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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: 06-03 (22), 06-02 (21), 06-07 (21), 06-04 (20), 06-05 (20) — by astronomy; check the weather when the night is within four days.
2028-05-15astronomy score per night — click a bar for that night2028-06-13
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2028-05-15 Mon 3 — unknown 03:50–04:05 (marginal, 0.25 h) 89.5° 10:25 5.55 55% 70.5°
2028-05-16 Tue 4 — unknown 03:45–04:05 (marginal, 0.33 h) 89.6° 10:25 5.5 46% 60.3°
2028-05-17 Wed 5 — unknown 03:45–04:05 (marginal, 0.33 h) 89.7° 10:20 5.45 36% 50.7°
2028-05-18 Thu 5 — unknown 03:40–04:00 (marginal, 0.33 h) 89.7° 10:15 5.39 27% 41.7°
2028-05-19 Fri 6 — unknown 03:35–04:00 (marginal, 0.42 h) 89.6° 10:10 5.34 19% 34.2°
2028-05-20 Sat 8 — unknown 03:30–04:00 (marginal, 0.5 h) 89.5° 10:10 5.29 12% 29.2°
2028-05-21 Sun 9 — unknown 04:00–04:45 (marginal, 0.75 h) 89.6° 10:05 5.24 6% 28.6°
2028-05-22 Mon 9 — unknown 03:25–04:45 (marginal, 1.33 h) 89.7° 10:00 5.2 2% 32.8°
2028-05-23 Tue 10 — unknown 03:50–03:55 (good, 0.08 h) 89.7° 09:55 5.15 0% 40.6°
2028-05-24 Wed 11 — unknown 03:50–03:55 (good, 0.08 h) 89.6° 09:50 5.1 0% 50.5°
2028-05-25 Thu 12 — unknown 03:45–03:50 (good, 0.08 h) 89.5° 09:50 5.06 3% 61.6°
2028-05-26 Fri 13 — unknown 03:40–03:50 (good, 0.17 h) 89.7° 09:45 5.01 8% 73.4°
2028-05-27 Sat 14 — unknown 03:35–03:50 (good, 0.25 h) 89.7° 09:40 4.97 15% 85.6°
2028-05-28 Sun 15 — unknown 03:30–03:50 (good, 0.33 h) 89.7° 09:35 4.93 24% 98.0°
2028-05-29 Mon 16 — unknown 03:30–03:50 (good, 0.33 h) 89.5° 09:30 4.89 34% 110.3°
2028-05-30 Tue 17 — unknown 03:25–03:45 (good, 0.33 h) 89.6° 09:30 4.85 46% 122.3°
2028-05-31 Wed 18 — unknown 03:20–03:45 (good, 0.42 h) 89.7° 09:25 4.81 57% 133.6°
2028-06-01 Thu 19 — unknown 03:15–03:45 (good, 0.5 h) 89.7° 09:20 4.78 68% 143.4°
2028-06-02 Fri 21 — unknown 03:15–03:45 (good, 0.5 h) 89.6° 09:15 4.74 78% 150.1°
2028-06-03 Sat 22 — unknown 03:15–03:45 (good, 0.5 h) 89.5° 09:10 4.71 87% 151.5°
2028-06-04 Sun 20 — unknown 03:15–03:40 (good, 0.42 h) 89.6° 09:10 4.68 93% 147.1°
2028-06-05 Mon 20 — unknown 03:10–03:40 (good, 0.5 h) 89.7° 09:05 4.65 98% 138.7°
2028-06-06 Tue 20 — unknown 03:10–03:40 (good, 0.5 h) 89.7° 09:00 4.62 100% 128.6°
2028-06-07 Wed 21 — unknown 03:05–03:40 (good, 0.58 h) 89.6° 08:55 4.59 99% 117.7°
2028-06-08 Thu 19 — unknown 03:10–03:40 (good, 0.5 h) 89.5° 08:55 4.57 97% 106.6°
2028-06-09 Fri 18 — unknown 03:10–03:40 (good, 0.5 h) 89.7° 08:50 4.54 92% 95.5°
2028-06-10 Sat 17 — unknown 03:20–03:40 (good, 0.33 h) 89.7° 08:45 4.52 86% 84.6°
2028-06-11 Sun 16 — unknown 02:05–03:40 (marginal, 1.58 h) 89.7° 08:40 4.5 79% 73.9°
2028-06-12 Mon 17 — unknown 02:00–03:40 (marginal, 1.67 h) 89.5° 08:35 4.49 71% 63.6°
2028-06-13 Tue 18 — unknown 01:55–04:30 (marginal, 2.58 h) 89.6° 08:35 4.47 62% 53.7°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2028-05-15&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.