The Short Version
computing…Reading the sky…
The Night Sky
The Moon's Mood
- Phase
- —
- Illuminated
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- Moonrise
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- Moonset
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Tonight, Hour by Hour
The verdict says whether; this strip says when. Three things decide an observing hour — how dark the sky is, where the moon is, and what the clouds are doing — and here they are, hour by hour from sunset to sunrise. Green is go.
The observing strip
computing…
good
middling
working against you
still bright
Darkness and moon are computed in your browser; the cloud row is Open-Meteo's hourly forecast for your spot. Hover any cell for the hour's detail.
Darkness
"True dark" is astronomical twilight's end — the Sun 18° below the horizon, when the sky stops glowing and the faint stuff comes out.
Planets Tonight
Computed for your spot, for tonight's dark hours. "Highest" is the best time to look — a planet near the horizon swims in thick air; one 30° up or more is crisp.
Meteor Watch
Is a shower active tonight, and is the moon going to let you see it? Dates and rates from the International Meteor Organization's calendar; the moon math is computed for tonight.
Checking the calendar…
The Station
ISS passes tonight
computing…A visible pass looks like the brightest star in the sky, moving fast and steady, no blinking. It's the size of a football field and there are people inside.