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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.

2040-05-02astronomy score per night — click a bar for that night2040-05-31
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2040-05-02 Wed 0 — unknown — 79.2° 12:15 6.27 60% 93.4°
2040-05-03 Thu 0 — unknown — 79.2° 12:10 6.21 49% 80.4°
2040-05-04 Fri 0 — unknown — 79.2° 12:05 6.16 38% 67.6°
2040-05-05 Sat 0 — unknown — 79.2° 12:00 6.1 27% 55.2°
2040-05-06 Sun 0 — unknown — 79.2° 11:55 6.04 18% 43.5°
2040-05-07 Mon 0 — unknown — 79.2° 11:50 5.98 11% 33.0°
2040-05-08 Tue 0 — unknown — 79.2° 11:45 5.93 5% 25.0°
2040-05-09 Wed 0 — unknown — 79.2° 11:40 5.87 2% 22.0°
2040-05-10 Thu 0 — unknown — 79.2° 11:40 5.82 0% 25.5°
2040-05-11 Fri 0 — unknown — 79.2° 11:35 5.76 1% 33.4°
2040-05-12 Sat 0 — unknown — 79.2° 11:30 5.71 3% 43.1°
2040-05-13 Sun 0 — unknown — 79.2° 11:25 5.65 7% 53.5°
2040-05-14 Mon 0 — unknown — 79.2° 11:20 5.6 13% 64.2°
2040-05-15 Tue 0 — unknown — 79.2° 11:20 5.55 20% 75.1°
2040-05-16 Wed 0 — unknown — 79.2° 11:15 5.49 28% 86.0°
2040-05-17 Thu 0 — unknown — 79.2° 11:10 5.44 37% 97.0°
2040-05-18 Fri 0 — unknown — 79.2° 11:05 5.39 46% 108.1°
2040-05-19 Sat 0 — unknown — 79.2° 11:05 5.34 56% 119.2°
2040-05-20 Sun 0 — unknown — 79.2° 11:00 5.29 66% 130.3°
2040-05-21 Mon 0 — unknown — 79.2° 10:55 5.24 75% 141.1°
2040-05-22 Tue 0 — unknown — 79.2° 10:50 5.19 84% 150.8°
2040-05-23 Wed 0 — unknown — 79.2° 10:45 5.15 91% 157.2°
2040-05-24 Thu 0 — unknown — 79.2° 10:45 5.1 97% 156.7°
2040-05-25 Fri 0 — unknown — 79.2° 10:40 5.05 100% 148.9°
2040-05-26 Sat 0 — unknown — 79.2° 10:35 5.01 100% 137.5°
2040-05-27 Sun 0 — unknown — 79.2° 10:30 4.97 97% 124.5°
2040-05-28 Mon 0 — unknown — 79.2° 10:25 4.93 91% 111.0°
2040-05-29 Tue 0 — unknown — 79.2° 10:25 4.89 84% 97.4°
2040-05-30 Wed 0 — unknown — 79.2° 10:20 4.85 74% 83.9°
2040-05-31 Thu 0 — unknown — 79.2° 10:15 4.81 63% 70.7°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2040-05-02&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.