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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: 06-12 (20), 06-04 (19), 06-01 (18), 06-03 (18), 06-05 (18) — by astronomy; check the weather when the night is within four days.
2031-05-14astronomy score per night — click a bar for that night2031-06-12
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2031-05-14 Wed 3 — unknown 03:55–04:10 (marginal, 0.25 h) 89.7° 10:35 5.64 38% 53.8°
2031-05-15 Thu 3 — unknown 03:55–04:05 (marginal, 0.17 h) 89.7° 10:30 5.59 27% 44.0°
2031-05-16 Fri 4 — unknown 04:30–04:50 (marginal, 0.33 h) 89.7° 10:25 5.54 18% 36.0°
2031-05-17 Sat 6 — unknown 03:45–04:05 (marginal, 0.33 h) 89.5° 10:20 5.48 11% 31.3°
2031-05-18 Sun 7 — unknown 04:15–04:50 (marginal, 0.58 h) 89.6° 10:20 5.43 6% 31.0°
2031-05-19 Mon 7 — unknown 04:10–04:45 (marginal, 0.58 h) 89.7° 10:15 5.38 2% 35.1°
2031-05-20 Tue 7 — unknown 04:05–04:45 (marginal, 0.67 h) 89.7° 10:10 5.33 0% 42.1°
2031-05-21 Wed 8 — unknown 04:05–04:45 (marginal, 0.67 h) 89.6° 10:05 5.28 0% 50.7°
2031-05-22 Thu 9 — unknown 04:00–04:45 (marginal, 0.75 h) 89.5° 10:05 5.23 2% 60.1°
2031-05-23 Fri 10 — unknown 03:20–04:45 (marginal, 1.42 h) 89.7° 10:00 5.18 6% 70.0°
2031-05-24 Sat 10 — unknown 03:50–03:55 (good, 0.08 h) 89.7° 09:55 5.14 12% 80.1°
2031-05-25 Sun 11 — unknown 03:45–03:55 (good, 0.17 h) 89.7° 09:50 5.09 18% 90.2°
2031-05-26 Mon 12 — unknown 03:45–03:50 (good, 0.08 h) 89.6° 09:45 5.05 26% 100.4°
2031-05-27 Tue 13 — unknown 03:40–03:50 (good, 0.17 h) 89.6° 09:45 5.0 35% 110.6°
2031-05-28 Wed 15 — unknown 03:35–03:50 (good, 0.25 h) 89.7° 09:40 4.96 45% 120.5°
2031-05-29 Thu 16 — unknown 03:30–03:50 (good, 0.33 h) 89.7° 09:35 4.92 55% 130.2°
2031-05-30 Fri 15 — unknown 03:30–03:45 (good, 0.25 h) 89.7° 09:30 4.88 65% 139.0°
2031-05-31 Sat 17 — unknown 03:25–03:45 (good, 0.33 h) 89.5° 09:25 4.84 74% 146.0°
2031-06-01 Sun 18 — unknown 03:20–03:45 (good, 0.42 h) 89.6° 09:25 4.8 83% 149.4°
2031-06-02 Mon 17 — unknown 03:25–03:45 (good, 0.33 h) 89.7° 09:20 4.77 91% 147.4°
2031-06-03 Tue 18 — unknown 03:20–03:45 (good, 0.42 h) 89.7° 09:15 4.73 96% 140.5°
2031-06-04 Wed 19 — unknown 03:20–03:45 (good, 0.42 h) 89.6° 09:10 4.7 100% 130.4°
2031-06-05 Thu 18 — unknown 03:15–03:40 (good, 0.42 h) 89.5° 09:10 4.67 100% 118.6°
2031-06-06 Fri 17 — unknown 03:20–03:40 (good, 0.33 h) 89.7° 09:05 4.64 97% 106.0°
2031-06-07 Sat 15 — unknown 03:25–03:40 (good, 0.25 h) 89.7° 09:00 4.61 91% 93.2°
2031-06-08 Sun 14 — unknown 02:20–03:40 (marginal, 1.33 h) 89.7° 08:55 4.59 83% 80.4°
2031-06-09 Mon 14 — unknown 02:15–03:40 (marginal, 1.42 h) 89.6° 08:50 4.56 74% 68.1°
2031-06-10 Tue 15 — unknown 02:10–03:40 (marginal, 1.5 h) 89.5° 08:50 4.54 63% 56.6°
2031-06-11 Wed 18 — unknown 03:10–03:40 (good, 0.5 h) 89.7° 08:45 4.52 52% 46.2°
2031-06-12 Thu 20 — unknown 03:00–03:40 (good, 0.67 h) 89.7° 08:40 4.5 41% 37.6°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2031-05-14&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.