← single night · whole-night plan

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 Great Orion Nebula: 11-14 (89), 11-15 (89), 11-16 (89), 11-17 (89), 11-18 (89) — by astronomy; check the weather when the night is within four days.
2025-11-14astronomy score per night — click a bar for that night2025-12-13
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2025-11-14 Fri 89 100 89 23:05–05:30 (good, 6.42 h) 42.9° 02:20 10.94 24% 90.6°
2025-11-15 Sat 89 44 39 04:00–05:00 (good, 1.0 h) 42.9° 02:15 10.97 16% 100.7°
2025-11-16 Sun 89 16 14 23:00–00:00 (marginal, 1.0 h) 42.9° 02:10 10.99 10% 110.6°
2025-11-17 Mon 89 0 0 — 42.9° 02:10 11.02 5% 120.0°
2025-11-18 Tue 89 0 0 — 42.9° 02:05 11.05 2% 128.8°
2025-11-19 Wed 89 6 6 02:00–03:00 (marginal, 1.0 h) 42.9° 02:00 11.08 0% 136.5°
2025-11-20 Thu 89 5 4 — 42.9° 01:55 11.1 0% 142.5°
2025-11-21 Fri 89 0 0 — 42.9° 01:55 11.13 3% 145.9°
2025-11-22 Sat 89 0 0 — 42.9° 01:50 11.15 6% 145.9°
2025-11-23 Sun 89 100 89 22:30–05:05 (good, 6.58 h) 42.9° 01:45 11.17 12% 142.3°
2025-11-24 Mon 89 56 50 22:25–02:00 (good, 3.58 h) 42.9° 01:40 11.2 18% 136.0°
2025-11-25 Tue 89 0 0 — 42.9° 01:35 11.22 27% 127.8°
2025-11-26 Wed 89 0 0 — 42.9° 01:35 11.24 36% 118.4°
2025-11-27 Thu 89 0 0 — 42.9° 01:30 11.26 46% 108.2°
2025-11-28 Fri 89 0 0 — 42.9° 01:25 11.28 57% 97.3°
2025-11-29 Sat 88 0 0 — 42.9° 01:20 11.3 67% 86.0°
2025-11-30 Sun 85 0 0 — 42.9° 01:15 11.32 78% 74.3°
2025-12-01 Mon 71 56 40 21:50–02:00 (marginal, 4.17 h) 42.9° 01:15 11.34 86% 62.6°
2025-12-02 Tue 37 74 27 02:00–04:50 (marginal, 2.83 h) 42.9° 01:10 11.35 94% 51.5°
2025-12-03 Wed 21 5 1 — 42.9° 01:05 11.37 98% 41.7°
2025-12-04 Thu 12 0 0 — 42.9° 01:00 11.38 100% 35.2°
2025-12-05 Fri 11 0 0 — 42.9° 01:00 11.4 98% 33.8°
2025-12-06 Sat 18 0 0 — 42.9° 00:55 11.41 94% 38.1°
2025-12-07 Sun 32 0 0 — 42.9° 00:50 11.42 88% 46.1°
2025-12-08 Mon 51 0 0 — 42.9° 00:45 11.44 79% 56.0°
2025-12-09 Tue 80 15 12 23:00–01:00 (marginal, 2.0 h) 42.9° 00:40 11.45 70% 66.5°
2025-12-10 Wed 86 32 28 03:00–04:15 (marginal, 1.25 h) 42.9° 00:40 11.46 60% 77.2°
2025-12-11 Thu 88 22 19 20:50–23:00 (marginal, 2.17 h) 42.9° 00:35 11.47 49% 87.8°
2025-12-12 Fri 89 41 36 21:15–23:00 (good, 1.75 h) 42.9° 00:30 11.47 40% 98.1°
2025-12-13 Sat 89 6 6 — 42.9° 00:25 11.48 30% 108.1°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2025-11-14&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.