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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: 06-11 (31), 06-10 (30), 06-09 (28), 06-08 (27), 06-07 (26) — by astronomy; check the weather when the night is within four days.
2046-05-13astronomy score per night — click a bar for that night2046-06-11
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
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°
2046-05-23 Wed 7 — unknown 03:20–03:55 (marginal, 0.58 h) 89.6° 10:00 5.17 84% 97.0°
2046-05-24 Thu 7 — unknown 03:15–03:55 (marginal, 0.67 h) 89.8° 09:55 5.12 76% 85.9°
2046-05-25 Fri 7 — unknown 03:15–03:55 (marginal, 0.67 h) 89.8° 09:50 5.07 67% 75.1°
2046-05-26 Sat 7 — unknown 03:10–03:50 (marginal, 0.67 h) 89.7° 09:45 5.03 57% 64.7°
2046-05-27 Sun 9 — unknown 03:05–03:50 (marginal, 0.75 h) 89.5° 09:40 4.99 48% 54.8°
2046-05-28 Mon 10 — unknown 03:00–03:50 (marginal, 0.83 h) 89.7° 09:40 4.94 39% 45.5°
2046-05-29 Tue 12 — unknown 03:45–03:50 (good, 0.08 h) 89.8° 09:35 4.9 30% 37.3°
2046-05-30 Wed 13 — unknown 03:35–03:45 (good, 0.17 h) 89.8° 09:30 4.86 21% 31.1°
2046-05-31 Thu 16 — unknown 03:25–03:45 (good, 0.33 h) 89.6° 09:25 4.83 14% 28.3°
2046-06-01 Fri 19 — unknown 03:20–03:45 (good, 0.42 h) 89.5° 09:25 4.79 8% 30.2°
2046-06-02 Sat 21 — unknown 03:15–03:45 (good, 0.5 h) 89.7° 09:20 4.75 3% 36.2°
2046-06-03 Sun 22 — unknown 03:10–03:45 (good, 0.58 h) 89.8° 09:15 4.72 1% 45.0°
2046-06-04 Mon 23 — unknown 03:05–03:45 (good, 0.67 h) 89.8° 09:10 4.69 0% 55.2°
2046-06-05 Tue 24 — unknown 03:05–03:40 (good, 0.58 h) 89.6° 09:05 4.66 2% 66.5°
2046-06-06 Wed 25 — unknown 03:00–03:40 (good, 0.67 h) 89.6° 09:05 4.63 6% 78.3°
2046-06-07 Thu 26 — unknown 02:55–03:40 (good, 0.75 h) 89.8° 09:00 4.6 12% 90.4°
2046-06-08 Fri 27 — unknown 02:50–03:40 (good, 0.83 h) 89.8° 08:55 4.58 21% 102.7°
2046-06-09 Sat 28 — unknown 02:45–03:40 (good, 0.92 h) 89.7° 08:50 4.55 31% 114.9°
2046-06-10 Sun 30 — unknown 02:45–03:40 (good, 0.92 h) 89.5° 08:45 4.53 42% 126.7°
2046-06-11 Mon 31 — unknown 02:40–03:40 (good, 1.0 h) 89.7° 08:45 4.51 53% 137.5°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2046-05-13&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.