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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 Vega: 10-17 (100), 10-18 (100), 10-19 (100), 10-20 (100), 10-21 (100) — by astronomy; check the weather when the night is within four days.
2025-10-17astronomy score per night — click a bar for that night2025-11-15
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2025-10-17 Fri 100 0 0 — 87.1° 18:15 9.92 12% 103.7°
2025-10-18 Sat 100 0 0 — 87.1° 18:10 9.96 6% 99.3°
2025-10-19 Sun 100 0 0 — 87.1° 18:05 10.0 2% 94.6°
2025-10-20 Mon 100 44 44 20:05–21:00 (good, 0.92 h) 87.1° 18:00 10.04 0% 89.7°
2025-10-21 Tue 100 23 23 23:00–00:00 (marginal, 1.0 h) 87.1° 18:00 10.08 0% 84.9°
2025-10-22 Wed 100 67 67 20:05–22:00 (good, 1.92 h) 87.1° 17:55 10.13 2% 80.3°
2025-10-23 Thu 98 44 43 20:05–21:00 (good, 0.92 h) 87.1° 17:50 10.17 5% 76.1°
2025-10-24 Fri 97 59 57 20:00–21:00 (good, 1.0 h) 87.1° 17:45 10.21 10% 72.5°
2025-10-25 Sat 96 64 61 20:00–22:00 (good, 2.0 h) 87.1° 17:40 10.25 17% 69.5°
2025-10-26 Sun 87 0 0 — 87.1° 16:40 10.29 24% 67.4°
2025-10-27 Mon 78 92 72 19:00–22:35 (good, 3.58 h) 87.1° 16:35 10.32 33% 66.3°
2025-10-28 Tue 69 98 68 18:55–22:30 (good, 3.58 h) 87.1° 16:30 10.36 42% 66.3°
2025-10-29 Wed 60 100 60 18:55–22:05 (good, 3.17 h) 87.1° 16:25 10.4 52% 67.5°
2025-10-30 Thu 53 48 26 21:00–21:10 (good, 0.17 h) 87.1° 16:20 10.44 63% 69.8°
2025-10-31 Fri 47 0 0 — 87.1° 16:20 10.47 73% 73.4°
2025-11-01 Sat 43 92 40 20:00–20:35 (good, 0.58 h) 87.1° 16:15 10.51 82% 77.9°
2025-11-02 Sun 41 76 31 18:50–20:00 (good, 1.17 h) 87.1° 16:10 10.55 90% 83.3°
2025-11-03 Mon 43 11 5 18:50–19:00 (marginal, 0.17 h) 87.1° 16:05 10.58 96% 89.2°
2025-11-04 Tue 46 0 0 — 87.1° 16:05 10.62 99% 95.3°
2025-11-05 Wed 51 0 0 — 87.1° 16:00 10.65 100% 101.1°
2025-11-06 Thu 57 0 0 — 87.1° 15:55 10.69 97% 106.2°
2025-11-07 Fri 61 0 0 — 87.1° 15:50 10.72 92% 110.3°
2025-11-08 Sat 73 0 0 — 87.1° 15:45 10.75 84% 112.9°
2025-11-09 Sun 74 7 6 — 87.1° 15:45 10.78 74% 113.9°
2025-11-10 Mon 74 0 0 — 87.1° 15:40 10.82 64% 113.4°
2025-11-11 Tue 74 88 65 18:40–21:30 (good, 2.83 h) 87.1° 15:35 10.85 53% 111.6°
2025-11-12 Wed 72 38 28 21:00–21:30 (good, 0.5 h) 87.1° 15:30 10.88 43% 108.6°
2025-11-13 Thu 71 99 70 18:40–21:25 (good, 2.75 h) 87.1° 15:25 10.91 33% 104.8°
2025-11-14 Fri 69 100 69 18:40–21:25 (good, 2.75 h) 87.1° 15:25 10.94 24% 100.5°
2025-11-15 Sat 67 92 62 18:40–20:50 (good, 2.17 h) 87.1° 15:20 10.97 16% 95.8°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2025-10-17&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.