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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: 08-10 (100), 08-11 (100), 08-12 (100), 08-13 (100), 08-14 (100) — by astronomy; check the weather when the night is within four days.
2026-08-10astronomy score per night — click a bar for that night2026-09-08
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2026-08-10 Mon 100 98 98 22:20–04:40 (good, 6.33 h) 87.1° 22:40 6.35 5% 114.8°
2026-08-11 Tue 100 100 100 22:15–04:35 (good, 6.33 h) 87.1° 22:40 6.41 1% 113.9°
2026-08-12 Wed 100 97 97 22:15–04:35 (good, 6.33 h) 87.1° 22:35 6.47 0% 111.4°
2026-08-13 Thu 100 35 35 22:15–01:00 (good, 2.75 h) 87.1° 22:30 6.53 2% 107.6°
2026-08-14 Fri 100 70 70 22:10–02:00 (good, 3.83 h) 87.1° 22:25 6.58 6% 103.0°
2026-08-15 Sat 100 99 99 22:10–04:20 (good, 6.17 h) 87.1° 22:20 6.64 12% 97.8°
2026-08-16 Sun 100 100 100 22:05–04:15 (good, 6.17 h) 87.1° 22:20 6.7 20% 92.4°
2026-08-17 Mon 100 100 100 22:05–04:15 (good, 6.17 h) 87.1° 22:15 6.76 29% 87.0°
2026-08-18 Tue 100 68 68 22:05–02:00 (good, 3.92 h) 87.1° 22:10 6.81 39% 82.0°
2026-08-19 Wed 100 100 100 22:00–04:05 (good, 6.08 h) 87.1° 22:05 6.87 48% 77.3°
2026-08-20 Thu 100 99 99 22:00–04:00 (good, 6.0 h) 87.1° 22:00 6.93 58% 73.2°
2026-08-21 Fri 100 100 100 21:55–04:00 (good, 6.08 h) 87.1° 22:00 6.99 67% 69.8°
2026-08-22 Sat 94 89 83 01:00–03:55 (good, 2.92 h) 87.1° 21:55 7.04 76% 67.2°
2026-08-23 Sun 86 87 75 23:00–03:40 (good, 4.67 h) 87.1° 21:50 7.1 83% 65.7°
2026-08-24 Mon 72 41 29 02:00–03:10 (good, 1.17 h) 87.1° 21:45 7.16 90% 65.2°
2026-08-25 Tue 64 97 62 23:00–01:10 (good, 2.17 h) 87.1° 21:45 7.22 95% 65.9°
2026-08-26 Wed 62 93 58 21:45–04:00 (marginal, 6.25 h) 87.1° 21:40 7.27 98% 67.8°
2026-08-27 Thu 62 97 60 23:00–00:10 (good, 1.17 h) 87.1° 21:35 7.33 100% 70.8°
2026-08-28 Fri 65 95 62 21:45–22:40 (good, 0.92 h) 87.1° 21:30 7.39 99% 74.8°
2026-08-29 Sat 73 25 18 21:40–22:00 (good, 0.33 h) 87.1° 21:25 7.44 97% 79.5°
2026-08-30 Sun 78 97 76 21:40–01:35 (good, 3.92 h) 87.1° 21:25 7.5 92% 84.9°
2026-08-31 Mon 83 99 82 21:35–02:20 (good, 4.75 h) 87.1° 21:20 7.56 85% 90.5°
2026-09-01 Tue 100 92 92 21:35–02:45 (good, 5.17 h) 87.1° 21:15 7.61 76% 96.2°
2026-09-02 Wed 100 9 9 — 87.1° 21:10 7.67 66% 101.7°
2026-09-03 Thu 100 89 89 21:30–02:50 (good, 5.33 h) 87.1° 21:05 7.72 55% 106.6°
2026-09-04 Fri 100 96 96 21:30–02:55 (good, 5.42 h) 87.1° 21:05 7.78 43% 110.6°
2026-09-05 Sat 100 100 100 21:25–02:55 (good, 5.5 h) 87.1° 21:00 7.83 32% 113.4°
2026-09-06 Sun 100 99 99 21:25–02:55 (good, 5.5 h) 87.1° 20:55 7.89 22% 114.7°
2026-09-07 Mon 100 100 100 21:25–02:50 (good, 5.42 h) 87.1° 20:50 7.94 13% 114.4°
2026-09-08 Tue 100 100 100 21:20–02:45 (good, 5.42 h) 87.1° 20:50 8.0 6% 112.5°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2026-08-10&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.