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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 HD 189733: 05-10 (84), 05-11 (84), 05-08 (83), 05-09 (83), 05-07 (82) — by astronomy; check the weather when the night is within four days.
2030-04-12astronomy score per night — click a bar for that night2030-05-11
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2030-04-12 Fri 56 — unknown 03:00–05:10 (good, 2.17 h) 71.1° 07:55 7.46 68% 141.8°
2030-04-13 Sat 54 — unknown 03:00–05:05 (good, 2.08 h) 71.1° 07:55 7.41 77% 139.1°
2030-04-14 Sun 55 — unknown 02:55–05:05 (good, 2.17 h) 71.1° 07:50 7.35 86% 133.0°
2030-04-15 Mon 50 — unknown 02:55–05:00 (good, 2.08 h) 71.1° 07:45 7.29 93% 124.4°
2030-04-16 Tue 46 — unknown 02:55–05:00 (good, 2.08 h) 71.1° 07:40 7.23 98% 114.2°
2030-04-17 Wed 41 — unknown 03:00–05:00 (good, 2.0 h) 71.1° 07:40 7.18 100% 102.9°
2030-04-18 Thu 35 — unknown 03:10–04:55 (good, 1.75 h) 71.1° 07:35 7.12 99% 91.1°
2030-04-19 Fri 31 — unknown 03:50–04:55 (good, 1.08 h) 71.1° 07:30 7.06 95% 79.2°
2030-04-20 Sat 28 — unknown 04:15–04:50 (good, 0.58 h) 71.1° 07:25 7.0 89% 67.8°
2030-04-21 Sun 28 — unknown 04:15–04:50 (good, 0.58 h) 71.1° 07:20 6.94 80% 57.2°
2030-04-22 Mon 31 — unknown 03:35–04:50 (good, 1.25 h) 71.1° 07:20 6.89 70% 48.2°
2030-04-23 Tue 36 — unknown 02:35–04:45 (good, 2.17 h) 71.1° 07:15 6.83 59% 41.6°
2030-04-24 Wed 48 — unknown 02:10–04:45 (good, 2.58 h) 71.1° 07:10 6.77 48% 38.3°
2030-04-25 Thu 55 — unknown 02:05–04:45 (good, 2.67 h) 71.1° 07:05 6.71 38% 38.9°
2030-04-26 Fri 61 — unknown 02:00–04:40 (good, 2.67 h) 71.1° 07:00 6.65 28% 42.9°
2030-04-27 Sat 67 — unknown 01:55–04:40 (good, 2.75 h) 71.1° 07:00 6.59 20% 49.3°
2030-04-28 Sun 71 — unknown 01:55–04:35 (good, 2.67 h) 71.1° 06:55 6.54 12% 57.2°
2030-04-29 Mon 73 — unknown 01:50–04:35 (good, 2.75 h) 71.1° 06:50 6.48 7% 65.9°
2030-04-30 Tue 74 — unknown 01:45–04:35 (good, 2.83 h) 71.1° 06:45 6.42 3% 75.1°
2030-05-01 Wed 74 — unknown 01:40–04:30 (good, 2.83 h) 71.1° 06:45 6.36 0% 84.4°
2030-05-02 Thu 76 — unknown 01:35–04:30 (good, 2.92 h) 71.1° 06:40 6.3 0% 93.7°
2030-05-03 Fri 78 — unknown 01:35–04:30 (good, 2.92 h) 71.1° 06:35 6.25 2% 103.0°
2030-05-04 Sat 78 — unknown 01:30–04:25 (good, 2.92 h) 71.1° 06:30 6.19 5% 112.0°
2030-05-05 Sun 79 — unknown 01:25–04:25 (good, 3.0 h) 71.1° 06:25 6.13 10% 120.6°
2030-05-06 Mon 80 — unknown 01:20–04:20 (good, 3.0 h) 71.1° 06:25 6.07 16% 128.5°
2030-05-07 Tue 82 — unknown 01:20–04:20 (good, 3.0 h) 71.1° 06:20 6.02 24% 135.2°
2030-05-08 Wed 83 — unknown 01:15–04:20 (good, 3.08 h) 71.1° 06:15 5.96 32% 140.0°
2030-05-09 Thu 83 — unknown 01:15–04:15 (good, 3.0 h) 71.1° 06:10 5.9 42% 142.0°
2030-05-10 Fri 84 — unknown 01:10–04:15 (good, 3.08 h) 71.1° 06:05 5.85 52% 140.6°
2030-05-11 Sat 84 — unknown 01:10–04:15 (good, 3.08 h) 71.1° 06:05 5.79 63% 135.8°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2030-04-12&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.