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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 Seven Sisters: 03-23 (29), 03-24 (27), 03-25 (23), 03-26 (20), 03-27 (16) — by astronomy; check the weather when the night is within four days.
2031-03-23astronomy score per night — click a bar for that night2031-04-21
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2031-03-23 Sun 29 — unknown 20:10–21:15 (good, 1.08 h) 72.5° 16:05 8.58 1% 46.9°
2031-03-24 Mon 27 — unknown 20:15–21:15 (good, 1.0 h) 72.5° 16:00 8.52 4% 33.9°
2031-03-25 Tue 23 — unknown 20:15–21:05 (good, 0.83 h) 72.5° 16:00 8.47 8% 21.2°
2031-03-26 Wed 20 — unknown 20:15–21:00 (good, 0.75 h) 72.5° 15:55 8.42 15% 9.2°
2031-03-27 Thu 16 — unknown 20:20–20:50 (good, 0.5 h) 72.5° 15:50 8.36 22% 5.7°
2031-03-28 Fri 13 — unknown 20:20–20:35 (good, 0.25 h) 72.5° 15:45 8.31 31% 16.6°
2031-03-29 Sat 10 — unknown 20:20–21:20 (marginal, 1.0 h) 72.5° 15:40 8.26 40% 28.2°
2031-03-30 Sun 8 — unknown 21:20–22:10 (marginal, 0.83 h) 72.5° 16:40 8.2 49% 40.0°
2031-03-31 Mon 6 — unknown 21:25–22:05 (marginal, 0.67 h) 72.5° 16:35 8.15 59% 51.8°
2031-04-01 Tue 5 — unknown 21:25–22:00 (marginal, 0.58 h) 72.5° 16:30 8.09 68% 63.7°
2031-04-02 Wed 5 — unknown 21:25–21:55 (marginal, 0.5 h) 72.5° 16:25 8.04 76% 75.8°
2031-04-03 Thu 5 — unknown 21:25–21:55 (marginal, 0.5 h) 72.5° 16:25 7.98 84% 88.2°
2031-04-04 Fri 4 — unknown 21:30–21:55 (marginal, 0.42 h) 72.5° 16:20 7.93 91% 100.9°
2031-04-05 Sat 5 — unknown 21:30–21:55 (marginal, 0.42 h) 72.5° 16:15 7.87 96% 113.9°
2031-04-06 Sun 4 — unknown 21:30–21:50 (marginal, 0.33 h) 72.5° 16:10 7.82 99% 127.3°
2031-04-07 Mon 3 — unknown 20:55–21:10 (marginal, 0.25 h) 72.5° 16:05 7.76 100% 140.9°
2031-04-08 Tue 3 — unknown 21:00–21:10 (marginal, 0.17 h) 72.5° 16:05 7.7 98% 154.8°
2031-04-09 Wed 2 — unknown 21:00–21:10 (marginal, 0.17 h) 72.5° 16:00 7.65 94% 168.5°
2031-04-10 Thu 2 — unknown 21:00–21:05 (marginal, 0.08 h) 72.5° 15:55 7.59 87% 174.5°
2031-04-11 Fri 1 — unknown — 72.5° 15:50 7.53 78% 161.6°
2031-04-12 Sat 1 — unknown — 72.5° 15:45 7.48 68% 147.5°
2031-04-13 Sun 1 — unknown — 72.5° 15:45 7.42 57% 133.4°
2031-04-14 Mon 1 — unknown — 72.5° 15:40 7.36 46% 119.3°
2031-04-15 Tue 0 — unknown — 72.5° 15:35 7.31 34% 105.4°
2031-04-16 Wed 0 — unknown — 72.5° 15:30 7.25 24% 91.6°
2031-04-17 Thu 0 — unknown — 72.5° 15:30 7.19 16% 78.0°
2031-04-18 Fri 0 — unknown — 72.5° 15:25 7.13 8% 64.5°
2031-04-19 Sat 0 — unknown — 72.5° 15:20 7.07 4% 51.3°
2031-04-20 Sun 0 — unknown — 72.5° 15:15 7.02 1% 38.3°
2031-04-21 Mon 0 — unknown — 72.5° 15:10 6.96 0% 25.6°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2031-03-23&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.