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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: 12-25 (13), 12-26 (10), 12-27 (8), 12-28 (7), 12-29 (6) — by astronomy; check the weather when the night is within four days.
2044-12-25astronomy score per night — click a bar for that night2045-01-23
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2044-12-25 Sun 13 — unknown 18:40–18:55 (good, 0.25 h) 71.1° 14:05 11.5 34% 52.9°
2044-12-26 Mon 10 — unknown 18:40–18:45 (good, 0.08 h) 71.1° 14:00 11.49 44% 59.6°
2044-12-27 Tue 8 — unknown 18:40–19:30 (marginal, 0.83 h) 71.1° 13:55 11.49 54% 67.5°
2044-12-28 Wed 7 — unknown 18:40–19:25 (marginal, 0.75 h) 71.1° 13:55 11.48 64% 76.3°
2044-12-29 Thu 6 — unknown 18:40–19:20 (marginal, 0.67 h) 71.1° 13:50 11.47 74% 85.9°
2044-12-30 Fri 5 — unknown 18:45–19:20 (marginal, 0.58 h) 71.1° 13:45 11.47 83% 95.9°
2044-12-31 Sat 5 — unknown 18:45–19:15 (marginal, 0.5 h) 71.1° 13:40 11.46 91% 106.0°
2045-01-01 Sun 5 — unknown 18:45–19:10 (marginal, 0.42 h) 71.1° 13:40 11.45 96% 115.9°
2045-01-02 Mon 5 — unknown 18:45–19:05 (marginal, 0.33 h) 71.1° 13:35 11.43 100% 124.8°
2045-01-03 Tue 4 — unknown 18:45–19:05 (marginal, 0.33 h) 71.1° 13:30 11.42 100% 131.7°
2045-01-04 Wed 4 — unknown 18:45–19:00 (marginal, 0.25 h) 71.1° 13:25 11.41 96% 135.5°
2045-01-05 Thu 3 — unknown 18:15–18:30 (marginal, 0.25 h) 71.1° 13:20 11.4 91% 135.3°
2045-01-06 Fri 2 — unknown 18:15–18:25 (marginal, 0.17 h) 71.1° 13:20 11.38 83% 131.4°
2045-01-07 Sat 2 — unknown 18:15–18:20 (marginal, 0.08 h) 71.1° 13:15 11.37 73% 124.9°
2045-01-08 Sun 1 — unknown — 71.1° 13:10 11.35 63% 116.9°
2045-01-09 Mon 1 — unknown — 71.1° 13:05 11.33 52% 108.1°
2045-01-10 Tue 1 — unknown — 71.1° 13:00 11.32 42% 99.0°
2045-01-11 Wed 1 — unknown — 71.1° 13:00 11.3 32% 90.0°
2045-01-12 Thu 0 — unknown — 71.1° 12:55 11.28 23% 81.1°
2045-01-13 Fri 0 — unknown — 71.1° 12:50 11.26 16% 72.6°
2045-01-14 Sat 0 — unknown — 71.1° 12:45 11.24 9% 64.6°
2045-01-15 Sun 0 — unknown — 71.1° 12:45 11.22 5% 57.4°
2045-01-16 Mon 0 — unknown — 71.1° 12:40 11.19 2% 51.4°
2045-01-17 Tue 0 — unknown — 71.1° 12:35 11.17 0% 46.8°
2045-01-18 Wed 0 — unknown — 71.1° 12:30 11.15 0% 44.4°
2045-01-19 Thu 0 — unknown — 71.1° 12:25 11.12 3% 44.3°
2045-01-20 Fri 0 — unknown — 71.1° 12:25 11.1 7% 46.8°
2045-01-21 Sat 0 — unknown — 71.1° 12:20 11.07 12% 51.4°
2045-01-22 Sun 0 — unknown — 71.1° 12:15 11.05 19% 57.7°
2045-01-23 Mon 0 — unknown — 71.1° 12:10 11.02 27% 65.2°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2044-12-25&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.