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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: 03-17 (33), 03-18 (29), 03-19 (23), 03-20 (19), 03-21 (14) — by astronomy; check the weather when the night is within four days.
2048-03-17astronomy score per night — click a bar for that night2048-04-15
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2048-03-17 Tue 33 — unknown 20:05–21:30 (good, 1.42 h) 42.9° 18:15 8.84 11% 55.5°
2048-03-18 Wed 29 — unknown 20:05–21:20 (good, 1.25 h) 42.9° 18:10 8.79 18% 46.2°
2048-03-19 Thu 23 — unknown 20:10–21:10 (good, 1.0 h) 42.9° 18:05 8.74 25% 38.1°
2048-03-20 Fri 19 — unknown 20:10–20:55 (good, 0.75 h) 42.9° 18:05 8.69 34% 32.1°
2048-03-21 Sat 14 — unknown 20:10–21:45 (marginal, 1.58 h) 42.9° 18:00 8.64 43% 29.4°
2048-03-22 Sun 10 — unknown 20:10–21:35 (marginal, 1.42 h) 42.9° 17:55 8.58 52% 30.9°
2048-03-23 Mon 8 — unknown 20:15–21:20 (marginal, 1.08 h) 42.9° 17:50 8.53 62% 36.2°
2048-03-24 Tue 7 — unknown 20:15–21:10 (marginal, 0.92 h) 42.9° 17:50 8.48 71% 44.2°
2048-03-25 Wed 7 — unknown 20:15–21:05 (marginal, 0.83 h) 42.9° 17:45 8.42 80% 53.8°
2048-03-26 Thu 7 — unknown 20:15–21:10 (marginal, 0.92 h) 42.9° 17:40 8.37 88% 64.5°
2048-03-27 Fri 8 — unknown 20:20–21:10 (marginal, 0.83 h) 42.9° 17:35 8.32 94% 76.0°
2048-03-28 Sat 9 — unknown 20:20–21:15 (marginal, 0.92 h) 42.9° 17:30 8.26 98% 88.1°
2048-03-29 Sun 11 — unknown 20:45–22:20 (marginal, 1.58 h) 42.9° 18:30 8.21 100% 100.5°
2048-03-30 Mon 10 — unknown 21:25–21:30 (good, 0.08 h) 42.9° 18:25 8.15 99% 113.0°
2048-03-31 Tue 12 — unknown 21:25–21:40 (good, 0.25 h) 42.9° 18:20 8.1 95% 125.1°
2048-04-01 Wed 10 — unknown 21:25–21:35 (good, 0.17 h) 42.9° 18:15 8.05 89% 136.3°
2048-04-02 Thu 9 — unknown 21:25–21:30 (good, 0.08 h) 42.9° 18:10 7.99 80% 145.4°
2048-04-03 Fri 7 — unknown 21:30–22:00 (marginal, 0.5 h) 42.9° 18:10 7.93 70% 150.4°
2048-04-04 Sat 6 — unknown 21:30–21:55 (marginal, 0.42 h) 42.9° 18:05 7.88 59% 149.4°
2048-04-05 Sun 5 — unknown 21:30–21:50 (marginal, 0.33 h) 42.9° 18:00 7.82 48% 143.2°
2048-04-06 Mon 4 — unknown 21:30–21:45 (marginal, 0.25 h) 42.9° 17:55 7.77 37% 134.1°
2048-04-07 Tue 3 — unknown 21:35–21:45 (marginal, 0.17 h) 42.9° 17:50 7.71 27% 123.7°
2048-04-08 Wed 3 — unknown 21:00–21:10 (marginal, 0.17 h) 42.9° 17:50 7.65 18% 112.7°
2048-04-09 Thu 2 — unknown 21:00–21:05 (marginal, 0.08 h) 42.9° 17:45 7.6 11% 101.5°
2048-04-10 Fri 1 — unknown — 42.9° 17:40 7.54 5% 90.4°
2048-04-11 Sat 1 — unknown — 42.9° 17:35 7.48 2% 79.4°
2048-04-12 Sun 1 — unknown — 42.9° 17:35 7.43 0% 68.7°
2048-04-13 Mon 1 — unknown — 42.9° 17:30 7.37 1% 58.5°
2048-04-14 Tue 0 — unknown — 42.9° 17:25 7.31 3% 48.9°
2048-04-15 Wed 0 — unknown — 42.9° 17:20 7.25 7% 40.3°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2048-03-17&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.