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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 North America Nebula: 05-23 (100), 05-24 (100), 05-25 (100), 05-22 (99), 05-21 (97) — by astronomy; check the weather when the night is within four days.
2044-04-26astronomy score per night — click a bar for that night2044-05-25
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2044-04-26 Tue 76 — unknown 01:45–04:40 (good, 2.92 h) 87.2° 08:00 6.62 1% 65.3°
2044-04-27 Wed 77 — unknown 01:40–04:40 (good, 3.0 h) 87.2° 07:55 6.56 0% 71.1°
2044-04-28 Thu 78 — unknown 01:35–04:35 (good, 3.0 h) 87.2° 07:50 6.5 2% 78.1°
2044-04-29 Fri 80 — unknown 01:30–04:35 (good, 3.08 h) 87.2° 07:45 6.44 6% 85.7°
2044-04-30 Sat 80 — unknown 01:25–04:30 (good, 3.08 h) 87.2° 07:40 6.38 14% 93.6°
2044-05-01 Sun 81 — unknown 01:25–04:30 (good, 3.08 h) 87.2° 07:40 6.33 23% 101.1°
2044-05-02 Mon 82 — unknown 01:25–04:30 (good, 3.08 h) 87.2° 07:35 6.27 33% 108.1°
2044-05-03 Tue 82 — unknown 01:20–04:25 (good, 3.08 h) 87.2° 07:30 6.21 44% 113.9°
2044-05-04 Wed 82 — unknown 01:20–04:25 (good, 3.08 h) 87.2° 07:25 6.15 56% 118.4°
2044-05-05 Thu 84 — unknown 01:15–04:25 (good, 3.17 h) 87.2° 07:25 6.1 66% 121.2°
2044-05-06 Fri 82 — unknown 01:15–04:20 (good, 3.08 h) 87.2° 07:20 6.04 76% 122.0°
2044-05-07 Sat 82 — unknown 01:10–04:20 (good, 3.17 h) 87.2° 07:15 5.98 84% 121.0°
2044-05-08 Sun 75 — unknown 01:10–04:20 (good, 3.17 h) 87.2° 07:10 5.93 91% 118.4°
2044-05-09 Mon 71 — unknown 01:10–04:15 (good, 3.08 h) 87.2° 07:05 5.87 96% 114.4°
2044-05-10 Tue 67 — unknown 01:10–04:15 (good, 3.08 h) 87.2° 07:05 5.81 99% 109.4°
2044-05-11 Wed 64 — unknown 01:10–04:15 (good, 3.08 h) 87.2° 07:00 5.76 100% 103.7°
2044-05-12 Thu 59 — unknown 01:05–04:10 (good, 3.08 h) 87.2° 06:55 5.7 99% 97.5°
2044-05-13 Fri 57 — unknown 01:05–04:10 (good, 3.08 h) 87.2° 06:50 5.65 96% 91.2°
2044-05-14 Sat 56 — unknown 01:00–04:10 (good, 3.17 h) 87.2° 06:45 5.6 92% 84.9°
2044-05-15 Sun 56 — unknown 00:55–04:05 (good, 3.17 h) 87.2° 06:45 5.54 86% 78.8°
2044-05-16 Mon 65 — unknown 00:25–04:05 (good, 3.67 h) 87.2° 06:40 5.49 79% 73.1°
2044-05-17 Tue 72 — unknown 00:20–04:05 (good, 3.75 h) 87.2° 06:35 5.44 71% 67.9°
2044-05-18 Wed 78 — unknown 00:15–04:00 (good, 3.75 h) 87.2° 06:30 5.39 62% 63.5°
2044-05-19 Thu 85 — unknown 00:10–04:00 (good, 3.83 h) 87.2° 06:30 5.34 52% 60.1°
2044-05-20 Fri 91 — unknown 00:10–04:00 (good, 3.83 h) 87.2° 06:25 5.29 42% 58.2°
2044-05-21 Sat 97 — unknown 00:05–03:55 (good, 3.83 h) 87.2° 06:20 5.24 32% 58.0°
2044-05-22 Sun 99 — unknown 00:00–03:55 (good, 3.92 h) 87.2° 06:15 5.19 23% 59.6°
2044-05-23 Mon 100 — unknown 23:55–03:55 (good, 4.0 h) 87.2° 06:10 5.14 14% 63.1°
2044-05-24 Tue 100 — unknown 23:55–03:55 (good, 4.0 h) 87.2° 06:10 5.1 7% 68.3°
2044-05-25 Wed 100 — unknown 23:50–03:50 (good, 4.0 h) 87.2° 06:05 5.05 2% 75.0°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2044-04-26&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.