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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.

2031-04-07astronomy score per night — click a bar for that night2031-05-06
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2031-04-07 Mon 0 — unknown — 79.1° 13:55 7.76 100% 159.6°
2031-04-08 Tue 0 — unknown — 79.1° 13:50 7.7 98% 162.7°
2031-04-09 Wed 0 — unknown — 79.1° 13:45 7.65 94% 156.1°
2031-04-10 Thu 0 — unknown — 79.1° 13:45 7.59 87% 144.8°
2031-04-11 Fri 0 — unknown — 79.1° 13:40 7.53 78% 132.0°
2031-04-12 Sat 0 — unknown — 79.1° 13:35 7.48 68% 118.6°
2031-04-13 Sun 0 — unknown — 79.1° 13:30 7.42 57% 105.1°
2031-04-14 Mon 0 — unknown — 79.1° 13:25 7.36 46% 91.7°
2031-04-15 Tue 0 — unknown — 79.1° 13:25 7.31 34% 78.3°
2031-04-16 Wed 0 — unknown — 79.1° 13:20 7.25 24% 65.1°
2031-04-17 Thu 0 — unknown — 79.1° 13:15 7.19 16% 52.3°
2031-04-18 Fri 0 — unknown — 79.1° 13:10 7.13 8% 40.0°
2031-04-19 Sat 0 — unknown — 79.1° 13:05 7.07 4% 28.8°
2031-04-20 Sun 0 — unknown — 79.1° 13:05 7.02 1% 19.9°
2031-04-21 Mon 0 — unknown — 79.1° 13:00 6.96 0% 17.3°
2031-04-22 Tue 0 — unknown — 79.1° 12:55 6.9 2% 22.6°
2031-04-23 Wed 0 — unknown — 79.1° 12:50 6.84 5% 32.0°
2031-04-24 Thu 0 — unknown — 79.1° 12:50 6.78 10% 42.6°
2031-04-25 Fri 0 — unknown — 79.1° 12:45 6.72 16% 53.6°
2031-04-26 Sat 0 — unknown — 79.1° 12:40 6.67 24% 64.8°
2031-04-27 Sun 0 — unknown — 79.1° 12:35 6.61 32% 76.0°
2031-04-28 Mon 0 — unknown — 79.1° 12:30 6.55 42% 87.3°
2031-04-29 Tue 0 — unknown — 79.1° 12:30 6.49 51% 98.8°
2031-04-30 Wed 0 — unknown — 79.1° 12:25 6.43 61% 110.3°
2031-05-01 Thu 0 — unknown — 79.1° 12:20 6.38 70% 122.0°
2031-05-02 Fri 0 — unknown — 79.1° 12:15 6.32 79% 133.8°
2031-05-03 Sat 0 — unknown — 79.1° 12:10 6.26 87% 145.5°
2031-05-04 Sun 0 — unknown — 79.1° 12:10 6.2 94% 156.2°
2031-05-05 Mon 0 — unknown — 79.1° 12:05 6.14 98% 162.7°
2031-05-06 Tue 0 — unknown — 79.1° 12:00 6.09 100% 159.5°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2031-04-07&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.