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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: 03-21 (44), 03-22 (44), 03-23 (44), 03-19 (42), 03-20 (42) — by astronomy; check the weather when the night is within four days.
2026-02-22astronomy score per night — click a bar for that night2026-03-23
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2026-02-22 Sun 21 2 0 — 87.3° 11:10 9.96 32% 72.3°
2026-02-23 Mon 23 25 6 05:00–05:35 (marginal, 0.58 h) 87.3° 11:05 9.91 43% 79.3°
2026-02-24 Tue 23 7 2 — 87.3° 11:00 9.87 55% 86.9°
2026-02-25 Wed 24 0 0 — 87.3° 10:55 9.83 66% 94.6°
2026-02-26 Thu 25 58 15 04:30–05:30 (marginal, 1.0 h) 87.3° 10:50 9.78 76% 102.0°
2026-02-27 Fri 24 94 23 04:50–05:30 (good, 0.67 h) 87.3° 10:50 9.74 85% 109.0°
2026-02-28 Sat 21 100 21 04:40–05:25 (good, 0.75 h) 87.3° 10:45 9.69 92% 114.9°
2026-03-01 Sun 22 56 12 04:45–05:00 (good, 0.25 h) 87.3° 10:40 9.65 97% 119.4°
2026-03-02 Mon 23 0 0 — 87.3° 10:35 9.6 100% 122.2°
2026-03-03 Tue 23 99 23 04:30–05:20 (good, 0.83 h) 87.3° 10:30 9.56 100% 123.0°
2026-03-04 Wed 23 0 0 — 87.3° 10:30 9.51 98% 121.8°
2026-03-05 Thu 24 100 24 04:25–05:20 (good, 0.92 h) 87.3° 10:25 9.46 94% 119.0°
2026-03-06 Fri 24 70 17 03:30–05:15 (marginal, 1.75 h) 87.3° 10:20 9.41 88% 114.8°
2026-03-07 Sat 24 85 20 04:20–05:00 (good, 0.67 h) 87.3° 10:15 9.37 81% 109.6°
2026-03-08 Sun 24 27 7 05:00–05:15 (good, 0.25 h) 87.3° 10:15 9.32 72% 103.8°
2026-03-09 Mon 25 85 21 04:20–05:10 (good, 0.83 h) 87.3° 10:10 9.27 64% 97.6°
2026-03-10 Tue 26 100 26 04:05–05:10 (good, 1.08 h) 87.3° 10:05 9.22 54% 91.2°
2026-03-11 Wed 28 55 15 03:20–05:10 (marginal, 1.83 h) 87.3° 10:00 9.17 45% 84.8°
2026-03-12 Thu 30 98 29 04:00–05:05 (good, 1.08 h) 87.3° 09:55 9.13 36% 78.5°
2026-03-13 Fri 34 100 34 03:40–05:05 (good, 1.42 h) 87.3° 09:55 9.08 27% 72.4°
2026-03-14 Sat 37 95 35 03:40–05:05 (good, 1.42 h) 87.3° 09:50 9.03 18% 66.9°
2026-03-15 Sun 38 100 38 03:30–05:00 (good, 1.5 h) 87.3° 09:45 8.98 11% 62.2°
2026-03-16 Mon 39 72 28 03:50–05:00 (good, 1.17 h) 87.3° 09:40 8.93 5% 58.8°
2026-03-17 Tue 40 0 0 — 87.3° 09:35 8.88 2% 57.1°
2026-03-18 Wed 40 0 0 — 87.3° 09:35 8.82 0% 57.5°
2026-03-19 Thu 42 0 0 — 87.3° 09:30 8.77 1% 60.0°
2026-03-20 Fri 42 0 0 — 87.3° 09:25 8.72 5% 64.5°
2026-03-21 Sat 44 0 0 — 87.3° 09:20 8.67 11% 70.5°
2026-03-22 Sun 44 0 0 — 87.3° 09:20 8.62 19% 77.5°
2026-03-23 Mon 44 0 0 — 87.3° 09:15 8.57 29% 85.1°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2026-02-22&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.