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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 North America Nebula: 01-21 (21), 02-19 (20), 01-22 (18), 02-18 (18), 02-16 (17) — by astronomy; check the weather when the night is within four days.
2026-01-21astronomy score per night — click a bar for that night2026-02-19
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2026-01-21 Wed 21 0 0 — 87.2° 13:15 11.08 10% 57.6°
2026-01-22 Thu 18 1 0 — 87.2° 13:15 11.06 17% 57.2°
2026-01-23 Fri 15 84 13 19:05–19:15 (good, 0.17 h) 87.3° 13:10 11.03 26% 58.9°
2026-01-24 Sat 12 0 0 — 87.3° 13:05 11.0 36% 62.4°
2026-01-25 Sun 10 0 0 — 87.2° 13:00 10.97 47% 67.5°
2026-01-26 Mon 8 0 0 — 87.2° 13:00 10.94 58% 73.9°
2026-01-27 Tue 7 31 2 — 87.3° 12:55 10.91 69% 81.1°
2026-01-28 Wed 7 0 0 — 87.3° 12:50 10.88 80% 88.9°
2026-01-29 Thu 7 0 0 — 87.3° 12:45 10.85 88% 96.7°
2026-01-30 Fri 6 0 0 — 87.2° 12:40 10.82 95% 104.3°
2026-01-31 Sat 6 0 0 — 87.2° 12:40 10.79 99% 111.1°
2026-02-01 Sun 7 0 0 — 87.3° 12:35 10.76 100% 116.7°
2026-02-02 Mon 7 0 0 — 87.3° 12:30 10.72 99% 120.6°
2026-02-03 Tue 8 18 1 — 87.3° 12:25 10.69 95% 122.7°
2026-02-04 Wed 7 0 0 — 87.2° 12:20 10.66 89% 122.7°
2026-02-05 Thu 8 0 0 — 87.2° 12:20 10.62 82% 120.8°
2026-02-06 Fri 8 0 0 — 87.3° 12:15 10.59 74% 117.4°
2026-02-07 Sat 9 14 1 — 87.3° 12:10 10.55 65% 112.9°
2026-02-08 Sun 9 11 1 — 87.2° 12:05 10.51 56% 107.6°
2026-02-09 Mon 9 0 0 — 87.3° 12:00 10.48 46% 101.7°
2026-02-10 Tue 10 0 0 — 87.3° 11:55 10.44 37% 95.5°
2026-02-11 Wed 11 0 0 — 87.3° 11:50 10.4 28% 89.0°
2026-02-12 Thu 13 0 0 — 87.2° 11:45 10.36 20% 82.6°
2026-02-13 Fri 13 59 8 05:20–05:45 (marginal, 0.42 h) 87.2° 11:45 10.32 13% 76.3°
2026-02-14 Sat 15 0 0 — 87.3° 11:40 10.29 7% 70.3°
2026-02-15 Sun 16 88 14 05:35–05:45 (good, 0.17 h) 87.3° 11:35 10.25 3% 65.1°
2026-02-16 Mon 17 0 0 — 87.3° 11:30 10.21 0% 60.8°
2026-02-17 Tue 17 0 0 — 87.2° 11:25 10.17 0% 58.0°
2026-02-18 Wed 18 100 18 05:10–05:40 (good, 0.5 h) 87.2° 11:25 10.12 2% 57.1°
2026-02-19 Thu 20 0 0 — 87.3° 11:20 10.08 7% 58.2°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2026-01-21&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.