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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: 02-28 (21), 02-27 (20), 02-26 (18), 02-25 (15), 02-24 (13) — by astronomy; check the weather when the night is within four days.
2041-01-30astronomy score per night — click a bar for that night2041-02-28
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2041-01-30 Wed 1 — unknown — 71.1° 11:40 10.81 3% 48.8°
2041-01-31 Thu 1 — unknown — 71.1° 11:35 10.78 0% 47.1°
2041-02-01 Fri 1 — unknown — 71.1° 11:30 10.75 1% 49.1°
2041-02-02 Sat 1 — unknown 06:25–06:30 (marginal, 0.08 h) 71.1° 11:30 10.71 5% 54.3°
2041-02-03 Sun 2 — unknown 06:25–06:30 (marginal, 0.08 h) 71.1° 11:25 10.68 11% 61.7°
2041-02-04 Mon 3 — unknown 06:20–06:30 (marginal, 0.17 h) 71.1° 11:20 10.64 19% 70.4°
2041-02-05 Tue 3 — unknown 06:15–06:30 (marginal, 0.25 h) 71.1° 11:15 10.61 29% 79.5°
2041-02-06 Wed 3 — unknown 06:10–06:25 (marginal, 0.25 h) 71.1° 11:10 10.57 39% 88.7°
2041-02-07 Thu 4 — unknown 05:40–05:55 (marginal, 0.25 h) 71.1° 11:10 10.54 50% 97.6°
2041-02-08 Fri 4 — unknown 05:35–05:50 (marginal, 0.25 h) 71.1° 11:05 10.5 60% 106.1°
2041-02-09 Sat 5 — unknown 05:30–05:50 (marginal, 0.33 h) 71.1° 11:00 10.46 69% 113.9°
2041-02-10 Sun 6 — unknown 05:55–06:25 (marginal, 0.5 h) 71.1° 10:55 10.43 78% 120.8°
2041-02-11 Mon 7 — unknown 05:25–06:20 (marginal, 0.92 h) 71.1° 10:50 10.39 85% 126.4°
2041-02-12 Tue 7 — unknown 05:20–05:50 (marginal, 0.5 h) 71.1° 10:50 10.35 91% 130.5°
2041-02-13 Wed 7 — unknown 05:15–05:45 (marginal, 0.5 h) 71.1° 10:45 10.31 96% 132.7°
2041-02-14 Thu 7 — unknown 05:10–05:45 (marginal, 0.58 h) 71.1° 10:40 10.27 99% 132.6°
2041-02-15 Fri 8 — unknown 05:10–06:15 (marginal, 1.08 h) 71.1° 10:35 10.23 100% 130.3°
2041-02-16 Sat 9 — unknown 05:40–05:45 (good, 0.08 h) 71.1° 10:35 10.19 99% 126.2°
2041-02-17 Sun 9 — unknown 05:00–06:15 (marginal, 1.25 h) 71.1° 10:30 10.15 97% 120.5°
2041-02-18 Mon 9 — unknown 04:55–06:10 (marginal, 1.25 h) 71.1° 10:25 10.11 93% 113.7°
2041-02-19 Tue 9 — unknown 05:35–05:40 (good, 0.08 h) 71.1° 10:20 10.07 87% 106.0°
2041-02-20 Wed 9 — unknown 05:35–05:40 (good, 0.08 h) 71.1° 10:15 10.03 80% 97.9°
2041-02-21 Thu 9 — unknown 04:45–06:10 (marginal, 1.42 h) 71.1° 10:15 9.98 71% 89.4°
2041-02-22 Fri 10 — unknown 05:30–05:35 (good, 0.08 h) 71.1° 10:10 9.94 61% 80.7°
2041-02-23 Sat 12 — unknown 05:20–05:35 (good, 0.25 h) 71.1° 10:05 9.9 51% 72.1°
2041-02-24 Sun 13 — unknown 05:15–05:30 (good, 0.25 h) 71.1° 10:00 9.85 40% 63.9°
2041-02-25 Mon 15 — unknown 05:05–05:30 (good, 0.42 h) 71.1° 09:55 9.81 29% 56.5°
2041-02-26 Tue 18 — unknown 04:50–05:30 (good, 0.67 h) 71.1° 09:55 9.77 20% 50.7°
2041-02-27 Wed 20 — unknown 04:50–05:25 (good, 0.58 h) 71.1° 09:50 9.72 11% 47.5°
2041-02-28 Thu 21 — unknown 04:45–05:25 (good, 0.67 h) 71.1° 09:45 9.68 5% 47.7°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2041-01-30&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.