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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: 05-27 (100), 05-26 (98), 05-25 (95), 05-10 (90), 05-11 (90) — by astronomy; check the weather when the night is within four days.
2030-04-28astronomy score per night — click a bar for that night2030-05-27
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2030-04-28 Sun 77 — unknown 01:35–04:35 (good, 3.0 h) 87.3° 07:50 6.54 12% 54.4°
2030-04-29 Mon 78 — unknown 01:35–04:35 (good, 3.0 h) 87.3° 07:50 6.48 7% 58.0°
2030-04-30 Tue 80 — unknown 01:30–04:35 (good, 3.08 h) 87.3° 07:45 6.42 3% 62.9°
2030-05-01 Wed 80 — unknown 01:25–04:30 (good, 3.08 h) 87.3° 07:40 6.36 0% 68.9°
2030-05-02 Thu 82 — unknown 01:20–04:30 (good, 3.17 h) 87.3° 07:35 6.3 0% 75.5°
2030-05-03 Fri 83 — unknown 01:20–04:30 (good, 3.17 h) 87.3° 07:35 6.25 2% 82.5°
2030-05-04 Sat 83 — unknown 01:15–04:25 (good, 3.17 h) 87.3° 07:30 6.19 5% 89.7°
2030-05-05 Sun 86 — unknown 01:10–04:25 (good, 3.25 h) 87.3° 07:25 6.13 10% 96.9°
2030-05-06 Mon 86 — unknown 01:05–04:20 (good, 3.25 h) 87.3° 07:20 6.07 16% 104.0°
2030-05-07 Tue 88 — unknown 01:00–04:20 (good, 3.33 h) 87.3° 07:15 6.02 24% 110.7°
2030-05-08 Wed 88 — unknown 01:00–04:20 (good, 3.33 h) 87.3° 07:15 5.96 32% 116.8°
2030-05-09 Thu 89 — unknown 01:00–04:15 (good, 3.25 h) 87.3° 07:10 5.9 42% 122.0°
2030-05-10 Fri 90 — unknown 00:55–04:15 (good, 3.33 h) 87.3° 07:05 5.85 52% 125.8°
2030-05-11 Sat 90 — unknown 00:55–04:15 (good, 3.33 h) 87.3° 07:00 5.79 63% 127.7°
2030-05-12 Sun 89 — unknown 00:50–04:10 (good, 3.33 h) 87.3° 06:55 5.74 73% 127.2°
2030-05-13 Mon 89 — unknown 00:50–04:10 (good, 3.33 h) 87.3° 06:55 5.68 82% 124.2°
2030-05-14 Tue 82 — unknown 00:50–04:10 (good, 3.33 h) 87.3° 06:50 5.63 90% 118.9°
2030-05-15 Wed 74 — unknown 00:50–04:05 (good, 3.25 h) 87.3° 06:45 5.58 96% 111.7°
2030-05-16 Thu 66 — unknown 00:50–04:05 (good, 3.25 h) 87.3° 06:40 5.52 100% 103.3°
2030-05-17 Fri 59 — unknown 00:55–04:05 (good, 3.17 h) 87.3° 06:40 5.47 100% 94.1°
2030-05-18 Sat 53 — unknown 01:15–04:00 (good, 2.75 h) 87.3° 06:35 5.42 97% 84.8°
2030-05-19 Sun 50 — unknown 01:15–04:00 (good, 2.75 h) 87.3° 06:30 5.37 91% 75.9°
2030-05-20 Mon 51 — unknown 00:45–04:00 (good, 3.25 h) 87.3° 06:25 5.32 83% 67.8°
2030-05-21 Tue 65 — unknown 00:05–04:00 (good, 3.92 h) 87.3° 06:20 5.27 74% 61.0°
2030-05-22 Wed 72 — unknown 00:05–03:55 (good, 3.83 h) 87.3° 06:20 5.22 64% 55.9°
2030-05-23 Thu 81 — unknown 00:00–03:55 (good, 3.92 h) 87.3° 06:15 5.17 53% 52.9°
2030-05-24 Fri 90 — unknown 23:55–03:55 (good, 4.0 h) 87.3° 06:10 5.13 43% 52.2°
2030-05-25 Sat 95 — unknown 23:50–03:55 (good, 4.08 h) 87.3° 06:05 5.08 33% 53.6°
2030-05-26 Sun 98 — unknown 23:45–03:50 (good, 4.08 h) 87.3° 06:00 5.04 24% 56.9°
2030-05-27 Mon 100 — unknown 23:45–03:50 (good, 4.08 h) 87.3° 06:00 4.99 16% 61.6°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2030-04-28&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.