Cosmic Highlights
A monthly night sky guide to what’s worth capturing right now.
SEPTEMBER 2026
September — Equal Nights
On 23 September at 00:05 UT, the Sun crosses the celestial equator, and every observer on Earth gets the same night. Not roughly the same — the same. Whether you are setting up in Sweden or in South Australia, the darkness you are working in that night is the same length as everybody else's. It is the only date in the year when that is true, and it is worth pausing on, because for the other three hundred and sixty-four we all get a different deal.
From that one shared night the two hemispheres walk off in opposite directions, and September's targets go with them. Everything worth photographing this month belongs clearly to one side of the world or the other. In the north, four objects sit close together in Cassiopeia and Cepheus — an open cluster and three clouds of glowing hydrogen, all high overhead around midnight, and three of the four asking for a narrowband filter and real hours on target. In the south, three objects in Sculptor and Tucana, all of them bright, none of them needing a filter at all, and two of them finished inside three hours. That means the two halves of this page are not the same page twice. They are two genuinely different kinds of night. The New Moon falls on the 11th, so the dark run from roughly the 7th to the 15th is where the faint work belongs, and on the 26th Neptune comes to opposition, sitting fifteen arcminutes from the celestial equator — about as evenly shared as an object gets.
Equal nights, then two different skies. Take whichever one is over your head.
The Night Sky at a Glance
Northern Hemisphere Sky – Midnight at New Moon (at +40° latitude)
Image from the app Stellarium
Cassiopeia's W stands high in the northeast at nightfall and passes near the zenith by midnight, carrying every northern target this month — M52, the Bubble and the Lobster Claw all within a couple of degrees of one another, with the Wizard just across the border in Cepheus. Low in the west the Summer Triangle begins its long slide out of the sky. Meanwhile, Pegasus and Andromeda climb in the east, and with the equinox at hand the nights finally run longer than the days.
Southern Hemisphere Sky – Midnight at New Moon (at -30° latitude)
Image from the app Stellarium
Sculptor and Tucana ride high through the middle of the night, carrying all three southern targets. The Small Magellanic Cloud climbs with them and 47 Tucanae sits alongside it, close enough that one wide frame holds both. Fomalhaut points the way toward the Sculptor group, where NGC 55 and NGC 7793 are as well placed as they get all year. Spring is beginning, so the nights shorten from here.
The Best-Placed Objects This Month
These objects reach their highest point around midnight. That means better visibility, longer imaging windows, and a great chance to explore some of the best deep-sky objects.
Every night, for your sky
This page tells you what is best placed this month. TonightPlan tells you what is worth photographing tonight, from where you are actually standing, with the gear you own, under tonight's Moon and tonight's weather. It knows when your darkness starts and ends, which targets clear your horizon, and which ones the Moon has ruled out. No sign-up, nothing to install, and nothing stored about you on any server. Free, because the sky above us is for everyone.
M52 — Scorpion Cluster
Object type: Open cluster
Constellation: Cassiopeia
Apparent dimensions: ~13′
Filtering: No filter
Recommended integration: 1–3h
Peak month: September
Altitude at peak: Northern: High | Southern: Not visible
The first thing you notice is the crowding. M52's core is noticeably denser than its outer edges, and that gradient gives the cluster a sense of depth that most open clusters simply do not have — it reads as a three-dimensional object rather than a scatter of dots. Blue-white stars dominate, with warm orange members sprinkled through them, and the whole thing sits in one of the richest Milky Way fields in Cassiopeia. It is around 4,600 light-years away, though heavy foreground dust makes that number hard to pin down, and roughly 35 million years old — old enough for a few stars to have swelled into orange giants, young enough that blue still wins. Charles Messier catalogued it in 1774. It is one of the better open clusters in the sky, and it gets overlooked every year in favour of flashier neighbours.
This is the easiest target on the page and a good one to start a September night with. No filter, no narrowband, nothing clever — an hour to three hours of ordinary broadband data brings up the colour separation between the blue members and the orange ones, which is the whole picture here. Because the cluster is small at about thirteen arcminutes, a longer focal length suits it, but if your field of view is wide enough, consider framing to include some of the surrounding star field rather than centring tightly. The background is doing a lot of work in this image. The Bubble Nebula sits about half a degree away if you want to make a night of it.
M52, captured using a ZWO Seestar S50 smart telescope by Cosmic Captures
The one people skip on their way to the nebulae next door, and it shouldn't be — the dense core gives it a depth most open clusters never have. Ninety minutes on a Seestar S50 resolves it completely, blue-white against orange, in a very rich field.
NGC 7635 — Bubble Nebula
Object type: Emission nebula
Constellation: Cassiopeia
Apparent dimensions: 15′ × 8′
Filtering: Dual / Narrowband
Recommended integration: 3–6h
Peak month: September
Altitude at peak: Northern: High | Southern: Not visible
A star caught mid-breath, blowing a bubble into space. The shell is not a trick of perspective or a coincidence of shape — it is real gas, pushed outward by the wind of a single hot, massive star that sits just inside it and off to one side of its own creation. That star sheds material fast enough to carve a near-perfect sphere several light-years across out of the denser cloud around it, and the bright rim you see is where the wind is piling into the surrounding gas. Because the cloud is not evenly dense, the bubble is being pushed lopsided as it expands, which is why the star is not in the middle. William Herschel found it in 1787, and it lies about 7,100 light-years away.
The bubble itself is small — fifteen arcminutes by eight — but it sits inside a much larger field of glowing hydrogen, so the framing decision is the real one here. A tight frame makes the shell the subject; a wider frame catches both the bubble and the cloud it is inflating, and picks up M52 half a degree away into the bargain. A dual-band filter isolates the emission and lifts the shell out of the background, which matters because the rim is the picture and it is fainter than it looks. Three to six hours is where the structure starts to hold together properly. It takes patience to build up, but the structure earns it.
NGC 7635, captured with a Sky-Watcher Esprit 100 at f/4.12 and an ASI2600MM Pro camera using LRGBHSO filters
NG 7635, captured using a Seestar S50 smart telescope by Cosmic Captures
Small, and worth it anyway — a real sphere of gas blown by one star, and at half a Moon across you can see that it is a sphere. Two and a half hours on a Seestar S50 with a dual filter gives the shell and the cloud around it.
Sh2-157 — Lobster Claw Nebula
Object type: Emission nebula
Constellation: Cassiopeia
Apparent dimensions: 50′ × 30′
Filtering: Dual / Narrowband
Recommended integration: 6–15h
Peak month: September
Altitude at peak: Northern: High | Southern: Horizon
That whole claw is the work of a single star. Buried in the little cluster at its heart is a Wolf-Rayet — a massive star in a late, violent stage of its life — blowing a wind fierce enough to carve a ring this size out of the surrounding hydrogen. It sits far out along the Perseus Arm of the Milky Way, in a region where stars are still forming, and it is a neighbour to the brighter Bubble Nebula. The distance is genuinely uncertain: published estimates run from about 8,000 to 16,000 light-years, so anyone quoting you a precise figure is being more confident than the data allows.
This is the one target this month that does not give itself up easily. It is big at fifty arcminutes by thirty, it is faint, and its surface brightness is low, which is the combination that punishes short sessions. Narrowband is the way in — it lifts the claw cleanly off the background — but it wants dark skies and real hours before the structure fills in. Six to fifteen hours is not a padded number here. Rush it and you get a faint smudge that technically contains the nebula; give it the time and the ring and its wind-blown edges come through properly. If you are working a wide field, the Bubble sits a little over a degree away and the two make a strong frame together.
Sh2-157, captured with a Sky-Watcher Esprit 100 at f/4.12 and an ASI2600MM Pro camera using LRGBHSO filters
The whole claw was carved by the wind of one dying star. It is too wide for the tightest smart-scope frames and you cannot rotate the sensor, so go wide or use mosaic mode. Dual-band filter, a moonless week, several nights — 6 to 15 hours.
Sh2-142 — Wizard Nebula
Object type: Emission nebula
Constellation: Cepheus
Apparent dimensions: ~30′
Filtering: Dual / Narrowband
Recommended integration: 3–6h
Peak month: September
Altitude at peak: Northern: High | Southern: Horizon
The wizard takes a little imagination. The pointed hat sits near the middle of the cloud, with the cloak, shoulders and outstretched arms spilling outward — and see it once and it is hard to unsee, miss it and it stays an intricate cloud of gas. Either way, what lights and sculpts it is the little cluster buried inside, NGC 7380, and at its centre a pair of massive O-type stars whose radiation and winds have carved the gas into those folds. Caroline Herschel found the cluster in 1787. The nebula lies about 8,500 light-years away.
The stars come through easily — the cluster is the straightforward part of this target. The nebula benefits greatly from narrowband, which lifts its structure off the background. Under suburban skies, a dual-band filter does the job well: three to six hours gets you a proper image rather than a hint of one. At about thirty arcminutes it frames comfortably in a medium rig or a smart scope without needing a mosaic. More time only brings out more detail, so if the sky stays clear, there is no point where extra hours stop helping.
Sh2-142, captured with a Sky-Watcher Esprit 100 at f/4.12 and an ASI2600MM Pro camera using RGBHSO filters
Sh2-142, captured using a ZWO Seestar S50 smart telescope by Cosmic Captures
See the wizard once and you cannot unsee it — the hat, the shoulders, the outstretched arms. It fits any smart-scope frame and puts up with some Moon, so it need not wait for the darkest week. Dual-band filter, 3 to 6 hours.
NGC 7793
Object type: Spiral galaxy
Constellation: Sculptor
Apparent dimensions: 10′ × 6′
Filtering: No filter
Recommended integration: 3–6h
Peak month: September
Altitude at peak: Northern: Very low | Southern: High
Most spiral galaxies have clean, sweeping arms, wound by density waves moving through the disc like ripples through a crowd. NGC 7793 does not. Its arms are patchy, fluffy and discontinuous — the technical word is flocculent, and the mechanism behind it is much less tidy. Here, waves of supernovae trigger star formation nearby, which produces more massive stars, which explode and trigger more. It is self-propagating chaos rather than ordered geometry, and you can see the difference in the image. It lies about 12 million light-years away in the Sculptor Group, which makes it a near-neighbour by galaxy standards, and it is one of the five brightest galaxies in that group. James Dunlop discovered it from Australia in 1826. Hidden in one of the outer arms is an ultra-luminous X-ray pulsar — material falling onto a neutron star at a rate that ought to be physically impossible.
The disc is tilted just enough to show you the structure rather than hide it, which is lucky, because the structure is the reason to shoot this one. No filter is needed. It is small at ten arcminutes by six and it is not bright, so this is a target for a longer focal length and a patient three to six hours rather than a quick pass. From southern latitudes it rides high and there is no excuse not to give it the time. From the northern hemisphere it barely clears the horizon, and there are better uses of a September night than fighting for it through the thickest air in your sky.
NGC7793, processed by Cosmic Captures from Telescope.Live image data
I have not imaged this one with a smart telescope yet, but from its data it should be a rewarding target. At about a third the width of the full Moon it will land small in the frame, so expect to crop in afterwards. No filter needed.
NGC 55 — String of Pearls Galaxy
Object type: Barred spiral galaxy
Constellation: Sculptor
Apparent dimensions: 32′ × 4′
Filtering: No filter
Recommended integration: 1–3h
Peak month: September
Altitude at peak: Northern: Very low | Southern: High
NGC 55 is larger than the Large Magellanic Cloud and only about 6.5 million light-years away, but we see it almost exactly edge-on, so all that size is compressed into a long thin sliver of light. Strung along the spine are bright knots of hot blue star clusters and pink hydrogen regions, and that is where the name comes from — it really does read as a string of pearls. Longer exposures start to reveal filaments and bubbles of ionised hydrogen being driven outward by generations of massive stars, which is the galaxy visibly losing material. It is gravitationally bound to NGC 300, about a million light-years from it, and the pair sit in the foreground of the Sculptor Group, on the doorstep of our own Local Group. James Dunlop found it in 1826.
Bright, large and needing no filter, this is one of the most generous targets on the page. One to three hours is genuinely enough for a good image, which is not something you get to say about many galaxies. Because it is thirty-two arcminutes long and only four wide, framing matters more than usual — give it a diagonal across the frame rather than fighting to fit it horizontally, and leave room, because the faint outer extensions go further than the bright part suggests. From southern dark sites it climbs nearly overhead. From the north it scrapes the horizon, and there is no filter or technique that fixes that.
NGC55, processed by Cosmic Captures from Telescope.Live image data
NGC55, captured using a ZWO Seestar S50 smart telescope by Cosmic Captures
As long as the full Moon is wide, but a thin, narrow sliver. Two hours on a Seestar S50 gives the full bar with the dust mottling and the blue knots along it, and no filter to fuss with.
NGC 104 — 47 Tucanae
Object type: Globular cluster
Constellation: Tucana
Apparent dimensions: ~44′
Filtering: No filter
Recommended integration: 1–3h
Peak month: September
Altitude at peak: Northern: Not visible | Southern: Medium
There are two truly great globular clusters in the sky — this one and Omega Centauri — and both belong to the southern hemisphere. 47 Tucanae packs somewhere in the region of half a million stars into a sphere about 120 light-years across, with a brilliant concentrated core that fades outward through layer after layer of resolved stars into a wide diffuse halo. The colour mix is the striking part: mostly yellow and orange old stars, because the cluster is around 13 billion years old, with bright blue exceptions scattered through. Those blue ones are stragglers — stars that collided and merged in the crush of the cluster and got a second youth out of it. Nicolas-Louis de Lacaille recorded it in 1751, initially as the nucleus of a comet, before anyone understood what it was. Look at the edge of a wide frame and you will often catch a second, smaller fuzzy patch: another globular cluster in the same line of sight.
One imaging note matters more than everything else here. The core is so bright that even thirty-second subs will burn it out, so if you want detail in the core itself rather than a white blob, you need much shorter exposures — and the usual approach is to mix short subs for the core with longer ones for the outer halo and blend them. Without a filter and from a reasonably dark sky, about an hour and a half resolves the halo and brings up the colour gradient cleanly, which is a remarkably short session for a result this good. At forty-four arcminutes it is large, so a wide field also picks up the Small Magellanic Cloud alongside it. It is hard to overstate how much better this looks than the famous northern globulars.
NGC104, processed by Cosmic Captures from Telescope.Live image data
NGC104, captured using a DwarfLAB Dwarf Mini smart telescope by Cosmic Captures
A bit bigger than the full Moon, so check it fits your field before you start. Ninety minutes on a Dwarf Mini resolves the halo down through its layers with the colour holding cleanly; the core clips to white at 30s exposures. Use shorter exposures.
The main Moon Phases in September 2026
Planning your imaging sessions? The Moon plays a massive role in what we can capture.
Here’s what’s happening this month:
Last Quarter
September 4
Deep-sky imaging is best in the first half of the night, before the Moon rises.
New Moon
September 11
The darkest skies of the month. The nights around it (roughly the 7th–15th) are September's prime deep-sky window.
First Quarter
September 18
Deep-sky imaging is best after midnight. Strong terminator shadows make it a good evening for lunar surface detail.
Full Moon
September 26
September's full Moon is the Harvest Moon — the full Moon closest to the equinox, and this year it lands just three days after it. It rises at close to the same time for several nights running, which is where the name comes from. A night for the Moon itself, or for the globular clusters that shrug off moonlight.
The September Equinox — September 23
The Sun crosses the celestial equator moving south, and day and night come out equal almost everywhere on Earth. In the north, it is the start of autumn and the point where the nights finally run longer than the days; in the south, it is the start of spring and the nights begin shortening. Both halves of the world pass through the same moment and then head in opposite directions. (It falls at 00:05 UT, so in the Americas it lands on the evening of the 22nd — which is why you will see both dates quoted.)
There is a practical bonus. Around both equinoxes, the Earth's magnetic field lines up with the solar wind in a way that lets more energy through, and geomagnetic activity rises measurably — the Russell-McPherron effect. That is why September and October, like March and April, are the strongest aurora months, at both ends of the Earth.
Image © timeanddate.com
Nightscape Opportunities
n the north, September is the Milky Way core's last comfortable month: it sits low in the southwest at nightfall and sets earlier every week, so the moonless window around the 11th is the final good run at it before next year. After that the band still arches overhead — it is the dense, dusty centre that goes. The equinox brings the other opportunity: geomagnetic activity climbs around both equinoxes, so this is the month to put the aurora forecast back on your phone.
In the south, the core has left the zenith and leans west through the evening, which is the geometry that actually suits a landscape — the galactic centre settling over a horizon rather than standing awkwardly overhead. Later the Magellanic Clouds and 47 Tucanae climb high, and that pairing needs no telescope at all: a fast wide lens on a tripod holds a satellite galaxy and a great globular in one frame. The same equinox aurora boost applies here.
Image by Cosmic Captures