Sky of Your Day

Which star shares your age?

Starlight travels for years before it reaches us. Somewhere in the sky there is a star whose light set out on the day you were born, and is reaching you right now.

Your date of birth

Your date of birth never leaves your device.

Make a poster for another date
Tonight’s sky

How it works

Light takes time to travel. From a star 40 light years away, the light you see tonight set out 40 years ago.

So for every age there is a star at just the right distance: the light that left it on the day you were born is reaching Earth right about now. We search a catalogue of more than 4,000 nearby stars, built from the Hipparcos, Yale and Gliese catalogues, for the one that matches your date, and prefer stars you can see with your own eyes.

Then we work out, for where you are, when it rises, how high it climbs and which way to face, and draw the real sky above you with your star in it. On a phone you can hold it up to the sky and follow the arrow.

Questions

Is it a real star?
Yes. Every star here is a real star with a measured distance. Nothing is invented or "named" for you: it is the star whose distance in light years matches your age.
How precise is the date?
Star distances come from parallax measurements. For nearby stars the uncertainty ranges from a few weeks to a few months of light travel, so the date is a close estimate rather than exact to the day.
What if my star is too faint to see?
We prefer stars visible to the naked eye. For some ages the closest match is faint: we tell you whether you need a dark sky, binoculars or a telescope, and list the other stars your age.
What about babies and young children?
The nearest star, Proxima Centauri, is 4.2 light years away. For children under four, the light that left a star on their birthday has not arrived yet: we show which star it is and the date its light will reach Earth.
Is it free? What happens to my data?
It is free, with no sign-up. Your date of birth is used only in your browser and is never sent anywhere. If you search for a city, only its name is sent to the Open-Meteo geocoding service.