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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 Andromeda Galaxy: 10-16 (100), 10-17 (100), 10-18 (100), 10-19 (100), 10-20 (100) — by astronomy; check the weather when the night is within four days.
2025-10-16astronomy score per night — click a bar for that night2025-11-14
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2025-10-16 Thu 100 0 0 — 89.5° 00:25 9.87 19% 117.2°
2025-10-17 Fri 100 0 0 — 89.6° 00:20 9.92 12% 127.3°
2025-10-18 Sat 100 1 1 — 89.7° 00:15 9.96 6% 136.4°
2025-10-19 Sun 100 0 0 — 89.7° 00:10 10.0 2% 144.0°
2025-10-20 Mon 100 18 18 20:05–21:00 (good, 0.92 h) 89.5° 00:05 10.04 0% 148.9°
2025-10-21 Tue 100 10 10 23:00–00:00 (marginal, 1.0 h) 89.5° 00:05 10.08 0% 149.9°
2025-10-22 Wed 100 30 30 20:05–00:00 (good, 3.92 h) 89.7° 00:00 10.13 2% 146.8°
2025-10-23 Thu 100 17 17 20:05–22:00 (good, 1.92 h) 89.7° 23:55 10.17 5% 140.7°
2025-10-24 Fri 100 69 69 01:00–06:00 (good, 5.0 h) 89.6° 23:50 10.21 10% 132.6°
2025-10-25 Sat 100 47 47 20:00–22:00 (good, 2.0 h) 89.5° 23:45 10.25 17% 123.5°
2025-10-26 Sun 100 5 5 04:00–04:30 (marginal, 0.5 h) 89.6° 22:45 10.29 24% 113.7°
2025-10-27 Mon 100 65 65 19:00–01:00 (good, 6.0 h) 89.7° 22:40 10.32 33% 103.5°
2025-10-28 Tue 100 99 99 18:55–04:45 (good, 9.83 h) 89.7° 22:35 10.36 42% 92.9°
2025-10-29 Wed 100 100 100 18:55–04:40 (good, 9.75 h) 89.6° 22:30 10.4 52% 82.0°
2025-10-30 Thu 100 52 52 21:00–02:00 (good, 5.0 h) 89.5° 22:30 10.44 63% 70.9°
2025-10-31 Fri 96 38 37 00:00–02:30 (good, 2.5 h) 89.6° 22:25 10.47 73% 59.8°
2025-11-01 Sat 87 97 84 00:00–04:30 (good, 4.5 h) 89.7° 22:20 10.51 82% 48.9°
2025-11-02 Sun 71 85 60 04:05–04:20 (good, 0.25 h) 89.7° 22:15 10.55 90% 39.0°
2025-11-03 Mon 38 4 1 — 89.6° 22:10 10.58 96% 31.9°
2025-11-04 Tue 31 0 0 — 89.5° 22:10 10.62 99% 30.1°
2025-11-05 Wed 37 0 0 — 89.7° 22:05 10.65 100% 34.9°
2025-11-06 Thu 56 0 0 — 89.7° 22:00 10.69 97% 44.2°
2025-11-07 Fri 68 0 0 — 89.6° 21:55 10.72 92% 55.5°
2025-11-08 Sat 100 0 0 — 89.5° 21:50 10.75 84% 67.7°
2025-11-09 Sun 100 3 3 — 89.6° 21:50 10.78 74% 80.0°
2025-11-10 Mon 100 0 0 — 89.7° 21:45 10.82 64% 92.0°
2025-11-11 Tue 100 95 95 18:40–03:35 (good, 8.92 h) 89.7° 21:40 10.85 53% 103.7°
2025-11-12 Wed 100 78 78 20:00–03:40 (good, 7.67 h) 89.6° 21:35 10.88 43% 114.7°
2025-11-13 Thu 100 99 99 18:40–03:35 (good, 8.92 h) 89.5° 21:35 10.91 33% 125.1°
2025-11-14 Fri 100 100 100 18:40–03:35 (good, 8.92 h) 89.6° 21:30 10.94 24% 134.5°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2025-10-16&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.