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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: 02-25 (25), 02-26 (25), 02-27 (24), 02-23 (23), 02-24 (23) — by astronomy; check the weather when the night is within four days.
2026-01-30astronomy score per night — click a bar for that night2026-02-28
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
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°
2026-02-20 Fri 21 0 0 — 87.3° 11:15 10.04 14% 61.3°
2026-02-21 Sat 21 0 0 — 87.2° 11:10 10.0 22% 66.1°
2026-02-22 Sun 22 2 0 — 87.2° 11:10 9.96 32% 72.3°
2026-02-23 Mon 23 25 6 05:00–05:35 (marginal, 0.58 h) 87.3° 11:05 9.91 43% 79.3°
2026-02-24 Tue 23 7 2 — 87.3° 11:00 9.87 55% 86.8°
2026-02-25 Wed 25 0 0 — 87.3° 10:55 9.83 66% 94.5°
2026-02-26 Thu 25 58 15 04:25–05:30 (marginal, 1.08 h) 87.2° 10:50 9.78 76% 102.0°
2026-02-27 Fri 24 94 23 04:50–05:30 (good, 0.67 h) 87.2° 10:50 9.74 85% 108.9°
2026-02-28 Sat 22 100 22 04:40–05:25 (good, 0.75 h) 87.3° 10:45 9.69 92% 114.8°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2026-01-30&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.