GoodSeeing
Sun below −18° · next 30 nights

True darkness at Queenstown

Astronomical darkness starts only when the Sun is 18° below the horizon. These bars are calculated for the coordinates, so high-latitude nights correctly show no true darkness when twilight never ends.

Longest night9.0 h19 Sept
Nights reaching −18°30 / 30Astronomical darkness occurs
Longest window20:20–05:20Moonlight is shown separately in the planner.
Solar geometry, not a clock rule

Hours of astronomical darkness

19 Sept9.0 h56% moon
20 Sept9.0 h65% moon
21 Sept8.7 h74% moon
22 Sept8.3 h82% moon
23 Sept8.3 h89% moon
24 Sept8.3 h94% moon
25 Sept8.3 h98% moon
26 Sept8.3 h100% moon
27 Sept8.3 h99% moon
28 Sept8.3 h96% moon
29 Sept8.3 h91% moon
30 Sept8.0 h84% moon
1 Oct8.0 h74% moon
2 Oct8.0 h63% moon
3 Oct8.0 h52% moon
4 Oct8.0 h40% moon
5 Oct8.0 h29% moon
6 Oct7.7 h19% moon
7 Oct7.7 h11% moon
8 Oct7.7 h5% moon
9 Oct7.3 h1% moon
10 Oct7.3 h0% moon
11 Oct7.3 h1% moon
12 Oct7.3 h4% moon
13 Oct7.3 h9% moon
14 Oct7.3 h15% moon
15 Oct7.3 h22% moon
16 Oct7.3 h30% moon
17 Oct7.3 h39% moon
18 Oct6.7 h49% moon
9.0 hours

Use this as the outer boundary for faint-object work. Moon altitude, cloud and transparency will narrow the practical window. Add the Moon →

Keep planning

Same coordinates, different question

Moon

Moonless nights

Find the longest uninterrupted dark windows.

Core

Milky Way

See when the galactic core clears the horizon after dark.

−18°

Astronomical darkness

Track true darkness, including polar twilight.