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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: 02-26 (20), 02-25 (19), 02-23 (17), 02-24 (17), 02-22 (16) — by astronomy; check the weather when the night is within four days.
2042-01-28astronomy score per night — click a bar for that night2042-02-26
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2042-01-28 Tue 1 — unknown — 71.1° 11:50 10.88 55% 93.3°
2042-01-29 Wed 1 — unknown — 71.1° 11:45 10.85 65% 102.4°
2042-01-30 Thu 1 — unknown — 71.1° 11:40 10.82 75% 111.0°
2042-01-31 Fri 1 — unknown — 71.1° 11:35 10.79 83% 118.6°
2042-02-01 Sat 1 — unknown — 71.1° 11:35 10.75 90% 125.1°
2042-02-02 Sun 1 — unknown — 71.1° 11:30 10.72 95% 129.8°
2042-02-03 Mon 2 — unknown 05:55–06:00 (marginal, 0.08 h) 71.1° 11:25 10.69 98% 132.5°
2042-02-04 Tue 2 — unknown 05:50–05:55 (marginal, 0.08 h) 71.1° 11:20 10.65 100% 132.7°
2042-02-05 Wed 2 — unknown 05:50–05:55 (marginal, 0.08 h) 71.1° 11:15 10.62 99% 130.5°
2042-02-06 Thu 3 — unknown 05:45–05:55 (marginal, 0.17 h) 71.1° 11:15 10.58 97% 126.4°
2042-02-07 Fri 3 — unknown 05:40–05:55 (marginal, 0.25 h) 71.1° 11:10 10.55 93% 120.8°
2042-02-08 Sat 4 — unknown 05:35–05:55 (marginal, 0.33 h) 71.1° 11:05 10.51 87% 114.2°
2042-02-09 Sun 3 — unknown 05:35–05:50 (marginal, 0.25 h) 71.1° 11:00 10.47 80% 106.9°
2042-02-10 Mon 4 — unknown 05:30–05:50 (marginal, 0.33 h) 71.1° 10:55 10.44 72% 99.1°
2042-02-11 Tue 4 — unknown 05:25–05:50 (marginal, 0.42 h) 71.1° 10:55 10.4 63% 91.0°
2042-02-12 Wed 5 — unknown 05:20–05:50 (marginal, 0.5 h) 71.1° 10:50 10.36 54% 82.7°
2042-02-13 Thu 6 — unknown 05:15–05:45 (marginal, 0.5 h) 71.1° 10:45 10.32 44% 74.5°
2042-02-14 Fri 7 — unknown 05:15–05:45 (marginal, 0.5 h) 71.1° 10:40 10.28 34% 66.5°
2042-02-15 Sat 8 — unknown 05:10–06:15 (marginal, 1.08 h) 71.1° 10:40 10.24 24% 59.1°
2042-02-16 Sun 10 — unknown 05:30–05:45 (good, 0.25 h) 71.1° 10:35 10.2 15% 52.8°
2042-02-17 Mon 11 — unknown 05:30–05:40 (good, 0.17 h) 71.1° 10:30 10.16 8% 48.5°
2042-02-18 Tue 12 — unknown 05:25–05:40 (good, 0.25 h) 71.1° 10:25 10.12 3% 47.2°
2042-02-19 Wed 13 — unknown 05:20–05:40 (good, 0.33 h) 71.1° 10:20 10.08 0% 49.3°
2042-02-20 Thu 14 — unknown 05:15–05:40 (good, 0.42 h) 71.1° 10:20 10.04 1% 54.5°
2042-02-21 Fri 15 — unknown 05:15–05:35 (good, 0.33 h) 71.1° 10:15 9.99 4% 62.1°
2042-02-22 Sat 16 — unknown 05:10–05:35 (good, 0.42 h) 71.1° 10:10 9.95 10% 71.1°
2042-02-23 Sun 17 — unknown 05:05–05:35 (good, 0.5 h) 71.1° 10:05 9.91 18% 80.8°
2042-02-24 Mon 17 — unknown 05:00–05:30 (good, 0.5 h) 71.1° 10:00 9.86 28% 90.5°
2042-02-25 Tue 19 — unknown 04:55–05:30 (good, 0.58 h) 71.1° 10:00 9.82 39% 100.0°
2042-02-26 Wed 20 — unknown 04:55–05:30 (good, 0.58 h) 71.1° 09:55 9.78 50% 108.8°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2042-01-28&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.