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Xenith

Should I go stargazing tonight?

Deciding whether to drive out and look at the sky used to take me four tabs and a bit of guesswork. Xenith gives one stargazing score for every hour of the night, so the answer is one glance away.

Seven nights, hour by hourEvery hour is shaded by its score, darker for a clearer sky. Opening a night shows its moon arc, the four judgements and when the moon rises and sets.
TonightOne score for the best hour of the night, the condition in plain words, the window worth going out for, and how dark the sky is at the site.
Tonight by hourTapping an hour swaps the rings to that hour. The moon arc sits on the same width as the strip, so moonset lines up with its hour.

Too many tabs for one question

Cloud cover lived on one site. The moon lived on another. Light pollution had its own map, and the forecast was somewhere else again. By the time I had pieced it together, the night was half gone.

I only ever wanted one answer. Should I go tonight?

The best window, not the average

Pick a place and a date. Xenith scores every hour from 0 to 100. Cloud counts most, then the moon, then how clear the air is. All of that is scaled by how dark the sky really is: twilight, plus how much light pollution sits over that spot.

The daily score is the best window of the night, not an average of the day. A clear hour at 2AM should not be dragged down by the afternoon.

Judgement first, numbers later

The grid shows seven nights of 24 hours. Darker cells mean clearer sky. Hover an hour and it says Poor, Good or Excellent before it says anything else. Raw values stay in the background, because a percentage of cloud tells me very little at 9PM.

I also made it score conservatively. If it says a night is good, I want it to be good, not hopeful.

Functional to me

It runs entirely in the browser on free public data, with no account and no backend. It is still a work in progress, but it is functional to me, and I open it every time I think about heading out.