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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: 07-22 (100), 07-23 (100), 07-24 (100), 07-25 (100), 07-26 (100) — by astronomy; check the weather when the night is within four days.
2025-07-05astronomy score per night — click a bar for that night2025-08-03
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
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°
2025-07-07 Mon 74 99 74 01:05–03:50 (good, 2.75 h) 89.7° 07:00 4.7 91% 130.0°
2025-07-08 Tue 68 100 68 01:05–03:50 (good, 2.75 h) 89.7° 06:55 4.74 96% 120.3°
2025-07-09 Wed 61 100 61 01:05–03:50 (good, 2.75 h) 89.5° 06:50 4.77 99% 110.0°
2025-07-10 Thu 56 80 45 03:00–03:55 (good, 0.92 h) 89.5° 06:50 4.81 100% 99.1°
2025-07-11 Fri 48 60 29 02:00–03:55 (marginal, 1.92 h) 89.7° 06:45 4.85 99% 88.0°
2025-07-12 Sat 41 89 37 02:50–03:55 (good, 1.08 h) 89.7° 06:40 4.88 95% 76.6°
2025-07-13 Sun 36 48 17 03:00–03:55 (marginal, 0.92 h) 89.6° 06:35 4.92 90% 65.3°
2025-07-14 Mon 35 100 35 00:00–04:00 (marginal, 4.0 h) 89.5° 06:30 4.97 82% 54.3°
2025-07-15 Tue 36 92 33 00:00–04:00 (marginal, 4.0 h) 89.6° 06:30 5.01 73% 44.0°
2025-07-16 Wed 41 90 37 23:50–04:00 (marginal, 4.17 h) 89.7° 06:25 5.05 62% 35.6°
2025-07-17 Thu 51 64 32 02:35–03:00 (good, 0.42 h) 89.7° 06:20 5.1 51% 30.6°
2025-07-18 Fri 70 92 64 00:20–04:00 (good, 3.67 h) 89.6° 06:15 5.14 40% 31.1°
2025-07-19 Sat 82 100 82 00:10–04:05 (good, 3.92 h) 89.5° 06:15 5.19 29% 37.0°
2025-07-20 Sun 92 100 92 00:05–04:05 (good, 4.0 h) 89.6° 06:10 5.24 19% 46.3°
2025-07-21 Mon 97 100 97 00:00–04:10 (good, 4.17 h) 89.7° 06:05 5.28 11% 57.3°
2025-07-22 Tue 100 100 100 23:55–04:10 (good, 4.25 h) 89.7° 06:00 5.33 5% 69.1°
2025-07-23 Wed 100 97 97 00:00–04:10 (good, 4.17 h) 89.6° 05:55 5.38 1% 81.1°
2025-07-24 Thu 100 100 100 23:50–04:15 (good, 4.42 h) 89.5° 05:55 5.43 0% 93.1°
2025-07-25 Fri 100 100 100 23:45–04:15 (good, 4.5 h) 89.7° 05:50 5.48 2% 104.8°
2025-07-26 Sat 100 100 100 23:40–04:15 (good, 4.58 h) 89.7° 05:45 5.54 5% 116.0°
2025-07-27 Sun 100 96 96 23:40–04:20 (good, 4.67 h) 89.6° 05:40 5.59 11% 126.5°
2025-07-28 Mon 100 99 99 23:35–04:20 (good, 4.75 h) 89.5° 05:35 5.64 18% 135.9°
2025-07-29 Tue 100 95 95 00:00–04:20 (good, 4.33 h) 89.6° 05:35 5.7 26% 143.6°
2025-07-30 Wed 100 0 0 — 89.7° 05:30 5.75 35% 148.6°
2025-07-31 Thu 100 10 10 04:00–04:25 (good, 0.42 h) 89.7° 05:25 5.81 44% 149.9°
2025-08-01 Fri 100 86 86 23:35–04:25 (good, 4.83 h) 89.6° 05:20 5.86 54% 147.1°
2025-08-02 Sat 100 100 100 23:20–04:25 (good, 5.08 h) 89.5° 05:15 5.92 63% 141.1°
2025-08-03 Sun 100 99 99 23:20–04:30 (good, 5.17 h) 89.6° 05:15 5.97 72% 133.0°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2025-07-05&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.