Star Chart – Your Sky Tonight

Star chart: a sky map for exactly where and when you are looking

This star chart draws the whole sky above your head for any place, date and minute: 530 bright stars, stick-figure lines and names for 67 constellations, the Moon with its phase, the Sun when it is up, the five naked-eye planets plus Uranus and Neptune, the ecliptic and the celestial equator. Pick a city or use your location, set the time or press Now, and read the map the way a planisphere is meant to be read — held overhead, with the rim as your horizon.

Hover or tap any star or planet for its name, magnitude, altitude and azimuth. Rotate the chart so the direction you are facing is at the bottom, zoom in on that part of the sky, hide faint stars for a light-polluted town, and download the result as a crisp SVG or a 1200-pixel PNG. All positions are computed in your browser with the Meeus and Schlyter algorithms; nothing is fetched and your location is never sent anywhere.

How to use the Star Chart

1. Choose a City or enter Latitude and Longitude (or press Use my location) and check the Time zone.
2. Set the Date and Time, press Now, or step through the night with the −1 h and +1 h buttons.
3. Face the direction you want to explore and move the Rotate slider until that direction is at the bottom of the chart; use Zoom to enlarge that part of the sky.
4. Set Faintest stars to match your sky — magnitude 3 for a city centre, 4.5 for suburbs, 5 for a dark site — and toggle lines, labels, the ecliptic and planets as you like.
5. Hover or tap objects for details, then Download SVG or PNG to print the chart.

Star Chart features

How to read the chart

The chart is an azimuthal equidistant projection of the sky: the centre is the zenith directly above you, the outer circle is your horizon, and distance from the centre is proportional to zenith distance, so the dashed circles mark 60° and 30° altitude. North is at the top and east is on the left — the opposite of a ground map — because a sky map is meant to be held above your head facing down at you. If you hold a printout overhead with “N” pointing north, every star lines up with the real one.

On the ground, rotate the chart until the direction you are facing is at the bottom; the stars just above the bottom rim are then the ones just above the horizon in front of you. Zooming keeps that horizon in view and enlarges the sky in front of you. Star sizes follow brightness: magnitude 0 stars such as Vega and Arcturus are the largest dots, magnitude 4 stars the smallest.

What moves and what does not

The stars keep their places relative to each other, but the whole pattern turns around the celestial pole once every 23 h 56 m, so the same sky appears four minutes earlier each night and two hours earlier each month. The planets wander along the ecliptic and the Moon moves its own width every hour, which is why the chart recomputes everything for the exact minute you enter. The sidereal time calculator shows the sidereal time behind this rotation, and planets visible tonight gives each planet’s rise and set times.

Accuracy and limits

• Star positions are J2000 catalogue values drawn to about 0.1°; precession since 2000 (under half a degree) is not applied, which is far below what the eye can see on a chart of this scale.
• Sun and Moon come from Meeus’ algorithms (0.01° and about 10″); planets from Schlyter’s elements (1–2′ for the bright planets). Refraction is not drawn, so objects at the very rim are in reality lifted by up to half a degree.
• Deep-sky objects, the Milky Way and stars fainter than magnitude 5 are not included; this is a naked-eye guide, not a telescope atlas.
• For a bright Moon that will wash out faint stars, check the moon phase calculator; for the one moving object brighter than everything here, the ISS pass predictor.