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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 3C 273: 07-14 (2), 07-15 (1), 07-16 (1), 07-17 (1), 07-18 (1) — by astronomy; check the weather when the night is within four days.
2025-07-14astronomy score per night — click a bar for that night2025-08-12
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2025-07-14 Mon 2 98 2 — 50.2° 18:20 4.97 82% 156.6°
2025-07-15 Tue 1 71 1 — 50.2° 18:15 5.01 73% 169.2°
2025-07-16 Wed 1 75 1 — 50.2° 18:15 5.05 62% 172.0°
2025-07-17 Thu 1 32 0 — 50.2° 18:10 5.1 51% 160.0°
2025-07-18 Fri 1 98 1 — 50.2° 18:05 5.14 40% 146.2°
2025-07-19 Sat 1 99 1 — 50.2° 18:00 5.19 29% 132.1°
2025-07-20 Sun 1 99 1 — 50.2° 17:55 5.24 19% 117.9°
2025-07-21 Mon 1 99 1 — 50.2° 17:55 5.28 11% 103.7°
2025-07-22 Tue 0 100 0 — 50.2° 17:50 5.33 5% 89.5°
2025-07-23 Wed 0 85 0 — 50.2° 17:45 5.38 1% 75.5°
2025-07-24 Thu 0 86 0 — 50.2° 17:40 5.43 0% 61.7°
2025-07-25 Fri 0 99 0 — 50.2° 17:35 5.48 2% 48.2°
2025-07-26 Sat 0 100 0 — 50.2° 17:35 5.54 5% 35.1°
2025-07-27 Sun 0 99 0 — 50.2° 17:30 5.59 11% 22.6°
2025-07-28 Mon 0 96 0 — 50.2° 17:25 5.64 18% 11.0°
2025-07-29 Tue 0 22 0 — 50.2° 17:20 5.7 26% 7.0°
2025-07-30 Wed 0 0 0 — 50.2° 17:20 5.75 35% 16.5°
2025-07-31 Thu 0 0 0 — 50.2° 17:15 5.81 44% 27.9°
2025-08-01 Fri 0 78 0 — 50.2° 17:10 5.86 54% 39.5°
2025-08-02 Sat 0 99 0 — 50.2° 17:05 5.92 63% 51.2°
2025-08-03 Sun 0 99 0 — 50.2° 17:00 5.97 72% 63.1°
2025-08-04 Mon 0 83 0 — 50.2° 17:00 6.03 80% 75.1°
2025-08-05 Tue 0 50 0 — 50.2° 16:55 6.08 88% 87.4°
2025-08-06 Wed 0 0 0 — 50.2° 16:50 6.14 94% 99.9°
2025-08-07 Thu 0 0 0 — 50.2° 16:45 6.2 98% 112.8°
2025-08-08 Fri 0 0 0 — 50.2° 16:40 6.25 100% 125.9°
2025-08-09 Sat 0 0 0 — 50.2° 16:40 6.31 100% 139.3°
2025-08-10 Sun 0 0 0 — 50.2° 16:35 6.37 97% 152.8°
2025-08-11 Mon 0 0 0 — 50.2° 16:30 6.43 92% 166.0°
2025-08-12 Tue 0 0 0 — 50.2° 16:25 6.48 84% 173.5°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2025-07-14&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.