Skywatching

When Is It Dark Enough to Stargaze?

Understand the three stages of twilight and choose a simple observing window.

By AstroboatPublished 2026-10-242 min read

Prepared with AI assistance using the primary sources linked below. How Astroboat works

Sunset is not the start of darkness

The sky stays bright after sunset because sunlight still reaches the atmosphere above you. As the Sun sinks farther below the horizon, that scattered light fades. The same process runs in reverse before sunrise.

How long this takes depends on your latitude and the season. Waiting a fixed half-hour after sunset will not give the same sky conditions everywhere.

Reference: US Naval Observatory: Rise, Set, and Twilight Definitions

Know the three stages

Twilight stages use the position of the Sun's center below the horizon. They describe a gradual transition, not a sudden change in the sky.

Civil twilight: from sunset until the Sun's center is 6 degrees below the horizon. The sky is still bright.
Nautical twilight: from 6 to 12 degrees below. More stars become visible as the sky darkens.
Astronomical twilight: from 12 to 18 degrees below. After it ends, ordinary twilight is no longer the main limit on darkness.

Reference: US National Weather Service: Types of Twilight

Match your timing to the target

For faint stars or a meteor shower, look for an interval after astronomical twilight with little Moon interference. For a bright Moon or planet, twilight can still offer a useful view. A low western target may set before full darkness.

As a planning example, if astronomical twilight ends at 20:00 and the Moon rises at 21:00, that hour may be worth considering. Those are illustrative times, not tonight's forecast; cloud and the target's position still matter.

Check more than the clock

Use a location-specific twilight table, confirm its time zone, and check Moonrise, Moonset, and weather. City lights, haze, and moonlight can keep a sky bright even after astronomical twilight.

At some high-latitude locations in summer, astronomical twilight never ends because the Sun does not sink far enough. A missing darkness interval can be a real seasonal result, not a broken prediction.