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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: 04-29 (100), 04-30 (100), 05-01 (100), 05-02 (100), 05-03 (100) — by astronomy; check the weather when the night is within four days.
2025-04-29astronomy score per night — click a bar for that night2025-05-28
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2025-04-29 Tue 100 100 100 23:30–04:35 (good, 5.08 h) 87.1° 05:25 6.47 7% 108.0°
2025-04-30 Wed 100 91 91 23:30–04:35 (good, 5.08 h) 87.1° 05:20 6.41 14% 111.2°
2025-05-01 Thu 100 20 20 03:00–04:30 (marginal, 1.5 h) 87.1° 05:20 6.35 23% 113.0°
2025-05-02 Fri 100 99 99 23:25–04:30 (good, 5.08 h) 87.1° 05:15 6.29 33% 113.4°
2025-05-03 Sat 100 100 100 23:25–04:25 (good, 5.0 h) 87.1° 05:10 6.23 43% 112.4°
2025-05-04 Sun 100 25 25 23:25–01:00 (marginal, 1.58 h) 87.1° 05:05 6.18 54% 110.2°
2025-05-05 Mon 100 80 80 23:35–02:00 (good, 2.42 h) 87.1° 05:00 6.12 64% 107.2°
2025-05-06 Tue 100 0 0 — 87.1° 05:00 6.06 73% 103.4°
2025-05-07 Wed 100 81 81 23:25–04:00 (good, 4.58 h) 87.1° 04:55 6.0 81% 99.1°
2025-05-08 Thu 85 75 64 00:00–04:00 (good, 4.0 h) 87.1° 04:50 5.95 88% 94.6°
2025-05-09 Fri 81 0 0 — 87.1° 04:45 5.89 93% 89.9°
2025-05-10 Sat 77 3 2 — 87.1° 04:40 5.84 97% 85.2°
2025-05-11 Sun 74 0 0 — 87.1° 04:40 5.78 99% 80.7°
2025-05-12 Mon 69 0 0 — 87.1° 04:35 5.73 100% 76.5°
2025-05-13 Tue 68 0 0 — 87.1° 04:30 5.67 98% 72.8°
2025-05-14 Wed 73 97 71 23:40–04:10 (good, 4.5 h) 87.1° 04:25 5.62 95% 69.8°
2025-05-15 Thu 86 0 0 — 87.1° 04:25 5.56 90% 67.7°
2025-05-16 Fri 92 0 0 — 87.1° 04:20 5.51 84% 66.6°
2025-05-17 Sat 97 21 21 00:00–01:00 (good, 1.0 h) 87.1° 04:15 5.46 76% 66.6°
2025-05-18 Sun 100 100 100 22:40–04:00 (good, 5.33 h) 87.1° 04:10 5.41 66% 67.9°
2025-05-19 Mon 100 94 94 22:40–04:00 (good, 5.33 h) 87.1° 04:05 5.36 56% 70.4°
2025-05-20 Tue 100 42 42 22:40–00:00 (good, 1.33 h) 87.1° 04:05 5.31 45% 73.9°
2025-05-21 Wed 100 68 68 23:00–02:00 (good, 3.0 h) 87.1° 04:00 5.26 34% 78.5°
2025-05-22 Thu 100 96 96 22:45–03:55 (good, 5.17 h) 87.1° 03:55 5.21 24% 83.8°
2025-05-23 Fri 100 6 6 — 87.1° 03:50 5.16 15% 89.5°
2025-05-24 Sat 100 0 0 — 87.1° 03:45 5.12 7% 95.4°
2025-05-25 Sun 100 0 0 — 87.1° 03:45 5.07 2% 101.1°
2025-05-26 Mon 100 77 77 22:50–03:50 (good, 5.0 h) 87.1° 03:40 5.03 0% 106.1°
2025-05-27 Tue 100 99 99 22:50–03:50 (good, 5.0 h) 87.1° 03:35 4.98 1% 110.1°
2025-05-28 Wed 100 91 91 22:55–03:50 (good, 4.92 h) 87.1° 03:30 4.94 5% 112.6°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2025-04-29&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.