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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 V1057 Cyg: 08-04 (100), 08-05 (100), 08-06 (100), 08-07 (100), 08-08 (100) — by astronomy; check the weather when the night is within four days.
2026-08-04astronomy score per night — click a bar for that night2026-09-02
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2026-08-04 Tue 100 95 95 22:30–04:30 (good, 6.0 h) 87.3° 01:25 6.01 63% 65.0°
2026-08-05 Wed 100 90 90 22:30–04:30 (good, 6.0 h) 87.3° 01:25 6.07 52% 71.0°
2026-08-06 Thu 100 90 90 22:25–04:35 (good, 6.17 h) 87.3° 01:20 6.13 40% 78.1°
2026-08-07 Fri 100 97 97 22:25–04:35 (good, 6.17 h) 87.3° 01:15 6.18 30% 85.8°
2026-08-08 Sat 100 77 77 22:20–03:00 (good, 4.67 h) 87.3° 01:10 6.24 19% 93.9°
2026-08-09 Sun 100 94 94 22:20–04:40 (good, 6.33 h) 87.3° 01:05 6.3 11% 101.8°
2026-08-10 Mon 100 99 99 22:20–04:40 (good, 6.33 h) 87.3° 01:05 6.35 5% 109.3°
2026-08-11 Tue 100 100 100 22:15–04:40 (good, 6.42 h) 87.3° 01:00 6.41 1% 115.6°
2026-08-12 Wed 100 97 97 22:15–04:45 (good, 6.5 h) 87.3° 00:55 6.47 0% 120.4°
2026-08-13 Thu 100 31 31 22:15–01:00 (good, 2.75 h) 87.3° 00:50 6.53 2% 123.2°
2026-08-14 Fri 100 68 68 22:10–02:00 (good, 3.83 h) 87.3° 00:50 6.58 6% 123.7°
2026-08-15 Sat 100 99 99 22:10–04:45 (good, 6.58 h) 87.3° 00:45 6.64 12% 122.1°
2026-08-16 Sun 100 100 100 22:05–04:50 (good, 6.75 h) 87.3° 00:40 6.7 20% 118.7°
2026-08-17 Mon 100 100 100 22:05–04:50 (good, 6.75 h) 87.3° 00:35 6.76 29% 114.0°
2026-08-18 Tue 100 62 62 22:05–02:00 (good, 3.92 h) 87.3° 00:30 6.81 39% 108.4°
2026-08-19 Wed 100 100 100 22:00–04:55 (good, 6.92 h) 87.3° 00:30 6.87 48% 102.2°
2026-08-20 Thu 100 99 99 22:00–04:55 (good, 6.92 h) 87.3° 00:25 6.93 58% 95.8°
2026-08-21 Fri 100 100 100 21:55–04:55 (good, 7.0 h) 87.3° 00:20 6.99 67% 89.2°
2026-08-22 Sat 100 91 91 01:00–05:00 (good, 4.0 h) 87.3° 00:15 7.04 76% 82.6°
2026-08-23 Sun 100 85 85 23:00–05:00 (good, 6.0 h) 87.3° 00:10 7.1 83% 76.3°
2026-08-24 Mon 96 54 52 02:00–05:00 (good, 3.0 h) 87.3° 00:10 7.16 90% 70.3°
2026-08-25 Tue 88 97 85 23:00–05:00 (good, 6.0 h) 87.3° 00:05 7.22 95% 65.0°
2026-08-26 Wed 61 94 58 21:45–05:05 (marginal, 7.33 h) 87.3° 00:00 7.27 98% 60.6°
2026-08-27 Thu 60 97 58 21:45–05:05 (marginal, 7.33 h) 87.3° 23:55 7.33 100% 57.6°
2026-08-28 Fri 61 92 56 21:45–05:05 (marginal, 7.33 h) 87.3° 23:55 7.39 99% 56.2°
2026-08-29 Sat 64 20 13 21:40–23:00 (marginal, 1.33 h) 87.3° 23:50 7.44 97% 56.8°
2026-08-30 Sun 69 98 67 22:00–22:45 (good, 0.75 h) 87.3° 23:45 7.5 92% 59.4°
2026-08-31 Mon 75 99 74 21:35–01:05 (good, 3.5 h) 87.3° 23:40 7.56 85% 63.7°
2026-09-01 Tue 100 88 88 21:35–03:00 (good, 5.42 h) 87.3° 23:35 7.61 76% 69.5°
2026-09-02 Wed 100 7 7 — 87.3° 23:35 7.67 66% 76.4°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2026-08-04&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.