How to use Tonight Observing Score

Tool walkthrough · 0:47 · silent, with on-screen words

A walkthrough of Tonight Observing Score for Georgetown, recorded from the real tool with a dated forecast: the Go, Maybe or Skip dial, what goes into it, and when to go.

The video file (MP4, 1735 kB)

Shows Tonight Observing Score at Georgetown with the Open-Meteo forecast fetched on 6 October 2026 at 15:50 GYT, Guyana time.

Chapters

  1. 0:04 The score
  2. 0:12 What goes into it
  3. 0:21 When to go
  4. 0:34 What the bands mean

From the lesson How to Use Tonight Observing Score.

What the video shows, in words

A silent walkthrough recorded from the real Tonight Observing Score tool on this site, for Georgetown, Guyana, with a dated forecast, the cursor and on-screen words showing each step.

With the Open-Meteo forecast fetched at Tue 6 Oct, 15:50 GYT, the tool scores tonight 83 out of 100, Go (Go tonight — solid window, dew is a concern), from 25% cloud, watch dew, transparency excellent, 10.0h astro dark, moon 14% lit, clear window soon. Its best clear window is tonight, 20:00–02:00 GMT-4, excellent. The best night this week is tonight at 83. The bands: 70–100 Go (Clear enough to drive for.); 45–69 Maybe (Watch dew and gaps.); 0–44 Skip (Cloud, dew, moon, or no dark window.).

  1. 0:00 Tonight Observing Score answers one question for your place: go, maybe, or skip?
  2. 0:04 The dial scores tonight out of 100. With the forecast of Tue 6 Oct, 15:50 GYT Georgetown scores 83: Go.
  3. 0:12 The chips are its inputs: cloud, dew, haze, hours of astronomical dark, the Moon, and a bonus for a clear window soon. Tonight: 25% cloud, watch dew, moon 14% lit.
  4. 0:21 The best clear window is tonight, 20:00–02:00 GMT-4, rated excellent.
  5. 0:28 It also ranks the week: the best night is tonight, at 83.
  6. 0:34 70–100 is Go, 45–69 is Maybe, 0–44 is Skip. Go means clear enough to drive for.
  7. 0:43 Check the score in the afternoon, and the window before you leave.

Tools · Learn