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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: 05-31 (13), 05-30 (11), 05-29 (10), 05-28 (9), 05-27 (8) — by astronomy; check the weather when the night is within four days.
2035-05-02astronomy score per night — click a bar for that night2035-05-31
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2035-05-02 Wed 1 — unknown — 89.6° 11:20 6.32 28% 57.0°
2035-05-03 Thu 1 — unknown — 89.5° 11:15 6.26 19% 48.4°
2035-05-04 Fri 1 — unknown — 89.6° 11:15 6.2 11% 41.4°
2035-05-05 Sat 1 — unknown — 89.8° 11:10 6.14 5% 37.3°
2035-05-06 Sun 2 — unknown 05:00–05:05 (marginal, 0.08 h) 89.7° 11:05 6.09 1% 37.7°
2035-05-07 Mon 2 — unknown 05:00–05:05 (marginal, 0.08 h) 89.6° 11:00 6.03 0% 42.7°
2035-05-08 Tue 2 — unknown 04:55–05:00 (marginal, 0.08 h) 89.5° 11:00 5.97 2% 51.1°
2035-05-09 Wed 2 — unknown 04:50–05:00 (marginal, 0.17 h) 89.7° 10:55 5.92 7% 61.4°
2035-05-10 Thu 2 — unknown 04:45–05:00 (marginal, 0.25 h) 89.8° 10:50 5.86 14% 72.7°
2035-05-11 Fri 3 — unknown 04:40–04:55 (marginal, 0.25 h) 89.7° 10:45 5.81 23% 84.3°
2035-05-12 Sat 3 — unknown 04:40–04:55 (marginal, 0.25 h) 89.5° 10:40 5.75 33% 95.7°
2035-05-13 Sun 4 — unknown 04:35–04:55 (marginal, 0.33 h) 89.6° 10:40 5.7 44% 106.8°
2035-05-14 Mon 5 — unknown 04:30–04:55 (marginal, 0.42 h) 89.7° 10:35 5.64 55% 117.1°
2035-05-15 Tue 4 — unknown 04:25–04:50 (marginal, 0.42 h) 89.8° 10:30 5.59 66% 126.4°
2035-05-16 Wed 5 — unknown 04:25–04:50 (marginal, 0.42 h) 89.7° 10:25 5.53 75% 134.3°
2035-05-17 Thu 5 — unknown 04:20–04:50 (marginal, 0.5 h) 89.5° 10:20 5.48 83% 140.1°
2035-05-18 Fri 6 — unknown 03:40–04:05 (marginal, 0.42 h) 89.6° 10:20 5.43 90% 142.9°
2035-05-19 Sat 5 — unknown 04:20–04:45 (marginal, 0.42 h) 89.8° 10:15 5.38 95% 142.3°
2035-05-20 Sun 6 — unknown 03:35–04:00 (marginal, 0.42 h) 89.7° 10:10 5.33 98% 138.5°
2035-05-21 Mon 7 — unknown 03:30–04:00 (marginal, 0.5 h) 89.6° 10:05 5.28 100% 132.4°
2035-05-22 Tue 7 — unknown 03:25–03:55 (marginal, 0.5 h) 89.5° 10:05 5.23 99% 124.8°
2035-05-23 Wed 7 — unknown 03:20–03:55 (marginal, 0.58 h) 89.7° 10:00 5.18 97% 116.3°
2035-05-24 Thu 7 — unknown 03:20–03:55 (marginal, 0.58 h) 89.8° 09:55 5.14 93% 107.3°
2035-05-25 Fri 7 — unknown 03:15–03:55 (marginal, 0.67 h) 89.7° 09:50 5.09 88% 98.0°
2035-05-26 Sat 7 — unknown 03:10–03:50 (marginal, 0.67 h) 89.5° 09:45 5.05 81% 88.5°
2035-05-27 Sun 8 — unknown 03:05–03:50 (marginal, 0.75 h) 89.6° 09:45 5.0 73% 78.9°
2035-05-28 Mon 9 — unknown 03:00–03:50 (marginal, 0.83 h) 89.7° 09:40 4.96 64% 69.4°
2035-05-29 Tue 10 — unknown 03:00–03:50 (marginal, 0.83 h) 89.8° 09:35 4.92 54% 60.2°
2035-05-30 Wed 11 — unknown 02:55–03:45 (marginal, 0.83 h) 89.7° 09:30 4.88 44% 51.5°
2035-05-31 Thu 13 — unknown 03:40–03:45 (good, 0.08 h) 89.5° 09:25 4.84 33% 43.9°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2035-05-02&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.