Engagement Star Map — the Sky the Moment You Proposed
A proposal happens at one point on Earth, at one minute, under one arrangement of stars that will never repeat. This tool rebuilds that exact sky and captions it with the date you asked.
Make your engagement star map
Free, in your browser — no account, nothing uploaded. Both downloads are the complete chart: a vector SVG and a 300 dpi PNG, with nothing held back and nothing to buy.
Unlike a wedding, a proposal is often somewhere off the map — the overlook at the end of a hike, a rented cabin, a rooftop, a stretch of coast. That is exactly where entering a city falls short and coordinates win.
Getting the proposal right
- Use coordinates, not the town. Long-press the pin on your phone's map at the exact spot and copy the latitude/longitude into the generator's place field. A proposal a few kilometres out of town barely changes the stars, but it changes which caption line rings true.
- Pin the minute if you know it. If you got the time off a photo's timestamp or a text you sent right after, use it — the moment is the whole point. If not, the evening hour of that date is plenty; the sky turns only about 15° per hour.
- Mind the date rollover. A proposal at 12:40 a.m. after a long dinner belongs to the next calendar day on the form, even though you'd tell the story as "that night".
For the caption, couples usually put both first names as the title and a short line as the subtitle — "The night I asked", "She said yes", or the place name. The navy night theme reads as celebratory and frames well in a bedroom or hallway; the ink-on-paper theme is the quieter, letterpress-style alternative if you want it to sit beside other prints.
Printing it: download the file and take it to any print shop or online poster service — the tool makes the artwork, not the paper. A 30×40 cm print in a simple frame is the common choice; if you plan to hang the proposal and the wedding side by side later, pick the size now so the pair matches.
How the map is computed
You give it three things: a date, a time, and a place. For the place, type a town or city name and pick it from the list — 29,919 towns and cities of 18,000 people or more, from GeoNames — or enter an exact latitude and longitude instead. Accents are optional (“malmo” finds Malmö), but type the name on its own: “Roskilde Denmark” finds nothing, and a typo finds nothing rather than the wrong sky.
Your date, time and place are converted to a Julian Date and then to local sidereal time — the astronomer’s clock for “which way is the sky facing.” Each of the 1,630 stars in the Yale Bright Star Catalogue (every star brighter than magnitude 5.0, i.e. every star a good naked eye can see) is transformed to its altitude and azimuth at that exact moment, and every one of those stars above the horizon is projected onto the circular chart: zenith at the centre, horizon at the rim, north at the top — and east on the left, because a star map is read looking up, which mirrors east and west compared to a ground map.
The 89 constellation figures are drawn with the same math and clipped at the horizon. Star dots are scaled by real brightness (magnitude) and tinted by star colour. The Moon is drawn at its real altitude, azimuth and phase for your moment, and left off entirely when it was below your horizon. It does not show the planets, comets or satellites — those wander against the fixed stars and need ephemerides, which this version does not compute. Everything runs in your browser — nothing is uploaded, there is no account, and the page works offline once loaded.
Common questions
We proposed somewhere with no address — a hilltop, a beach. What do I enter?
Use the coordinates, not a place name. On the generator, enter the latitude and longitude of the exact spot — you can read them off any phone map by long-pressing the pin. For a remote proposal that spot may sit between towns, and the coordinates are the only way to get it right.
It was a daytime proposal. Does a star map still work?
Yes. The stars were overhead in daylight too; the chart shows the ones that were really above the horizon at that minute, whether or not the Sun hid them. If you'd rather show a visible sky, use the same date but the evening hour instead — both are honest to the day.
Should the engagement map match the wedding map we'll make later?
Many couples make both and frame them as a pair — the proposal and the wedding, same theme and size. The two skies will look clearly different if the events are months apart, which is the charm of the diptych.