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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 Andromeda Galaxy: 07-06 (74), 07-05 (73), 07-04 (70), 07-03 (68), 07-02 (66) — by astronomy; check the weather when the night is within four days.
2025-06-07astronomy score per night — click a bar for that night2025-07-06
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2025-06-07 Sat 25 100 25 03:00–03:40 (good, 0.67 h) 89.5° 09:00 4.6 90% 148.2°
2025-06-08 Sun 24 100 24 03:00–03:40 (good, 0.67 h) 89.6° 08:55 4.57 95% 143.4°
2025-06-09 Mon 24 97 23 02:55–03:40 (good, 0.75 h) 89.7° 08:50 4.55 98% 136.1°
2025-06-10 Tue 25 39 10 03:10–03:40 (marginal, 0.5 h) 89.7° 08:45 4.53 100% 127.2°
2025-06-11 Wed 25 90 23 03:05–03:40 (good, 0.58 h) 89.5° 08:40 4.51 100% 117.4°
2025-06-12 Thu 23 100 23 02:55–03:40 (good, 0.75 h) 89.5° 08:40 4.49 97% 107.0°
2025-06-13 Fri 22 93 20 03:00–03:40 (good, 0.67 h) 89.7° 08:35 4.47 93% 96.2°
2025-06-14 Sat 20 74 15 02:00–03:40 (marginal, 1.67 h) 89.7° 08:30 4.46 87% 85.2°
2025-06-15 Sun 20 94 19 02:00–03:40 (marginal, 1.67 h) 89.6° 08:25 4.45 79% 74.0°
2025-06-16 Mon 20 100 20 03:15–03:40 (good, 0.42 h) 89.5° 08:20 4.44 70% 62.9°
2025-06-17 Tue 22 100 22 02:45–03:40 (good, 0.92 h) 89.6° 08:20 4.43 60% 52.1°
2025-06-18 Wed 24 100 24 02:35–03:40 (good, 1.08 h) 89.7° 08:15 4.43 49% 42.1°
2025-06-19 Thu 29 100 29 02:25–03:40 (good, 1.25 h) 89.7° 08:10 4.42 37% 34.2°
2025-06-20 Fri 35 90 32 02:25–03:40 (good, 1.25 h) 89.6° 08:05 4.42 26% 30.4°
2025-06-21 Sat 41 98 40 02:00–03:40 (good, 1.67 h) 89.5° 08:05 4.42 17% 32.5°
2025-06-22 Sun 47 100 47 01:55–03:40 (good, 1.75 h) 89.6° 08:00 4.42 9% 39.7°
2025-06-23 Mon 49 100 49 01:50–03:40 (good, 1.83 h) 89.7° 07:55 4.43 3% 49.9°
2025-06-24 Tue 50 100 50 01:45–03:40 (good, 1.92 h) 89.7° 07:50 4.44 1% 61.5°
2025-06-25 Wed 53 100 53 01:45–03:40 (good, 1.92 h) 89.5° 07:45 4.45 0% 73.6°
2025-06-26 Thu 55 100 55 01:40–03:40 (good, 2.0 h) 89.5° 07:45 4.46 3% 85.8°
2025-06-27 Fri 56 68 38 01:40–03:00 (good, 1.33 h) 89.7° 07:40 4.47 8% 97.7°
2025-06-28 Sat 58 45 26 03:00–03:40 (good, 0.67 h) 89.7° 07:35 4.48 15% 109.2°
2025-06-29 Sun 60 100 60 01:30–03:40 (good, 2.17 h) 89.6° 07:30 4.5 23% 120.0°
2025-06-30 Mon 63 92 58 01:25–03:45 (good, 2.33 h) 89.5° 07:25 4.52 32% 129.9°
2025-07-01 Tue 65 98 64 01:25–03:45 (good, 2.33 h) 89.6° 07:25 4.54 42% 138.6°
2025-07-02 Wed 66 100 66 01:15–03:45 (good, 2.5 h) 89.7° 07:20 4.56 51% 145.4°
2025-07-03 Thu 68 100 68 01:10–03:45 (good, 2.58 h) 89.7° 07:15 4.59 61% 149.3°
2025-07-04 Fri 70 100 70 01:15–03:45 (good, 2.5 h) 89.6° 07:10 4.62 70% 149.2°
2025-07-05 Sat 73 100 73 01:10–03:50 (good, 2.67 h) 89.5° 07:10 4.64 78% 145.3°
2025-07-06 Sun 74 100 74 01:10–03:50 (good, 2.67 h) 89.6° 07:05 4.67 85% 138.5°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2025-06-07&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.