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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 V1057 Cyg: 06-15 (100), 06-16 (100), 06-17 (100), 06-18 (100), 06-19 (100) — by astronomy; check the weather when the night is within four days.
2026-06-15astronomy score per night — click a bar for that night2026-07-14
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2026-06-15 Mon 100 64 64 02:00–03:40 (good, 1.67 h) 87.3° 04:45 4.45 1% 100.5°
2026-06-16 Tue 100 0 0 — 87.3° 04:40 4.44 5% 108.2°
2026-06-17 Wed 100 35 35 03:00–03:40 (good, 0.67 h) 87.3° 04:35 4.43 12% 114.7°
2026-06-18 Thu 100 74 74 23:10–03:40 (good, 4.5 h) 87.3° 04:30 4.43 20% 119.7°
2026-06-19 Fri 100 92 92 23:10–03:40 (good, 4.5 h) 87.3° 04:30 4.42 30% 122.7°
2026-06-20 Sat 100 98 98 23:15–03:40 (good, 4.42 h) 87.3° 04:25 4.42 40% 123.6°
2026-06-21 Sun 100 99 99 23:15–03:40 (good, 4.42 h) 87.3° 04:20 4.42 50% 122.5°
2026-06-22 Mon 100 89 89 23:15–03:40 (good, 4.42 h) 87.3° 04:15 4.42 60% 119.7°
2026-06-23 Tue 100 59 59 01:00–03:40 (good, 2.67 h) 87.3° 04:10 4.43 70% 115.6°
2026-06-24 Wed 100 86 86 23:15–03:40 (good, 4.42 h) 87.3° 04:10 4.43 78% 110.4°
2026-06-25 Thu 100 89 89 23:15–03:40 (good, 4.42 h) 87.3° 04:05 4.44 86% 104.6°
2026-06-26 Fri 100 95 95 23:15–03:40 (good, 4.42 h) 87.3° 04:00 4.45 92% 98.4°
2026-06-27 Sat 82 67 55 23:20–03:00 (good, 3.67 h) 87.3° 03:55 4.47 96% 91.9°
2026-06-28 Sun 77 100 77 23:15–03:40 (good, 4.42 h) 87.3° 03:50 4.48 99% 85.3°
2026-06-29 Mon 69 89 62 02:00–03:40 (good, 1.67 h) 87.3° 03:50 4.5 100% 78.9°
2026-06-30 Tue 62 96 60 23:50–03:45 (good, 3.92 h) 87.3° 03:45 4.52 99% 72.8°
2026-07-01 Wed 60 27 16 23:10–00:00 (marginal, 0.83 h) 87.3° 03:40 4.54 96% 67.2°
2026-07-02 Thu 60 74 45 23:10–03:45 (marginal, 4.58 h) 87.3° 03:35 4.56 92% 62.5°
2026-07-03 Fri 84 32 27 02:00–03:00 (marginal, 1.0 h) 87.3° 03:35 4.58 86% 58.9°
2026-07-04 Sat 92 72 67 01:00–02:00 (good, 1.0 h) 87.3° 03:30 4.61 78% 56.8°
2026-07-05 Sun 95 89 85 23:10–03:00 (good, 3.83 h) 87.3° 03:25 4.64 70% 56.4°
2026-07-06 Mon 98 97 95 23:10–03:50 (good, 4.67 h) 87.3° 03:20 4.67 59% 58.0°
2026-07-07 Tue 100 96 96 23:10–03:50 (good, 4.67 h) 87.3° 03:15 4.7 49% 61.4°
2026-07-08 Wed 100 0 0 — 87.3° 03:15 4.73 38% 66.5°
2026-07-09 Thu 100 91 91 23:05–03:50 (good, 4.75 h) 87.3° 03:10 4.76 27% 73.0°
2026-07-10 Fri 100 97 97 23:05–03:55 (good, 4.83 h) 87.3° 03:05 4.8 17% 80.5°
2026-07-11 Sat 100 100 100 23:05–03:55 (good, 4.83 h) 87.3° 03:00 4.84 9% 88.6°
2026-07-12 Sun 100 89 89 23:05–03:55 (good, 4.83 h) 87.3° 02:55 4.87 3% 96.9°
2026-07-13 Mon 100 89 89 23:00–03:55 (good, 4.92 h) 87.3° 02:55 4.91 0% 104.9°
2026-07-14 Tue 100 98 98 23:00–04:00 (good, 5.0 h) 87.3° 02:50 4.96 0% 112.1°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2026-06-15&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.