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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: 02-29 (24), 03-01 (24), 03-02 (22), 03-03 (21), 03-04 (19) — by astronomy; check the weather when the night is within four days.
2040-02-29astronomy score per night — click a bar for that night2040-03-29
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2040-02-29 Wed 24 — unknown 19:45–20:30 (good, 0.75 h) 89.8° 14:30 9.66 96% 135.7°
2040-03-01 Thu 24 — unknown 19:45–20:35 (good, 0.83 h) 89.7° 14:25 9.62 91% 141.3°
2040-03-02 Fri 22 — unknown 19:50–20:30 (good, 0.67 h) 89.5° 14:20 9.57 84% 143.5°
2040-03-03 Sat 21 — unknown 19:50–20:25 (good, 0.58 h) 89.6° 14:20 9.53 75% 141.6°
2040-03-04 Sun 19 — unknown 19:50–20:25 (good, 0.58 h) 89.8° 14:15 9.48 65% 135.9°
2040-03-05 Mon 17 — unknown 19:50–20:20 (good, 0.5 h) 89.8° 14:10 9.43 54% 127.6°
2040-03-06 Tue 14 — unknown 19:55–20:15 (good, 0.33 h) 89.6° 14:05 9.39 43% 117.7°
2040-03-07 Wed 13 — unknown 19:55–20:10 (good, 0.25 h) 89.5° 14:05 9.34 32% 106.8°
2040-03-08 Thu 11 — unknown 19:55–20:10 (good, 0.25 h) 89.7° 14:00 9.29 22% 95.4°
2040-03-09 Fri 10 — unknown 19:55–20:05 (good, 0.17 h) 89.8° 13:55 9.24 13% 83.8°
2040-03-10 Sat 9 — unknown 19:55–20:00 (good, 0.08 h) 89.7° 13:50 9.19 6% 72.4°
2040-03-11 Sun 7 — unknown 20:00–20:30 (marginal, 0.5 h) 89.6° 13:45 9.15 2% 61.5°
2040-03-12 Mon 6 — unknown 20:00–20:25 (marginal, 0.42 h) 89.6° 13:45 9.1 0% 51.6°
2040-03-13 Tue 5 — unknown 20:00–20:20 (marginal, 0.33 h) 89.7° 13:40 9.05 1% 43.5°
2040-03-14 Wed 4 — unknown 20:00–20:15 (marginal, 0.25 h) 89.8° 13:35 9.0 4% 38.1°
2040-03-15 Thu 3 — unknown 20:05–20:15 (marginal, 0.17 h) 89.7° 13:30 8.95 10% 36.4°
2040-03-16 Fri 2 — unknown 20:05–20:10 (marginal, 0.08 h) 89.5° 13:25 8.9 16% 38.6°
2040-03-17 Sat 1 — unknown — 89.6° 13:25 8.84 24% 43.8°
2040-03-18 Sun 1 — unknown — 89.8° 13:20 8.79 33% 50.9°
2040-03-19 Mon 1 — unknown — 89.8° 13:15 8.74 42% 59.2°
2040-03-20 Tue 0 — unknown — 89.6° 13:10 8.69 52% 68.1°
2040-03-21 Wed 0 — unknown — 89.5° 13:10 8.64 61% 77.3°
2040-03-22 Thu 0 — unknown — 89.7° 13:05 8.59 70% 86.8°
2040-03-23 Fri 0 — unknown — 89.8° 13:00 8.53 78% 96.5°
2040-03-24 Sat 0 — unknown — 89.7° 12:55 8.48 86% 106.2°
2040-03-25 Sun 0 — unknown — 89.6° 13:50 8.43 92% 115.8°
2040-03-26 Mon 0 — unknown — 89.6° 13:50 8.37 97% 125.0°
2040-03-27 Tue 0 — unknown — 89.7° 13:45 8.32 99% 133.4°
2040-03-28 Wed 0 — unknown — 89.8° 13:40 8.27 100% 139.9°
2040-03-29 Thu 0 — unknown — 89.7° 13:35 8.21 98% 143.4°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2040-02-29&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.