Galactic core · next 30 nights

Milky Way windows at Cerro Tololo Observatory

This tracks the Sagittarius galactic core only when the Sun is at least 18° below the horizon and the core is at least 10° high. It is geometry, not a weather promise.

Best night10 Oct3.3 h of core visibility in darkness

Highest core altitude49°near 21:20

Usable nights30 / 30Moonlight and cloud still decide image contrast.

Computed local geometry

Core hours after astronomical twilight

10 Oct3.3 h1% moon

11 Oct3.3 h3% moon

12 Oct3.3 h7% moon

13 Oct3.0 h13% moon

14 Oct3.0 h20% moon

15 Oct3.0 h28% moon

16 Oct3.0 h36% moon

17 Oct3.0 h45% moon

18 Oct3.0 h55% moon

19 Oct2.7 h64% moon

20 Oct2.3 h73% moon

21 Oct2.3 h82% moon

22 Oct2.3 h89% moon

23 Oct2.3 h95% moon

24 Oct2.0 h98% moon

25 Oct2.0 h100% moon

26 Oct2.0 h99% moon

27 Oct2.0 h95% moon

28 Oct2.0 h89% moon

29 Oct1.7 h81% moon

30 Oct1.7 h71% moon

31 Oct1.7 h60% moon

1 Nov1.7 h48% moon

2 Nov1.7 h36% moon

3 Nov1.3 h26% moon

4 Nov1.3 h17% moon

5 Nov1.3 h10% moon

6 Nov1.3 h4% moon

7 Nov1.3 h1% moon

8 Nov0.7 h0% moon

21:20–00:40

This is the widest geometric window in the next month. Check the live forecast before travelling, then favor the darkest moonless portion. Check live cloud and transparency →

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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.