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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 3C 273: 06-29 (7), 06-30 (5), 07-01 (4), 07-02 (3), 07-08 (3) — by astronomy; check the weather when the night is within four days.
2047-06-29astronomy score per night — click a bar for that night2047-07-28
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2047-06-29 Sat 7 — unknown 23:10–23:40 (marginal, 0.5 h) 50.1° 19:20 4.5 41% 12.8°
2047-06-30 Sun 5 — unknown 23:10–23:40 (marginal, 0.5 h) 50.1° 19:20 4.52 52% 11.6°
2047-07-01 Mon 4 — unknown 23:10–23:25 (marginal, 0.25 h) 50.1° 19:15 4.54 64% 22.4°
2047-07-02 Tue 3 — unknown 23:10–23:20 (marginal, 0.17 h) 50.1° 19:10 4.56 74% 35.8°
2047-07-03 Wed 2 — unknown 23:10–23:15 (marginal, 0.08 h) 50.1° 19:05 4.58 84% 49.8°
2047-07-04 Thu 2 — unknown 23:10–23:15 (marginal, 0.08 h) 50.1° 19:00 4.61 92% 64.0°
2047-07-05 Fri 2 — unknown 23:10–23:15 (marginal, 0.08 h) 50.1° 19:00 4.64 97% 78.2°
2047-07-06 Sat 2 — unknown 23:10–23:15 (marginal, 0.08 h) 50.1° 18:55 4.67 100% 92.3°
2047-07-07 Sun 2 — unknown 22:15–22:25 (marginal, 0.17 h) 50.1° 18:50 4.7 100% 106.2°
2047-07-08 Mon 3 — unknown 22:15–22:30 (marginal, 0.25 h) 50.1° 18:45 4.73 97% 119.7°
2047-07-09 Tue 3 — unknown 22:15–22:25 (marginal, 0.17 h) 50.1° 18:45 4.76 92% 132.8°
2047-07-10 Wed 2 — unknown 22:15–22:30 (marginal, 0.25 h) 50.1° 18:40 4.8 86% 145.4°
2047-07-11 Thu 2 — unknown 22:15–22:25 (marginal, 0.17 h) 50.1° 18:35 4.83 78% 157.2°
2047-07-12 Fri 2 — unknown 22:15–22:20 (marginal, 0.08 h) 50.1° 18:30 4.87 70% 167.1°
2047-07-13 Sat 2 — unknown 22:15–22:20 (marginal, 0.08 h) 50.1° 18:25 4.91 60% 169.3°
2047-07-14 Sun 2 — unknown 22:10–22:15 (marginal, 0.08 h) 50.1° 18:25 4.95 51% 161.3°
2047-07-15 Mon 1 — unknown — 50.1° 18:20 5.0 41% 150.7°
2047-07-16 Tue 1 — unknown — 50.1° 18:15 5.04 32% 139.4°
2047-07-17 Wed 1 — unknown — 50.1° 18:10 5.08 24% 127.8°
2047-07-18 Thu 1 — unknown — 50.1° 18:05 5.13 16% 116.0°
2047-07-19 Fri 1 — unknown — 50.1° 18:05 5.17 9% 104.0°
2047-07-20 Sat 1 — unknown — 50.1° 18:00 5.22 4% 91.7°
2047-07-21 Sun 1 — unknown — 50.1° 17:55 5.27 1% 79.1°
2047-07-22 Mon 0 — unknown — 50.1° 17:50 5.32 0% 66.2°
2047-07-23 Tue 0 — unknown — 50.1° 17:50 5.37 1% 53.2°
2047-07-24 Wed 0 — unknown — 50.1° 17:45 5.42 5% 40.0°
2047-07-25 Thu 0 — unknown — 50.1° 17:40 5.47 10% 26.9°
2047-07-26 Fri 0 — unknown — 50.1° 17:35 5.52 18% 14.9°
2047-07-27 Sat 0 — unknown — 50.1° 17:30 5.57 28% 10.3°
2047-07-28 Sun 0 — unknown — 50.1° 17:30 5.63 39% 19.6°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2047-06-29&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.