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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 North America Nebula: 03-25 (47), 03-24 (46), 03-26 (46), 03-27 (46), 03-23 (45) — by astronomy; check the weather when the night is within four days.
2026-02-26astronomy score per night — click a bar for that night2026-03-27
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2026-02-26 Thu 25 58 15 04:25–05:30 (marginal, 1.08 h) 87.2° 10:50 9.78 76% 102.0°
2026-02-27 Fri 24 94 23 04:50–05:30 (good, 0.67 h) 87.2° 10:50 9.74 85% 108.9°
2026-02-28 Sat 22 100 22 04:40–05:25 (good, 0.75 h) 87.3° 10:45 9.69 92% 114.8°
2026-03-01 Sun 22 56 12 04:45–05:00 (good, 0.25 h) 87.3° 10:40 9.65 97% 119.3°
2026-03-02 Mon 23 0 0 — 87.3° 10:35 9.6 100% 122.1°
2026-03-03 Tue 23 99 23 04:30–05:20 (good, 0.83 h) 87.2° 10:30 9.56 100% 122.9°
2026-03-04 Wed 23 0 0 — 87.2° 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% 118.9°
2026-03-06 Fri 24 70 17 03:30–05:15 (marginal, 1.75 h) 87.3° 10:20 9.41 88% 114.7°
2026-03-07 Sat 24 85 20 04:20–05:00 (good, 0.67 h) 87.2° 10:15 9.37 81% 109.6°
2026-03-08 Sun 24 27 7 05:00–05:15 (good, 0.25 h) 87.2° 10:15 9.32 72% 103.8°
2026-03-09 Mon 25 85 21 04:20–05:10 (good, 0.83 h) 87.2° 10:10 9.27 64% 97.6°
2026-03-10 Tue 27 100 27 04:05–05:10 (good, 1.08 h) 87.3° 10:05 9.22 54% 91.3°
2026-03-11 Wed 28 55 15 03:20–05:10 (marginal, 1.83 h) 87.3° 10:00 9.17 45% 84.9°
2026-03-12 Thu 30 98 29 04:00–05:05 (good, 1.08 h) 87.2° 09:55 9.13 36% 78.5°
2026-03-13 Fri 34 100 34 03:40–05:05 (good, 1.42 h) 87.2° 09:55 9.08 27% 72.5°
2026-03-14 Sat 37 95 35 03:40–05:05 (good, 1.42 h) 87.3° 09:50 9.03 18% 67.0°
2026-03-15 Sun 38 100 38 03:30–05:00 (good, 1.5 h) 87.3° 09:45 8.98 11% 62.3°
2026-03-16 Mon 39 72 28 03:50–05:00 (good, 1.17 h) 87.3° 09:40 8.93 5% 58.9°
2026-03-17 Tue 41 0 0 — 87.2° 09:35 8.88 2% 57.2°
2026-03-18 Wed 41 0 0 — 87.2° 09:35 8.82 0% 57.5°
2026-03-19 Thu 42 0 0 — 87.3° 09:30 8.77 1% 60.1°
2026-03-20 Fri 42 0 0 — 87.3° 09:25 8.72 5% 64.5°
2026-03-21 Sat 44 0 0 — 87.2° 09:20 8.67 11% 70.5°
2026-03-22 Sun 44 0 0 — 87.2° 09:20 8.62 19% 77.5°
2026-03-23 Mon 45 0 0 — 87.2° 09:15 8.57 29% 85.1°
2026-03-24 Tue 46 0 0 — 87.3° 09:10 8.51 40% 92.8°
2026-03-25 Wed 47 76 36 02:55–04:00 (good, 1.08 h) 87.3° 09:05 8.46 52% 100.3°
2026-03-26 Thu 46 0 0 — 87.2° 09:00 8.41 63% 107.3°
2026-03-27 Fri 46 11 5 02:40–03:00 (marginal, 0.33 h) 87.2° 09:00 8.35 73% 113.4°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2026-02-26&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.