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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: 07-14 (100), 07-15 (100), 07-16 (100), 07-17 (100), 07-18 (100) — by astronomy; check the weather when the night is within four days.
2026-07-14astronomy score per night — click a bar for that night2026-08-12
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2026-07-14 Tue 100 98 98 23:00–04:00 (good, 5.0 h) 87.1° 00:30 4.96 0% 114.7°
2026-07-15 Wed 100 57 57 02:00–04:00 (good, 2.0 h) 87.1° 00:25 5.0 3% 113.0°
2026-07-16 Thu 100 22 22 23:00–00:00 (good, 1.0 h) 87.1° 00:20 5.04 9% 109.9°
2026-07-17 Fri 100 98 98 22:55–04:00 (good, 5.08 h) 87.1° 00:15 5.08 16% 105.7°
2026-07-18 Sat 100 95 95 22:55–04:05 (good, 5.17 h) 87.1° 00:10 5.13 25% 100.9°
2026-07-19 Sun 100 98 98 22:55–04:05 (good, 5.17 h) 87.1° 00:10 5.18 35% 95.7°
2026-07-20 Mon 100 53 53 02:00–04:05 (good, 2.08 h) 87.1° 00:05 5.22 45% 90.4°
2026-07-21 Tue 100 73 73 23:00–03:00 (good, 4.0 h) 87.1° 00:00 5.27 55% 85.2°
2026-07-22 Wed 100 96 96 22:50–04:10 (good, 5.33 h) 87.1° 23:55 5.32 64% 80.4°
2026-07-23 Thu 100 61 61 23:00–02:00 (good, 3.0 h) 87.1° 23:50 5.37 73% 75.9°
2026-07-24 Fri 100 0 0 — 87.1° 23:50 5.42 81% 72.0°
2026-07-25 Sat 98 87 85 01:00–04:15 (good, 3.25 h) 87.1° 23:45 5.47 88% 68.9°
2026-07-26 Sun 91 87 79 00:00–04:05 (good, 4.08 h) 87.1° 23:40 5.52 93% 66.6°
2026-07-27 Mon 66 99 65 22:45–04:20 (good, 5.58 h) 87.1° 23:35 5.58 97% 65.3°
2026-07-28 Tue 65 90 59 23:00–23:10 (good, 0.17 h) 87.1° 23:35 5.63 100% 65.2°
2026-07-29 Wed 65 100 65 22:40–02:10 (good, 3.5 h) 87.1° 23:30 5.68 100% 66.3°
2026-07-30 Thu 68 100 68 22:40–02:05 (good, 3.42 h) 87.1° 23:25 5.74 98% 68.5°
2026-07-31 Fri 73 100 73 22:35–02:25 (good, 3.83 h) 87.1° 23:20 5.79 95% 71.8°
2026-08-01 Sat 77 100 77 22:35–02:55 (good, 4.33 h) 87.1° 23:15 5.85 89% 76.0°
2026-08-02 Sun 82 99 81 22:35–03:35 (good, 5.0 h) 87.1° 23:15 5.9 82% 80.8°
2026-08-03 Mon 100 99 99 22:30–04:25 (good, 5.92 h) 87.1° 23:10 5.96 73% 86.2°
2026-08-04 Tue 100 95 95 22:30–04:30 (good, 6.0 h) 87.1° 23:05 6.01 63% 91.9°
2026-08-05 Wed 100 90 90 22:30–04:30 (good, 6.0 h) 87.1° 23:00 6.07 52% 97.5°
2026-08-06 Thu 100 90 90 22:25–04:35 (good, 6.17 h) 87.1° 22:55 6.13 40% 102.9°
2026-08-07 Fri 100 97 97 22:25–04:35 (good, 6.17 h) 87.1° 22:55 6.18 30% 107.7°
2026-08-08 Sat 100 78 78 22:20–03:00 (good, 4.67 h) 87.1° 22:50 6.24 19% 111.5°
2026-08-09 Sun 100 94 94 22:20–04:40 (good, 6.33 h) 87.1° 22:45 6.3 11% 114.0°
2026-08-10 Mon 100 98 98 22:20–04:40 (good, 6.33 h) 87.1° 22:40 6.35 5% 114.8°
2026-08-11 Tue 100 100 100 22:15–04:35 (good, 6.33 h) 87.1° 22:40 6.41 1% 113.9°
2026-08-12 Wed 100 97 97 22:15–04:35 (good, 6.33 h) 87.1° 22:35 6.47 0% 111.4°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2026-07-14&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.