Back to the hill

About this hill

A place to watch the sky over a city you choose, as it is right now, from a dark hill in the quiet company of others. No sign-up, no chat.

How the sky is drawn

The positions of the sun, moon and planets, and the moon's phase, are computed for this very moment with an astronomy library (astronomy-engine).
Stars come from a real catalog down to magnitude 6, placed where they are in the sky right now. Their positions are left as they are; only their brightness and size are adjusted so they read well on a phone screen.
The moon is drawn at about its real apparent size. When a full moon is up, faint stars fade accordingly.
Weather (clouds, haze) and city lights aren't included. This is a clear sky, seen from a hill with no lights around.

How the meteors fall

Each shower's activity is computed from the International Meteor Organization (IMO) 2026 Meteor Shower Calendar, taking into account how high the radiant is over the city you chose, along with moonlight and twilight. Meteors are rare on ordinary nights and plentiful at the height of a shower.
Meteors are scheduled second by second from real observed rates (IMO), and fall at the same moment whichever city you chose. They aren't the actual meteors crossing that sky. Fewer show in a city where it's daytime or where the radiant is low.
We won't tell you when the next one is coming. The waiting is part of the sky.
A phone screen is narrower than your field of view, so only part of the sky fits. If a meteor passes just off the screen, in a spot you would have caught from the corner of your eye had you been looking that way (within about 50° of your line of sight), that edge of the screen glows briefly and you can wish on that meteor too. The view doesn't turn by itself, and you'll still see fewer than the "about N an hour" at the bottom of the screen. Drag the screen to look at other parts of the sky.

What does "about N an hour" mean?

Numbers in the news such as "up to 150 an hour" are usually the ZHR: a theoretical rate that assumes the radiant is straight overhead and stars down to magnitude 6.5 are visible.

The "about N an hour" at the bottom of the screen is the HR. It reflects how high the radiant is over that city at that moment and how bright the moonlight and twilight are. It's how many meteors one person can expect to see from a clear hill, so it's usually smaller than the ZHR. Compare HR only with HR.

The patch of sky one person takes in at once (the effective field of view) has a radius of about 50° (IMO). This hill spreads meteors evenly over the whole sky above 12° altitude, so the whole sky gets (1 − sin 12°) ÷ (1 − cos 50°) ≈ 2.2 times the HR. The ones that come onto the screen are visible, and clear ones that pass off-screen within 50° of your line of sight are signaled by the edge glow.

Sitting together

The people on the hill are real people connected right now. No names, no words, just a small light beside each of them. The white light is you. If you're alone, only you are sitting there.
Up to 8 people sit on one hill. As more people arrive there are more hills, and you're seated with someone who chose the same city if possible, otherwise with someone who chose a city in the same country. People from other cities and countries can share a hill, each looking at their own city's sky.
Drag the screen to look around the sky, and tap the hill briefly to move there. Others see you walk over. While a meteor passes and wishes are being taken, you stay where you are.
We never receive what you wish for. We only count how many people pressed the button, and show how many wished on that meteor. The count covers all the hills, and each person (each connection) is counted once per meteor. While that count is showing after your wish, the wish button won't light up again even if another meteor passes.

Privacy

What we don't collect: Names, email addresses, phone numbers, location, or what you wish for. There's no sign-up.
Only while you're connected: The server gives each connection a random anonymous number and remembers its seat on the hill and the city it chose. To keep one person from opening too many connections, it also counts, in memory only, how many connections are open at once from one address (IP). None of this is stored, and it disappears as soon as the connection ends.
What we keep: Only anonymous daily totals: visits, wishes, the largest number of people connected at once, how often the save-scene button was shown and pressed, how often the support link was opened, how many connections came from an old version of the page after an update, and how many couldn't sit together because it was crowded. There's no way to tell who did what.
Only on this device: Your chosen city and language, the direction you last looked and where you sat, and whether you've seen the hints. These stay in browser storage and are never sent to the server. Your first city is picked from your device's time zone, which is likewise used only on this device and never sent. Clearing this site's data in your browser removes them.

Sources

Star catalog, star names and Milky Way map: d3-celestial data (based on the Hipparcos catalog, BSD 3-Clause, © 2015 Olaf Frohn)
Shower peak times, ZHR, radiants and population indices: IMO Meteor Shower Calendar 2026
Effective field of view (radius about 50°): International Meteor Organization observing guide
Fonts: Gowun Batang and Gowun Dodum; on the Japanese pages, Zen Old Mincho and Zen Maru Gothic (all SIL Open Font License)