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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 HD 189733: 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.
2025-06-08astronomy score per night — click a bar for that night2025-07-07
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2025-06-08 Sun 72 100 72 00:15–03:40 (good, 3.42 h) 71.1° 04:10 4.57 95% 83.3°
2025-06-09 Mon 62 94 58 01:10–03:40 (good, 2.5 h) 71.1° 04:10 4.55 98% 75.1°
2025-06-10 Tue 54 55 30 00:00–03:00 (marginal, 3.0 h) 71.1° 04:05 4.53 100% 67.2°
2025-06-11 Wed 48 94 45 23:10–03:40 (marginal, 4.5 h) 71.1° 04:00 4.51 100% 59.8°
2025-06-12 Thu 44 100 44 23:10–03:40 (marginal, 4.5 h) 71.1° 03:55 4.49 97% 53.4°
2025-06-13 Fri 62 71 44 00:00–03:40 (marginal, 3.67 h) 71.1° 03:55 4.47 93% 48.6°
2025-06-14 Sat 72 36 26 02:00–03:40 (marginal, 1.67 h) 71.1° 03:50 4.46 87% 45.9°
2025-06-15 Sun 83 81 67 00:00–00:25 (good, 0.42 h) 71.1° 03:45 4.45 79% 45.9°
2025-06-16 Mon 93 97 91 23:10–03:40 (good, 4.5 h) 71.1° 03:40 4.44 70% 48.8°
2025-06-17 Tue 96 99 95 23:10–03:40 (good, 4.5 h) 71.1° 03:35 4.43 60% 54.2°
2025-06-18 Wed 99 97 96 23:10–03:40 (good, 4.5 h) 71.1° 03:35 4.43 49% 61.6°
2025-06-19 Thu 100 97 97 23:10–03:40 (good, 4.5 h) 71.1° 03:30 4.42 37% 70.3°
2025-06-20 Fri 100 91 91 23:15–03:40 (good, 4.42 h) 71.1° 03:25 4.42 26% 80.0°
2025-06-21 Sat 100 83 83 00:00–03:40 (good, 3.67 h) 71.1° 03:20 4.42 17% 90.1°
2025-06-22 Sun 100 100 100 23:15–03:40 (good, 4.42 h) 71.1° 03:15 4.42 9% 100.4°
2025-06-23 Mon 100 100 100 23:15–03:40 (good, 4.42 h) 71.1° 03:15 4.43 3% 110.3°
2025-06-24 Tue 100 100 100 23:15–03:40 (good, 4.42 h) 71.1° 03:10 4.44 1% 119.4°
2025-06-25 Wed 100 100 100 23:15–03:40 (good, 4.42 h) 71.1° 03:05 4.45 0% 126.9°
2025-06-26 Thu 100 100 100 23:15–03:40 (good, 4.42 h) 71.1° 03:00 4.46 3% 132.1°
2025-06-27 Fri 100 78 78 23:15–03:40 (good, 4.42 h) 71.1° 03:00 4.47 8% 134.5°
2025-06-28 Sat 100 38 38 03:00–03:40 (good, 0.67 h) 71.1° 02:55 4.48 15% 133.7°
2025-06-29 Sun 100 100 100 23:10–03:40 (good, 4.5 h) 71.1° 02:50 4.5 23% 130.1°
2025-06-30 Mon 100 94 94 23:10–03:45 (good, 4.58 h) 71.1° 02:45 4.52 32% 124.7°
2025-07-01 Tue 100 88 88 00:00–03:45 (good, 3.75 h) 71.1° 02:40 4.54 42% 117.9°
2025-07-02 Wed 100 100 100 23:10–03:45 (good, 4.58 h) 71.1° 02:40 4.56 51% 110.4°
2025-07-03 Thu 100 100 100 23:10–03:45 (good, 4.58 h) 71.1° 02:35 4.59 61% 102.4°
2025-07-04 Fri 100 100 100 23:10–03:45 (good, 4.58 h) 71.1° 02:30 4.62 70% 94.2°
2025-07-05 Sat 100 100 100 23:10–03:50 (good, 4.67 h) 71.1° 02:25 4.64 78% 85.9°
2025-07-06 Sun 100 99 99 23:10–03:50 (good, 4.67 h) 71.1° 02:20 4.67 85% 77.6°
2025-07-07 Mon 100 99 99 23:15–03:50 (good, 4.58 h) 71.1° 02:20 4.7 91% 69.6°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2025-06-08&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.