The observatory · computed, never fetched
The time of day.
Everywhere at once.
A board of world clocks — drawn analog faces beside their digital reading — for any of 100 cities on a hand-kept register, each told through the real IANA time zone your own browser carries, so a half-hour zone reads half past and Kathmandu reads its famous :45. Each face wears the sky over that city right now: day, twilight or night, worked out from the sun’s actual altitude.
Below the clocks, an observatory: sunrise, sunset and civil twilight for any city on the register, the moon inked at its current phase, and an orrery of the eight planets you can scrub fifty years either way. Every figure on this page is computed by the page itself, from published astronomical arithmetic — nothing arrives over a wire, so nothing here can break in an outage.
100 cities on the register · 18 dials · 12 sets of hands · the browser’s own IANA zones · NOAA solar arithmetic · a J2000 orrery · zero requests
The clocks
A hundred cities. Every continent.
The board deals thirty-two of them, taken round-robin across the regions so it reaches Africa and South America before it reaches the Americas twice — six Antarctic research stations are on the register, and they keep real time on real clocks. It is yours after that: add any city the register knows, retire the ones you don’t watch, walk a clock left or right, and hover one to see where on the earth it actually is. The arrangement is remembered in this browser and nowhere else.
World clocks
winding…
Spin for a fresh thirty-two cities out of the hundred on the register, a dial for every clock out of eighteen, and hands for every clock out of twelve.
Dial—
Hands—
Focus takes the arrows, the cross and the three lines of type off every card and prints the city on the dial instead — where a watch carries its maker’s name, under twelve — with the time where a sub-dial goes, at six. It travels into a popped window with the board.
The sky over each city — day, civil twilight or night, from the sun’s computed altitude — is the word under the time and the hairline along the top of the card. The arrows walk a clock along the board, × retires it, and the arrow on a card opens that one clock in a window of its own. Ticks pause while the tab is hidden.
The bench
Ten instruments, to the hundredth.
Stopwatches and countdowns, run together, each with its own start, lap and reset. Nothing counts up: every reading is worked out from a stamp, so a stopwatch left running in a background tab comes back with the right number rather than a slow one, and a countdown is aimed at a moment on the wall clock rather than at a tally of ticks.
The sun
Today’s daylight, worked out by hand.
Pick a city and the page computes its day: civil dawn, sunrise, solar noon, sunset, civil dusk — drawn as an arc of today’s daylight with the sun placed where it is this minute. Computed with the NOAA solar equations, in your browser, from nothing but the date and the register’s coordinates. The moon has a section of its own below.
The sky desk
Sun times carry the NOAA algorithm’s honest error — a minute or two at mid-latitudes, a few more near the poles, where a degree of refraction is a long stretch of horizon. All times are the city’s own, from its IANA zone.
The moon
Tonight’s moon, photographed and then lit.
The disc is the near side as the Lunar Reconnaissance Orbiter mapped it — Tranquillitatis, Crisium up on the eastern limb, Procellarum spread across the west, Tycho throwing its rays across the southern highlands — projected as a sphere for the face the Earth is actually shown. The light on it is not in the photograph: the phase, the terminator and the shading are worked out here from the true angle between the moon and the sun, rather than from an average month, so it is right on the nights the average is wrong. Walk it forward or back a month, or press play and watch a whole lunation cross in about half a minute.
The moon
What comes next
The orrery
Eight planets, fifty years either way.
A drawn orrery: every planet placed at its computed heliocentric longitude for the date on the scrub, from the JPL mean orbital elements at epoch J2000. Drag the scrub and watch Mercury whip round eight-hundred-odd times while Neptune barely clears a third of its orbit.
The orrery
Not to scale — the spacing between orbits is drawn for reading, not measured; the angles are the computed positions. Elements are the JPL/Standish J2000 table, stated valid 1800–2050 — the outer years of the scrub lean on its slow, known drift. Orbits are drawn as circles; the real ellipses are within a few percent of round.
About
Nothing here can go down.
Every other instrument on labs.llc reads a wire, and says so. This one is the exception, and that is its whole flex: zero upstream. No feed, no key, no proxy — not one figure on this page arrives over a wire. The page computes everything it shows, so an outage anywhere on earth cannot blank a single number. Load it once and it works on an airplane.
The clocks are the browser’s own: Intl.DateTimeFormat against real IANA zone names, which is the same tz database — DST rules, half-hour zones, Nepal’s :45 — that your operating system keeps current. The register of 100 cities is hand-kept in the page: name, zone, coordinates, country, continent — nothing else. Every zone on it has been checked against the tz database itself, and the continent is stored rather than guessed from the zone name, because the zone name is not a continent: America/ covers two of them, Atlantic/Reykjavik is Europe, and Pacific/Honolulu is Oceania in a country most of which is not.
The sun figures use the NOAA solar position equations — declination and the equation of time from the Julian century, rise and set at zenith 90.833°, civil twilight at 96° — good to a minute or two at mid-latitudes, honestly worse near the poles. The moon is computed, not averaged: Meeus’s lunar theory for its position and distance and his solar theory for the sun’s, with the phase taken from the angle between them — the moon’s longitude good to about ten arcseconds and the phase instants to about a minute. This page used to read the moon off the mean synodic month, which is a fair description of an average and a poor one of any particular night: over 2026–27 the mean runs up to fourteen hours away from the true phase, and it is more than six hours out for three nights in four. The drawn disc is a geocentric view with north up; libration is not modelled, so features near the limb sit where they average rather than where they are tonight. The orrery runs on the JPL approximate Keplerian elements — Standish’s J2000 table with per-century rates, stated valid 1800–2050 — with Kepler’s equation solved on each scrub. What the arithmetic cannot honestly say, the page does not draw.
Your board of clocks and your chosen sky city are remembered in this browser and nowhere else. A link to the page can carry a city or an orrery date with it.