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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 Seven Sisters: 08-08 (46), 08-07 (43), 08-06 (42), 08-05 (39), 08-04 (38) — by astronomy; check the weather when the night is within four days.
2041-07-10astronomy score per night — click a bar for that night2041-08-08
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2041-07-10 Wed 1 — unknown — 72.5° 09:50 4.81 89% 168.9°
2041-07-11 Thu 2 — unknown 04:40–04:45 (marginal, 0.08 h) 72.5° 09:50 4.85 95% 155.1°
2041-07-12 Fri 2 — unknown — 72.5° 09:45 4.89 99% 140.7°
2041-07-13 Sat 2 — unknown 04:40–04:45 (marginal, 0.08 h) 72.5° 09:40 4.93 100% 126.1°
2041-07-14 Sun 2 — unknown — 72.5° 09:35 4.97 98% 111.2°
2041-07-15 Mon 2 — unknown — 72.5° 09:30 5.01 93% 96.2°
2041-07-16 Tue 2 — unknown — 72.5° 09:30 5.06 86% 81.4°
2041-07-17 Wed 2 — unknown 04:00–04:05 (marginal, 0.08 h) 72.5° 09:25 5.1 77% 66.7°
2041-07-18 Thu 3 — unknown 03:55–04:05 (marginal, 0.17 h) 72.5° 09:20 5.15 66% 52.3°
2041-07-19 Fri 3 — unknown 03:50–04:05 (marginal, 0.25 h) 72.5° 09:15 5.19 55% 38.3°
2041-07-20 Sat 4 — unknown 03:40–04:05 (marginal, 0.42 h) 72.5° 09:10 5.24 44% 24.7°
2041-07-21 Sun 7 — unknown 03:35–04:10 (marginal, 0.58 h) 72.5° 09:10 5.29 34% 11.5°
2041-07-22 Mon 9 — unknown 03:30–04:55 (marginal, 1.42 h) 72.5° 09:05 5.34 24% 3.2°
2041-07-23 Tue 12 — unknown 04:00–04:10 (good, 0.17 h) 72.5° 09:00 5.39 16% 15.0°
2041-07-24 Wed 16 — unknown 03:55–04:15 (good, 0.33 h) 72.5° 08:55 5.44 9% 27.4°
2041-07-25 Thu 19 — unknown 03:45–04:15 (good, 0.5 h) 72.5° 08:55 5.49 4% 39.8°
2041-07-26 Fri 20 — unknown 03:45–04:15 (good, 0.5 h) 72.5° 08:50 5.54 1% 52.0°
2041-07-27 Sat 23 — unknown 03:40–04:20 (good, 0.67 h) 72.5° 08:45 5.6 0% 64.1°
2041-07-28 Sun 24 — unknown 03:35–04:20 (good, 0.75 h) 72.5° 08:40 5.65 1% 76.1°
2041-07-29 Mon 26 — unknown 03:30–04:20 (good, 0.83 h) 72.5° 08:35 5.7 3% 87.9°
2041-07-30 Tue 28 — unknown 03:25–04:25 (good, 1.0 h) 72.5° 08:35 5.76 8% 99.7°
2041-07-31 Wed 30 — unknown 03:25–04:25 (good, 1.0 h) 72.5° 08:30 5.81 13% 111.5°
2041-08-01 Thu 32 — unknown 03:20–04:25 (good, 1.08 h) 72.5° 08:25 5.87 20% 123.4°
2041-08-02 Fri 34 — unknown 03:15–04:30 (good, 1.25 h) 72.5° 08:20 5.92 28% 135.3°
2041-08-03 Sat 35 — unknown 03:10–04:30 (good, 1.33 h) 72.5° 08:15 5.98 38% 147.4°
2041-08-04 Sun 38 — unknown 03:05–04:30 (good, 1.42 h) 72.5° 08:15 6.03 47% 159.7°
2041-08-05 Mon 39 — unknown 03:05–04:30 (good, 1.42 h) 72.5° 08:10 6.09 57% 172.1°
2041-08-06 Tue 42 — unknown 03:00–04:35 (good, 1.58 h) 72.5° 08:05 6.15 68% 174.0°
2041-08-07 Wed 43 — unknown 02:55–04:35 (good, 1.67 h) 72.5° 08:00 6.2 77% 160.8°
2041-08-08 Thu 46 — unknown 02:50–04:35 (good, 1.75 h) 72.5° 08:00 6.26 86% 146.9°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2041-07-10&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.