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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: 02-10 (61), 02-11 (59), 02-12 (57), 02-13 (54), 02-14 (53) — by astronomy; check the weather when the night is within four days.
2026-02-10astronomy score per night — click a bar for that night2026-03-11
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2026-02-10 Tue 61 0 0 — 89.5° 15:45 10.44 37% 133.7°
2026-02-11 Wed 59 0 0 — 89.6° 15:40 10.4 28% 124.5°
2026-02-12 Thu 57 0 0 — 89.7° 15:35 10.36 20% 114.6°
2026-02-13 Fri 54 0 0 — 89.7° 15:30 10.32 13% 104.3°
2026-02-14 Sat 53 1 0 — 89.5° 15:25 10.29 7% 93.5°
2026-02-15 Sun 50 0 0 — 89.5° 15:25 10.25 3% 82.5°
2026-02-16 Mon 48 23 11 19:30–20:00 (marginal, 0.5 h) 89.7° 15:20 10.21 0% 71.3°
2026-02-17 Tue 46 0 0 — 89.7° 15:15 10.17 0% 60.2°
2026-02-18 Wed 44 97 43 19:35–21:10 (good, 1.58 h) 89.6° 15:10 10.12 2% 49.5°
2026-02-19 Thu 41 0 0 — 89.5° 15:05 10.08 7% 39.8°
2026-02-20 Fri 35 0 0 — 89.6° 15:05 10.04 14% 32.3°
2026-02-21 Sat 29 0 0 — 89.7° 15:00 10.0 22% 29.3°
2026-02-22 Sun 22 63 14 19:40–20:00 (good, 0.33 h) 89.7° 14:55 9.96 32% 32.1°
2026-02-23 Mon 18 15 3 — 89.6° 14:50 9.91 43% 39.5°
2026-02-24 Tue 14 36 5 21:00–21:20 (marginal, 0.33 h) 89.5° 14:50 9.87 55% 49.6°
2026-02-25 Wed 12 100 12 19:40–21:15 (marginal, 1.58 h) 89.6° 14:45 9.83 66% 60.9°
2026-02-26 Thu 11 93 10 19:45–21:05 (marginal, 1.33 h) 89.7° 14:40 9.78 76% 72.8°
2026-02-27 Fri 12 90 11 19:45–21:00 (marginal, 1.25 h) 89.7° 14:35 9.74 85% 85.0°
2026-02-28 Sat 14 100 14 19:45–19:55 (good, 0.17 h) 89.6° 14:30 9.69 92% 97.2°
2026-03-01 Sun 16 100 16 19:45–20:15 (good, 0.5 h) 89.5° 14:30 9.65 97% 109.1°
2026-03-02 Mon 18 51 9 19:45–20:30 (marginal, 0.75 h) 89.7° 14:25 9.6 100% 120.6°
2026-03-03 Tue 17 0 0 — 89.7° 14:20 9.56 100% 131.2°
2026-03-04 Wed 17 2 0 — 89.6° 14:15 9.51 98% 140.4°
2026-03-05 Thu 18 0 0 — 89.5° 14:10 9.46 94% 147.3°
2026-03-06 Fri 16 83 13 19:50–20:00 (good, 0.17 h) 89.6° 14:10 9.41 88% 150.6°
2026-03-07 Sat 13 82 11 19:55–20:00 (good, 0.08 h) 89.7° 14:05 9.37 81% 149.3°
2026-03-08 Sun 12 60 7 19:55–20:35 (marginal, 0.67 h) 89.7° 14:00 9.32 72% 144.1°
2026-03-09 Mon 11 42 5 19:55–20:00 (marginal, 0.08 h) 89.6° 13:55 9.27 64% 136.6°
2026-03-10 Tue 9 100 9 19:55–20:00 (good, 0.08 h) 89.5° 13:55 9.22 54% 127.8°
2026-03-11 Wed 7 48 3 — 89.6° 13:50 9.17 45% 118.2°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2026-02-10&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.