Time & date
Night Sky Map
See which stars, planets and constellations are above you right now, or at any time from 1900 to 2100, from anywhere on Earth.
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Works in your browser. No account needed.
Frequently asked questions
Which stars does the map show?
All 5,080 stars of magnitude 6.0 and brighter from the Yale Bright Star Catalogue (5th revised edition, Hoffleit and Warren, 1991). That is roughly every star the eye can see from a very dark site. The map shows stars to magnitude 5.5 by default; set Faintest stars to 3 or 4 to match what you can see from a city. Star names are the official ones from the International Astronomical Union’s Working Group on Star Names.
How accurate are the positions?
Star positions come from the catalogue’s J2000 coordinates, moved to the chosen date for precession, which shifts them by about a third of a degree every 25 years. The Sun and Moon use the algorithms in Jean Meeus’s Astronomical Algorithms, and agree with NASA JPL’s Horizons ephemeris to within 0.01° for the Sun and 0.05° for the Moon in our tests. Planets use JPL’s approximate orbital elements: between 1900 and 2100 they were typically within a few arcminutes of Horizons, and Saturn, the worst, within about a third of a degree. The positions include atmospheric refraction, which lifts objects near the horizon by about half a degree.
Where do the constellation lines come from?
There are 88 official constellations, but their stick figures are not official: the International Astronomical Union defines each constellation by its boundary, not by lines between stars. This map uses the figures from the d3-celestial project by Olaf Frohn, which follow the IAU’s own constellation charts, and the boundaries from the Catalogue of Constellation Boundary Data (Davenhall and Leggett, 1989). Turn on Boundaries to see which area of sky belongs to each constellation.
How does compass mode work?
It reads your phone’s motion and orientation sensors, the same ones a compass app uses, to point the map where the back of the phone points. On an iPhone or iPad, Safari asks for permission first. Compass readings can be off by 10° or more near metal, magnets or electronics, so check the map against a bright star you recognise.
Why use red mode?
Your eyes take 20 to 30 minutes to fully adapt to the dark, and a bright white screen undoes much of that in seconds. Dim red light affects dark adaptation far less, which is why astronomers use red torches. Red mode turns the tool red; turn your screen brightness down as well, and use Full screen to hide the rest of the page.
Can I see all of these stars from my town?
Probably not. Light pollution, haze and moonlight hide the fainter stars: from a city centre you may see only stars brighter than magnitude 3, while a truly dark site shows stars down to magnitude 6 or fainter. Stars near the horizon are dimmed by the extra air their light passes through. The planets, the Moon and the brightest stars can be found from almost anywhere, and while the Sun is up the map shows where stars are even though they cannot be seen.
About this tool
This night sky map shows the sky as it appears from your location at any moment, now or on any date from 1900 to 2100. It draws the stars to magnitude 6.0 from the Yale Bright Star Catalogue, the 88 constellations with their lines, names and IAU boundaries, the Sun, the Moon with its current phase, and the seven planets from Mercury to Neptune. Everything is calculated in your browser, and no location data is sent anywhere.
The map is a stereographic projection of the sky, the projection used by planispheres and most star charts because it keeps the shapes of constellations true. At the default whole-sky view the circle is the horizon and its centre is the point straight overhead. Zoom in or press Horizon to look toward one direction, as if you were standing outside facing it; the ground is drawn below the horizon, so you can still see what lies just out of view.
Each position is worked out in the same steps an astronomer would use: the catalogue coordinates are precessed from the year 2000 to your date, turned into altitude and azimuth with the local sidereal time for your longitude (Meeus, Astronomical Algorithms, chapters 12, 13 and 21), and raised slightly for refraction by the atmosphere. The calculations are checked against the worked examples in Meeus’s book and against NASA JPL’s Horizons ephemeris.
Select any object to see its current altitude and compass direction, its next rise and set times and the time it is highest in the sky, all in your local time zone. That makes the map useful for planning: find out when Orion rises in the autumn, where to look for Venus after sunset, or whether Jupiter is up tonight. The list under the map shows the Moon and every planet above the horizon at the chosen time.