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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 Seven Sisters: 11-15 (100), 11-16 (100), 11-17 (100), 11-18 (100), 11-19 (100) — by astronomy; check the weather when the night is within four days.
2025-11-15astronomy score per night — click a bar for that night2025-12-14
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2025-11-15 Sat 100 59 59 19:25–23:00 (good, 3.58 h) 72.5° 00:30 10.97 16% 126.5°
2025-11-16 Sun 100 23 23 19:05–21:00 (marginal, 1.92 h) 72.5° 00:25 10.99 10% 138.6°
2025-11-17 Mon 100 0 0 — 72.5° 00:20 11.02 5% 150.5°
2025-11-18 Tue 100 0 0 — 72.5° 00:15 11.05 2% 162.3°
2025-11-19 Wed 100 5 5 02:00–03:00 (marginal, 1.0 h) 72.5° 00:10 11.08 0% 174.1°
2025-11-20 Thu 100 9 9 22:00–23:00 (marginal, 1.0 h) 72.5° 00:10 11.1 0% 173.9°
2025-11-21 Fri 100 0 0 — 72.5° 00:05 11.13 3% 162.1°
2025-11-22 Sat 100 14 14 20:00–21:00 (good, 1.0 h) 72.5° 00:00 11.15 6% 150.2°
2025-11-23 Sun 100 99 99 19:00–05:05 (good, 10.08 h) 72.5° 23:55 11.17 12% 138.2°
2025-11-24 Mon 100 71 71 18:50–02:00 (good, 7.17 h) 72.5° 23:55 11.2 18% 126.1°
2025-11-25 Tue 100 0 0 — 72.5° 23:50 11.22 27% 113.8°
2025-11-26 Wed 100 3 3 21:00–22:00 (marginal, 1.0 h) 72.5° 23:45 11.24 36% 101.2°
2025-11-27 Thu 100 0 0 — 72.5° 23:40 11.26 46% 88.4°
2025-11-28 Fri 100 0 0 — 72.5° 23:35 11.28 57% 75.1°
2025-11-29 Sat 99 0 0 — 72.5° 23:35 11.3 67% 61.5°
2025-11-30 Sun 89 0 0 — 72.5° 23:30 11.32 78% 47.4°
2025-12-01 Mon 77 64 49 19:00–02:00 (marginal, 7.0 h) 72.5° 23:25 11.34 86% 32.8°
2025-12-02 Tue 37 54 20 02:00–04:40 (marginal, 2.67 h) 72.5° 23:20 11.35 94% 17.9°
2025-12-03 Wed 24 8 2 — 72.5° 23:15 11.37 98% 2.8°
2025-12-04 Thu 24 0 0 — 72.5° 23:15 11.38 100% 12.6°
2025-12-05 Fri 30 0 0 — 72.5° 23:10 11.4 98% 27.8°
2025-12-06 Sat 53 0 0 — 72.5° 23:05 11.41 94% 42.8°
2025-12-07 Sun 89 2 2 — 72.5° 23:00 11.42 88% 57.3°
2025-12-08 Mon 98 15 15 19:00–20:00 (good, 1.0 h) 72.5° 23:00 11.44 79% 71.5°
2025-12-09 Tue 100 10 10 23:00–01:00 (marginal, 2.0 h) 72.5° 22:55 11.45 70% 85.1°
2025-12-10 Wed 100 24 24 03:00–03:10 (good, 0.17 h) 72.5° 22:50 11.46 60% 98.3°
2025-12-11 Thu 100 43 43 18:35–22:00 (good, 3.42 h) 72.5° 22:45 11.47 49% 111.0°
2025-12-12 Fri 100 58 58 18:35–23:00 (good, 4.42 h) 72.5° 22:40 11.47 40% 123.4°
2025-12-13 Sat 100 15 15 18:35–20:00 (marginal, 1.42 h) 72.5° 22:40 11.48 30% 135.6°
2025-12-14 Sun 100 63 63 18:35–22:00 (good, 3.42 h) 72.5° 22:35 11.49 22% 147.5°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2025-11-15&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.