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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: 11-23 (25), 11-22 (24), 11-21 (22), 11-20 (19), 11-19 (16) — by astronomy; check the weather when the night is within four days.
2041-10-25astronomy score per night — click a bar for that night2041-11-23
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2041-10-25 Fri 0 — unknown — 50.1° 11:30 10.25 1% 37.1°
2041-10-26 Sat 0 — unknown — 50.1° 10:30 10.29 3% 49.7°
2041-10-27 Sun 0 — unknown — 50.1° 10:25 10.33 8% 62.5°
2041-10-28 Mon 0 — unknown — 50.1° 10:20 10.37 15% 75.5°
2041-10-29 Tue 0 — unknown — 50.1° 10:15 10.4 23% 88.7°
2041-10-30 Wed 0 — unknown — 50.1° 10:10 10.44 33% 102.1°
2041-10-31 Thu 0 — unknown — 50.1° 10:10 10.48 44% 115.7°
2041-11-01 Fri 0 — unknown — 50.1° 10:05 10.51 55% 129.6°
2041-11-02 Sat 0 — unknown — 50.1° 10:00 10.55 66% 143.8°
2041-11-03 Sun 1 — unknown — 50.1° 09:55 10.59 76% 158.1°
2041-11-04 Mon 1 — unknown — 50.1° 09:55 10.62 86% 172.5°
2041-11-05 Tue 1 — unknown — 50.1° 09:50 10.66 93% 172.3°
2041-11-06 Wed 1 — unknown — 50.1° 09:45 10.69 98% 157.9°
2041-11-07 Thu 2 — unknown 05:25–05:30 (marginal, 0.08 h) 50.1° 09:40 10.72 100% 143.4°
2041-11-08 Fri 3 — unknown 05:20–05:30 (marginal, 0.17 h) 50.1° 09:35 10.76 99% 129.1°
2041-11-09 Sat 3 — unknown 05:20–05:30 (marginal, 0.17 h) 50.1° 09:35 10.79 96% 115.1°
2041-11-10 Sun 3 — unknown 05:15–05:30 (marginal, 0.25 h) 50.1° 09:30 10.82 91% 101.6°
2041-11-11 Mon 3 — unknown 05:15–05:35 (marginal, 0.33 h) 50.1° 09:25 10.85 84% 88.4°
2041-11-12 Tue 3 — unknown 05:15–05:35 (marginal, 0.33 h) 50.1° 09:20 10.88 76% 75.6°
2041-11-13 Wed 4 — unknown 05:15–05:35 (marginal, 0.33 h) 50.1° 09:15 10.91 67% 63.2°
2041-11-14 Thu 4 — unknown 05:05–05:35 (marginal, 0.5 h) 50.1° 09:15 10.94 57% 51.0°
2041-11-15 Fri 6 — unknown 05:00–05:40 (marginal, 0.67 h) 50.1° 09:10 10.97 48% 39.1°
2041-11-16 Sat 7 — unknown 04:50–05:40 (marginal, 0.83 h) 50.1° 09:05 11.0 38% 27.3°
2041-11-17 Sun 10 — unknown 05:35–05:40 (good, 0.08 h) 50.1° 09:00 11.03 29% 15.5°
2041-11-18 Mon 13 — unknown 05:25–05:40 (good, 0.25 h) 50.1° 09:00 11.05 21% 4.1°
2041-11-19 Tue 16 — unknown 05:15–05:40 (good, 0.42 h) 50.1° 08:55 11.08 14% 8.8°
2041-11-20 Wed 19 — unknown 05:05–05:45 (good, 0.67 h) 50.1° 08:50 11.1 8% 20.8°
2041-11-21 Thu 22 — unknown 05:00–05:45 (good, 0.75 h) 50.1° 08:45 11.13 3% 33.2°
2041-11-22 Fri 24 — unknown 04:55–05:45 (good, 0.83 h) 50.1° 08:40 11.15 1% 45.9°
2041-11-23 Sat 25 — unknown 04:50–05:45 (good, 0.92 h) 50.1° 08:40 11.18 0% 58.8°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2041-10-25&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.