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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: 05-13 (4), 05-14 (4), 05-15 (4), 05-16 (4), 05-10 (3) — by astronomy; check the weather when the night is within four days.
2030-04-17astronomy score per night — click a bar for that night2030-05-16
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2030-04-17 Wed 0 — unknown — 89.6° 12:25 7.18 100% 150.6°
2030-04-18 Thu 0 — unknown — 89.7° 12:20 7.12 99% 147.6°
2030-04-19 Fri 0 — unknown — 89.7° 12:15 7.06 95% 139.5°
2030-04-20 Sat 0 — unknown — 89.6° 12:10 7.0 89% 128.6°
2030-04-21 Sun 0 — unknown — 89.5° 12:05 6.94 80% 116.7°
2030-04-22 Mon 0 — unknown — 89.7° 12:00 6.89 70% 104.4°
2030-04-23 Tue 0 — unknown — 89.7° 12:00 6.83 59% 92.3°
2030-04-24 Wed 0 — unknown — 89.6° 11:50 6.77 48% 80.5°
2030-04-25 Thu 0 — unknown — 89.5° 11:50 6.71 38% 69.1°
2030-04-26 Fri 0 — unknown — 89.7° 11:45 6.65 28% 58.3°
2030-04-27 Sat 1 — unknown — 89.7° 11:40 6.59 20% 48.4°
2030-04-28 Sun 1 — unknown — 89.7° 11:35 6.54 12% 39.6°
2030-04-29 Mon 1 — unknown — 89.5° 11:30 6.48 7% 33.0°
2030-04-30 Tue 1 — unknown — 89.6° 11:30 6.42 3% 29.6°
2030-05-01 Wed 1 — unknown — 89.7° 11:25 6.36 0% 30.5°
2030-05-02 Thu 1 — unknown — 89.7° 11:20 6.3 0% 35.2°
2030-05-03 Fri 1 — unknown — 89.6° 11:15 6.25 2% 42.5°
2030-05-04 Sat 1 — unknown — 89.5° 11:10 6.19 5% 51.2°
2030-05-05 Sun 2 — unknown — 89.6° 11:10 6.13 10% 60.7°
2030-05-06 Mon 2 — unknown 05:00–05:05 (marginal, 0.08 h) 89.7° 11:05 6.07 16% 70.7°
2030-05-07 Tue 2 — unknown 04:55–05:05 (marginal, 0.17 h) 89.7° 11:00 6.02 24% 81.1°
2030-05-08 Wed 2 — unknown 04:55–05:00 (marginal, 0.08 h) 89.6° 10:55 5.96 32% 91.7°
2030-05-09 Thu 2 — unknown 04:50–05:00 (marginal, 0.17 h) 89.5° 10:55 5.9 42% 102.5°
2030-05-10 Fri 3 — unknown 04:45–05:00 (marginal, 0.25 h) 89.7° 10:50 5.85 52% 113.4°
2030-05-11 Sat 3 — unknown 04:40–04:55 (marginal, 0.25 h) 89.7° 10:45 5.79 63% 124.3°
2030-05-12 Sun 3 — unknown 04:35–04:55 (marginal, 0.33 h) 89.7° 10:40 5.74 73% 134.7°
2030-05-13 Mon 4 — unknown 04:35–04:55 (marginal, 0.33 h) 89.5° 10:35 5.68 82% 143.9°
2030-05-14 Tue 4 — unknown 04:30–04:55 (marginal, 0.42 h) 89.6° 10:35 5.63 90% 149.8°
2030-05-15 Wed 4 — unknown 03:50–04:05 (marginal, 0.25 h) 89.7° 10:30 5.58 96% 149.8°
2030-05-16 Thu 4 — unknown 04:30–04:50 (marginal, 0.33 h) 89.7° 10:25 5.52 100% 143.6°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2030-04-17&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.