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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 HD 189733: 12-26 (10), 12-27 (9), 12-28 (8), 12-29 (8), 12-30 (8) — by astronomy; check the weather when the night is within four days.
2036-12-26astronomy score per night — click a bar for that night2037-01-24
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2036-12-26 Fri 10 — unknown 18:05–19:35 (marginal, 1.5 h) 71.1° 14:00 11.49 61% 78.3°
2036-12-27 Sat 9 — unknown 18:05–19:30 (marginal, 1.42 h) 71.1° 13:55 11.49 70% 87.5°
2036-12-28 Sun 8 — unknown 18:40–19:25 (marginal, 0.75 h) 71.1° 13:55 11.48 79% 97.1°
2036-12-29 Mon 8 — unknown 18:40–19:25 (marginal, 0.75 h) 71.1° 13:50 11.47 87% 106.8°
2036-12-30 Tue 8 — unknown 18:10–19:20 (marginal, 1.17 h) 71.1° 13:45 11.47 94% 116.3°
2036-12-31 Wed 6 — unknown 18:45–19:15 (marginal, 0.5 h) 71.1° 13:40 11.46 98% 125.2°
2037-01-01 Thu 6 — unknown 18:45–19:10 (marginal, 0.42 h) 71.1° 13:35 11.45 100% 132.5°
2037-01-02 Fri 5 — unknown 18:45–19:05 (marginal, 0.33 h) 71.1° 13:35 11.44 99% 137.1°
2037-01-03 Sat 5 — unknown 18:10–18:35 (marginal, 0.42 h) 71.1° 13:30 11.42 95% 137.8°
2037-01-04 Sun 4 — unknown 18:45–19:00 (marginal, 0.25 h) 71.1° 13:25 11.41 89% 134.3°
2037-01-05 Mon 3 — unknown 18:15–18:30 (marginal, 0.25 h) 71.1° 13:20 11.4 80% 127.7°
2037-01-06 Tue 2 — unknown 18:15–18:25 (marginal, 0.17 h) 71.1° 13:20 11.38 70% 119.1°
2037-01-07 Wed 2 — unknown 18:15–18:20 (marginal, 0.08 h) 71.1° 13:15 11.37 59% 109.5°
2037-01-08 Thu 1 — unknown — 71.1° 13:10 11.35 48% 99.5°
2037-01-09 Fri 1 — unknown — 71.1° 13:05 11.34 37% 89.5°
2037-01-10 Sat 1 — unknown — 71.1° 13:00 11.32 27% 79.7°
2037-01-11 Sun 1 — unknown — 71.1° 13:00 11.3 19% 70.3°
2037-01-12 Mon 0 — unknown — 71.1° 12:55 11.28 11% 61.6°
2037-01-13 Tue 0 — unknown — 71.1° 12:50 11.26 6% 54.0°
2037-01-14 Wed 0 — unknown — 71.1° 12:45 11.24 2% 47.8°
2037-01-15 Thu 0 — unknown — 71.1° 12:40 11.22 0% 43.6°
2037-01-16 Fri 0 — unknown — 71.1° 12:40 11.2 0% 42.0°
2037-01-17 Sat 0 — unknown — 71.1° 12:35 11.17 2% 43.2°
2037-01-18 Sun 0 — unknown — 71.1° 12:30 11.15 6% 46.8°
2037-01-19 Mon 0 — unknown — 71.1° 12:25 11.12 11% 52.4°
2037-01-20 Tue 0 — unknown — 71.1° 12:25 11.1 17% 59.3°
2037-01-21 Wed 0 — unknown — 71.1° 12:20 11.07 25% 67.1°
2037-01-22 Thu 0 — unknown — 71.1° 12:15 11.05 34% 75.6°
2037-01-23 Fri 0 — unknown — 71.1° 12:10 11.02 43% 84.5°
2037-01-24 Sat 0 — unknown — 71.1° 12:05 10.99 53% 93.7°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2036-12-26&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.