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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: 02-25 (12), 02-20 (11), 02-16 (10), 02-18 (10), 02-19 (10) — by astronomy; check the weather when the night is within four days.
2038-01-27astronomy score per night — click a bar for that night2038-02-25
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2038-01-27 Wed 0 — unknown — 71.1° 11:50 10.91 50% 86.9°
2038-01-28 Thu 1 — unknown — 71.1° 11:50 10.88 39% 77.0°
2038-01-29 Fri 1 — unknown — 71.1° 11:45 10.85 28% 67.5°
2038-01-30 Sat 1 — unknown — 71.1° 11:40 10.82 19% 59.0°
2038-01-31 Sun 1 — unknown — 71.1° 11:35 10.79 11% 51.8°
2038-02-01 Mon 1 — unknown — 71.1° 11:35 10.75 6% 46.6°
2038-02-02 Tue 1 — unknown 06:25–06:30 (marginal, 0.08 h) 71.1° 11:30 10.72 2% 43.9°
2038-02-03 Wed 2 — unknown 05:55–06:00 (marginal, 0.08 h) 71.1° 11:25 10.69 0% 44.2°
2038-02-04 Thu 3 — unknown 06:20–06:30 (marginal, 0.17 h) 71.1° 11:20 10.65 0% 47.3°
2038-02-05 Fri 3 — unknown 06:15–06:30 (marginal, 0.25 h) 71.1° 11:15 10.62 3% 52.4°
2038-02-06 Sat 3 — unknown 06:10–06:25 (marginal, 0.25 h) 71.1° 11:15 10.58 7% 59.1°
2038-02-07 Sun 4 — unknown 05:40–05:55 (marginal, 0.25 h) 71.1° 11:10 10.55 13% 66.6°
2038-02-08 Mon 5 — unknown 05:35–05:55 (marginal, 0.33 h) 71.1° 11:05 10.51 20% 74.6°
2038-02-09 Tue 5 — unknown 06:00–06:25 (marginal, 0.42 h) 71.1° 11:00 10.47 28% 83.0°
2038-02-10 Wed 6 — unknown 05:55–06:25 (marginal, 0.5 h) 71.1° 10:55 10.44 36% 91.5°
2038-02-11 Thu 6 — unknown 05:25–06:20 (marginal, 0.92 h) 71.1° 10:55 10.4 46% 100.1°
2038-02-12 Fri 8 — unknown 05:20–06:20 (marginal, 1.0 h) 71.1° 10:50 10.36 55% 108.6°
2038-02-13 Sat 8 — unknown 05:15–06:20 (marginal, 1.08 h) 71.1° 10:45 10.32 65% 116.7°
2038-02-14 Sun 8 — unknown 05:40–05:45 (good, 0.08 h) 71.1° 10:40 10.28 74% 124.3°
2038-02-15 Mon 9 — unknown 05:35–05:45 (good, 0.17 h) 71.1° 10:40 10.24 83% 130.6°
2038-02-16 Tue 10 — unknown 05:40–05:45 (good, 0.08 h) 71.1° 10:35 10.2 90% 135.0°
2038-02-17 Wed 9 — unknown 05:35–05:40 (good, 0.08 h) 71.1° 10:30 10.16 96% 136.2°
2038-02-18 Thu 10 — unknown 05:35–05:40 (good, 0.08 h) 71.1° 10:25 10.12 99% 133.9°
2038-02-19 Fri 10 — unknown 05:30–05:40 (good, 0.17 h) 71.1° 10:20 10.08 100% 128.3°
2038-02-20 Sat 11 — unknown 05:30–05:40 (good, 0.17 h) 71.1° 10:20 10.04 98% 120.2°
2038-02-21 Sun 10 — unknown 05:30–05:35 (good, 0.08 h) 71.1° 10:15 10.0 92% 110.6°
2038-02-22 Mon 10 — unknown 05:30–05:35 (good, 0.08 h) 71.1° 10:10 9.95 85% 100.3°
2038-02-23 Tue 10 — unknown 05:30–05:35 (good, 0.08 h) 71.1° 10:05 9.91 76% 89.8°
2038-02-24 Wed 10 — unknown 05:25–05:30 (good, 0.08 h) 71.1° 10:00 9.87 65% 79.5°
2038-02-25 Thu 12 — unknown 05:20–05:30 (good, 0.17 h) 71.1° 10:00 9.82 54% 69.7°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2038-01-27&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.