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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: 06-19 (100), 06-20 (100), 06-21 (100), 06-22 (100), 06-23 (100) — by astronomy; check the weather when the night is within four days.
2025-06-11astronomy score per night — click a bar for that night2025-07-10
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2025-06-11 Wed 68 94 64 23:15–03:40 (good, 4.42 h) 87.3° 05:00 4.51 100% 84.3°
2025-06-12 Thu 64 100 64 23:10–03:40 (good, 4.5 h) 87.3° 04:55 4.49 97% 78.0°
2025-06-13 Fri 75 71 54 03:00–03:40 (good, 0.67 h) 87.3° 04:50 4.47 93% 72.0°
2025-06-14 Sat 82 38 31 02:00–02:40 (good, 0.67 h) 87.3° 04:45 4.46 87% 66.7°
2025-06-15 Sun 89 82 73 02:00–03:40 (good, 1.67 h) 87.3° 04:45 4.45 79% 62.4°
2025-06-16 Mon 92 97 90 23:10–03:40 (good, 4.5 h) 87.3° 04:40 4.44 70% 59.4°
2025-06-17 Tue 95 98 93 23:10–03:40 (good, 4.5 h) 87.3° 04:35 4.43 60% 58.2°
2025-06-18 Wed 98 97 95 23:10–03:40 (good, 4.5 h) 87.3° 04:30 4.43 49% 59.0°
2025-06-19 Thu 100 96 96 23:10–03:40 (good, 4.5 h) 87.3° 04:25 4.42 37% 61.8°
2025-06-20 Fri 100 91 91 23:15–03:40 (good, 4.42 h) 87.3° 04:25 4.42 26% 66.4°
2025-06-21 Sat 100 83 83 00:00–03:40 (good, 3.67 h) 87.3° 04:20 4.42 17% 72.5°
2025-06-22 Sun 100 100 100 23:15–03:40 (good, 4.42 h) 87.3° 04:15 4.42 9% 79.6°
2025-06-23 Mon 100 100 100 23:15–03:40 (good, 4.42 h) 87.3° 04:10 4.43 3% 87.2°
2025-06-24 Tue 100 100 100 23:15–03:40 (good, 4.42 h) 87.3° 04:05 4.44 1% 95.0°
2025-06-25 Wed 100 100 100 23:15–03:40 (good, 4.42 h) 87.3° 04:05 4.45 0% 102.4°
2025-06-26 Thu 100 100 100 23:15–03:40 (good, 4.42 h) 87.3° 04:00 4.46 3% 109.0°
2025-06-27 Fri 100 78 78 23:15–03:40 (good, 4.42 h) 87.3° 03:55 4.47 8% 114.6°
2025-06-28 Sat 100 38 38 03:00–03:40 (good, 0.67 h) 87.3° 03:50 4.48 15% 118.7°
2025-06-29 Sun 100 100 100 23:10–03:40 (good, 4.5 h) 87.3° 03:45 4.5 23% 121.2°
2025-06-30 Mon 100 94 94 23:10–03:45 (good, 4.58 h) 87.3° 03:45 4.52 32% 121.9°
2025-07-01 Tue 100 88 88 00:00–03:45 (good, 3.75 h) 87.3° 03:40 4.54 42% 121.0°
2025-07-02 Wed 100 100 100 23:10–03:45 (good, 4.58 h) 87.3° 03:35 4.56 51% 118.5°
2025-07-03 Thu 100 100 100 23:10–03:45 (good, 4.58 h) 87.3° 03:30 4.59 61% 114.9°
2025-07-04 Fri 100 100 100 23:10–03:45 (good, 4.58 h) 87.3° 03:30 4.62 70% 110.3°
2025-07-05 Sat 100 100 100 23:10–03:50 (good, 4.67 h) 87.3° 03:25 4.64 78% 104.9°
2025-07-06 Sun 100 99 99 23:10–03:50 (good, 4.67 h) 87.3° 03:20 4.67 85% 99.0°
2025-07-07 Mon 100 99 99 23:10–03:50 (good, 4.67 h) 87.3° 03:15 4.7 91% 92.7°
2025-07-08 Tue 80 100 80 23:05–03:50 (good, 4.75 h) 87.3° 03:10 4.74 96% 86.2°
2025-07-09 Wed 75 99 74 23:05–03:50 (good, 4.75 h) 87.3° 03:10 4.77 99% 79.8°
2025-07-10 Thu 68 81 55 23:35–01:00 (good, 1.42 h) 87.3° 03:05 4.81 100% 73.6°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2025-06-11&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.