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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 Andromeda Galaxy: 02-22 (38), 02-23 (36), 02-24 (33), 02-25 (33), 02-26 (31) — by astronomy; check the weather when the night is within four days.
2036-02-22astronomy score per night — click a bar for that night2036-03-22
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2036-02-22 Fri 38 — unknown 19:35–21:05 (good, 1.5 h) 89.5° 15:00 9.97 16% 97.0°
2036-02-23 Sat 36 — unknown 19:40–21:05 (good, 1.42 h) 89.7° 14:55 9.93 10% 87.7°
2036-02-24 Sun 33 — unknown 19:40–21:00 (good, 1.33 h) 89.8° 14:50 9.89 5% 78.4°
2036-02-25 Mon 33 — unknown 19:40–20:55 (good, 1.25 h) 89.7° 14:45 9.84 2% 69.2°
2036-02-26 Tue 31 — unknown 19:40–20:50 (good, 1.17 h) 89.6° 14:40 9.8 0% 60.3°
2036-02-27 Wed 28 — unknown 19:45–20:45 (good, 1.0 h) 89.6° 14:40 9.76 0% 52.1°
2036-02-28 Thu 27 — unknown 19:45–20:45 (good, 1.0 h) 89.7° 14:35 9.71 3% 45.0°
2036-02-29 Fri 24 — unknown 19:45–20:40 (good, 0.92 h) 89.8° 14:30 9.67 7% 40.0°
2036-03-01 Sat 21 — unknown 19:45–20:30 (good, 0.75 h) 89.7° 14:25 9.62 14% 38.0°
2036-03-02 Sun 17 — unknown 19:50–20:20 (good, 0.5 h) 89.5° 14:20 9.57 22% 39.6°
2036-03-03 Mon 14 — unknown 19:50–20:05 (good, 0.25 h) 89.6° 14:20 9.53 31% 44.7°
2036-03-04 Tue 11 — unknown 19:50–19:55 (good, 0.08 h) 89.7° 14:15 9.48 42% 52.3°
2036-03-05 Wed 9 — unknown 19:50–20:50 (marginal, 1.0 h) 89.8° 14:10 9.44 53% 61.6°
2036-03-06 Thu 7 — unknown 19:55–20:45 (marginal, 0.83 h) 89.6° 14:05 9.39 64% 72.0°
2036-03-07 Fri 6 — unknown 19:55–20:40 (marginal, 0.75 h) 89.5° 14:05 9.34 75% 83.2°
2036-03-08 Sat 6 — unknown 19:55–20:40 (marginal, 0.75 h) 89.7° 14:00 9.29 84% 94.6°
2036-03-09 Sun 6 — unknown 19:55–20:35 (marginal, 0.67 h) 89.8° 13:55 9.24 92% 106.1°
2036-03-10 Mon 7 — unknown 19:55–20:35 (marginal, 0.67 h) 89.7° 13:50 9.2 97% 117.1°
2036-03-11 Tue 5 — unknown 20:00–20:30 (marginal, 0.5 h) 89.6° 13:45 9.15 100% 127.2°
2036-03-12 Wed 5 — unknown 20:00–20:25 (marginal, 0.42 h) 89.6° 13:45 9.1 100% 135.4°
2036-03-13 Thu 4 — unknown 20:00–20:20 (marginal, 0.33 h) 89.7° 13:40 9.05 97% 140.6°
2036-03-14 Fri 4 — unknown 20:00–20:15 (marginal, 0.25 h) 89.8° 13:35 9.0 92% 142.0°
2036-03-15 Sat 3 — unknown 20:05–20:15 (marginal, 0.17 h) 89.7° 13:30 8.95 85% 139.4°
2036-03-16 Sun 2 — unknown 20:05–20:10 (marginal, 0.08 h) 89.5° 13:25 8.9 77% 133.8°
2036-03-17 Mon 1 — unknown — 89.6° 13:25 8.85 68% 126.4°
2036-03-18 Tue 1 — unknown — 89.7° 13:20 8.8 58% 118.0°
2036-03-19 Wed 1 — unknown — 89.8° 13:15 8.74 48% 109.1°
2036-03-20 Thu 1 — unknown — 89.6° 13:10 8.69 39% 99.9°
2036-03-21 Fri 0 — unknown — 89.5° 13:10 8.64 30% 90.6°
2036-03-22 Sat 0 — unknown — 89.7° 13:05 8.59 22% 81.3°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2036-02-22&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.