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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: 05-23 (8), 05-18 (7), 05-20 (7), 05-21 (7), 05-22 (7) — by astronomy; check the weather when the night is within four days.
2043-04-24astronomy score per night — click a bar for that night2043-05-23
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2043-04-24 Fri 0 — unknown — 89.6° 11:55 6.78 100% 147.0°
2043-04-25 Sat 0 — unknown — 89.8° 11:50 6.72 98% 142.1°
2043-04-26 Sun 0 — unknown — 89.8° 11:45 6.66 94% 134.8°
2043-04-27 Mon 1 — unknown — 89.7° 11:40 6.6 88% 126.2°
2043-04-28 Tue 1 — unknown — 89.5° 11:35 6.54 82% 116.8°
2043-04-29 Wed 1 — unknown — 89.6° 11:35 6.49 74% 106.8°
2043-04-30 Thu 1 — unknown — 89.8° 11:30 6.43 64% 96.4°
2043-05-01 Fri 1 — unknown — 89.8° 11:25 6.37 55% 85.7°
2043-05-02 Sat 1 — unknown — 89.6° 11:20 6.31 44% 74.7°
2043-05-03 Sun 1 — unknown — 89.5° 11:20 6.25 34% 63.7°
2043-05-04 Mon 1 — unknown — 89.7° 11:15 6.2 24% 52.8°
2043-05-05 Tue 1 — unknown — 89.8° 11:10 6.14 15% 42.7°
2043-05-06 Wed 2 — unknown 05:00–05:05 (marginal, 0.08 h) 89.7° 11:05 6.08 7% 34.9°
2043-05-07 Thu 2 — unknown 05:00–05:05 (marginal, 0.08 h) 89.6° 11:00 6.03 2% 31.5°
2043-05-08 Fri 2 — unknown 04:55–05:00 (marginal, 0.08 h) 89.6° 11:00 5.97 0% 34.3°
2043-05-09 Sat 2 — unknown 04:50–05:00 (marginal, 0.17 h) 89.7° 10:55 5.91 1% 42.2°
2043-05-10 Sun 2 — unknown 04:45–05:00 (marginal, 0.25 h) 89.8° 10:50 5.86 5% 52.7°
2043-05-11 Mon 3 — unknown 04:40–04:55 (marginal, 0.25 h) 89.7° 10:45 5.8 12% 64.4°
2043-05-12 Tue 3 — unknown 04:40–04:55 (marginal, 0.25 h) 89.5° 10:40 5.75 20% 76.4°
2043-05-13 Wed 4 — unknown 04:35–04:55 (marginal, 0.33 h) 89.6° 10:40 5.69 30% 88.3°
2043-05-14 Thu 5 — unknown 04:30–04:55 (marginal, 0.42 h) 89.8° 10:35 5.64 40% 99.8°
2043-05-15 Fri 4 — unknown 04:25–04:50 (marginal, 0.42 h) 89.8° 10:30 5.58 50% 110.8°
2043-05-16 Sat 5 — unknown 04:25–04:50 (marginal, 0.42 h) 89.7° 10:25 5.53 61% 121.1°
2043-05-17 Sun 6 — unknown 04:20–04:50 (marginal, 0.5 h) 89.5° 10:25 5.48 70% 130.6°
2043-05-18 Mon 7 — unknown 04:15–04:50 (marginal, 0.58 h) 89.7° 10:20 5.43 79% 138.8°
2043-05-19 Tue 6 — unknown 04:10–04:45 (marginal, 0.58 h) 89.8° 10:15 5.38 86% 145.0°
2043-05-20 Wed 7 — unknown 04:15–04:45 (marginal, 0.5 h) 89.8° 10:10 5.33 92% 148.3°
2043-05-21 Thu 7 — unknown 03:30–04:00 (marginal, 0.5 h) 89.6° 10:05 5.28 96% 147.7°
2043-05-22 Fri 7 — unknown 03:25–03:55 (marginal, 0.5 h) 89.6° 10:05 5.23 99% 143.5°
2043-05-23 Sat 8 — unknown 03:20–03:55 (marginal, 0.58 h) 89.7° 10:00 5.18 100% 136.8°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2043-04-24&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.