Interactive star map

Guided tours

• Find the North Star The Plough, the pointers, and your own latitude.
• Arc to Arcturus Follow the handle round to Arcturus and on to Spica.
• The same hour, all year Hold the clock, run the date: why the winter stars are winter’s.

A tour hands control back between steps, and you can start either of them again from here as often as you like.

The instruments

• This bar Search, the sky, your viewpoint, night mode, sharing and more. One panel opens at a time; on a phone it comes up from the bottom and a drag down on its title puts it away. Each button names itself when you hover or tab onto it.
• Sky How the sky is drawn, all in one place. Pick a look — naked eye, learn, clean or imaging — or set it yourself: what is drawn, what is named, the grids, how dark your sky is on Bortle's scale, the air and the Milky Way, and night mode for your eyes. Your choices are remembered. Turning Air & glow off removes the haze and the Earth together, so you see the whole celestial sphere at once. With Dark adaptation on, night mode starts your eyes from scratch: the bright stars first, the faint ones over about fifteen minutes, as they arrive under a real sky. Star trails draw each star's path over the last hour as you run the clock.
• Share A link to this exact view, or a picture of it with the place and time written underneath.
• Framing F Draws your camera's field on the sky: pick a sensor and a focal length and it says whether the target fits. It is under More, and on the card of any deep-sky object as Frame this.
• Viewpoint V Takes the camera off the ground. Step back and your own horizon becomes a plane drawn through where you are standing; step back again and you are looking at the whole orbit with the Sun in the middle. The sky never moves — only the camera does.
• Aim with phone On a phone, the switch on the pointing readout makes the sky follow the phone: hold it up and the map shows what is behind it. Dragging the sky, or asking the map to look somewhere, hands control back. It steers by the phone's compass, which reads magnetic north and is good to a few degrees, so if the view looks turned, move the phone in a figure-8 to calibrate it.
• Copy link Puts the address of exactly what you are looking at — direction, field, time and selection — on the clipboard. The address bar keeps it up to date as you move, so Back walks your jumps instead of leaving the map.
• Compass Bottom right. It is a control, not a picture — click any point in the dial to look there, or tab to it and steer with the arrow keys. Enter looks straight up; Home resets the view.
• Time The bar along the bottom. Drag the track to scrub through the night against the twilight bands, press play to run it, pick another date from the calendar, and NOW returns to the present.
• Location In the pointing readout, top left. Everything horizon-shaped — the ground, the compass, twilight, every rise time — is computed from it, so it is worth correcting.

Gestures

• Drag Swing the view across the sky. Let go mid-drag and it glides.
• Scroll · Pinch Zoom the field of view in and out around the pointer.
• Click a star Opens its card: spectral class, distance, how bright it really is.
• Hover · Hold Rest the cursor — or hold a finger down — to name what is under it without selecting it. Keep still over empty sky and the constellation you are in lights up.
• Click a symbol Same for a deep-sky object — the glyphs below are all clickable.
• Click empty sky Washes the constellation whose territory you clicked. Click it again to clear.

Keyboard

• ← ↑ ↓ → Pan by a fraction of the current field, so the step feels equal at any zoom. During a tour they step through it instead.
• + − Zoom in and out from the centre.
• N Step to the next named object in view, brightest first. ⇧ N goes back.
• Enter Select whatever is at the centre of the view — the keyboard's version of a click.
• Home Put the view back: due south, level, default field.
• [ ] The same time a day earlier or later. The YEAR button on the clock turns its track into a year at that time, with the Sun's path traced as it goes.
• ⌘ +K Search stars, constellations, planets and Messier numbers.
• F Open and close the framing tool.
• ? Open and close this guide.
• Esc Close whatever is open, then drop the current selection.

Deep-sky symbols

The same shapes a printed star atlas uses. Size follows the object's real angular extent; faint objects get a quieter glyph.

• Galaxy
• Open cluster
• Globular cluster
• Planetary nebula
• Bright nebula
• Supernova remnant
• Dark nebula

Label colours

• Vega Amber, monospaced — a named star.
• M 31 Warmer amber, two lines — a deep-sky object and its catalogue number.
• ORION Blue, wide-tracked caps — a constellation figure, the joined-up pattern.
• ORIONIS Slate, widest tracking — the IAU boundary that owns that patch of sky.
• The Plough Italic amber — an informal asterism, not one of the official 88.