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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 V1057 Cyg: 08-22 (100), 08-23 (100), 08-24 (100), 08-25 (100), 08-26 (100) — by astronomy; check the weather when the night is within four days.
2025-08-22astronomy score per night — click a bar for that night2025-09-20
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2025-08-22 Fri 100 96 96 21:55–05:00 (good, 7.08 h) 87.3° 00:15 7.06 0% 119.6°
2025-08-23 Sat 100 84 84 21:55–05:00 (good, 7.08 h) 87.3° 00:10 7.12 0% 121.7°
2025-08-24 Sun 100 92 92 22:00–05:00 (good, 7.0 h) 87.3° 00:05 7.17 3% 122.0°
2025-08-25 Mon 100 80 80 23:00–05:05 (good, 6.08 h) 87.3° 00:05 7.23 7% 120.6°
2025-08-26 Tue 100 51 51 01:00–05:05 (good, 4.08 h) 87.3° 00:00 7.29 13% 117.8°
2025-08-27 Wed 100 100 100 21:45–05:05 (good, 7.33 h) 87.3° 23:55 7.34 20% 113.7°
2025-08-28 Thu 100 100 100 21:45–05:05 (good, 7.33 h) 87.3° 23:50 7.4 28% 108.8°
2025-08-29 Fri 100 100 100 21:40–05:10 (good, 7.5 h) 87.3° 23:50 7.46 37% 103.2°
2025-08-30 Sat 100 62 62 23:00–04:00 (good, 5.0 h) 87.3° 23:45 7.51 47% 97.2°
2025-08-31 Sun 100 99 99 21:35–05:10 (good, 7.58 h) 87.3° 23:40 7.57 56% 90.9°
2025-09-01 Mon 100 97 97 21:35–05:10 (good, 7.58 h) 87.3° 23:35 7.62 66% 84.4°
2025-09-02 Tue 100 100 100 21:35–05:15 (good, 7.67 h) 87.3° 23:30 7.68 75% 78.1°
2025-09-03 Wed 98 36 36 02:30–03:00 (good, 0.5 h) 87.3° 23:30 7.74 83% 72.0°
2025-09-04 Thu 89 38 34 05:00–05:15 (good, 0.25 h) 87.3° 23:25 7.79 90% 66.5°
2025-09-05 Fri 81 12 9 04:00–05:20 (marginal, 1.33 h) 87.3° 23:20 7.85 96% 62.0°
2025-09-06 Sat 61 89 54 21:00–05:20 (marginal, 8.33 h) 87.3° 23:15 7.9 99% 59.0°
2025-09-07 Sun 61 0 0 — 87.3° 23:10 7.96 100% 57.9°
2025-09-08 Mon 64 50 32 01:00–05:20 (marginal, 4.33 h) 87.3° 23:10 8.01 98% 59.0°
2025-09-09 Tue 69 98 68 21:20–23:15 (good, 1.92 h) 87.3° 23:05 8.06 94% 62.3°
2025-09-10 Wed 76 62 47 22:00–00:00 (good, 2.0 h) 87.3° 23:00 8.12 87% 67.4°
2025-09-11 Thu 100 28 28 02:00–05:00 (marginal, 3.0 h) 87.3° 22:55 8.17 78% 73.8°
2025-09-12 Fri 100 27 27 21:15–22:00 (good, 0.75 h) 87.3° 22:55 8.23 67% 80.9°
2025-09-13 Sat 100 94 94 21:10–04:45 (good, 7.58 h) 87.3° 22:50 8.28 56% 88.4°
2025-09-14 Sun 100 35 35 02:00–04:00 (good, 2.0 h) 87.3° 22:45 8.33 44% 95.8°
2025-09-15 Mon 100 100 100 21:05–04:50 (good, 7.75 h) 87.3° 22:40 8.38 34% 102.8°
2025-09-16 Tue 100 100 100 21:05–04:50 (good, 7.75 h) 87.3° 22:35 8.44 24% 109.2°
2025-09-17 Wed 100 92 92 21:05–04:45 (good, 7.67 h) 87.3° 22:35 8.49 15% 114.6°
2025-09-18 Thu 100 100 100 21:00–04:50 (good, 7.83 h) 87.3° 22:30 8.54 8% 118.7°
2025-09-19 Fri 100 98 98 21:00–04:40 (good, 7.67 h) 87.3° 22:25 8.59 4% 121.3°
2025-09-20 Sat 100 73 73 01:00–04:40 (good, 3.67 h) 87.3° 22:20 8.64 1% 122.1°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2025-08-22&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.