The real sky for a city or your current location: find something now, explore any moment, or plan what to look at on a chosen night.
How to use this sky map
Three uses. — Find now shows the sky at this moment and suggests what to look for first; Explore lets you change the date and time and play it forward; Plan a night shows a target's altitude through the night, astronomical darkness and moonlight, and the city forecast.
Finding things. — Pick a suggestion, search, or tap a star on the chart, then press “Point at it” and the chart turns to face it.
Changing the time. — Dates and times are local to the chosen place, not your phone's time zone. “Back to now” returns to live.
Planning a night. — The altitude curve is geometry; cloud and rain come from the city forecast, which only covers the next few days. The two are shown separately.
Gestures. — On the page, two fingers turn and zoom the chart and one finger scrolls the page; in full screen one finger drags the sky. On a computer, hold Ctrl (⌘ on a Mac) while scrolling to zoom, or use the + and − buttons.
Location and compass. — “Use my location” reads GPS once; “Follow my phone” only turns the chart with the compass. Neither is needed — choosing a city is enough.
Layers and views. — Switch constellation lines, names, the Milky Way, the ecliptic and the grid on or off. The facing view is what you see looking one way; the whole-sky disc shows everything, with straight up in the middle.
Limits. — The horizon is flat — no hills or buildings. Whether you can see something also depends on light pollution, cloud and moonlight.
Put the sky map into the whole plan
The map tells you where to face, but it does not decide whether the sky is dark enough. Before leaving, combine the map with the stargazing score and dark-sky sites so you know both where the objects are and where to wait for them.
Check tonight's score and dark window before committing.
Choose a low-light site with the right open view.
Find the dates and peak times of meteor showers, eclipses and other events, and plan your session around them.
“Follow my phone” turns the chart left and right with the compass only. It does not use the camera and does not follow the phone tilting up or down. Location and compass are separate, and neither is used until you press its button.
Drawn for the chosen place and time, with stars to about magnitude 6. Whether you can see them also depends on light pollution, cloud and moonlight.
Rendered with d3-celestial (BSD license); star data from the Hipparcos catalogue.