Night sky, September 2024: What you can see tonight [maps]

The night sky tonight and on any clear night offers an ever-changing display of fascinating objects you can see, from stars and constellations to bright planets, the moon, and sometimes special events like meteor showers.

Observing the night sky can be done with no special equipment, although a sky map can be very useful, and a good telescope or binoculars will enhance some experiences and bring some otherwise invisible objects into view. You can also use astronomy accessories to make your observing easier, and use our Satellite Tracker page powered by N2YO.comto find out when and how to see the International Space Station and other satellites. We also have a helpful guide on how you can see and track a Starlink satellite train. 

You can also capture the night sky by using any of the best cameras for astrophotography, along with a selection of the best lenses for astrophotography. 

Read on to find out what's up in the night sky tonight (planets visible now, moon phases, observing highlights this month) plus other resources (skywatching terms, night sky observing tips and further reading)

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

Monthly skywatching information is provided to Space.com by Chris Vaughan of Starry Night Education, the leader in space science curriculum solutions. Follow Starry Night on Twitter @StarryNightEdu and Chris at @Astrogeoguy 

Editor's note: If you have an amazing skywatching photo and would like to share them with Space.com's readers, send your photo(s), comments, and your name and location to spacephotos@space.com.

Calendar of observing highlights

Sunday, Sept. 1 - Earthshine moon near Mercury (pre-dawn)

Early risers on Sunday, Sept. 1 can look for the delicate crescent of the old moon shining several finger-widths to the upper left (or celestial north) of the bright speck of Mercury in the eastern sky before sunrise. 

The duo will be cozy enough to share the view in binoculars (orange circle), but take care to turn all optics away from the eastern horizon before the sun rises. Watch for earthshine, sunlight reflected off the Earth and cast onto the unlit portion of the moon's face, brightening it slightly. 

Monday, Sept. 2 - Morning zodiacal light for mid-northern observers (pre-dawn)

During autumn at mid-northern latitudes every year, the ecliptic extends nearly vertically upward from the eastern horizon before dawn. That geometry favors the appearance of the faint Zodiacal light in the eastern sky for about half an hour before dawn on moonless mornings. 

Zodiacal light is sunlight scattered by interplanetary particles that are concentrated in the plane of the solar system - the same material that produces meteor showers. It is more readily seen in areas free of urban light pollution. Between now and the full moon on Sept. 17, look for a broad wedge of faint light extending upwards from the eastern horizon and centered on the ecliptic (the green line). 

It will be strongest in the lower third of the sky below the twin stars of Gemini. Don't confuse the zodiacal light with the Milky Way, which is positioned nearby in the southeastern sky. 

Monday, Sept. 2/Tuesday, Sept. 3 - New Moon

On Monday, Sept. 2 at 9:56 p.m. EDT (or Tuesday, Sept. 3 at 0156 GMT), the moon will officially reach its new moon phase. At that time our natural satellite will be located in Leo, 1.5 degrees north of the sun. 

While new, the moon is traveling between Earth and the sun. Since sunlight can only illuminate the far side of the moon, and the moon is in the same region of the sky as the sun, it becomes completely hidden from view from anywhere on Earth for about a day. After the new moon phase, Earth's celestial night light will return to shine as a young crescent in the western evening sky. 

Tuesday, Sept. 3 - The Andromeda Galaxy (all night)

September evenings feature the Andromeda Galaxy, which is already climbing the northeastern sky after dusk. This large spiral galaxy, also designated Messier 31 (or M31) and NGC 224, is the closest large galaxy to us — at a distance of "only" 2.5 million light years. It covers an area of the sky measuring 3 by 1 degrees (or six by two full moon diameters). 

Under dark skies, the galaxy can be seen with unaided eyes as a faint smudge located 1.4 fist diameters to the left (or 14 degrees to the celestial northeast) of Alpheratz, the star that forms the left-hand (northwestern) corner of the square of Pegasus. The three highest (westernmost) stars of Cassiopeia, Caph, Shedar, and Navi (Gamma Cas), also conveniently form a triangle that points towards M31. Binoculars (orange circle) will show the galaxy best. 

For telescopes, use low magnification and look for M31's two smaller companion galaxies, the foreground Messier 32 and more distant Messier 110 (inset).

Wednesday, Sept. 4 - Young moon visits Venus (after sunset)

Immediately after sunset on Wednesday, Sept. 4 and Thursday, Sept. 5, the waxing crescent moon will be posing above the western horizon near the brilliant planet Venus. On Wednesday, the moon's extremely thin crescent will appear several finger-widths to Venus' lower right (to its celestial west) — proximate enough to share the view in binoculars (orange circle). 

Observers viewing the pair from southerly latitudes will see the moon more easily. On Thursday, the moon's orbital motion will bring it about a palm's width to Venus' left (or 6 degrees to its celestial southeast). In the interim, skywatchers located in parts of Antarctica and the Atlantic Ocean south of Africa can see the moon occult Venus in a bright sky. 

Thursday, Sept. 5 - Mercury at greatest western elongation (pre-dawn)

On Thursday, Sept. 5, the planet Mercury will reach a maximum angle of 18 degrees from the sun, and peak visibility, for its current morning apparition. Look for the innermost planet shining brightly while it climbs the eastern pre-dawn sky between about 5:45 and 6:15 a.m. in your local time zone. 

In a telescope (inset) Mercury will exhibit a 47%-illuminated, waxing phase. Mercury's position above the nearly upright morning ecliptic (green line) will make this an excellent apparition for Northern Hemisphere observers, but a so-so one for those located south of the Equator, where the ecliptic will be tipped over. 

Friday, Sept. 6 - Crescent moon covers Spica (after sunset)

Look low in the western sky after sunset on Friday, Sept. 6 to see the slim, waxing crescent moon shining well to the left of the brilliant planet Venus. Use binoculars (orange circle) to search just to the right of the moon for Virgo's brightest star, Spica. The moon slides eastward in its orbit by its own diameter every hour. 

Rewinding time to midday on Friday in the Americas will find the moon passing directly in front of Spica in a daytime lunar occultation that will be visible in large binoculars and backyard telescopes (inset). The zone in which the occultation is visible will include northeastern North America and Bermuda, then south and east across the Atlantic to the Azores, Ascension Island, and most of western and central Africa, where the occultation will occur in a dark sky. 

Saturday, Sept. 7 - Saturn at opposition (overnight)

On Saturday night, Sept. 7 in the Americas, Saturn will reach opposition. You can see the creamy-yellow dot of the ringed planet all night long, shining to the left of the rather faint stars of Aquarius. Planets at opposition rise at sunset and set at sunrise because Earth is positioned between them and the sun. 

That night, Saturn will be at a distance of 804.7 million miles, 1.295 billion kilometers, or 72 light-minutes from Earth. It will shine at a magnitude of 0.57, its brightest for 2024. While planets always look their brightest at opposition, Saturn's brilliance will be boosted by the Seeliger effect — backscattered sunlight from its rings. In a telescope (inset) Saturn's disk and rings will show maximum apparent diameters of 19 arc-seconds and 44 arc-seconds, respectively. 

Saturn's rings will be aligning more edge-on to Earth every month until March 2025. Opposition is also the optimal time to view Saturn's moons through a backyard telescope in a dark sky. Owners of large telescopes can catch the transits of the larger Saturnian moons and their black shadows across the planet's globe.  

Sunday, Sept. 8 - Mars clips a cluster (wee hours)

On the way to Mars' bright opposition in January, the red planet will slide closely past several planets and deep sky objects. On Sunday night, Sept. 8, Mars will pass less than a finger's width to the lower right (or 0.9 degrees to the celestial south) of the large open star cluster in Gemini named the Shoe-Buckle, Messier 35, and NGC 2168. 

The planet and the distant cluster will share the field of view in a backyard telescope (green circle) from Friday to Wednesday, and in binoculars for a week on either side of Sept. 8. Mars will approach the cluster from the right (celestial west), but your telescope will likely flip and/or mirror the view. 

Monday, Sept. 9 - Mercury raids Regulus (before sunrise)

Skywatchers with a clear view to the east before sunrise on Monday morning, Sept. 9 can use binoculars (orange circle) or a backyard telescope to see the speedy planet Mercury shining very close to the 7 times fainter, white star Regulus. Mercury's daily descent towards the sun will cause it to approach Regulus from above on the prior mornings and then drop out of sight about a week later. 

On Monday, Mercury will appear just half a degree to Regulus' left (or celestial north). In a telescope, Mercury will display a waxing gibbous phase. 

Monday, Sept. 9 - Moon dances with the Scorpion (early evening)

Once the sky has darkened on Monday evening, Sept. 9, the stars of Scorpius will appear to the left (or celestial east) of the waxing crescent moon. The bright, reddish star Antares, which marks the heart of the scorpion, will shine a palm's width to the moon's left. The up-down row of fainter stars that form the claws of the critter will extend upwards through the moon. 

Observers located in eastern Canada and the northeastern U.S. can see the moon occult a magnitude 2.85 claw star Pi Scorpii. Hours later, on Tuesday evening, observers in a zone west of central Australia and southeastern Indonesia can watch the moon occult Antares. An app like Starry Night can provide the occultation circumstances where you live. On Tuesday evening, the moon will hop east to shine to Antares' left.  

Tuesday, Sept. 10 - Ptolemaeus, Alphonsus and Arzachel (evening)

On Tuesday night, Sept. 10, the terminator boundary on the waxing gibbous moon will fall just to the west of a trio of large craters located a short distance south of the moon's center (red lines). Ptolemaeus, Alphonsus, and Arzachel are all large enough to see with binoculars and any size of telescope. 

The northernmost crater Ptolemaeus (96 miles or 154 km wide) has been battered by later impacts that confirm its older age. The flat, almost featureless floor has been filled by lava flows, submerging its central peak and elevating its floor. 

Alphonsus (74 miles or 119 km wide) is older yet, and only partially filled, allowing its central peak to remain visible. Alphonsus contains a triangle of dark spots that are most prominent when the moon is full — ash deposits from long-ago volcanic venting. 

Relatively young Arzachel (60 miles or 96 km wide) has an unaltered floor and a terraced rim. Numerous north-south lineations carved by ejecta blasted out during the powerful Imbrium Basin impact event surround those craters. 

Wednesday, Sept. 11 - First Quarter Moon (at 06:06 GMT)

When the moon completes the first quarter of its journey around Earth on Wednesday, Sept. 11 at 2:06 a.m. EDT or 06:06 GMT, its 90-degree angle away from the sun will cause us to see the moon half-illuminated - on its eastern side. 

At first quarter, the moon always rises around mid-day and sets around midnight, so it is also visible in the afternoon daytime sky, too. The evenings surrounding first quarter are the best ones for seeing the lunar terrain when it is dramatically lit by low-angled sunlight, especially along the terminator, the pole-to-pole boundary that separates the lit and dark hemispheres. 

Friday, Sept. 13 - Major Mare Imbrium (evening)

On Friday, Sept. 13, the lunar terminator will fall just beyond the western rim of Mare Imbrium, the Sea of Rains, allowing it to be fully illuminated. That dark, circular feature dominates the northwestern quadrant of the moon's Earth-facing hemisphere. 

The mare is the moon's largest impact basin, measuring more than 715 miles (1,145 km) in diameter. It was formed during the late heavy bombardment period approximately 3.94 billion years ago. Telescope views of Mare Imbrium at this phase will reveal ejecta blankets around its major craters (Aristillus and Archimedes), several nearly-submerged ghost craters (Cassini and Wallace), and numerous subtle wrinkle ridges (Heim, Stille).

Saturday, Sept. 14 - The Aristarchus Plateau (all night)

Three prominent craters break up the expanse of Oceanus Procellarum, the widespread dark region on the moon's left-hand side. Large Copernicus is the easternmost of the craters. Its extensive, ragged ray system intermingles with that of the smaller crater Kepler to its southwest. The very bright crater Aristarchus positioned northwest of them occupies the southeastern corner of a diamond-shaped plateau that is one of the most colorful regions on the moon. 

NASA orbiters have detected high levels of radioactive radon there. Use a telescope and high magnification to view features like the large, sinuous rille named Vallis Schröteri. Its snake-like form begins between Aristarchus and next-door Herodotus and meanders across the plateau. 

Monday, Sept. 16 - Bright moon shines with Saturn (all night)

After the bright, waxing gibbous moon clears the eastern rooftops in the early evening on Monday, Sept. 16, the yellowish dot of Saturn will shine prominently to its left (or celestial northeast). As the pair cross the sky overnight, the moon's eastward orbital motion will carry it closer to Saturn. 

Meanwhile, the diurnal rotation of the sky will lift Saturn above the moon by the time they set in the west before dawn. Observers on the west coast of North America and within a zone extending south and west to northern Australia, Melanesia, southern and eastern Micronesia, and northwestern Polynesia (including Hawaii) can watch the moon occult Saturn. Use an app like Starry Night to look up the occultation timings for your location. 

Tuesday, Sept. 17 - Full Harvest Supermoon

The moon will officially reach its full phase on Tuesday, Sept. 17 at 10:34 p.m. EDT or 7:34 p.m. PDT, which converts to 02:34 GMT on Wednesday. With perigee arriving only 10 hours later, this full moon will also be the second of four supermoons in 2024. It will appear about 6% larger and 16% brighter than an average full moon (shown by the red circle), cross the sky from sunset to sunrise, and produce large tides around the world. The September full moon, traditionally known as the "Corn Moon" and "Barley Moon", always shines in or near the stars of Aquarius and Pisces. 

The indigenous Anishinaabe people of the Great Lakes region call this moon Waatebagaa-giizis or Waabaagbagaa-giizis, the Leaves Turning or Leaves Falling Moon. Because this is the closest full moon to the autumnal equinox in 2024, it is also the Harvest Moon. 

On the evenings around its full phase, the moon normally rises about 50 minutes later than the previous night. But the shallow slope of the evening ecliptic (and the moon's orbit) around the equinox causes Harvest Moons to rise at almost the same time each night — only delayed by as little as 10 minutes, depending on your latitude. This phenomenon traditionally allowed farmers to work into the evening under bright moonlight — hence the name. 

Tuesday, Sept. 17 - Partially eclipsed Harvest Supermoon

The northerly portion of this full moon will also dip into Earth's umbra for 63.7 minutes, generating a shallow partial lunar eclipse visible across the Americas (except Alaska), the Atlantic Ocean, and western Europe and Africa. 

The moon will begin to enter Earth's penumbra, slightly darkening it, at 8:41 p.m. EDT. A small "bite" out of the moon will be visible between 10:13 p.m. and 11:16 p.m. EDT, with a maximum of 8.5% of the moon within Earth's shadow at 10:45 p.m. EDT. The moon will fully emerge from Earth's penumbra at 12:48 a.m. EDT. 

Lunar eclipses are completely safe to look at without protective filters. 

Wednesday, Sept. 18 - Bright lunar ray systems (all night)

While the moon is near its full phase, bright ray features may be seen radiating from the younger craters on the lunar nearside. The impact that created the bright crater Tycho, which is located in the south-central area of the moon, produced streaks of bright material that extend in multiple directions across the moon's near side. 

Another particularly interesting ray system surrounds the crater Proclus. The 16-mile (27 km) wide crater and its ray system are visible in binoculars. They are located at the lower left edge of Mare Crisium, the round grey basin near the moon's upper right edge (northeast of the moon). 

The Proclus rays, about 370 miles (600 km) in length, only appear on the eastern, right-hand side of the crater, and within Mare Crisium, suggesting that the impactor arrived at a shallow angle from the southwest. The small crater Menelaus on the southern edge of Mare Serenitatis hosts some small rays. A long, possibly unrelated, ray passes through both Menelaus and the mare. (Note that east and west are reversed on the moon). 

Friday, Sept. 20 - Neptune at opposition (all night)

On Friday night, Sept. 20, Neptune will reach opposition. At that time the distant planet will be closest to Earth for this year — a distance of "merely" 2.68 billion miles, 4.32 billion km, 4 light-hours, or 28.9 Astronomical Units. 

At opposition, blue Neptune will shine with a slightly enhanced magnitude of 7.8. Since it will be opposite the sun in the sky, Neptune will be visible all night long in backyard telescopes. Good binoculars (orange circle) can show it, too, if your sky is very dark — but unfortunately, Neptune will have to share the sky with a very bright moon. Your best views will come after 9 p.m. local time when the blue planet has risen higher. Around opposition, Neptune's apparent disk size will peak at 2.4 arc-seconds and its large moon Triton will be the most visible (inset). 

Throughout September, Neptune will be located below (or celestial southeast of) the circle of stars that forms Pisces' western fish, and about a thumb's width above the medium-bright star pair 29 and 27 Piscium. Much brighter Saturn will shine 1.3 fist diameters to the upper right (or 13.5 degrees to the celestial west-southwest) of Neptune. 

Saturday, Sept. 21 - Bright moon kisses the Seven Sisters (overnight)

When the still very full and bright, waning gibbous moon rises over the rooftops to the east on Saturday evening, Sept. 21, the bright little cluster known as the Pleiades, the Seven Sisters, the Hole in the Sky, Matariki, and Messier 45 will be sparkling several finger-widths to the moon's lower left — close enough for them to share the view in binoculars (orange circle). 

To better see the stars, which are spread over an area nearly four times larger than the moon, hide the moon beyond the upper right edge of your binoculars' field of view. Skywatchers viewing the scene later at night, and in more westerly time zones, will see the moon approach closer to the cluster, pass among its stars around 11:00 GMT, and then begin to move off to their east. 

The faint blue speck of Uranus will also be positioned less than a palm's width to the right (or 5 degrees to the celestial SSW) of the Pleiades. 

Sunday, Sept. 22 - September Equinox

On Sunday, Sept. 22 at 8:44 a.m. EDT, 5:44 a.m. PDT, or 12:44 GMT, the sun's apparent motion along the ecliptic (green line) will carry it across the celestial equator traveling southward, marking the autumnal equinox in the Northern Hemisphere and the beginning of autumn there. 

On the equinoxes in March and September, day and night are of equal length and the sun rises due east and sets due west (yellow arc). 

Monday, Sept. 23 - The moon visits Jupiter in the Winter Hexagon (wee hours to dawn)

Late on Monday evening, Sept. 23, the gorgeous half-moon will rise in the east with brilliant Jupiter shining a palm's width to its right (or 6 degrees to its celestial southwest). The prominent star Elnath, which marks the northern horn tip of Taurus, the Bull, will sparkle just above the moon. 

The trio will climb high into the southern sky by dawn. If you head outside before the sky brightens, watch for the bright ring of the Winter Hexagon asterism's stars surrounding Jupiter and the moon. Jupiter will spend the coming year wandering inside the hexagon. The moon will visit it monthly. 

Tuesday, Sept. 24 - Third Quarter Moon

The moon will complete three-quarters of its orbit around Earth, measured from the previous new moon, on Tuesday, Sept. 24 at 2:50 p.m. EDT and 11:50 a.m. PDT or 18:50 GMT. At the third (or last) quarter phase the moon appears half-illuminated, on its western, sunward side. 

It will rise around midnight local time, and then remain visible until it sets in the western daytime sky in the early afternoon. Third quarter moons are positioned ahead of the Earth in our trip around the sun. About 3.5 hours later, Earth will occupy that same location in space. The week of dark, moonless evening skies that follow this phase are the best ones for observing fainter deep sky targets.

Wednesday, Sept. 25 - Crescent moon meets Mars (wee hours to dawn

Once the waning crescent moon has cleared the eastern treetops shortly after midnight on Wednesday morning, Sept. 25, look for the prominent ochre dot of Mars shining less than a palm's width below it (or about 5 degrees to the celestial south). The pair will be close enough to share the view in binoculars (orange circle) and will make a nice widefield photo when framed with bright Jupiter and the bright winter stars off to their upper right. 

Thursday, Sept. 26 - Waning moon passes Gemini's Twins (pre-dawn)

Early risers on Thursday morning, Sept. 26, can see the pretty sight of the waning crescent moon shining below Gemini's brightest stars Pollux and Castor. The moon will be close enough to the lower star, warm-tinted Pollux, for them to share the field of view of binoculars (orange circle) and backyard telescopes. Reddish Mars will be shining to the moon's upper right. With each passing hour, the moon will shift noticeably right to left (or eastward) below Pollux. 

Saturday, Sept. 28 - The first known exoplanet (all night)

Pegasus, which climbs the Eastern sky during the evenings in September, contains one of the most recognizable asterisms in the sky, a giant square of four similarly bright stars called the Great Square. The square's edges are about 1.6 fist diameters (or 16°) in length, and it spans two fist-widths (about 20°) measured corner to corner. The pattern might remind you of a baseball diamond when you see it because it's often tilted with one corner downwards. 

For the Lakota people, the square represented the great shell of Keya, the Turtle. The Anishinaabe of the Great Lakes region view the square as the torso of Mooz, the Moose. Using unaided eyes only, from the suburbs, the Great Square appears empty. Look carefully for two dim stars offset to the upper right from the center of the square. They represent the moose's heart. 

Saturday, Sept. 28 - The first known exoplanet (all night)

In the eastern sky on starry September evenings, look for a dim star shining a thumb's width just outside of the baseball diamond shape of Pegasus' Great Square, midway between the top and right corners. That yellow, sunlike star named Helvetios (or 51 Pegasi) is orbited by the first exoplanet ever discovered, in 1995.

 The planet, which orbits that star every 4.23 days at a distance much closer to the star than Mercury does in our solar system, is categorized as a Hot Jupiter type. Originally nick-named Bellerophon, one of the original riders of Pegasus in Greek mythology, the planet is now officially named Dimidium, the Latin word for "half" — since the planet has half the mass of Jupiter.  

Visible planets in September

Mercury

As September begins, Mercury will be well into its best morning apparition of the year for Northern Hemisphere observers, but a very poor one for those at southern latitudes. The speedy planet will stretch to a maximum of 18 degrees west of the sun on Sept. 5 — with peak visibility arriving around 6 a.m. local time for several mornings. 

After that it will steadily drop sunward each morning and disappear from view about 10 days before reaching superior conjunction on Sept. 30. Mercury will grow in brightness every day, even while it is sinking into the thick blanket of air above the eastern horizon. 

Viewed in a telescope, Mercury will display a waxing crescent that is 8 arc-seconds across on Sept. 1, a half-illuminated, 7 arc-seconds-wide disk while at maximum elongation, and then an increasingly gibbous phase that shrinks daily through the rest of the month. (Turn all optics away from the eastern horizon before the sun rises.) On Sept. 1, the waning crescent moon will shine just 4 degrees to the planet's upper left. 

Venus

Venus will spend September increasing its angle from the evening sun from 24 to 31 degrees, but the shallow angle of the ecliptic after sunset will keep the brilliant, magnitude -3.9 planet pinned just above the western horizon for mid-northern latitude observers. Venus will spend most of September traveling through Virgo, and then cross into next-door Libra on Sept. 29. 

Skywatchers in the tropics and the Southern Hemisphere will see Venus higher in the sky, allowing a backyard telescope to show its nearly fully-illuminated disk as it swells from 11 to 12.2 arc-seconds. On Sept. 5 Venus will shine 6 degrees to the right (northwest) of the young crescent moon and then it will pass 2 degrees above (north of) Virgo's brightest star Spica on Sept. 18. 

Mars

For mid-latitude observers, Mars will begin to rise before midnight at the end of September. The reddish planet will shine in the eastern sky from the wee hours until sunrise all month long. It will spend the first week of the month traveling eastward through eastern Taurus, end then occupy Gemini from Sept. 6 onward. 

Its passage across the winter Milky Way will bring Mars close to several deep sky objects, notably the open cluster NGC 2129 on Sept. 5-6, in between the cluster IC 2157 and the star 1 Geminorum on Sept. 6-7, then 0.9 degrees south of prominent Messier 35, aka the Shoe-buckle Cluster, on Sept. 8, and one degree north of the star Propus and the Jellyfish Nebula on Sept. 11-12. 

Over the month, Mars will brighten from magnitude 0.74 to 0.5. Viewed in a telescope it will exhibit a small, 7 arc-seconds-wide disk that is only 87.5%-illuminated due to its significant angle away from the sun. The waning crescent moon will shine near Mars on Sept. 25, setting up some nice photo opportunities when nearby Jupiter is included. 

Jupiter

Brilliant, white Jupiter will already be rising before midnight as September begins, climbing the eastern sky during the wee hours of the morning and dominating the southeast before sunrise, with 16 times less bright Mars positioned to its lower left (celestial east). By the end of the month, Jupiter will be rising around 10 p.m. local time. During September the giant planet will be drifting eastward between the horns of Taurus, the Bull. 

Visually, it will brighten slightly from magnitude -2.28 to -2.48. Binoculars will reveal Jupiter's four large Galilean moons flanking the planet. A backyard telescope will show its equatorial bands, while a better quality instrument will reveal the Great Red Spot every second or third night, Jupiter's Galilean satellites frequently eclipsing and occulting one another, and times when they cast their round, black shadows on the planet. The waning moon will drop past Jupiter and Mars from Sept. 23 to 26, setting up some nice photo opportunities. 

Saturn

Creamy-yellow Saturn will be available for viewing all night long during September because it will be rising shortly after dusk. The ringed planet will be traveling retrograde westward through the stars of eastern Aquarius - with faint Neptune positioned 14 degrees to its left (or celestial ENE). Unfortunately, the low late-summer ecliptic will prevent Saturn from climbing very high into the southern sky when it culminates every night. 

On Sept. 8, Saturn will reach opposition. At that time, the ringed planet will be at a distance of 804.7 million miles, 1.295 billion km, or 72 light-minutes from Earth. While planets at opposition always look their brightest, Saturn's peak magnitude 0.57 will be boosted by the Seeliger effect, backscattered sunlight from its rings. Viewed in a telescope on the nights around opposition Saturn will show an apparent disk diameter of 19.2 arc-seconds, and its rings will subtend 44.7 arc-seconds. Saturn's rings will be tilted by a mere 3.3 degrees and will become even more edge-on to Earth until the spring of 2025. 

Opposition is also the optimal time to view Saturn's moons through a backyard telescope in a dark sky. They will be aligned with the ring plane this year, allowing you to see the transits of them and their tiny black shadows across Saturn's globe — sometimes in pairs — through large, high-quality telescopes. The nearly full moon will hop past Saturn from Sept. 16 to 17. Around 11:40 GMT on Sept. 17, observers on the west coast of North America and within a zone extending south and west to northern Australia, Melanesia, southern and eastern Micronesia, and northwestern Polynesia (including Hawaii) can watch the moon occult Saturn. 

Uranus

During September, magnitude 5.7 Uranus will be nicely positioned for viewing overnight through binoculars and telescopes of any size. The planet will rise around 10:30 p.m. local time on Sept. 1 and then at 8:40 p.m. at month's end. 

Uranus will be shifting almost imperceptibly retrograde westward through the stars of western Taurus, less than a palm's width to the lower right (or 5.3 degrees to the celestial SSW of) the Pleiades Star cluster. Mars and Jupiter will follow it across the sky about two hours behind it. 

In a telescope, Uranus will display a blue-green, 3.7 arc-seconds-wide disk. The bright, waning gibbous moon will shine above Uranus and Pleiades on Sept. 22.  

Neptune

During September, the distant, magnitude 7.8 planet Neptune will cross the night sky all night long, following much brighter Saturn, which will be shining about 13 degrees to Neptune's upper right (or celestial west). Both planets will be moving retrograde westward. 

On Sept. 21, Neptune will reach opposition — closest to Earth for this year at a distance of 2.68 billion miles, 4.32 billion km, 4 light-hours, or 28.9 Astronomical Units. Around opposition, Neptune's apparent disk size will peak at 2.4 arc-seconds and its large moon Triton will be the most readily visible. Neptune will be located 7 degrees below the circle of stars that forms Pisces' western fish, and about 2 degrees above (or celestial north) of the upright rectangle formed by the medium-bright stars 27, 29, 30, and 33 Piscium. 

Skywatching terms

Gibbous: Used to describe a planet or moon that is more than 50% illuminated.

Asterism: A noteworthy or striking pattern of stars within a larger constellation.

Degrees (measuring the sky): The sky is 360 degrees all the way around, which means roughly 180 degrees from horizon to horizon. It's easy to measure distances between objects: Your fist on an outstretched arm covers about 10 degrees of sky, while a finger covers about one degree.

Visual Magnitude: This is the astronomer's scale for measuring the brightness of objects in the sky. The dimmest object visible in the night sky under perfectly dark conditions is about magnitude 6.5. Brighter stars are magnitude 2 or 1. The brightest objects get negative numbers. Venus can be as bright as magnitude minus 4.9. The full moon is minus 12.7 and the sun is minus 26.8.

Terminator: The boundary on the moon between sunlight and shadow.

Zenith: The point in the sky directly overhead.

Night sky observing tips

Adjust to the dark: If you wish to observe fainter objects, such as meteors, dim stars, nebulas, and galaxies, give your eyes at least 15 minutes to adjust to the darkness. Avoid looking at your phone's bright screen by keeping it tucked away. If you must use it, set the brightness to minimum — or cover it with clingy red film. 

Light Pollution: Even from a big city, one can see the moon, a handful of bright stars, and the brightest planets - if they are above the horizon. But to fully enjoy the heavens — especially a meteor shower, the fainter constellations, or to see the amazing swath across the sky that is the disk of our home galaxy, the Milky Way — rural areas are best for night sky viewing. If you're stuck in a city or suburban area, use a tree or dark building to block ambient light (or moonlight) and help reveal fainter sky objects. If you're in the suburbs, simply turning off outdoor lights can help.

Prepare for skywatching: If you plan to be outside for more than a few minutes, and it's not a warm summer evening, dress more warmly than you think is necessary. An hour of winter observing can chill you to the bone. For meteor showers, a blanket or lounge chair will prove to be much more comfortable than standing, or sitting in a chair and craning your neck to see overhead.

Daytime skywatching: On the days surrounding first quarter, the moon is visible in the afternoon daytime sky. At last quarter, the moon rises before sunrise and lingers into the morning daytime sky. When Venus is at a significant angle away from the sun it can often be spotted during the day as a brilliant point of light - but you'll need to consult an astronomy app to know when and where to look for it. When large sunspots develop on the sun, they can be seen without a telescope — as long as you use proper solar filters, such as eclipse glasses. Permanent eye damage can occur if you look at the sun for any length of time without protective eyewear.