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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: 07-24 (16), 07-23 (13), 07-21 (11), 07-22 (11), 07-20 (8) — by astronomy; check the weather when the night is within four days.
2031-06-25astronomy score per night — click a bar for that night2031-07-24
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2031-06-25 Wed 0 — unknown — 72.5° 10:50 4.44 30% 100.6°
2031-06-26 Thu 0 — unknown — 72.5° 10:50 4.45 39% 112.9°
2031-06-27 Fri 0 — unknown — 72.5° 10:45 4.46 49% 125.5°
2031-06-28 Sat 0 — unknown — 72.5° 10:40 4.48 60% 138.5°
2031-06-29 Sun 0 — unknown — 72.5° 10:35 4.5 70% 151.8°
2031-06-30 Mon 0 — unknown — 72.5° 10:35 4.51 80% 165.4°
2031-07-01 Tue 0 — unknown — 72.5° 10:30 4.53 88% 175.7°
2031-07-02 Wed 0 — unknown — 72.5° 10:25 4.56 95% 164.2°
2031-07-03 Thu 0 — unknown — 72.5° 10:20 4.58 99% 149.5°
2031-07-04 Fri 0 — unknown — 72.5° 10:15 4.6 100% 134.3°
2031-07-05 Sat 0 — unknown — 72.5° 10:15 4.63 98% 119.1°
2031-07-06 Sun 0 — unknown — 72.5° 10:10 4.66 93% 104.1°
2031-07-07 Mon 0 — unknown — 72.5° 10:05 4.69 86% 89.4°
2031-07-08 Tue 0 — unknown — 72.5° 10:00 4.72 77% 75.1°
2031-07-09 Wed 0 — unknown — 72.5° 09:55 4.76 66% 61.3°
2031-07-10 Thu 1 — unknown — 72.5° 09:55 4.79 56% 47.9°
2031-07-11 Fri 1 — unknown — 72.5° 09:50 4.83 45% 35.0°
2031-07-12 Sat 1 — unknown — 72.5° 09:45 4.87 36% 22.5°
2031-07-13 Sun 1 — unknown — 72.5° 09:40 4.91 26% 10.7°
2031-07-14 Mon 2 — unknown 04:40–04:45 (marginal, 0.08 h) 72.5° 09:40 4.95 18% 5.0°
2031-07-15 Tue 3 — unknown 04:35–04:50 (marginal, 0.25 h) 72.5° 09:35 4.99 12% 15.0°
2031-07-16 Wed 4 — unknown 04:25–04:50 (marginal, 0.42 h) 72.5° 09:30 5.03 6% 26.6°
2031-07-17 Thu 4 — unknown 04:20–04:50 (marginal, 0.5 h) 72.5° 09:25 5.08 2% 38.3°
2031-07-18 Fri 6 — unknown 04:15–04:50 (marginal, 0.58 h) 72.5° 09:20 5.12 0% 50.1°
2031-07-19 Sat 7 — unknown 04:10–04:50 (marginal, 0.67 h) 72.5° 09:20 5.17 0% 61.8°
2031-07-20 Sun 8 — unknown 04:10–04:55 (marginal, 0.75 h) 72.5° 09:15 5.21 2% 73.7°
2031-07-21 Mon 11 — unknown 04:05–04:10 (good, 0.08 h) 72.5° 09:10 5.26 5% 85.6°
2031-07-22 Tue 11 — unknown 04:00–04:10 (good, 0.17 h) 72.5° 09:05 5.31 10% 97.7°
2031-07-23 Wed 13 — unknown 03:55–04:10 (good, 0.25 h) 72.5° 09:00 5.36 17% 109.9°
2031-07-24 Thu 16 — unknown 03:50–04:15 (good, 0.42 h) 72.5° 09:00 5.41 25% 122.3°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2031-06-25&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.