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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: 03-20 (34), 03-21 (33), 03-22 (31), 03-23 (29), 03-24 (27) — by astronomy; check the weather when the night is within four days.
2047-03-20astronomy score per night — click a bar for that night2047-04-18
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2047-03-20 Wed 34 — unknown 20:10–21:30 (good, 1.33 h) 72.6° 16:20 8.73 27% 122.0°
2047-03-21 Thu 33 — unknown 20:10–21:25 (good, 1.25 h) 72.6° 16:15 8.67 18% 109.3°
2047-03-22 Fri 31 — unknown 20:10–21:20 (good, 1.17 h) 72.6° 16:10 8.62 12% 96.9°
2047-03-23 Sat 29 — unknown 20:15–21:15 (good, 1.0 h) 72.6° 16:05 8.57 6% 84.6°
2047-03-24 Sun 27 — unknown 20:15–21:15 (good, 1.0 h) 72.6° 16:00 8.52 2% 72.5°
2047-03-25 Mon 25 — unknown 20:15–21:10 (good, 0.92 h) 72.6° 16:00 8.46 0% 60.5°
2047-03-26 Tue 24 — unknown 20:15–21:05 (good, 0.83 h) 72.6° 15:55 8.41 0% 48.5°
2047-03-27 Wed 22 — unknown 20:20–21:00 (good, 0.67 h) 72.6° 15:50 8.36 2% 36.7°
2047-03-28 Thu 20 — unknown 20:20–21:00 (good, 0.67 h) 72.6° 15:45 8.3 6% 24.9°
2047-03-29 Fri 17 — unknown 20:20–20:50 (good, 0.5 h) 72.6° 15:45 8.25 10% 13.1°
2047-03-30 Sat 14 — unknown 20:20–20:40 (good, 0.33 h) 72.6° 15:40 8.2 17% 1.2°
2047-03-31 Sun 10 — unknown 21:25–21:30 (good, 0.08 h) 72.6° 16:35 8.14 25% 10.8°
2047-04-01 Mon 8 — unknown 21:25–22:10 (marginal, 0.75 h) 72.6° 16:30 8.09 33% 22.9°
2047-04-02 Tue 6 — unknown 21:25–22:05 (marginal, 0.67 h) 72.6° 16:25 8.03 43% 35.3°
2047-04-03 Wed 4 — unknown 21:25–21:55 (marginal, 0.5 h) 72.6° 16:25 7.98 53% 48.0°
2047-04-04 Thu 3 — unknown 21:30–21:50 (marginal, 0.33 h) 72.6° 16:20 7.92 63% 61.0°
2047-04-05 Fri 3 — unknown 21:30–21:45 (marginal, 0.25 h) 72.6° 16:15 7.87 74% 74.6°
2047-04-06 Sat 3 — unknown 21:30–21:45 (marginal, 0.25 h) 72.6° 16:10 7.81 83% 88.6°
2047-04-07 Sun 2 — unknown 21:35–21:45 (marginal, 0.17 h) 72.6° 16:05 7.75 91% 103.1°
2047-04-08 Mon 2 — unknown 21:35–21:40 (marginal, 0.08 h) 72.6° 16:05 7.7 96% 117.9°
2047-04-09 Tue 2 — unknown 21:35–21:40 (marginal, 0.08 h) 72.6° 16:00 7.64 99% 133.1°
2047-04-10 Wed 1 — unknown — 72.6° 15:55 7.58 99% 148.4°
2047-04-11 Thu 1 — unknown 21:00–21:05 (marginal, 0.08 h) 72.6° 15:50 7.53 96% 163.6°
2047-04-12 Fri 1 — unknown — 72.6° 15:50 7.47 91% 178.6°
2047-04-13 Sat 1 — unknown — 72.6° 15:45 7.41 83% 166.7°
2047-04-14 Sun 1 — unknown — 72.6° 15:40 7.36 73% 152.5°
2047-04-15 Mon 0 — unknown — 72.6° 15:35 7.3 63% 138.7°
2047-04-16 Tue 0 — unknown — 72.6° 15:30 7.24 52% 125.4°
2047-04-17 Wed 0 — unknown — 72.6° 15:30 7.18 42% 112.4°
2047-04-18 Thu 0 — unknown — 72.6° 15:25 7.12 32% 99.9°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2047-03-20&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.