Computed in your browser · NASA · NOAA

Tonight

What is actually worth going outside for, from coordinates you type — and computed on your own machine, so they never leave it.

This composes engines that already exist rather than adding astronomy of its own: the twilight, Moon and planet calculators, the ISS pass finder built on NASA's published trajectory, the observing calendar, and NOAA's geomagnetic index. Each of those pages explains its own accuracy; this one only puts them together.

Where you are observing from

Type coordinates. Nothing asks your browser for your position, and everything below is worked out on your own device from data already loaded — none of it is sent to AsteriaStar, nothing is remembered between visits, and the address bar never changes. There is exactly one request this page can make with what you type, and only if you press the cloud-cover button below: your browser then asks the Norwegian Meteorological Institute directly, with the coordinates rounded to about a kilometre. That is described in full before you press it.

Latitude

Longitude

Date (optional)

Decimal degrees. North and east are positive; south and west are negative. Leave the date blank for tonight. Times are shown in your device's own time zone, which the browser knows without being told.

Enter a latitude and longitude to build a plan for tonight.

Everywhere on Earth tonight

These do not depend on where you are, so they are the same for every reader and were computed on the server.

Geomagnetic activity

Kp 1.7

Quiet

Observed at 9/17/2026, 3:00:00 AM. Whether aurora reaches YOUR sky depends on your geomagnetic latitude, which is not your geographic one, and on how far the oval has expanded — AsteriaStar does not compute a verdict for a place, and NOAA publishes the viewline that does.

Events in the next two days

First Quarter Moon — Fri, 18 Sep 2026 20:47 UTC
Moon at apogee — Sat, 19 Sep 2026 06:03 UTC