Astronomical Twilight Times

When the last trace of twilight fades — and when true darkness for stargazing begins.

Finding your city…

Astronomical twilight

--:--

Calculating for your time zone…

Location Date

Enter latitude / longitude

Latitude Longitude Time zone

All sun times for this day

What is astronomical twilight?

Astronomical twilight is when the Sun's centre is between 12° and 18° below the horizon. To the eye the sky already looks dark, but a faint glow still washes out the dimmest stars, nebulae and galaxies. After astronomical dusk (−18°) the Sun adds no light to the sky at all — that's astronomical night.

Phase	Sun below horizon	What you see
Civil twilight	0° to 6°	Enough light to work outdoors; brightest planets appear
Nautical twilight	6° to 12°	Horizon still visible at sea; bright stars visible
Astronomical twilight	12° to 18°	Sky looks dark to most people; faint glow remains
Night	more than 18°	No sunlight scattered in the sky

Stargazing tips

Plan deep-sky observing and Milky Way photos between astronomical dusk and astronomical dawn.
Check the moon phase too — a bright Moon washes out faint objects even in full darkness.
In summer at latitudes above about 48.5°, the sky may never get astronomically dark around the solstice.

Frequently asked questions

When is it completely dark?

After astronomical dusk, when the Sun is more than 18° below the horizon. The tool shows that time and counts down to it.

Why is there no astronomical night in summer?

Far from the equator the Sun stays less than 18° below the horizon around midsummer, so twilight lasts all night.

Study smarter with Stuon

Take your focus further.

Turn what you learn into lasting knowledge with active recall, spaced repetition, and simple study tracking.

Continue on Stuon