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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 Triangulum Pinwheel: 08-02 (100), 08-03 (100), 08-04 (100), 08-05 (100), 08-06 (100) — by astronomy; check the weather when the night is within four days.
2025-07-25astronomy score per night — click a bar for that night2025-08-23
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2025-07-25 Fri 82 100 82 01:15–04:15 (good, 3.0 h) 79.1° 06:40 5.48 2% 102.6°
2025-07-26 Sat 84 100 84 01:10–04:15 (good, 3.08 h) 79.1° 06:35 5.54 5% 115.3°
2025-07-27 Sun 89 94 84 01:05–04:20 (good, 3.25 h) 79.1° 06:30 5.59 11% 127.6°
2025-07-28 Mon 91 99 90 01:00–04:20 (good, 3.33 h) 79.1° 06:30 5.64 18% 139.2°
2025-07-29 Tue 92 99 91 01:00–04:20 (good, 3.33 h) 79.1° 06:25 5.7 26% 150.1°
2025-07-30 Wed 95 0 0 — 79.1° 06:20 5.75 35% 159.2°
2025-07-31 Thu 97 14 14 04:00–04:25 (good, 0.42 h) 79.1° 06:15 5.81 44% 164.2°
2025-08-01 Fri 99 84 84 01:05–04:25 (good, 3.33 h) 79.1° 06:10 5.86 54% 161.4°
2025-08-02 Sat 100 100 100 00:40–04:25 (good, 3.75 h) 79.1° 06:10 5.92 63% 153.3°
2025-08-03 Sun 100 99 99 00:45–04:30 (good, 3.75 h) 79.1° 06:05 5.97 72% 143.1°
2025-08-04 Mon 100 44 44 02:00–04:00 (good, 2.0 h) 79.1° 06:00 6.03 80% 132.0°
2025-08-05 Tue 100 75 75 00:40–02:00 (good, 1.33 h) 79.1° 05:55 6.08 88% 120.3°
2025-08-06 Wed 100 54 54 02:00–04:35 (good, 2.58 h) 79.1° 05:55 6.14 94% 108.3°
2025-08-07 Thu 75 43 32 04:00–04:35 (good, 0.58 h) 79.1° 05:50 6.2 98% 95.9°
2025-08-08 Fri 60 100 60 01:40–04:35 (good, 2.92 h) 79.1° 05:45 6.25 100% 83.1°
2025-08-09 Sat 47 100 47 03:10–04:40 (good, 1.5 h) 79.1° 05:40 6.31 100% 70.1°
2025-08-10 Sun 35 100 35 00:00–04:40 (marginal, 4.67 h) 79.1° 05:35 6.37 97% 56.9°
2025-08-11 Mon 26 100 26 00:00–04:40 (marginal, 4.67 h) 79.1° 05:35 6.43 92% 43.8°
2025-08-12 Tue 23 100 23 23:55–04:45 (marginal, 4.83 h) 79.1° 05:30 6.48 84% 31.2°
2025-08-13 Wed 30 100 30 23:40–04:45 (marginal, 5.08 h) 79.1° 05:25 6.54 75% 20.3°
2025-08-14 Thu 42 79 33 23:30–04:00 (marginal, 4.5 h) 79.1° 05:20 6.6 65% 15.7°
2025-08-15 Fri 58 100 58 00:15–04:50 (good, 4.58 h) 79.1° 05:15 6.66 53% 21.7°
2025-08-16 Sat 76 98 75 23:45–04:50 (good, 5.08 h) 79.1° 05:15 6.71 42% 33.0°
2025-08-17 Sun 86 96 83 23:45–04:50 (good, 5.08 h) 79.1° 05:10 6.77 31% 45.7°
2025-08-18 Mon 93 41 38 01:05–02:00 (good, 0.92 h) 79.1° 05:05 6.83 21% 58.8°
2025-08-19 Tue 100 0 0 — 79.1° 05:00 6.89 13% 72.0°
2025-08-20 Wed 100 100 100 23:30–04:55 (good, 5.42 h) 79.1° 05:00 6.94 6% 85.2°
2025-08-21 Thu 100 100 100 23:25–04:55 (good, 5.5 h) 79.1° 04:55 7.0 2% 98.1°
2025-08-22 Fri 100 100 100 23:25–05:00 (good, 5.58 h) 79.1° 04:50 7.06 0% 110.9°
2025-08-23 Sat 100 88 88 00:35–05:00 (good, 4.42 h) 79.1° 04:45 7.12 0% 123.2°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2025-07-25&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.