Space Time: a free 3D universe explorer in your browser

A real-time 3D model of the solar system

Every planet, moon, dwarf planet, asteroid and live comet rides its true orbit, rendered with real surface maps at 60fps. Positions come from the astronomy-engine library, which is built on JPL ephemeris data, so what you see on screen matches the actual sky.

🪐 All the planets & moons<br>Mercury through Neptune, plus Pluto, Ceres and Eris with their major moons. The asteroid belt is in there too, along with live comets and near-Earth asteroids pulled from JPL.

🛰️ Apollo & spacecraft<br>Replay the Apollo missions on their historical trajectories. You can also ride along with the ISS, Hubble, JWST and the Parker Solar Probe.

⏱️ Travel through time<br>The clock scrubs forward and back through any date. Speed it up and alignments, conjunctions and retrograde loops play out in front of you.

Stand on any world and look up

Drop to the surface of Earth, the Moon or Mars. The Sun, Moon, planets, constellations and the Milky Way appear exactly as they would from that spot at any date and time, so it doubles as a what's-up-tonight view. You can trace the Sun's analemma figure-8 onto the sky, or a planet's retrograde loop. Deep Time goes further: scrub through 28 millennia of axial precession and watch the pole star pass from Thuban, the pyramid builders' north star, to Polaris and on toward Vega.

Standing on the Moon. The sky above is the accurate one.<br>“Tonight's Best”: ranked targets for your location, right now.<br>The analemma, the Sun's year-long figure-8, traced in your sky.<br>Deep Time: the sky of 2601 BCE, when Thuban marked the celestial pole.

Watch eclipses & sky events

The eclipse view predicts solar and lunar eclipses for any date and place, then plays them out: totality with the Sun's corona, or Earth's shadow turning the Moon blood-red, viewed from the ground or from space. There's a full sky events calendar too. Lunar occultations are computed for your location, and Jupiter's moons transit and cast shadows at the real times, including the rare double shadow transits. Every event opens in 3D with one click and exports to your calendar.

Totality. The sky darkens and the corona appears.<br>Replay the Apollo 11 mission in accurate 3D.<br>Voyager 2's Grand Tour, Jupiter to Neptune, on the real trajectory.<br>A Galilean moon's shadow crawling across Jupiter, at the real times.<br>The sky events almanac. Every entry opens in 3D and exports to your calendar.

From the solar system to the edge of the universe

Zoom out and the planets give way to the nearby stars, then the full Milky Way, then the cosmic web of galaxies, all the way to the cosmic microwave background. It's one continuous powers-of-ten pull-back, with no loading screens between scales.

Fly out to the structure of the Milky Way.<br>207 deep-sky objects with real survey imagery.

An observer's toolkit

Tools for people who actually haul a telescope outside. There's an ephemeris generator with almanac tables, brightness and distance graphs, and CSV export for any planet. A Moon phase calendar flags supermoons, and the clickable Moon atlas puts 277 named craters, maria and landing sites on the 3D globe.

🔭 Telescope & eyepiece simulator<br>Check how a target fits your scope, eyepiece or camera sensor before you set up. The field-of-view overlay is drawn to scale on real sky imagery.

📈 Ephemeris generator<br>Generate almanac tables for any body: position, brightness, apparent size, over whatever date range you want. Export to CSV. Oppositions and best nights get flagged automatically.

📡 ISS & satellite passes<br>Visible-pass predictions for the ISS, Tiangong and Hubble, computed from live TLEs with SGP4. It tells you when to go outside.

📷 AR camera sky<br>Turn on your phone camera and the star chart overlays whatever the lens is pointed at. It labels what you're looking at, and it works in daylight too.

🌙 Moon calendar & atlas<br>Daily phases, exact full-moon times, supermoon flags. The atlas side lets you fly to Tycho, the maria or any Apollo landing site on the 3D Moon.

🌌 Deep sky & 118K stars<br>Search galaxies, nebulae and clusters against a 118,000-star sky. Wind the clock far enough and the stars drift with their true proper motion.

🪐 Exoplanet systems<br>TRAPPIST-1, Kepler-90 and other real systems, with planets on their measured orbits. Habitable zones are shaded so you can see which worlds sit inside.

🌞 Live aurora & space weather<br>NOAA's live Kp index and aurora data, plus current comets and asteroids streamed from JPL.

Mars brightening toward its 2027 opposition in the ephemeris generator. The data exports to CSV.<br>The Moon atlas: 277 named features and every landing site, clickable on the globe.<br>AR camera mode, with the chart over the actual sky through your phone's lens.<br>July 1054. The Crab supernova ignites where Chinese astronomers logged it.

Who uses it

Teachers run it in class. Stargazers use the planner before a night out, astrophotographers use the framing...