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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: 01-22 (32), 01-21 (31), 01-20 (30), 01-19 (29), 01-18 (27) — by astronomy; check the weather when the night is within four days.
2025-12-24astronomy score per night — click a bar for that night2026-01-22
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2025-12-24 Wed 10 0 0 — 87.1° 12:45 11.5 21% 70.9°
2025-12-25 Thu 9 7 1 — 87.1° 12:40 11.5 30% 74.7°
2025-12-26 Fri 8 54 4 18:40–19:00 (marginal, 0.33 h) 87.1° 12:40 11.5 41% 79.3°
2025-12-27 Sat 7 100 7 18:40–19:05 (marginal, 0.42 h) 87.1° 12:35 11.49 51% 84.5°
2025-12-28 Sun 7 48 3 06:30–06:45 (marginal, 0.25 h) 87.1° 12:30 11.48 62% 90.2°
2025-12-29 Mon 7 100 7 05:55–06:10 (marginal, 0.25 h) 87.1° 12:25 11.48 73% 96.0°
2025-12-30 Tue 8 97 8 05:50–06:10 (marginal, 0.33 h) 87.1° 12:20 11.47 83% 101.6°
2025-12-31 Wed 8 57 5 18:45–18:50 (marginal, 0.08 h) 87.1° 12:20 11.46 91% 106.6°
2026-01-01 Thu 7 77 5 06:05–06:10 (marginal, 0.08 h) 87.1° 12:15 11.45 97% 110.6°
2026-01-02 Fri 8 22 2 — 87.1° 12:10 11.44 100% 113.3°
2026-01-03 Sat 8 35 3 06:00–06:10 (marginal, 0.17 h) 87.1° 12:05 11.43 100% 114.3°
2026-01-04 Sun 8 0 0 — 87.1° 12:00 11.42 97% 113.5°
2026-01-05 Mon 9 0 0 — 87.1° 11:55 11.4 92% 111.3°
2026-01-06 Tue 9 22 2 — 87.1° 11:50 11.39 84% 108.0°
2026-01-07 Wed 10 0 0 — 87.1° 11:45 11.37 76% 103.7°
2026-01-08 Thu 11 89 10 05:15–06:10 (marginal, 0.92 h) 87.1° 11:45 11.36 67% 99.0°
2026-01-09 Fri 12 5 1 — 87.1° 11:40 11.34 57% 94.1°
2026-01-10 Sat 14 0 0 — 87.1° 11:35 11.32 47% 89.1°
2026-01-11 Sun 16 0 0 — 87.1° 11:30 11.31 38% 84.3°
2026-01-12 Mon 18 99 18 05:40–06:10 (good, 0.5 h) 87.1° 11:25 11.29 29% 79.7°
2026-01-13 Tue 20 13 3 — 87.1° 11:25 11.27 21% 75.4°
2026-01-14 Wed 21 100 21 05:25–06:10 (good, 0.75 h) 87.1° 11:20 11.25 14% 71.8°
2026-01-15 Thu 24 72 17 06:00–06:10 (good, 0.17 h) 87.1° 11:15 11.23 8% 68.8°
2026-01-16 Fri 25 0 0 — 87.1° 11:10 11.2 4% 66.8°
2026-01-17 Sat 26 0 0 — 87.1° 11:10 11.18 1% 65.8°
2026-01-18 Sun 27 0 0 — 87.1° 11:05 11.16 0% 66.0°
2026-01-19 Mon 29 100 29 05:05–06:10 (good, 1.08 h) 87.1° 11:00 11.13 1% 67.4°
2026-01-20 Tue 30 0 0 — 87.1° 10:55 11.11 5% 70.0°
2026-01-21 Wed 31 0 0 — 87.1° 10:50 11.08 10% 73.6°
2026-01-22 Thu 32 0 0 — 87.1° 10:50 11.06 17% 78.1°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2025-12-24&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.