← single night · whole-night plan

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: 07-28 (100), 07-29 (100), 07-30 (100), 07-31 (100), 08-01 (100) — by astronomy; check the weather when the night is within four days.
2025-07-28astronomy score per night — click a bar for that night2025-08-26
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2025-07-28 Mon 100 99 99 22:40–04:20 (good, 5.67 h) 71.1° 00:55 5.64 18% 120.6°
2025-07-29 Tue 100 90 90 22:40–04:20 (good, 5.67 h) 71.1° 00:50 5.7 26% 113.2°
2025-07-30 Wed 100 0 0 — 71.1° 00:50 5.75 35% 105.2°
2025-07-31 Thu 100 7 7 04:00–04:25 (marginal, 0.42 h) 71.1° 00:45 5.81 44% 97.0°
2025-08-01 Fri 100 86 86 22:35–04:25 (good, 5.83 h) 71.1° 00:40 5.86 54% 88.7°
2025-08-02 Sat 100 100 100 22:35–04:25 (good, 5.83 h) 71.1° 00:35 5.92 63% 80.4°
2025-08-03 Sun 100 99 99 22:30–04:30 (good, 6.0 h) 71.1° 00:30 5.97 72% 72.3°
2025-08-04 Mon 100 44 44 02:00–04:00 (good, 2.0 h) 71.1° 00:30 6.03 80% 64.5°
2025-08-05 Tue 97 67 65 00:00–02:00 (good, 2.0 h) 71.1° 00:25 6.08 88% 57.4°
2025-08-06 Wed 90 38 34 03:40–04:35 (good, 0.92 h) 71.1° 00:20 6.14 94% 51.4°
2025-08-07 Thu 56 32 18 04:00–04:35 (marginal, 0.58 h) 71.1° 00:15 6.2 98% 47.1°
2025-08-08 Fri 50 100 50 22:20–04:35 (marginal, 6.25 h) 71.1° 00:10 6.25 100% 45.4°
2025-08-09 Sat 51 100 51 22:20–04:40 (marginal, 6.33 h) 71.1° 00:10 6.31 100% 46.7°
2025-08-10 Sun 57 100 57 22:20–22:55 (good, 0.58 h) 71.1° 00:05 6.37 97% 50.9°
2025-08-11 Mon 69 100 69 22:15–00:15 (good, 2.0 h) 71.1° 00:00 6.43 92% 57.6°
2025-08-12 Tue 76 100 76 22:15–02:10 (good, 3.92 h) 71.1° 23:55 6.48 84% 65.8°
2025-08-13 Wed 100 100 100 22:10–03:25 (good, 5.25 h) 71.1° 23:55 6.54 75% 75.1°
2025-08-14 Thu 100 86 86 22:10–03:20 (good, 5.17 h) 71.1° 23:50 6.6 65% 84.9°
2025-08-15 Fri 100 99 99 22:10–04:35 (good, 6.42 h) 71.1° 23:45 6.66 53% 94.9°
2025-08-16 Sat 100 99 99 22:05–04:35 (good, 6.5 h) 71.1° 23:40 6.71 42% 104.7°
2025-08-17 Sun 100 96 96 22:05–04:35 (good, 6.5 h) 71.1° 23:35 6.77 31% 113.9°
2025-08-18 Mon 100 45 45 00:00–02:00 (good, 2.0 h) 71.1° 23:35 6.83 21% 122.1°
2025-08-19 Tue 100 0 0 — 71.1° 23:30 6.89 13% 128.7°
2025-08-20 Wed 100 99 99 22:00–04:30 (good, 6.5 h) 71.1° 23:25 6.94 6% 133.1°
2025-08-21 Thu 100 100 100 21:55–04:25 (good, 6.5 h) 71.1° 23:20 7.0 2% 134.6°
2025-08-22 Fri 100 96 96 21:55–04:25 (good, 6.5 h) 71.1° 23:15 7.06 0% 133.1°
2025-08-23 Sat 100 82 82 21:55–04:20 (good, 6.42 h) 71.1° 23:15 7.12 0% 129.0°
2025-08-24 Sun 100 92 92 22:00–04:10 (good, 6.17 h) 71.1° 23:10 7.17 3% 123.0°
2025-08-25 Mon 100 77 77 23:00–04:10 (good, 5.17 h) 71.1° 23:05 7.23 7% 115.9°
2025-08-26 Tue 100 42 42 01:00–04:10 (good, 3.17 h) 71.1° 23:00 7.29 13% 108.1°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2025-07-28&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.