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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: 03-30 (17), 03-31 (14), 04-01 (13), 04-02 (11), 04-03 (10) — by astronomy; check the weather when the night is within four days.
2035-03-30astronomy score per night — click a bar for that night2035-04-28
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2035-03-30 Fri 17 — unknown 21:20–21:50 (good, 0.5 h) 72.5° 16:40 8.2 60% 149.5°
2035-03-31 Sat 14 — unknown 21:25–21:45 (good, 0.33 h) 72.5° 16:35 8.15 50% 138.1°
2035-04-01 Sun 13 — unknown 21:25–21:40 (good, 0.25 h) 72.5° 16:30 8.09 41% 126.4°
2035-04-02 Mon 11 — unknown 21:25–21:35 (good, 0.17 h) 72.5° 16:25 8.04 31% 114.4°
2035-04-03 Tue 10 — unknown 21:25–21:35 (good, 0.17 h) 72.5° 16:25 7.98 22% 102.1°
2035-04-04 Wed 7 — unknown 20:55–21:55 (marginal, 1.0 h) 72.5° 16:20 7.93 14% 89.4°
2035-04-05 Thu 7 — unknown 21:30–21:55 (marginal, 0.42 h) 72.5° 16:15 7.87 8% 76.4°
2035-04-06 Fri 6 — unknown 21:30–21:50 (marginal, 0.33 h) 72.5° 16:10 7.82 3% 62.9°
2035-04-07 Sat 4 — unknown 20:55–21:20 (marginal, 0.42 h) 72.5° 16:05 7.76 0% 49.2°
2035-04-08 Sun 3 — unknown 21:00–21:15 (marginal, 0.25 h) 72.5° 16:05 7.7 0% 35.3°
2035-04-09 Mon 2 — unknown 21:00–21:10 (marginal, 0.17 h) 72.5° 16:00 7.65 3% 21.6°
2035-04-10 Tue 2 — unknown — 72.5° 15:55 7.59 8% 10.4°
2035-04-11 Wed 1 — unknown — 72.5° 15:50 7.53 16% 13.2°
2035-04-12 Thu 1 — unknown — 72.5° 15:45 7.48 26% 25.7°
2035-04-13 Fri 0 — unknown — 72.5° 15:45 7.42 37% 39.4°
2035-04-14 Sat 0 — unknown — 72.5° 15:40 7.36 48% 53.1°
2035-04-15 Sun 0 — unknown — 72.5° 15:35 7.3 59% 66.8°
2035-04-16 Mon 0 — unknown — 72.5° 15:30 7.25 70% 80.2°
2035-04-17 Tue 0 — unknown — 72.5° 15:30 7.19 79% 93.5°
2035-04-18 Wed 0 — unknown — 72.5° 15:25 7.13 87% 106.5°
2035-04-19 Thu 0 — unknown — 72.5° 15:20 7.07 93% 119.2°
2035-04-20 Fri 0 — unknown — 72.5° 15:15 7.01 97% 131.8°
2035-04-21 Sat 0 — unknown — 72.5° 15:10 6.96 100% 144.0°
2035-04-22 Sun 0 — unknown — 72.5° 15:10 6.9 100% 155.7°
2035-04-23 Mon 0 — unknown — 72.5° 15:05 6.84 98% 166.2°
2035-04-24 Tue 0 — unknown — 72.5° 15:00 6.78 94% 170.8°
2035-04-25 Wed 0 — unknown — 72.5° 14:55 6.72 90% 163.7°
2035-04-26 Thu 0 — unknown — 72.5° 14:50 6.67 83% 153.1°
2035-04-27 Fri 0 — unknown — 72.5° 14:50 6.61 75% 141.9°
2035-04-28 Sat 0 — unknown — 72.5° 14:45 6.55 67% 130.3°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2035-03-30&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.