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Rozhen Observation Calendar

Which nights are best for a target over the coming weeks. The astronomy mark (darkness × altitude × Moon) is computed for every night; the weather and the overall mark exist only where Open-Meteo has a forecast (the next four days) or ERA5 history (past nights) — the rest is honestly blank.

Best nights for Vega: 03-24 (100), 03-25 (100), 03-26 (100), 03-27 (100), 03-28 (100) — by astronomy; check the weather when the night is within four days.
2025-03-24astronomy score per night — click a bar for that night2025-04-22
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2025-03-24 Mon 100 0 0 — 87.1° 06:45 8.5 26% 67.5°
2025-03-25 Tue 100 0 0 — 87.1° 06:45 8.45 17% 69.6°
2025-03-26 Wed 100 2 2 — 87.1° 06:40 8.39 9% 73.1°
2025-03-27 Thu 100 2 2 — 87.1° 06:35 8.34 3% 77.6°
2025-03-28 Fri 100 0 0 — 87.1° 06:30 8.29 0% 83.0°
2025-03-29 Sat 100 0 0 — 87.1° 07:30 8.23 0% 88.9°
2025-03-30 Sun 100 7 7 01:30–02:00 (marginal, 0.5 h) 87.1° 07:25 8.18 3% 94.9°
2025-03-31 Mon 100 0 0 — 87.1° 07:20 8.12 9% 100.5°
2025-04-01 Tue 100 0 0 — 87.1° 07:15 8.07 17% 105.4°
2025-04-02 Wed 100 0 0 — 87.1° 07:10 8.01 27% 109.3°
2025-04-03 Thu 100 0 0 — 87.1° 07:10 7.96 37% 111.9°
2025-04-04 Fri 100 0 0 — 87.1° 07:05 7.9 48% 113.2°
2025-04-05 Sat 100 82 82 04:00–05:20 (good, 1.33 h) 87.1° 07:00 7.85 59% 113.1°
2025-04-06 Sun 100 0 0 — 87.1° 06:55 7.79 69% 111.8°
2025-04-07 Mon 100 13 13 02:00–03:00 (marginal, 1.0 h) 87.1° 06:50 7.74 78% 109.4°
2025-04-08 Tue 86 65 56 03:00–05:15 (good, 2.25 h) 87.1° 06:50 7.68 85% 106.1°
2025-04-09 Wed 81 91 74 02:00–05:15 (good, 3.25 h) 87.1° 06:45 7.62 92% 102.3°
2025-04-10 Thu 74 22 17 05:00–05:10 (good, 0.17 h) 87.1° 06:40 7.57 96% 97.9°
2025-04-11 Fri 69 2 1 — 87.1° 06:35 7.51 99% 93.3°
2025-04-12 Sat 64 10 6 00:15–01:00 (marginal, 0.75 h) 87.1° 06:35 7.45 100% 88.6°
2025-04-13 Sun 60 4 3 — 87.1° 06:30 7.39 99% 84.0°
2025-04-14 Mon 59 9 5 02:20–03:00 (marginal, 0.67 h) 87.1° 06:25 7.34 97% 79.6°
2025-04-15 Tue 60 78 47 00:25–05:00 (marginal, 4.58 h) 87.1° 06:20 7.28 92% 75.6°
2025-04-16 Wed 63 95 60 02:15–05:00 (good, 2.75 h) 87.1° 06:15 7.22 87% 72.1°
2025-04-17 Thu 79 0 0 — 87.1° 06:15 7.16 79% 69.3°
2025-04-18 Fri 88 0 0 — 87.1° 06:10 7.11 71% 67.5°
2025-04-19 Sat 94 62 58 00:15–03:00 (good, 2.75 h) 87.1° 06:05 7.05 62% 66.7°
2025-04-20 Sun 99 83 82 02:55–04:50 (good, 1.92 h) 87.1° 06:00 6.99 52% 67.0°
2025-04-21 Mon 100 60 60 02:00–04:50 (good, 2.83 h) 87.1° 05:55 6.93 41% 68.6°
2025-04-22 Tue 100 54 54 04:00–04:50 (good, 0.83 h) 87.1° 05:55 6.87 30% 71.5°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2025-03-24&days=30"
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&days=30&format=csv" -o m31-calendar.csv

One row per night: score_astronomy always, score_weather / score only where a forecast or history exists (null otherwise, with weather_source saying which), best window, dark hours, Moon illumination and separation, transit. 7–60 nights. Errors: 400 with invalid_date or target_unresolved. Results are cached for six hours; calculation version 2026-10-10.1.