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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: 07-03 (100), 07-04 (100), 07-05 (100), 07-06 (100), 07-07 (100) — by astronomy; check the weather when the night is within four days.
2037-06-24astronomy score per night — click a bar for that night2037-07-23
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2037-06-24 Wed 68 — unknown 00:10–03:40 (good, 3.5 h) 71.1° 03:10 4.44 92% 71.0°
2037-06-25 Thu 55 — unknown 01:15–03:40 (good, 2.42 h) 71.1° 03:05 4.45 97% 62.0°
2037-06-26 Fri 45 — unknown 03:35–03:40 (good, 0.08 h) 71.1° 03:00 4.46 99% 54.1°
2037-06-27 Sat 39 — unknown 23:15–03:40 (marginal, 4.42 h) 71.1° 03:00 4.47 100% 47.9°
2037-06-28 Sun 37 — unknown 23:10–03:40 (marginal, 4.5 h) 71.1° 02:55 4.49 98% 44.0°
2037-06-29 Mon 42 — unknown 23:10–03:40 (marginal, 4.5 h) 71.1° 02:50 4.51 95% 42.9°
2037-06-30 Tue 74 — unknown 23:10–01:05 (good, 1.92 h) 71.1° 02:45 4.52 89% 44.6°
2037-07-01 Wed 88 — unknown 23:10–02:55 (good, 3.75 h) 71.1° 02:40 4.55 83% 48.7°
2037-07-02 Thu 96 — unknown 23:10–03:45 (good, 4.58 h) 71.1° 02:40 4.57 75% 54.5°
2037-07-03 Fri 100 — unknown 23:10–03:45 (good, 4.58 h) 71.1° 02:35 4.59 66% 61.6°
2037-07-04 Sat 100 — unknown 23:10–03:45 (good, 4.58 h) 71.1° 02:30 4.62 57% 69.4°
2037-07-05 Sun 100 — unknown 23:10–03:50 (good, 4.67 h) 71.1° 02:25 4.65 47% 77.8°
2037-07-06 Mon 100 — unknown 23:10–03:50 (good, 4.67 h) 71.1° 02:20 4.68 38% 86.6°
2037-07-07 Tue 100 — unknown 23:05–03:50 (good, 4.75 h) 71.1° 02:20 4.71 28% 95.6°
2037-07-08 Wed 100 — unknown 23:05–03:50 (good, 4.75 h) 71.1° 02:15 4.74 20% 104.8°
2037-07-09 Thu 100 — unknown 23:05–03:50 (good, 4.75 h) 71.1° 02:10 4.78 12% 113.8°
2037-07-10 Fri 100 — unknown 23:05–03:55 (good, 4.83 h) 71.1° 02:05 4.81 6% 122.3°
2037-07-11 Sat 100 — unknown 23:05–03:55 (good, 4.83 h) 71.1° 02:05 4.85 2% 129.7°
2037-07-12 Sun 100 — unknown 23:05–03:55 (good, 4.83 h) 71.1° 02:00 4.89 0% 135.0°
2037-07-13 Mon 100 — unknown 23:00–03:55 (good, 4.92 h) 71.1° 01:55 4.93 1% 137.1°
2037-07-14 Tue 100 — unknown 23:00–04:00 (good, 5.0 h) 71.1° 01:50 4.97 5% 135.4°
2037-07-15 Wed 100 — unknown 23:00–04:00 (good, 5.0 h) 71.1° 01:45 5.01 11% 130.2°
2037-07-16 Thu 100 — unknown 23:00–04:00 (good, 5.0 h) 71.1° 01:45 5.06 19% 122.4°
2037-07-17 Fri 100 — unknown 22:55–04:05 (good, 5.17 h) 71.1° 01:40 5.1 29% 113.2°
2037-07-18 Sat 100 — unknown 22:55–04:05 (good, 5.17 h) 71.1° 01:35 5.15 40% 103.3°
2037-07-19 Sun 100 — unknown 22:55–04:05 (good, 5.17 h) 71.1° 01:30 5.19 52% 93.1°
2037-07-20 Mon 100 — unknown 22:55–04:05 (good, 5.17 h) 71.1° 01:25 5.24 63% 83.0°
2037-07-21 Tue 100 — unknown 22:50–04:10 (good, 5.33 h) 71.1° 01:25 5.29 73% 73.2°
2037-07-22 Wed 100 — unknown 22:50–04:10 (good, 5.33 h) 71.1° 01:20 5.34 82% 64.2°
2037-07-23 Thu 97 — unknown 23:25–04:10 (good, 4.75 h) 71.1° 01:15 5.39 90% 56.1°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2037-06-24&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.