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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: 05-20 (7), 05-18 (5), 05-19 (5), 05-16 (4), 05-17 (4) — by astronomy; check the weather when the night is within four days.
2036-04-21astronomy score per night — click a bar for that night2036-05-20
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2036-04-21 Mon 0 — unknown — 89.7° 12:05 6.91 20% 57.5°
2036-04-22 Tue 0 — unknown — 89.6° 12:00 6.85 13% 49.6°
2036-04-23 Wed 0 — unknown — 89.7° 11:55 6.8 7% 43.0°
2036-04-24 Thu 0 — unknown — 89.8° 11:50 6.74 3% 38.8°
2036-04-25 Fri 0 — unknown — 89.7° 11:45 6.68 0% 38.1°
2036-04-26 Sat 1 — unknown — 89.5° 11:40 6.62 0% 41.3°
2036-04-27 Sun 1 — unknown — 89.6° 11:40 6.56 3% 47.8°
2036-04-28 Mon 1 — unknown — 89.7° 11:35 6.5 8% 56.5°
2036-04-29 Tue 1 — unknown — 89.8° 11:30 6.45 15% 66.7°
2036-04-30 Wed 1 — unknown — 89.7° 11:25 6.39 25% 77.5°
2036-05-01 Thu 1 — unknown — 89.5° 11:20 6.33 35% 88.7°
2036-05-02 Fri 1 — unknown — 89.6° 11:20 6.27 46% 99.9°
2036-05-03 Sat 1 — unknown — 89.8° 11:15 6.21 58% 110.8°
2036-05-04 Sun 1 — unknown — 89.7° 11:10 6.16 69% 121.0°
2036-05-05 Mon 2 — unknown — 89.6° 11:05 6.1 78% 130.1°
2036-05-06 Tue 2 — unknown 05:00–05:05 (marginal, 0.08 h) 89.5° 11:05 6.04 87% 137.2°
2036-05-07 Wed 2 — unknown — 89.7° 11:00 5.99 93% 141.4°
2036-05-08 Thu 2 — unknown — 89.8° 10:55 5.93 98% 141.8°
2036-05-09 Fri 2 — unknown — 89.7° 10:50 5.87 100% 138.4°
2036-05-10 Sat 3 — unknown 04:10–04:15 (marginal, 0.08 h) 89.6° 10:45 5.82 99% 132.3°
2036-05-11 Sun 3 — unknown 04:05–04:15 (marginal, 0.17 h) 89.6° 10:45 5.76 97% 124.5°
2036-05-12 Mon 3 — unknown 04:00–04:10 (marginal, 0.17 h) 89.7° 10:40 5.71 93% 115.7°
2036-05-13 Tue 3 — unknown 04:00–04:10 (marginal, 0.17 h) 89.8° 10:35 5.65 87% 106.6°
2036-05-14 Wed 3 — unknown 03:55–04:10 (marginal, 0.25 h) 89.7° 10:30 5.6 80% 97.2°
2036-05-15 Thu 3 — unknown 03:50–04:05 (marginal, 0.25 h) 89.5° 10:25 5.55 72% 87.8°
2036-05-16 Fri 4 — unknown 03:45–04:05 (marginal, 0.33 h) 89.6° 10:25 5.49 63% 78.5°
2036-05-17 Sat 4 — unknown 03:45–04:05 (marginal, 0.33 h) 89.8° 10:20 5.44 54% 69.4°
2036-05-18 Sun 5 — unknown 03:40–04:00 (marginal, 0.33 h) 89.7° 10:15 5.39 45% 60.6°
2036-05-19 Mon 5 — unknown 03:35–04:00 (marginal, 0.42 h) 89.6° 10:10 5.34 35% 52.5°
2036-05-20 Tue 7 — unknown 03:30–04:00 (marginal, 0.5 h) 89.5° 10:10 5.29 26% 45.4°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2036-04-21&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.