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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 Vega: 03-23 (100), 03-24 (100), 04-11 (100), 04-12 (100), 03-22 (99) — by astronomy; check the weather when the night is within four days.
2026-03-14astronomy score per night — click a bar for that night2026-04-12
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2026-03-14 Sat 92 80 74 02:00–05:05 (good, 3.08 h) 87.1° 07:30 9.03 18% 66.3°
2026-03-15 Sun 92 97 89 01:50–05:00 (good, 3.17 h) 87.1° 07:25 8.98 11% 68.0°
2026-03-16 Mon 93 53 49 03:00–05:00 (good, 2.0 h) 87.1° 07:20 8.93 5% 71.0°
2026-03-17 Tue 95 0 0 — 87.1° 07:15 8.88 2% 75.0°
2026-03-18 Wed 96 0 0 — 87.1° 07:10 8.82 0% 79.9°
2026-03-19 Thu 97 0 0 — 87.1° 07:10 8.77 1% 85.4°
2026-03-20 Fri 97 0 0 — 87.1° 07:05 8.72 5% 91.3°
2026-03-21 Sat 98 0 0 — 87.1° 07:00 8.67 11% 97.1°
2026-03-22 Sun 99 0 0 — 87.1° 06:55 8.62 19% 102.6°
2026-03-23 Mon 100 0 0 — 87.1° 06:50 8.57 29% 107.3°
2026-03-24 Tue 100 0 0 — 87.1° 06:50 8.51 40% 111.0°
2026-03-25 Wed 99 83 82 01:00–04:00 (good, 3.0 h) 87.1° 06:45 8.46 52% 113.3°
2026-03-26 Thu 97 3 3 — 87.1° 06:40 8.41 63% 114.2°
2026-03-27 Fri 97 16 15 02:00–03:00 (marginal, 1.0 h) 87.1° 06:35 8.35 73% 113.6°
2026-03-28 Sat 93 0 0 — 87.1° 07:30 8.3 82% 111.7°
2026-03-29 Sun 79 0 0 — 87.1° 07:30 8.25 90% 108.5°
2026-03-30 Mon 74 0 0 — 87.1° 07:25 8.19 95% 104.5°
2026-03-31 Tue 68 0 0 — 87.1° 07:20 8.14 99% 99.8°
2026-04-01 Wed 64 0 0 — 87.1° 07:15 8.08 100% 94.8°
2026-04-02 Thu 60 0 0 — 87.1° 07:15 8.03 99% 89.6°
2026-04-03 Fri 57 0 0 — 87.1° 07:10 7.97 96% 84.6°
2026-04-04 Sat 57 20 12 — 87.1° 07:05 7.92 92% 79.8°
2026-04-05 Sun 58 83 48 04:00–05:20 (good, 1.33 h) 87.1° 07:00 7.86 86% 75.5°
2026-04-06 Mon 63 94 59 01:30–05:00 (good, 3.5 h) 87.1° 06:55 7.8 79% 71.8°
2026-04-07 Tue 77 59 45 04:00–05:20 (good, 1.33 h) 87.1° 06:55 7.75 71% 68.9°
2026-04-08 Wed 87 2 1 — 87.1° 06:50 7.69 62% 66.8°
2026-04-09 Thu 94 33 31 00:20–03:00 (marginal, 2.67 h) 87.1° 06:45 7.64 53% 65.8°
2026-04-10 Fri 98 0 0 — 87.1° 06:40 7.58 43% 65.9°
2026-04-11 Sat 100 24 24 01:30–02:00 (good, 0.5 h) 87.1° 06:35 7.52 33% 67.1°
2026-04-12 Sun 100 4 4 — 87.1° 06:35 7.47 24% 69.6°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2026-03-14&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.