a distance of 29.3 au, its magnitude 7.7 glow can be found just 1.0° north of Saturn, which is slightly less than ⅓ as distant as Neptune, 8.9 au.

Neptune is easy to find, as it is positioned just 1.1° north of Saturn, in Pisces.

As both Saturn and Neptune are moving through their apparent retrograde paths at this time, Saturn appears to be covering more sky per night due to its larger parallax, as it is 3.34 times closer to us than Neptune. As a result, the apparent distance between Neptune and Saturn grows slightly, ranging up to 1.5° in late August.

Minor Planets

Pluto

Pluto, in Capricornus, is still in its best position to observe, although bright moonlight interferes with its 14.4 magnitude glow until mid-month. The nearly full Moon is 0.4° to the south of Pluto early in the morning of the 8th. 

Pluto is 34.4 au away, and shines at magnitude 14.4.

Ceres

Dwarf planet Ceres is at magnitude 8.6 in Cetus, about 18° east of Saturn. It is located about 2.5° north-northwest of magnitude 3.6 theta Ceti, and moving towards the south-southeast each evening.

Ceres is stationary on the 13th.

Vesta

Vesta can be seen in binoculars, at magnitude 7.2, about 5° north of Zubenelgenubi (alpha Librae) in early August. It remains in the same binocular field of view as the star for much of the month, and appears as close as 3.7° to the north-northeast of the star on the 9th.

Vesta is located in the southwest during the early evening, in Libra. On August 13, it lies along the line connecting Zubenelgenubi (alpha) and Zubenelschamali (beta Librae). It is moving towards the east-southeast at about 0.4° per day.

Vesta is just 0.2° south of galaxy NGC 5878 on the 21st.

Pallas

Asteroid 2 Pallas is at opposition on the 7th, in Delphinus. From a distance of 2.5 au, the giant asteroid shines at a relatively dim 9.4 magnitude, and is moving southwestward at about 1/4° per day. On the 6th, it can be found within 1/2° northwest of the magnitude 4.6 star zeta Delphini.

You may notice that Delphinus is nowhere near the ecliptic, yet we’re looking at one of the largest objects in the asteroid belt traveling through it this month. That is because Pallas has an orbital inclination of 35° relative to the ecliptic, highly unusual for an object of its size, being the third largest object in the asteroid belt.

Meteors

Early August may show a few remaining meteors from a pair of showers that peaked in late July: the Southern delta Aquarids and the alpha Capricornids. 

The main activity in August originates from the Perseids, which are most active during mid-month, but may be present from late July through the third week of August.

These fast-moving remnants from comet 109P/Swift-Tuttle appear to originate from a point several degrees north of Mirfak, and close to the shared borders of Perseus, Camelopardalis, and Cassiopeia. As this area is circumpolar, there is no unfavorable time to wait until the radiant is above the horizon.

An observer under ideal sky conditions could see up to 100 meteors per hour, but we have an 82.3% waning gibbous Moon during the night of peak activity, the 12th-13th, which will likely interfere with visibility.

Stars

In many ways, August nights are the best of the year. The Sun is setting earlier each evening, giving us more evening darkness, and the nights should also be getting a bit cooler and less hazy. Awaiting us as darkness falls, the Milky Way arcs high overhead, and presents the galactic core and its celestial treasures for us to explore as the nocturnal chorus of katydids and crickets accompanies us on our journey into the cosmos.

In the west, Ursa Major and its familiar Big Dipper asterism begin to assume their right-side-up orientation that will be present through the end of autumn, as the star patterns slowly move lower in the northeast after each successive twilight fades.

Arcturus, the beacon of spring, no longer dominating the sky overhead, remains prominent in the west. Replacing it overhead, the familiar triangle of Vega, Deneb, and Altair, the Summer Triangle, stays with us well into the night. Pick a dark, moonless night, and explore the area in and around the triangle with binoculars or a small telescope. 

One area that is exceptionally interesting to explore is the constellation Lyra. Its compact geometric patterns contain many colorful double stars, including four entries in Astronomical League’s Double Star Observing Program. These are the well-known Double Double, epsilon Lyrae, as well as beta and zeta Lyrae, the two vertices marking the longer western segment of the parallelogram. Otto Struve 525, a lesser-known, but still bright and easy to find colorful pair, makes a right triangle with gamma and zeta Lyrae, within the southern area of the parallelogram.

Continue exploring this sparkling constellation under low magnification with any telescope and you will encounter many pairs of stars, including delta Lyrae, a fine color-contrasting arrangement that is easily visible in binoculars..

Additionally, there are two carbon stars worthy of tracking down with a telescope. T Lyrae and HK Lyrae will show a sharp color contrast with nearby blue-white Vega.