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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 Triangulum Pinwheel: 08-10 (100), 08-11 (100), 08-12 (100), 08-13 (100), 08-14 (100) — by astronomy; check the weather when the night is within four days.
2026-07-27astronomy score per night — click a bar for that night2026-08-25
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2026-07-27 Mon 66 99 65 01:25–04:20 (good, 2.92 h) 79.1° 06:35 5.58 97% 107.2°
2026-07-28 Tue 57 88 50 02:05–04:20 (good, 2.25 h) 79.1° 06:30 5.63 100% 95.6°
2026-07-29 Wed 47 100 47 02:20–04:20 (good, 2.0 h) 79.1° 06:25 5.68 100% 83.8°
2026-07-30 Thu 37 100 37 03:35–04:20 (good, 0.75 h) 79.1° 06:20 5.74 98% 71.8°
2026-07-31 Fri 30 100 30 00:35–04:25 (marginal, 3.83 h) 79.1° 06:15 5.79 95% 59.7°
2026-08-01 Sat 24 100 24 00:35–04:25 (marginal, 3.83 h) 79.1° 06:15 5.85 89% 47.6°
2026-08-02 Sun 22 100 22 00:35–04:25 (marginal, 3.83 h) 79.1° 06:10 5.9 82% 35.6°
2026-08-03 Mon 26 100 26 00:20–04:30 (marginal, 4.17 h) 79.1° 06:05 5.96 73% 24.3°
2026-08-04 Tue 35 98 34 00:15–04:30 (marginal, 4.25 h) 79.1° 06:00 6.01 63% 15.9°
2026-08-05 Wed 48 95 46 02:45–04:30 (good, 1.75 h) 79.1° 06:00 6.07 52% 16.4°
2026-08-06 Thu 64 91 58 02:00–04:35 (good, 2.58 h) 79.1° 05:55 6.13 40% 25.8°
2026-08-07 Fri 83 99 82 00:25–04:35 (good, 4.17 h) 79.1° 05:50 6.18 30% 38.3°
2026-08-08 Sat 92 71 65 02:00–03:00 (good, 1.0 h) 79.1° 05:45 6.24 19% 51.8°
2026-08-09 Sun 98 96 94 00:20–04:40 (good, 4.33 h) 79.1° 05:40 6.3 11% 65.8°
2026-08-10 Mon 100 100 100 00:10–04:40 (good, 4.5 h) 79.1° 05:40 6.35 5% 80.0°
2026-08-11 Tue 100 100 100 00:05–04:40 (good, 4.58 h) 79.1° 05:35 6.41 1% 94.2°
2026-08-12 Wed 100 98 98 00:05–04:45 (good, 4.67 h) 79.1° 05:30 6.47 0% 108.3°
2026-08-13 Thu 100 14 14 23:30–01:00 (marginal, 1.5 h) 79.1° 05:25 6.53 2% 122.0°
2026-08-14 Fri 100 59 59 00:05–01:00 (good, 0.92 h) 79.1° 05:20 6.58 6% 135.2°
2026-08-15 Sat 100 100 100 23:50–04:45 (good, 4.92 h) 79.1° 05:20 6.64 12% 147.5°
2026-08-16 Sun 100 100 100 23:45–04:50 (good, 5.08 h) 79.1° 05:15 6.7 20% 158.3°
2026-08-17 Mon 100 100 100 23:45–04:50 (good, 5.08 h) 79.1° 05:10 6.76 29% 165.0°
2026-08-18 Tue 100 56 56 00:00–02:00 (good, 2.0 h) 79.1° 05:05 6.81 39% 162.9°
2026-08-19 Wed 100 100 100 23:35–04:55 (good, 5.33 h) 79.1° 05:05 6.87 48% 154.6°
2026-08-20 Thu 100 99 99 23:35–04:55 (good, 5.33 h) 79.1° 05:00 6.93 58% 144.3°
2026-08-21 Fri 100 100 100 23:35–04:55 (good, 5.33 h) 79.1° 04:55 6.99 67% 133.4°
2026-08-22 Sat 100 90 90 01:00–05:00 (good, 4.0 h) 79.1° 04:50 7.04 76% 122.2°
2026-08-23 Sun 100 87 87 23:45–05:00 (good, 5.25 h) 79.1° 04:45 7.1 83% 110.8°
2026-08-24 Mon 100 63 63 02:00–05:00 (good, 3.0 h) 79.1° 04:45 7.16 90% 99.1°
2026-08-25 Tue 100 98 98 00:00–05:00 (good, 5.0 h) 79.1° 04:40 7.22 95% 87.3°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2026-07-27&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.