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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: 03-27 (20), 03-28 (19), 03-29 (18), 03-30 (13), 03-31 (11) — by astronomy; check the weather when the night is within four days.
2036-03-27astronomy score per night — click a bar for that night2036-04-25
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2036-03-27 Thu 20 — unknown 20:20–21:00 (good, 0.67 h) 72.5° 15:45 8.32 0% 51.7°
2036-03-28 Fri 19 — unknown 20:20–20:55 (good, 0.58 h) 72.5° 15:45 8.27 1% 39.1°
2036-03-29 Sat 18 — unknown 20:20–20:50 (good, 0.5 h) 72.5° 15:40 8.21 5% 26.5°
2036-03-30 Sun 13 — unknown 21:25–21:40 (good, 0.25 h) 72.5° 16:35 8.16 10% 14.7°
2036-03-31 Mon 11 — unknown 21:25–21:35 (good, 0.17 h) 72.5° 16:30 8.11 18% 9.5°
2036-04-01 Tue 8 — unknown 21:25–22:05 (marginal, 0.67 h) 72.5° 16:30 8.05 27% 18.4°
2036-04-02 Wed 5 — unknown 21:25–22:00 (marginal, 0.58 h) 72.5° 16:25 8.0 38% 31.1°
2036-04-03 Thu 4 — unknown 21:30–21:55 (marginal, 0.42 h) 72.5° 16:20 7.94 49% 44.7°
2036-04-04 Fri 3 — unknown 21:30–21:45 (marginal, 0.25 h) 72.5° 16:15 7.88 61% 58.5°
2036-04-05 Sat 2 — unknown 21:30–21:45 (marginal, 0.25 h) 72.5° 16:10 7.83 72% 72.5°
2036-04-06 Sun 2 — unknown 21:30–21:40 (marginal, 0.17 h) 72.5° 16:10 7.77 81% 86.6°
2036-04-07 Mon 2 — unknown 21:35–21:40 (marginal, 0.08 h) 72.5° 16:05 7.72 89% 100.7°
2036-04-08 Tue 2 — unknown 21:35–21:40 (marginal, 0.08 h) 72.5° 16:00 7.66 95% 114.7°
2036-04-09 Wed 1 — unknown — 72.5° 15:55 7.6 99% 128.5°
2036-04-10 Thu 1 — unknown — 72.5° 15:50 7.55 100% 142.0°
2036-04-11 Fri 1 — unknown — 72.5° 15:50 7.49 98% 154.9°
2036-04-12 Sat 1 — unknown — 72.5° 15:45 7.43 95% 166.3°
2036-04-13 Sun 1 — unknown — 72.5° 15:40 7.38 89% 170.5°
2036-04-14 Mon 1 — unknown — 72.5° 15:35 7.32 82% 162.3°
2036-04-15 Tue 0 — unknown — 72.5° 15:35 7.26 74% 151.2°
2036-04-16 Wed 0 — unknown — 72.5° 15:30 7.2 66% 139.6°
2036-04-17 Thu 0 — unknown — 72.5° 15:25 7.14 56% 128.0°
2036-04-18 Fri 0 — unknown — 72.5° 15:20 7.09 47% 116.4°
2036-04-19 Sat 0 — unknown — 72.5° 15:15 7.03 37% 104.7°
2036-04-20 Sun 0 — unknown — 72.5° 15:15 6.97 28% 92.9°
2036-04-21 Mon 0 — unknown — 72.5° 15:10 6.91 20% 80.9°
2036-04-22 Tue 0 — unknown — 72.5° 15:05 6.85 13% 68.7°
2036-04-23 Wed 0 — unknown — 72.5° 15:00 6.8 7% 56.2°
2036-04-24 Thu 0 — unknown — 72.5° 14:55 6.74 3% 43.5°
2036-04-25 Fri 0 — unknown — 72.5° 14:55 6.68 0% 30.6°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2036-03-27&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.