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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 Great Orion Nebula: 08-27 (5), 08-28 (5), 08-29 (5), 08-30 (5), 08-26 (4) — by astronomy; check the weather when the night is within four days.
2034-08-04astronomy score per night — click a bar for that night2034-09-02
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2034-08-04 Fri 0 — unknown — 42.9° 10:00 6.02 76% 72.8°
2034-08-05 Sat 0 — unknown — 42.9° 10:00 6.07 65% 60.2°
2034-08-06 Sun 0 — unknown — 42.9° 09:55 6.13 54% 47.9°
2034-08-07 Mon 0 — unknown — 42.9° 09:50 6.19 42% 36.6°
2034-08-08 Tue 0 — unknown — 42.9° 09:45 6.24 31% 27.5°
2034-08-09 Wed 0 — unknown — 42.9° 09:45 6.3 21% 23.5°
2034-08-10 Thu 0 — unknown — 42.9° 09:40 6.36 13% 27.0°
2034-08-11 Fri 0 — unknown — 42.9° 09:35 6.42 6% 35.7°
2034-08-12 Sat 0 — unknown — 42.9° 09:30 6.47 2% 46.7°
2034-08-13 Sun 0 — unknown — 42.9° 09:25 6.53 0% 58.5°
2034-08-14 Mon 0 — unknown — 42.9° 09:25 6.59 1% 70.5°
2034-08-15 Tue 0 — unknown — 42.9° 09:20 6.65 4% 82.4°
2034-08-16 Wed 0 — unknown — 42.9° 09:15 6.7 8% 94.1°
2034-08-17 Thu 0 — unknown — 42.9° 09:10 6.76 15% 105.5°
2034-08-18 Fri 0 — unknown — 42.9° 09:05 6.82 22% 116.6°
2034-08-19 Sat 1 — unknown — 42.9° 09:05 6.88 31% 127.2°
2034-08-20 Sun 1 — unknown — 42.9° 09:00 6.93 40% 137.2°
2034-08-21 Mon 1 — unknown — 42.9° 08:55 6.99 49% 146.2°
2034-08-22 Tue 1 — unknown — 42.9° 08:50 7.05 58% 153.3°
2034-08-23 Wed 1 — unknown — 42.9° 08:50 7.11 68% 156.5°
2034-08-24 Thu 2 — unknown 05:30–05:40 (marginal, 0.17 h) 42.9° 08:45 7.16 77% 154.3°
2034-08-25 Fri 3 — unknown 05:25–05:40 (marginal, 0.25 h) 42.9° 08:40 7.22 84% 147.4°
2034-08-26 Sat 4 — unknown 04:50–05:05 (marginal, 0.25 h) 42.9° 08:35 7.28 91% 137.8°
2034-08-27 Sun 5 — unknown 04:45–05:05 (marginal, 0.33 h) 42.9° 08:30 7.33 96% 126.8°
2034-08-28 Mon 5 — unknown 04:45–05:05 (marginal, 0.33 h) 42.9° 08:30 7.39 99% 114.9°
2034-08-29 Tue 5 — unknown 04:40–05:10 (marginal, 0.5 h) 42.9° 08:25 7.45 100% 102.4°
2034-08-30 Wed 5 — unknown 04:40–05:10 (marginal, 0.5 h) 42.9° 08:20 7.5 98% 89.5°
2034-08-31 Thu 4 — unknown 04:45–05:10 (marginal, 0.42 h) 42.9° 08:15 7.56 94% 76.4°
2034-09-01 Fri 4 — unknown 04:50–05:10 (marginal, 0.33 h) 42.9° 08:10 7.61 87% 63.4°
2034-09-02 Sat 4 — unknown 04:50–05:15 (marginal, 0.42 h) 42.9° 08:10 7.67 78% 50.8°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2034-08-04&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.