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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: 05-21 (7), 05-19 (6), 05-20 (6), 05-22 (6), 05-14 (5) — by astronomy; check the weather when the night is within four days.
2046-04-23astronomy score per night — click a bar for that night2046-05-22
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2046-04-23 Mon 0 — unknown — 89.8° 12:00 6.82 87% 126.4°
2046-04-24 Tue 0 — unknown — 89.6° 11:50 6.76 79% 115.2°
2046-04-25 Wed 0 — unknown — 89.6° 11:50 6.7 70% 104.1°
2046-04-26 Thu 0 — unknown — 89.8° 11:45 6.64 60% 93.0°
2046-04-27 Fri 0 — unknown — 89.8° 11:40 6.59 50% 82.3°
2046-04-28 Sat 1 — unknown — 89.7° 11:35 6.53 41% 71.8°
2046-04-29 Sun 1 — unknown — 89.5° 11:30 6.47 32% 61.6°
2046-04-30 Mon 1 — unknown — 89.7° 11:30 6.41 23% 51.9°
2046-05-01 Tue 1 — unknown — 89.8° 11:25 6.35 16% 42.9°
2046-05-02 Wed 1 — unknown — 89.8° 11:20 6.3 10% 35.2°
2046-05-03 Thu 1 — unknown — 89.6° 11:15 6.24 5% 29.9°
2046-05-04 Fri 1 — unknown — 89.6° 11:15 6.18 2% 28.5°
2046-05-05 Sat 2 — unknown — 89.7° 11:10 6.12 0% 31.8°
2046-05-06 Sun 2 — unknown 05:00–05:05 (marginal, 0.08 h) 89.8° 11:05 6.07 1% 38.8°
2046-05-07 Mon 2 — unknown 04:55–05:00 (marginal, 0.08 h) 89.7° 11:00 6.01 4% 47.9°
2046-05-08 Tue 2 — unknown 04:55–05:00 (marginal, 0.08 h) 89.6° 10:55 5.95 8% 58.3°
2046-05-09 Wed 2 — unknown 04:50–05:00 (marginal, 0.17 h) 89.6° 10:55 5.9 15% 69.5°
2046-05-10 Thu 3 — unknown 04:45–05:00 (marginal, 0.25 h) 89.8° 10:50 5.84 24% 81.2°
2046-05-11 Fri 3 — unknown 04:40–04:55 (marginal, 0.25 h) 89.8° 10:45 5.79 33% 93.2°
2046-05-12 Sat 3 — unknown 04:35–04:55 (marginal, 0.33 h) 89.7° 10:40 5.73 44% 105.3°
2046-05-13 Sun 4 — unknown 04:35–04:55 (marginal, 0.33 h) 89.5° 10:35 5.68 56% 117.4°
2046-05-14 Mon 5 — unknown 04:30–04:55 (marginal, 0.42 h) 89.7° 10:35 5.62 67% 129.1°
2046-05-15 Tue 5 — unknown 04:25–04:50 (marginal, 0.42 h) 89.8° 10:30 5.57 77% 139.8°
2046-05-16 Wed 5 — unknown 04:20–04:50 (marginal, 0.5 h) 89.8° 10:25 5.52 86% 148.1°
2046-05-17 Thu 5 — unknown 04:20–04:50 (marginal, 0.5 h) 89.6° 10:20 5.46 93% 151.6°
2046-05-18 Fri 5 — unknown 04:25–04:50 (marginal, 0.42 h) 89.6° 10:20 5.41 98% 148.7°
2046-05-19 Sat 6 — unknown 03:35–04:00 (marginal, 0.42 h) 89.7° 10:15 5.36 100% 141.0°
2046-05-20 Sun 6 — unknown 03:35–04:00 (marginal, 0.42 h) 89.8° 10:10 5.31 99% 130.8°
2046-05-21 Mon 7 — unknown 03:30–04:00 (marginal, 0.5 h) 89.7° 10:05 5.26 96% 119.7°
2046-05-22 Tue 6 — unknown 03:25–03:55 (marginal, 0.5 h) 89.6° 10:00 5.21 91% 108.3°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2046-04-23&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.