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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 Seven Sisters: 03-19 (37), 03-20 (34), 03-21 (32), 03-22 (31), 03-23 (29) — by astronomy; check the weather when the night is within four days.
2039-03-19astronomy score per night — click a bar for that night2039-04-17
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2039-03-19 Sat 37 — unknown 20:05–21:35 (good, 1.5 h) 72.5° 16:20 8.78 24% 118.7°
2039-03-20 Sun 34 — unknown 20:10–21:30 (good, 1.33 h) 72.5° 16:20 8.73 15% 105.4°
2039-03-21 Mon 32 — unknown 20:10–21:25 (good, 1.25 h) 72.5° 16:15 8.68 8% 92.3°
2039-03-22 Tue 31 — unknown 20:10–21:20 (good, 1.17 h) 72.5° 16:10 8.63 4% 79.4°
2039-03-23 Wed 29 — unknown 20:10–21:15 (good, 1.08 h) 72.5° 16:05 8.57 1% 66.7°
2039-03-24 Thu 27 — unknown 20:15–21:15 (good, 1.0 h) 72.5° 16:00 8.52 0% 54.2°
2039-03-25 Fri 25 — unknown 20:15–21:10 (good, 0.92 h) 72.5° 16:00 8.47 2% 41.9°
2039-03-26 Sat 24 — unknown 20:15–21:05 (good, 0.83 h) 72.5° 15:55 8.42 5% 30.0°
2039-03-27 Sun 20 — unknown 21:20–22:00 (good, 0.67 h) 72.5° 16:50 8.36 10% 18.4°
2039-03-28 Mon 17 — unknown 21:20–21:50 (good, 0.5 h) 72.5° 16:45 8.31 16% 8.3°
2039-03-29 Tue 14 — unknown 21:20–21:40 (good, 0.33 h) 72.5° 16:40 8.25 23% 9.0°
2039-03-30 Wed 11 — unknown 21:20–21:30 (good, 0.17 h) 72.5° 16:40 8.2 32% 19.3°
2039-03-31 Thu 7 — unknown 21:25–22:10 (marginal, 0.75 h) 72.5° 16:35 8.15 41% 30.7°
2039-04-01 Fri 6 — unknown 21:25–22:05 (marginal, 0.67 h) 72.5° 16:30 8.09 50% 42.5°
2039-04-02 Sat 5 — unknown 21:25–21:55 (marginal, 0.5 h) 72.5° 16:25 8.04 60% 54.7°
2039-04-03 Sun 4 — unknown 21:25–21:50 (marginal, 0.42 h) 72.5° 16:25 7.98 70% 67.2°
2039-04-04 Mon 3 — unknown 21:30–21:50 (marginal, 0.33 h) 72.5° 16:20 7.93 79% 80.0°
2039-04-05 Tue 3 — unknown 21:30–21:50 (marginal, 0.33 h) 72.5° 16:15 7.87 87% 93.4°
2039-04-06 Wed 4 — unknown 21:30–21:50 (marginal, 0.33 h) 72.5° 16:10 7.81 93% 107.1°
2039-04-07 Thu 3 — unknown 21:35–21:45 (marginal, 0.17 h) 72.5° 16:05 7.76 98% 121.3°
2039-04-08 Fri 2 — unknown 21:35–21:40 (marginal, 0.08 h) 72.5° 16:05 7.7 100% 135.8°
2039-04-09 Sat 2 — unknown 21:35–21:40 (marginal, 0.08 h) 72.5° 16:00 7.64 99% 150.4°
2039-04-10 Sun 2 — unknown 21:00–21:05 (marginal, 0.08 h) 72.5° 15:55 7.59 95% 164.6°
2039-04-11 Mon 1 — unknown — 72.5° 15:50 7.53 89% 173.8°
2039-04-12 Tue 1 — unknown — 72.5° 15:45 7.47 80% 163.3°
2039-04-13 Wed 1 — unknown — 72.5° 15:45 7.42 70% 149.4°
2039-04-14 Thu 1 — unknown — 72.5° 15:40 7.36 59% 135.5°
2039-04-15 Fri 0 — unknown — 72.5° 15:35 7.3 48% 121.8°
2039-04-16 Sat 0 — unknown — 72.5° 15:30 7.24 37% 108.5°
2039-04-17 Sun 0 — unknown — 72.5° 15:30 7.19 27% 95.4°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2039-03-19&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.