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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: 02-20 (41), 02-21 (40), 02-22 (38), 02-23 (35), 02-24 (33) — by astronomy; check the weather when the night is within four days.
2028-02-20astronomy score per night — click a bar for that night2028-03-20
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2028-02-20 Sun 41 — unknown 19:35–21:15 (good, 1.67 h) 89.7° 15:05 10.06 17% 103.3°
2028-02-21 Mon 40 — unknown 19:35–21:10 (good, 1.58 h) 89.6° 15:00 10.02 10% 92.8°
2028-02-22 Tue 38 — unknown 19:35–21:05 (good, 1.5 h) 89.5° 14:55 9.98 6% 82.3°
2028-02-23 Wed 35 — unknown 19:40–21:00 (good, 1.33 h) 89.6° 14:55 9.93 2% 71.9°
2028-02-24 Thu 33 — unknown 19:40–21:00 (good, 1.33 h) 89.7° 14:50 9.89 0% 61.8°
2028-02-25 Fri 32 — unknown 19:40–20:55 (good, 1.25 h) 89.7° 14:45 9.85 0% 52.0°
2028-02-26 Sat 31 — unknown 19:40–20:50 (good, 1.17 h) 89.6° 14:40 9.8 2% 42.9°
2028-02-27 Sun 27 — unknown 19:45–20:45 (good, 1.0 h) 89.5° 14:40 9.76 6% 35.1°
2028-02-28 Mon 24 — unknown 19:45–20:40 (good, 0.92 h) 89.7° 14:35 9.71 11% 29.7°
2028-02-29 Tue 20 — unknown 19:45–20:30 (good, 0.75 h) 89.7° 14:30 9.67 18% 28.3°
2028-03-01 Wed 17 — unknown 19:45–20:15 (good, 0.5 h) 89.7° 14:25 9.62 26% 31.5°
2028-03-02 Thu 13 — unknown 19:50–20:05 (good, 0.25 h) 89.5° 14:20 9.58 35% 38.5°
2028-03-03 Fri 11 — unknown 19:50–21:00 (marginal, 1.17 h) 89.6° 14:20 9.53 45% 47.8°
2028-03-04 Sat 8 — unknown 19:50–20:50 (marginal, 1.0 h) 89.7° 14:15 9.48 56% 58.5°
2028-03-05 Sun 7 — unknown 19:50–20:45 (marginal, 0.92 h) 89.7° 14:10 9.44 67% 70.2°
2028-03-06 Mon 7 — unknown 19:55–20:40 (marginal, 0.75 h) 89.6° 14:05 9.39 77% 82.6°
2028-03-07 Tue 7 — unknown 19:55–20:40 (marginal, 0.75 h) 89.5° 14:00 9.34 86% 95.4°
2028-03-08 Wed 7 — unknown 19:55–20:40 (marginal, 0.75 h) 89.6° 14:00 9.29 93% 108.5°
2028-03-09 Thu 7 — unknown 19:55–20:35 (marginal, 0.67 h) 89.7° 13:55 9.25 98% 121.4°
2028-03-10 Fri 7 — unknown 19:55–20:30 (marginal, 0.58 h) 89.7° 13:50 9.2 100% 133.6°
2028-03-11 Sat 6 — unknown 20:00–20:30 (marginal, 0.5 h) 89.6° 13:45 9.15 99% 144.0°
2028-03-12 Sun 6 — unknown 20:00–20:25 (marginal, 0.42 h) 89.5° 13:45 9.1 95% 150.6°
2028-03-13 Mon 5 — unknown 20:00–20:20 (marginal, 0.33 h) 89.7° 13:40 9.05 88% 151.2°
2028-03-14 Tue 4 — unknown 20:00–20:15 (marginal, 0.25 h) 89.7° 13:35 9.0 80% 145.9°
2028-03-15 Wed 3 — unknown 20:05–20:15 (marginal, 0.17 h) 89.7° 13:30 8.95 70% 137.3°
2028-03-16 Thu 2 — unknown 20:05–20:10 (marginal, 0.08 h) 89.5° 13:25 8.9 60% 127.2°
2028-03-17 Fri 1 — unknown — 89.6° 13:25 8.85 50% 116.7°
2028-03-18 Sat 1 — unknown — 89.7° 13:20 8.8 41% 106.1°
2028-03-19 Sun 1 — unknown — 89.7° 13:15 8.75 31% 95.5°
2028-03-20 Mon 1 — unknown — 89.6° 13:10 8.7 23% 85.0°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2028-02-20&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.