Skip to content
AsteriaStar
Night Sky Platform

Sun & Twilight Calculator

Source-backed sunrise, sunset, solar noon, day length, and civil, nautical, and astronomical twilight for any location and date — computed from public-domain solar formulae and timestamped. Enter a latitude and longitude; your location is used only for the calculation and is never stored.

Night SkyComputed (source-backed calculation)

Sun & twilight calculator

Computed

Privacy: your location is used only for this calculation and is not stored. No browser geolocation or IP lookup is used — coordinates come only from what you type. Times are shown in the timezone you enter (UTC if blank).

Enter a latitude and longitude to compute sunrise, sunset, solar noon, day length, and the three twilight phases. Nothing is shown until you do — no location is assumed.

How these times are found

Sunrise and sunset are the moments the Sun's centre sits 0.833° below the horizon — allowing for atmospheric refraction and the Sun's radius. Solar noon is when the Sun crosses your meridian, and day length is the time it spends above that horizon. The times above are computed from public-domain solar formulae and timestamped; they assume a flat, sea-level horizon and do not model local terrain.

The twilight phases

Between day and full darkness the sky passes through three twilight phases. Their times for your location appear in the calculator above; see the twilight page for more.

Civil twilight
The Sun is 0–6° below the horizon. The brightest objects are visible and, in clear conditions, there is enough natural light for most outdoor activity.
Nautical twilight
The Sun is 6–12° below the horizon. The horizon at sea is still faintly discernible and brighter stars are usable for navigation.
Astronomical twilight
The Sun is 12–18° below the horizon. Scattered sunlight still faintly lights the sky; beyond −18° is astronomical night, the darkest sky.

Related in the Knowledge Graph

The Sun
Earth

Sources & references

The primary and reference sources this topic draws on.

  • NOAA Solar CalculatorNOAA Global Monitoring Laboratory

    Public-domain solar-position geometry: sunrise, sunset, solar noon, twilight, declination, and the equation of time.

    Public domain (US Government work).

  • US Naval ObservatoryUnited States Naval Observatory

    Precise time, almanac data, Sun/Moon rise-set, and phases.