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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: 09-06 (100), 09-07 (100), 09-08 (100), 09-09 (100), 09-10 (100) — by astronomy; check the weather when the night is within four days.
2026-09-02astronomy score per night — click a bar for that night2026-10-01
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2026-09-02 Wed 57 8 4 — 79.1° 04:10 7.67 66% 23.2°
2026-09-03 Thu 75 87 65 00:00–03:00 (good, 3.0 h) 79.1° 04:05 7.72 55% 35.1°
2026-09-04 Fri 86 99 85 22:45–05:15 (good, 6.5 h) 79.1° 04:00 7.78 43% 48.1°
2026-09-05 Sat 95 100 95 22:30–05:15 (good, 6.75 h) 79.1° 03:55 7.83 32% 61.6°
2026-09-06 Sun 100 100 100 22:25–05:20 (good, 6.92 h) 79.1° 03:50 7.89 22% 75.4°
2026-09-07 Mon 100 100 100 22:20–05:20 (good, 7.0 h) 79.1° 03:50 7.94 13% 89.2°
2026-09-08 Tue 100 100 100 22:15–05:20 (good, 7.08 h) 79.1° 03:45 8.0 6% 103.0°
2026-09-09 Wed 100 85 85 22:20–05:00 (good, 6.67 h) 79.1° 03:40 8.05 2% 116.7°
2026-09-10 Thu 100 100 100 22:10–05:25 (good, 7.25 h) 79.1° 03:35 8.11 0% 129.9°
2026-09-11 Fri 100 100 100 22:05–05:25 (good, 7.33 h) 79.1° 03:30 8.16 1% 142.7°
2026-09-12 Sat 100 0 0 — 79.1° 03:30 8.21 4% 154.3°
2026-09-13 Sun 100 88 88 22:20–05:30 (good, 7.17 h) 79.1° 03:25 8.27 9% 163.2°
2026-09-14 Mon 100 36 36 00:00–03:00 (good, 3.0 h) 79.1° 03:20 8.32 15% 164.7°
2026-09-15 Tue 100 79 79 00:45–05:30 (good, 4.75 h) 79.1° 03:15 8.37 23% 157.9°
2026-09-16 Wed 100 98 98 21:55–05:30 (good, 7.58 h) 79.1° 03:15 8.42 32% 147.9°
2026-09-17 Thu 100 100 100 21:45–05:30 (good, 7.75 h) 79.1° 03:10 8.48 41% 137.1°
2026-09-18 Fri 100 87 87 22:40–05:35 (good, 6.92 h) 79.1° 03:05 8.53 51% 125.9°
2026-09-19 Sat 100 82 82 21:50–03:00 (good, 5.17 h) 79.1° 03:00 8.58 60% 114.6°
2026-09-20 Sun 100 99 99 21:50–05:35 (good, 7.75 h) 79.1° 02:55 8.63 69% 103.1°
2026-09-21 Mon 100 0 0 — 79.1° 02:55 8.68 78% 91.5°
2026-09-22 Tue 100 34 34 04:00–05:40 (good, 1.67 h) 79.1° 02:50 8.73 85% 79.6°
2026-09-23 Wed 100 93 93 01:35–05:40 (good, 4.08 h) 79.1° 02:45 8.78 92% 67.5°
2026-09-24 Thu 96 72 69 03:55–04:00 (good, 0.08 h) 79.1° 02:40 8.84 96% 55.2°
2026-09-25 Fri 54 2 1 — 79.1° 02:35 8.89 99% 42.8°
2026-09-26 Sat 32 0 0 — 79.1° 02:35 8.94 100% 30.6°
2026-09-27 Sun 26 70 18 — 79.1° 02:30 8.98 98% 19.8°
2026-09-28 Mon 32 31 10 22:00–23:00 (marginal, 1.0 h) 79.1° 02:25 9.03 94% 14.7°
2026-09-29 Tue 43 0 0 — 79.1° 02:20 9.08 87% 20.7°
2026-09-30 Wed 65 29 19 00:00–02:00 (marginal, 2.0 h) 79.1° 02:20 9.13 78% 32.1°
2026-10-01 Thu 84 67 56 22:00–05:50 (marginal, 7.83 h) 79.1° 02:15 9.18 68% 45.1°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2026-09-02&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.