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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 Andromeda Galaxy: 05-24 (11), 05-23 (10), 05-21 (9), 05-22 (9), 05-20 (8) — by astronomy; check the weather when the night is within four days.
2029-04-25astronomy score per night — click a bar for that night2029-05-24
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2029-04-25 Wed 0 — unknown — 89.6° 11:45 6.7 90% 141.8°
2029-04-26 Thu 1 — unknown — 89.5° 11:45 6.64 96% 149.4°
2029-04-27 Fri 1 — unknown — 89.7° 11:40 6.58 99% 151.1°
2029-04-28 Sat 1 — unknown — 89.7° 11:35 6.52 100% 146.1°
2029-04-29 Sun 1 — unknown — 89.7° 11:30 6.46 97% 136.8°
2029-04-30 Mon 1 — unknown — 89.5° 11:25 6.41 91% 125.5°
2029-05-01 Tue 1 — unknown — 89.6° 11:25 6.35 84% 113.7°
2029-05-02 Wed 1 — unknown — 89.7° 11:20 6.29 75% 101.9°
2029-05-03 Thu 1 — unknown — 89.7° 11:15 6.23 65% 90.3°
2029-05-04 Fri 1 — unknown — 89.6° 11:10 6.17 55% 79.0°
2029-05-05 Sat 1 — unknown — 89.5° 11:10 6.12 45% 68.2°
2029-05-06 Sun 1 — unknown — 89.6° 11:05 6.06 35% 58.0°
2029-05-07 Mon 1 — unknown — 89.7° 11:00 6.0 26% 48.4°
2029-05-08 Tue 2 — unknown — 89.7° 10:55 5.95 19% 39.8°
2029-05-09 Wed 2 — unknown 04:55–05:00 (marginal, 0.08 h) 89.6° 10:50 5.89 12% 33.0°
2029-05-10 Thu 3 — unknown 04:45–05:00 (marginal, 0.25 h) 89.5° 10:50 5.83 6% 29.0°
2029-05-11 Fri 4 — unknown 04:40–04:55 (marginal, 0.25 h) 89.7° 10:45 5.78 3% 29.3°
2029-05-12 Sat 4 — unknown 04:35–04:55 (marginal, 0.33 h) 89.7° 10:40 5.72 0% 33.6°
2029-05-13 Sun 4 — unknown 04:30–04:55 (marginal, 0.42 h) 89.7° 10:35 5.67 0% 40.9°
2029-05-14 Mon 5 — unknown 04:30–04:55 (marginal, 0.42 h) 89.5° 10:30 5.62 2% 49.9°
2029-05-15 Tue 5 — unknown 04:25–04:50 (marginal, 0.42 h) 89.6° 10:30 5.56 5% 59.9°
2029-05-16 Wed 6 — unknown 04:20–04:50 (marginal, 0.5 h) 89.7° 10:25 5.51 11% 70.6°
2029-05-17 Thu 6 — unknown 04:15–04:50 (marginal, 0.58 h) 89.7° 10:20 5.46 18% 81.7°
2029-05-18 Fri 7 — unknown 04:15–04:50 (marginal, 0.58 h) 89.6° 10:15 5.41 26% 93.1°
2029-05-19 Sat 7 — unknown 04:10–04:45 (marginal, 0.58 h) 89.5° 10:10 5.36 36% 104.7°
2029-05-20 Sun 8 — unknown 04:05–04:45 (marginal, 0.67 h) 89.6° 10:10 5.31 47% 116.4°
2029-05-21 Mon 9 — unknown 03:30–04:45 (marginal, 1.25 h) 89.7° 10:05 5.26 58% 127.8°
2029-05-22 Tue 9 — unknown 03:25–04:45 (marginal, 1.33 h) 89.7° 10:00 5.21 70% 138.5°
2029-05-23 Wed 10 — unknown 03:20–04:40 (marginal, 1.33 h) 89.6° 09:55 5.16 80% 147.1°
2029-05-24 Thu 11 — unknown 03:50–03:55 (good, 0.08 h) 89.5° 09:55 5.11 88% 151.4°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2029-04-25&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.