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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: 05-28 (15), 05-29 (15), 05-27 (13), 05-26 (12), 05-25 (11) — by astronomy; check the weather when the night is within four days.
2047-04-30astronomy score per night — click a bar for that night2047-05-29
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2047-04-30 Tue 1 — unknown — 89.8° 11:30 6.43 28% 78.4°
2047-05-01 Wed 1 — unknown — 89.8° 11:25 6.37 37% 89.6°
2047-05-02 Thu 1 — unknown — 89.6° 11:20 6.31 48% 101.0°
2047-05-03 Fri 1 — unknown — 89.6° 11:20 6.25 58% 112.6°
2047-05-04 Sat 1 — unknown — 89.7° 11:15 6.19 69% 124.3°
2047-05-05 Sun 1 — unknown — 89.8° 11:10 6.14 79% 135.4°
2047-05-06 Mon 2 — unknown 05:00–05:05 (marginal, 0.08 h) 89.8° 11:05 6.08 88% 145.1°
2047-05-07 Tue 2 — unknown 05:00–05:05 (marginal, 0.08 h) 89.6° 11:00 6.02 95% 151.0°
2047-05-08 Wed 2 — unknown — 89.6° 11:00 5.97 99% 150.4°
2047-05-09 Thu 2 — unknown — 89.8° 10:55 5.91 100% 143.4°
2047-05-10 Fri 2 — unknown 04:55–05:00 (marginal, 0.08 h) 89.8° 10:50 5.85 98% 133.0°
2047-05-11 Sat 3 — unknown 04:10–04:15 (marginal, 0.08 h) 89.7° 10:45 5.8 93% 121.2°
2047-05-12 Sun 2 — unknown 04:05–04:10 (marginal, 0.08 h) 89.5° 10:40 5.74 86% 108.9°
2047-05-13 Mon 3 — unknown 04:00–04:10 (marginal, 0.17 h) 89.7° 10:40 5.69 78% 96.7°
2047-05-14 Tue 3 — unknown 03:55–04:10 (marginal, 0.25 h) 89.8° 10:35 5.64 68% 84.9°
2047-05-15 Wed 3 — unknown 03:55–04:05 (marginal, 0.17 h) 89.8° 10:30 5.58 58% 73.5°
2047-05-16 Thu 3 — unknown 03:50–04:05 (marginal, 0.25 h) 89.6° 10:25 5.53 48% 62.7°
2047-05-17 Fri 4 — unknown 03:45–04:05 (marginal, 0.33 h) 89.5° 10:25 5.48 38% 52.5°
2047-05-18 Sat 5 — unknown 03:40–04:05 (marginal, 0.42 h) 89.7° 10:20 5.42 29% 43.3°
2047-05-19 Sun 5 — unknown 03:40–04:00 (marginal, 0.33 h) 89.8° 10:15 5.37 21% 35.4°
2047-05-20 Mon 7 — unknown 03:35–04:00 (marginal, 0.42 h) 89.8° 10:10 5.32 14% 30.0°
2047-05-21 Tue 8 — unknown 03:30–04:00 (marginal, 0.5 h) 89.6° 10:05 5.27 8% 28.4°
2047-05-22 Wed 9 — unknown 04:00–04:45 (marginal, 0.75 h) 89.6° 10:05 5.23 4% 31.0°
2047-05-23 Thu 10 — unknown 03:20–04:45 (marginal, 1.42 h) 89.8° 10:00 5.18 1% 37.2°
2047-05-24 Fri 10 — unknown 03:50–03:55 (good, 0.08 h) 89.8° 09:55 5.13 0% 45.4°
2047-05-25 Sat 11 — unknown 03:45–03:55 (good, 0.17 h) 89.7° 09:50 5.09 1% 54.9°
2047-05-26 Sun 12 — unknown 03:45–03:50 (good, 0.08 h) 89.5° 09:45 5.04 4% 65.2°
2047-05-27 Mon 13 — unknown 03:40–03:50 (good, 0.17 h) 89.7° 09:45 5.0 9% 76.0°
2047-05-28 Tue 15 — unknown 03:35–03:50 (good, 0.25 h) 89.8° 09:40 4.96 16% 87.0°
2047-05-29 Wed 15 — unknown 03:30–03:50 (good, 0.33 h) 89.8° 09:35 4.91 24% 98.4°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2047-04-30&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.