I built this because every astronomy tool I used assumed I was in the northern hemisphere, in a US timezone, with English-only feeds. I'm in South Africa — half the sky is different, the darkness windows are different, and most "tonight's sky" tools just don't work properly below the equator.
StarScope is a free web app (no signup required) that gives you:
•
"Worth It Tonight?" verdict — fuses GFS weather forecast (cloud/seeing/transparency via Open-Meteo) with astronomical darkness calculations and moon interference into a single go/no-go answer. Clear Outside makes you eyeball three rows; this gives you the decision.
•
Tonight's Sky panel — what's actually visible from your coordinates right now, computed with proper suncalc twilight (civil/nautical/astronomical), not just "it's dark". Handles edge cases like no astronomical darkness in summer at high latitudes.
•
Real-time feeds — Arxiv, NASA GCN, MPC, NEO, ESA/Hubble, Sky & Telescope, NOAA Space Weather, all filterable by topic. Hemisphere-aware so southern observers aren't buried in Polaris articles.
•
ISS passes, comet tracking, APOD — the daily utilities.
Technical bits: React + Express + tRPC, Open-Meteo GFS for weather (same model Clear Outside uses via 7Timer), suncalc for ephemeris, server-side caching so the free APIs aren't hammered. No tracking, no ads. The weather forecast is global — works the same whether you're in Cape Town or Copenhagen.
The "Worth It Tonight?" panel is what I'm most interested in feedback on. The scoring combines weather (cloud%, seeing, transparency), darkness (is there astronomical twilight tonight? when?), and moon (phase, altitude, illumination) into a 0-100 score. I'd like to know if the weighting feels right to experienced observers.
Try it: just allow location or type a city. No account needed.
StarScope is a free web app (no signup required) that gives you:
• "Worth It Tonight?" verdict — fuses GFS weather forecast (cloud/seeing/transparency via Open-Meteo) with astronomical darkness calculations and moon interference into a single go/no-go answer. Clear Outside makes you eyeball three rows; this gives you the decision.
• Tonight's Sky panel — what's actually visible from your coordinates right now, computed with proper suncalc twilight (civil/nautical/astronomical), not just "it's dark". Handles edge cases like no astronomical darkness in summer at high latitudes.
• Real-time feeds — Arxiv, NASA GCN, MPC, NEO, ESA/Hubble, Sky & Telescope, NOAA Space Weather, all filterable by topic. Hemisphere-aware so southern observers aren't buried in Polaris articles.
• ISS passes, comet tracking, APOD — the daily utilities.
Technical bits: React + Express + tRPC, Open-Meteo GFS for weather (same model Clear Outside uses via 7Timer), suncalc for ephemeris, server-side caching so the free APIs aren't hammered. No tracking, no ads. The weather forecast is global — works the same whether you're in Cape Town or Copenhagen.
The "Worth It Tonight?" panel is what I'm most interested in feedback on. The scoring combines weather (cloud%, seeing, transparency), darkness (is there astronomical twilight tonight? when?), and moon (phase, altitude, illumination) into a 0-100 score. I'd like to know if the weighting feels right to experienced observers.
Try it: just allow location or type a city. No account needed.