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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: 12-13 (36), 12-14 (35), 12-15 (34), 12-16 (32), 12-17 (31) — by astronomy; check the weather when the night is within four days.
2044-12-13astronomy score per night — click a bar for that night2045-01-11
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2044-12-13 Tue 36 — unknown 18:35–20:00 (good, 1.42 h) 71.1° 14:50 11.48 26% 105.8°
2044-12-14 Wed 35 — unknown 18:35–19:55 (good, 1.33 h) 71.1° 14:50 11.49 18% 96.8°
2044-12-15 Thu 34 — unknown 18:35–19:50 (good, 1.25 h) 71.1° 14:45 11.49 11% 87.8°
2044-12-16 Fri 32 — unknown 18:35–19:45 (good, 1.17 h) 71.1° 14:40 11.5 6% 79.0°
2044-12-17 Sat 31 — unknown 18:35–19:45 (good, 1.17 h) 71.1° 14:35 11.5 2% 70.6°
2044-12-18 Sun 29 — unknown 18:35–19:40 (good, 1.08 h) 71.1° 14:35 11.51 0% 62.8°
2044-12-19 Mon 27 — unknown 18:35–19:35 (good, 1.0 h) 71.1° 14:30 11.51 0% 55.8°
2044-12-20 Tue 26 — unknown 18:35–19:30 (good, 0.92 h) 71.1° 14:25 11.51 2% 50.1°
2044-12-21 Wed 24 — unknown 18:35–19:25 (good, 0.83 h) 71.1° 14:20 11.51 6% 46.0°
2044-12-22 Thu 21 — unknown 18:35–19:20 (good, 0.75 h) 71.1° 14:15 11.51 11% 44.2°
2044-12-23 Fri 18 — unknown 18:40–19:15 (good, 0.58 h) 71.1° 14:15 11.5 17% 44.8°
2044-12-24 Sat 15 — unknown 18:40–19:05 (good, 0.42 h) 71.1° 14:10 11.5 25% 47.9°
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°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2044-12-13&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.