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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: 02-25 (31), 02-26 (29), 02-27 (27), 02-28 (26), 03-01 (25) — by astronomy; check the weather when the night is within four days.
2041-02-25astronomy score per night — click a bar for that night2041-03-26
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2041-02-25 Mon 31 — unknown 19:40–20:50 (good, 1.17 h) 89.6° 14:45 9.81 29% 113.3°
2041-02-26 Tue 29 — unknown 19:45–20:50 (good, 1.08 h) 89.7° 14:40 9.77 20% 101.9°
2041-02-27 Wed 27 — unknown 19:45–20:45 (good, 1.0 h) 89.8° 14:35 9.72 11% 89.8°
2041-02-28 Thu 26 — unknown 19:45–20:40 (good, 0.92 h) 89.7° 14:30 9.68 5% 77.5°
2041-03-01 Fri 25 — unknown 19:45–20:35 (good, 0.83 h) 89.5° 14:25 9.63 1% 65.5°
2041-03-02 Sat 22 — unknown 19:50–20:30 (good, 0.67 h) 89.6° 14:25 9.58 0% 54.1°
2041-03-03 Sun 21 — unknown 19:50–20:30 (good, 0.67 h) 89.8° 14:20 9.54 3% 44.4°
2041-03-04 Mon 18 — unknown 19:50–20:20 (good, 0.5 h) 89.8° 14:15 9.49 8% 37.5°
2041-03-05 Tue 15 — unknown 19:50–20:15 (good, 0.42 h) 89.6° 14:10 9.45 15% 34.9°
2041-03-06 Wed 12 — unknown 19:50–20:00 (good, 0.17 h) 89.5° 14:10 9.4 23% 37.0°
2041-03-07 Thu 8 — unknown 19:55–20:45 (marginal, 0.83 h) 89.7° 14:05 9.35 33% 42.8°
2041-03-08 Fri 6 — unknown 19:55–20:40 (marginal, 0.75 h) 89.8° 14:00 9.3 43% 50.6°
2041-03-09 Sat 5 — unknown 19:55–20:35 (marginal, 0.67 h) 89.7° 13:55 9.25 53% 59.5°
2041-03-10 Sun 4 — unknown 19:55–20:25 (marginal, 0.5 h) 89.6° 13:50 9.21 62% 69.0°
2041-03-11 Mon 3 — unknown 20:00–20:25 (marginal, 0.42 h) 89.6° 13:50 9.16 71% 78.6°
2041-03-12 Tue 3 — unknown 20:00–20:20 (marginal, 0.33 h) 89.7° 13:45 9.11 80% 88.3°
2041-03-13 Wed 3 — unknown 20:00–20:20 (marginal, 0.33 h) 89.8° 13:40 9.06 86% 98.0°
2041-03-14 Thu 3 — unknown 20:00–20:20 (marginal, 0.33 h) 89.7° 13:35 9.01 92% 107.5°
2041-03-15 Fri 2 — unknown 20:05–20:15 (marginal, 0.17 h) 89.5° 13:30 8.96 96% 116.8°
2041-03-16 Sat 2 — unknown 20:05–20:10 (marginal, 0.08 h) 89.6° 13:30 8.91 99% 125.7°
2041-03-17 Sun 1 — unknown — 89.8° 13:25 8.86 100% 133.8°
2041-03-18 Mon 1 — unknown — 89.8° 13:20 8.81 99% 140.3°
2041-03-19 Tue 1 — unknown — 89.7° 13:15 8.75 96% 144.4°
2041-03-20 Wed 1 — unknown — 89.5° 13:15 8.7 91% 144.9°
2041-03-21 Thu 1 — unknown — 89.7° 13:10 8.65 84% 141.6°
2041-03-22 Fri 0 — unknown — 89.8° 13:05 8.6 76% 135.1°
2041-03-23 Sat 0 — unknown — 89.8° 13:00 8.55 66% 126.5°
2041-03-24 Sun 0 — unknown — 89.6° 12:55 8.49 56% 116.5°
2041-03-25 Mon 0 — unknown — 89.6° 12:55 8.44 44% 105.6°
2041-03-26 Tue 0 — unknown — 89.7° 12:50 8.39 33% 94.1°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2041-02-25&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.