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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.

2035-04-22astronomy score per night — click a bar for that night2035-05-21
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2035-04-22 Sun 0 — unknown — 79.1° 12:55 6.9 100% 156.3°
2035-04-23 Mon 0 — unknown — 79.1° 12:50 6.84 98% 151.3°
2035-04-24 Tue 0 — unknown — 79.1° 12:50 6.78 94% 143.3°
2035-04-25 Wed 0 — unknown — 79.1° 12:45 6.72 90% 133.7°
2035-04-26 Thu 0 — unknown — 79.1° 12:40 6.67 83% 123.5°
2035-04-27 Fri 0 — unknown — 79.1° 12:35 6.61 75% 112.9°
2035-04-28 Sat 0 — unknown — 79.1° 12:30 6.55 67% 102.2°
2035-04-29 Sun 0 — unknown — 79.1° 12:30 6.49 57% 91.2°
2035-04-30 Mon 0 — unknown — 79.1° 12:25 6.43 48% 80.0°
2035-05-01 Tue 0 — unknown — 79.1° 12:20 6.37 38% 68.6°
2035-05-02 Wed 0 — unknown — 79.1° 12:15 6.32 28% 57.2°
2035-05-03 Thu 0 — unknown — 79.1° 12:10 6.26 19% 45.8°
2035-05-04 Fri 0 — unknown — 79.1° 12:10 6.2 11% 35.0°
2035-05-05 Sat 0 — unknown — 79.1° 12:05 6.14 5% 26.4°
2035-05-06 Sun 0 — unknown — 79.1° 12:00 6.09 1% 23.3°
2035-05-07 Mon 0 — unknown — 79.1° 11:55 6.03 0% 28.3°
2035-05-08 Tue 0 — unknown — 79.1° 11:50 5.97 2% 38.5°
2035-05-09 Wed 0 — unknown — 79.1° 11:45 5.92 7% 50.9°
2035-05-10 Thu 0 — unknown — 79.1° 11:40 5.86 14% 64.0°
2035-05-11 Fri 0 — unknown — 79.1° 11:35 5.81 23% 77.3°
2035-05-12 Sat 0 — unknown — 79.1° 11:35 5.75 33% 90.5°
2035-05-13 Sun 0 — unknown — 79.1° 11:30 5.7 44% 103.3°
2035-05-14 Mon 0 — unknown — 79.1° 11:25 5.64 55% 115.6°
2035-05-15 Tue 0 — unknown — 79.1° 11:20 5.59 66% 127.3°
2035-05-16 Wed 0 — unknown — 79.1° 11:15 5.53 75% 138.2°
2035-05-17 Thu 0 — unknown — 79.1° 11:15 5.48 83% 147.7°
2035-05-18 Fri 0 — unknown — 79.1° 11:10 5.43 90% 154.6°
2035-05-19 Sat 0 — unknown — 79.1° 11:05 5.38 95% 156.7°
2035-05-20 Sun 0 — unknown — 79.1° 11:00 5.33 98% 153.1°
2035-05-21 Mon 0 — unknown — 79.1° 11:00 5.28 100% 145.7°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2035-04-22&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.