Sky calendar
The next 18 months of things that happen on a date, solved from the ephemeris rather than kept in a list. Almost every one is the same instant for everybody on Earth, so a date here needs no location to be true — what is visible tonight is the list that does depend on where you are standing.
Coming up
] SOONEST FIRST- SUNIN 14 DAYS23WED
September equinox
September equinox: the Sun crosses the celestial equator and day and night level up.
- SUNIN 104 DAYS21MON
December solstice
December solstice: the Sun reaches its furthest from the equator, and the year turns.
- SUNIN 193 DAYS20SAT
March equinox
March equinox: the Sun crosses the celestial equator and day and night level up.
+WHAT THE EIGHT KINDS ARE
- Eclipses — solar and lunar, with where on Earth a solar one is greatest.
- Meteor showers — dated by where the Earth is in its orbit, not by a fixed calendar day.
- Moon phases — the four quarters, which set what else is worth chasing that fortnight.
- Close pairings — two bright things within a few degrees of each other.
- Oppositions — the night each outer planet is closest, biggest and up all night.
- Elongations — the mornings and evenings Mercury and Venus stand furthest from the Sun.
- Equinoxes and solstices — the four turning points of the year.
- Flybys — near-Earth asteroids passing inside twenty lunar distances.
Every event now opens with the hours worth being outside for it from ATACAMA. Add only what I can see to set aside the ones that never rise there.
September 2026
] 1 EVENT- 23WEDSUN--:--
September equinox
The Sun crosses back south over the celestial equator, day and night level up again, and the nights start getting longer in the north and shorter in the south.
+WHAT TO EXPECTCLOSE
A moment rather than a sight: the Sun reaches a point in its own path, at the same instant for everybody on Earth.
Nothing to see on the night. What it marks is the shape of the months either side: which way the nights are going, and how much dark you will have to work with.
December 2026
] 1 EVENT- 21MONSUN--:--
December solstice
The Sun reaches its furthest south: the longest night of the year in the northern hemisphere, and the shortest in the southern.
+WHAT TO EXPECTCLOSE
A moment rather than a sight: the Sun reaches a point in its own path, at the same instant for everybody on Earth.
Nothing to see on the night. What it marks is the shape of the months either side: which way the nights are going, and how much dark you will have to work with.
March 2027
] 1 EVENT- 20SATSUN--:--
March equinox
The Sun crosses the celestial equator heading north, and day and night are very nearly equal length everywhere on Earth. Spring begins in the northern hemisphere and autumn in the southern.
+WHAT TO EXPECTCLOSE
A moment rather than a sight: the Sun reaches a point in its own path, at the same instant for everybody on Earth.
Nothing to see on the night. What it marks is the shape of the months either side: which way the nights are going, and how much dark you will have to work with.
June 2027
] 1 EVENT- 21MONSUN--:--
June solstice
The Sun reaches its furthest north, giving the northern hemisphere its longest day and its shortest, palest nights — and the southern hemisphere the long dark evenings that go with midwinter.
+WHAT TO EXPECTCLOSE
A moment rather than a sight: the Sun reaches a point in its own path, at the same instant for everybody on Earth.
Nothing to see on the night. What it marks is the shape of the months either side: which way the nights are going, and how much dark you will have to work with.
September 2027
] 1 EVENT- 23THUSUN--:--
September equinox
September equinox: the Sun crosses the celestial equator and day and night level up.
+WHAT TO EXPECTCLOSE
A moment rather than a sight: the Sun reaches a point in its own path, at the same instant for everybody on Earth.
Nothing to see on the night. What it marks is the shape of the months either side: which way the nights are going, and how much dark you will have to work with.
December 2027
] 1 EVENT- 22WEDSUN--:--
December solstice
December solstice: the Sun reaches its furthest from the equator, and the year turns.
+WHAT TO EXPECTCLOSE
A moment rather than a sight: the Sun reaches a point in its own path, at the same instant for everybody on Earth.
Nothing to see on the night. What it marks is the shape of the months either side: which way the nights are going, and how much dark you will have to work with.
6 events for the 18 months from today, of the kinds selected above. Times are instants, shown on your own clock; how every number here was made.
Nothing here is a hand-kept list. Every date except the flybys is solved from the same ephemeris the rest of the site uses to place the planets, at the moment you load the page; a meteor shower is dated by the longitude the Sun reaches rather than by a day of the month, which is why its date moves a little from year to year. The same events are available as JSON and CSV.
The 38 close approaches come from NASA/JPL Center for Near-Earth Object Studies, as they stood on 2026-08-30, and cover passes inside 20 lunar distances from 2026-07-31 through 2028-04-01. Unlike everything else on this page they cannot be computed from an ephemeris here — a newly discovered asteroid has no orbit until somebody measures one — so they are as complete as that date and no more.
COMMON QUESTIONS
] 10 ANSWERED- Why is there not an eclipse every month?
- Because the Moon's orbit is tilted about five degrees to the Earth's, so at most new moons its shadow passes above or below us and misses. Eclipses arrive in seasons roughly twice a year, when the two orbital planes happen to line up with the Sun.
- What fixes the date of a meteor shower?
- Where the Earth is in its orbit, not the calendar. A shower is the Earth crossing a stream of dust a comet left behind, so the peak falls at the same point in the orbit every year and drifts by a few hours against the clock — which is why the dates here are solved rather than looked up.
- Why are moon phases on a list of events?
- Because moonlight decides what else is worth chasing. A full moon costs several magnitudes of faint detail across the whole sky, so the fortnight around new moon is when meteors, galaxies and nebulae actually repay the trip outside.
- What is an opposition, and why is it the night to look?
- Opposition is the moment an outer planet sits opposite the Sun from Earth, so it rises at sunset, stands highest at midnight and sets at sunrise. It falls close to the planet's nearest approach as well, which makes it the biggest and brightest that planet gets in the year.
- What are the equinoxes and solstices, exactly?
- The four instants at which the Sun reaches its furthest north, its furthest south, or crosses the celestial equator between the two. They are moments rather than days, and they are the same moment everywhere on Earth — which is why one of them can fall on a different date depending on your time zone.
- How close does a listed flyby come?
- Inside twenty lunar distances, which is about eight million kilometres. That is close by the standards of the Solar System and by no other standard at all: nothing on this list is a hazard, and the orbits are known accurately enough to say so well in advance.
- Do I need to say where I am?
- Not for the dates. An eclipse maximum, a shower peak or an opposition is the same instant everywhere. For whether the event clears your horizon at a sensible hour — and, for a solar eclipse, for whether you are standing inside a track a few hundred kilometres wide — the answer does depend on where you are, and the page will ask if you want it.
- How far ahead can any of this be predicted?
- Centuries, for anything driven by the positions of the Sun, Moon and planets: the ephemeris behind them holds up over far longer than a lifetime, and eclipse dates thousands of years out are routine. Meteor showers are the exception — the dates are firm and the strength is not, because it depends on how the dust happens to be distributed along the stream.
- Why do the times differ by a few minutes from other sources?
- Usually because a different thing is being timed. A shower peak is a broad maximum rather than an instant, and the hour quoted for it is where the Sun reaches a longitude the observing community has agreed on, not a measurement of that year's dust; an eclipse can be quoted at greatest eclipse or at mid-totality; a phase or an eclipse can be given in different time scales. Everything here comes from one ephemeris and is stated in Universal Time, so the events are at least consistent with each other.
- Can I get these into my own calendar?
- Yes. The next twelve months are published as a subscribable feed, filtered the way the page is when you ask for it, so the events appear in whatever calendar application you already use — and a subscription slides forward on its own as the window does.