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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 Great Orion Nebula: 03-25 (24), 03-26 (22), 03-27 (20), 03-28 (18), 03-29 (17) — by astronomy; check the weather when the night is within four days.
2033-03-25astronomy score per night — click a bar for that night2033-04-23
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2033-03-25 Fri 24 — unknown 20:15–21:05 (good, 0.83 h) 42.9° 17:45 8.44 30% 138.6°
2033-03-26 Sat 22 — unknown 20:15–21:00 (good, 0.75 h) 42.9° 17:40 8.39 20% 126.8°
2033-03-27 Sun 20 — unknown 21:20–21:55 (good, 0.58 h) 42.9° 18:35 8.34 12% 113.9°
2033-03-28 Mon 18 — unknown 21:20–21:50 (good, 0.5 h) 42.9° 18:30 8.28 5% 100.4°
2033-03-29 Tue 17 — unknown 21:20–21:50 (good, 0.5 h) 42.9° 18:30 8.23 1% 86.6°
2033-03-30 Wed 15 — unknown 21:20–21:45 (good, 0.42 h) 42.9° 18:25 8.18 0% 72.7°
2033-03-31 Thu 12 — unknown 21:25–21:40 (good, 0.25 h) 42.9° 18:20 8.12 2% 59.2°
2033-04-01 Fri 10 — unknown 21:25–21:35 (good, 0.17 h) 42.9° 18:15 8.07 7% 46.4°
2033-04-02 Sat 8 — unknown 20:50–22:05 (marginal, 1.25 h) 42.9° 18:15 8.01 14% 35.2°
2033-04-03 Sun 6 — unknown 21:30–22:00 (marginal, 0.5 h) 42.9° 18:10 7.96 23% 26.9°
2033-04-04 Mon 4 — unknown 21:30–21:55 (marginal, 0.42 h) 42.9° 18:05 7.9 33% 24.0°
2033-04-05 Tue 3 — unknown 21:30–21:50 (marginal, 0.33 h) 42.9° 18:00 7.84 43% 27.6°
2033-04-06 Wed 2 — unknown 21:30–21:35 (marginal, 0.08 h) 42.9° 17:55 7.79 53% 35.3°
2033-04-07 Thu 1 — unknown — 42.9° 17:55 7.73 63% 44.8°
2033-04-08 Fri 1 — unknown — 42.9° 17:50 7.68 72% 55.0°
2033-04-09 Sat 1 — unknown — 42.9° 17:45 7.62 80% 65.6°
2033-04-10 Sun 1 — unknown — 42.9° 17:40 7.56 87% 76.3°
2033-04-11 Mon 1 — unknown — 42.9° 17:35 7.51 93% 87.1°
2033-04-12 Tue 0 — unknown — 42.9° 17:35 7.45 97% 97.9°
2033-04-13 Wed 0 — unknown — 42.9° 17:30 7.39 99% 108.7°
2033-04-14 Thu 0 — unknown — 42.9° 17:25 7.33 100% 119.4°
2033-04-15 Fri 0 — unknown — 42.9° 17:20 7.28 99% 129.9°
2033-04-16 Sat 0 — unknown — 42.9° 17:20 7.22 96% 139.9°
2033-04-17 Sun 0 — unknown — 42.9° 17:15 7.16 91% 148.6°
2033-04-18 Mon 0 — unknown — 42.9° 17:10 7.1 84% 154.7°
2033-04-19 Tue 0 — unknown — 42.9° 17:05 7.04 76% 155.6°
2033-04-20 Wed 0 — unknown — 42.9° 17:00 6.99 67% 150.6°
2033-04-21 Thu 0 — unknown — 42.9° 17:00 6.93 56% 141.7°
2033-04-22 Fri 0 — unknown — 42.9° 16:55 6.87 45% 130.7°
2033-04-23 Sat 0 — unknown — 42.9° 16:50 6.81 34% 118.6°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2033-03-25&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.