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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 North America Nebula: 11-23 (100), 12-09 (100), 12-10 (100), 11-24 (99), 12-08 (99) — by astronomy; check the weather when the night is within four days.
2025-11-23astronomy score per night — click a bar for that night2025-12-22
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2025-11-23 Sun 100 98 98 18:35–23:30 (good, 4.92 h) 87.3° 17:10 11.17 12% 77.3°
2025-11-24 Mon 99 98 97 18:35–23:25 (good, 4.83 h) 87.3° 17:05 11.2 18% 71.5°
2025-11-25 Tue 91 0 0 — 87.2° 17:00 11.22 27% 66.3°
2025-11-26 Wed 86 7 6 — 87.2° 17:00 11.24 36% 62.0°
2025-11-27 Thu 79 0 0 — 87.3° 16:55 11.26 46% 59.0°
2025-11-28 Fri 64 0 0 — 87.3° 16:50 11.28 57% 57.6°
2025-11-29 Sat 51 0 0 — 87.3° 16:45 11.3 67% 58.2°
2025-11-30 Sun 43 0 0 — 87.2° 16:40 11.32 78% 60.9°
2025-12-01 Mon 39 94 37 18:35–23:10 (marginal, 4.58 h) 87.2° 16:40 11.34 86% 65.6°
2025-12-02 Tue 39 9 4 — 87.3° 16:35 11.35 94% 71.9°
2025-12-03 Wed 44 13 6 18:35–19:00 (marginal, 0.42 h) 87.3° 16:30 11.37 98% 79.3°
2025-12-04 Thu 53 0 0 — 87.3° 16:25 11.38 100% 87.3°
2025-12-05 Fri 64 0 0 — 87.2° 16:20 11.4 98% 95.5°
2025-12-06 Sat 76 0 0 — 87.2° 16:20 11.41 94% 103.2°
2025-12-07 Sun 96 5 5 — 87.3° 16:15 11.42 88% 110.1°
2025-12-08 Mon 99 31 31 18:35–20:00 (good, 1.42 h) 87.3° 16:10 11.44 79% 115.7°
2025-12-09 Tue 100 0 0 — 87.2° 16:05 11.45 70% 119.8°
2025-12-10 Wed 100 3 3 — 87.2° 16:05 11.46 60% 122.1°
2025-12-11 Thu 98 86 84 18:35–21:40 (good, 3.08 h) 87.2° 16:00 11.47 49% 122.5°
2025-12-12 Fri 97 97 94 18:35–22:00 (good, 3.42 h) 87.3° 15:55 11.47 40% 121.2°
2025-12-13 Sat 95 34 33 18:35–19:00 (good, 0.42 h) 87.3° 15:50 11.48 30% 118.3°
2025-12-14 Sun 93 96 89 18:35–22:00 (good, 3.42 h) 87.2° 15:45 11.49 22% 114.3°
2025-12-15 Mon 91 100 91 18:35–22:05 (good, 3.5 h) 87.2° 15:45 11.49 15% 109.4°
2025-12-16 Tue 89 100 89 18:35–22:00 (good, 3.42 h) 87.3° 15:40 11.5 9% 103.8°
2025-12-17 Wed 87 98 85 18:35–21:55 (good, 3.33 h) 87.3° 15:35 11.5 4% 97.7°
2025-12-18 Thu 85 0 0 — 87.3° 15:30 11.5 1% 91.4°
2025-12-19 Fri 82 94 77 18:35–21:40 (good, 3.08 h) 87.2° 15:25 11.51 0% 85.0°
2025-12-20 Sat 81 21 17 18:35–19:00 (good, 0.42 h) 87.2° 15:25 11.51 1% 78.7°
2025-12-21 Sun 78 1 1 — 87.3° 15:20 11.51 3% 72.6°
2025-12-22 Mon 74 37 28 18:35–20:00 (good, 1.42 h) 87.3° 15:15 11.51 8% 67.2°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2025-11-23&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.