StarsOut
Should you go outside tonight?
Drop everything — go outside
Near-perfect conditions. Nights like this are rare.
Ostrava
9.5
out of 10
Peak 2h
10.023:00–01:00
Prime 21–01
9.721:00–01:00
Best this week
8.2Mon, Jul 20
Moon
Waxing Crescent
5% lit
Moon doesn’t interfere — perfect darkness
🔭 Moon up: 07:17–22:07
📍 E · 32°
Full moon: Jul 29
Sun ↓ 20:49·Dark from 21:49·50% clouds
Alert me on good nightsSky quality tonight
Best: 23:00–01:00This week’s nights
Europe/PragueHow the score works
60% weight
Cloud cover
Layer-weighted across the best 2-hour window of the night. Low clouds block everything, thin high cirrus still lets bright stars through.
40% weight
Moon darkness
A new moon boosts the score. A full moon near midnight washes out all but the brightest stars. We ease the penalty after midnight when the moon is setting.