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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: 11-28 (22), 11-27 (17), 11-18 (14), 11-19 (14), 11-16 (13) — by astronomy; check the weather when the night is within four days.
2040-10-30astronomy score per night — click a bar for that night2040-11-28
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2040-10-30 Tue 0 — unknown — 50.1° 10:10 10.45 24% 25.8°
2040-10-31 Wed 0 — unknown — 50.1° 10:05 10.49 16% 13.5°
2040-11-01 Thu 0 — unknown — 50.1° 10:05 10.52 9% 1.1°
2040-11-02 Fri 0 — unknown — 50.1° 10:00 10.56 4% 12.2°
2040-11-03 Sat 1 — unknown — 50.1° 09:55 10.59 1% 25.4°
2040-11-04 Sun 1 — unknown — 50.1° 09:50 10.63 0% 39.0°
2040-11-05 Mon 1 — unknown — 50.1° 09:50 10.66 2% 52.9°
2040-11-06 Tue 1 — unknown 05:55–06:00 (marginal, 0.08 h) 50.1° 09:45 10.7 6% 67.0°
2040-11-07 Wed 2 — unknown 05:25–05:30 (marginal, 0.08 h) 50.1° 09:40 10.73 12% 81.2°
2040-11-08 Thu 3 — unknown 05:50–06:05 (marginal, 0.25 h) 50.1° 09:35 10.76 21% 95.5°
2040-11-09 Fri 4 — unknown 05:15–05:30 (marginal, 0.25 h) 50.1° 09:30 10.8 31% 109.8°
2040-11-10 Sat 5 — unknown 05:15–05:35 (marginal, 0.33 h) 50.1° 09:30 10.83 42% 124.0°
2040-11-11 Sun 6 — unknown 05:10–06:05 (marginal, 0.92 h) 50.1° 09:25 10.86 53% 138.1°
2040-11-12 Mon 7 — unknown 05:05–06:05 (marginal, 1.0 h) 50.1° 09:20 10.89 64% 152.1°
2040-11-13 Tue 9 — unknown 05:30–05:35 (good, 0.08 h) 50.1° 09:15 10.92 75% 166.0°
2040-11-14 Wed 10 — unknown 05:25–05:35 (good, 0.17 h) 50.1° 09:10 10.95 84% 179.2°
2040-11-15 Thu 12 — unknown 05:20–05:40 (good, 0.33 h) 50.1° 09:10 10.98 91% 166.6°
2040-11-16 Fri 13 — unknown 05:25–05:40 (good, 0.25 h) 50.1° 09:05 11.0 96% 153.2°
2040-11-17 Sat 13 — unknown 05:25–05:40 (good, 0.25 h) 50.1° 09:00 11.03 99% 140.0°
2040-11-18 Sun 14 — unknown 05:20–05:40 (good, 0.33 h) 50.1° 08:55 11.06 100% 127.0°
2040-11-19 Mon 14 — unknown 05:20–05:40 (good, 0.33 h) 50.1° 08:55 11.08 99% 114.3°
2040-11-20 Tue 12 — unknown 05:30–05:45 (good, 0.25 h) 50.1° 08:50 11.11 95% 101.8°
2040-11-21 Wed 11 — unknown 04:35–05:45 (marginal, 1.17 h) 50.1° 08:45 11.13 90% 89.6°
2040-11-22 Thu 10 — unknown 04:35–05:45 (marginal, 1.17 h) 50.1° 08:40 11.16 84% 77.5°
2040-11-23 Fri 9 — unknown 04:35–05:45 (marginal, 1.17 h) 50.1° 08:35 11.18 76% 65.6°
2040-11-24 Sat 9 — unknown 04:35–05:45 (marginal, 1.17 h) 50.1° 08:35 11.2 68% 53.7°
2040-11-25 Sun 10 — unknown 04:25–05:50 (marginal, 1.42 h) 50.1° 08:30 11.23 59% 41.9°
2040-11-26 Mon 12 — unknown 04:20–05:50 (marginal, 1.5 h) 50.1° 08:25 11.25 50% 30.0°
2040-11-27 Tue 17 — unknown 05:35–05:50 (good, 0.25 h) 50.1° 08:20 11.27 40% 18.0°
2040-11-28 Wed 22 — unknown 04:50–05:50 (good, 1.0 h) 50.1° 08:15 11.29 31% 5.7°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2040-10-30&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.