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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 3C 273: 05-17 (83), 05-16 (82), 05-18 (81), 05-15 (80), 05-19 (79) — by astronomy; check the weather when the night is within four days.
2044-05-05astronomy score per night — click a bar for that night2044-06-03
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2044-05-05 Thu 37 — unknown 22:15–03:15 (marginal, 5.0 h) 50.1° 22:55 6.1 66% 31.2°
2044-05-06 Fri 28 — unknown 22:20–03:00 (marginal, 4.67 h) 50.1° 22:50 6.04 76% 18.4°
2044-05-07 Sat 22 — unknown 22:20–02:50 (marginal, 4.5 h) 50.1° 22:45 5.98 84% 7.6°
2044-05-08 Sun 18 — unknown 22:20–02:35 (marginal, 4.25 h) 50.1° 22:45 5.93 91% 10.5°
2044-05-09 Mon 17 — unknown 22:25–02:25 (marginal, 4.0 h) 50.1° 22:40 5.87 96% 21.9°
2044-05-10 Tue 20 — unknown 22:25–02:20 (marginal, 3.92 h) 50.1° 22:35 5.81 99% 33.9°
2044-05-11 Wed 28 — unknown 22:25–02:25 (marginal, 4.0 h) 50.1° 22:30 5.76 100% 46.0°
2044-05-12 Thu 38 — unknown 22:30–23:00 (good, 0.5 h) 50.1° 22:30 5.7 99% 57.9°
2044-05-13 Fri 68 — unknown 22:30–00:40 (good, 2.17 h) 50.1° 22:25 5.65 96% 69.8°
2044-05-14 Sat 77 — unknown 22:30–01:40 (good, 3.17 h) 50.1° 22:20 5.6 92% 81.6°
2044-05-15 Sun 80 — unknown 22:35–01:50 (good, 3.25 h) 50.1° 22:15 5.54 86% 93.4°
2044-05-16 Mon 82 — unknown 22:35–01:50 (good, 3.25 h) 50.1° 22:10 5.49 79% 105.1°
2044-05-17 Tue 83 — unknown 22:35–01:55 (good, 3.33 h) 50.1° 22:10 5.44 71% 116.9°
2044-05-18 Wed 81 — unknown 22:40–01:55 (good, 3.25 h) 50.1° 22:05 5.39 62% 128.8°
2044-05-19 Thu 79 — unknown 22:40–01:50 (good, 3.17 h) 50.1° 22:00 5.34 52% 140.9°
2044-05-20 Fri 77 — unknown 22:40–01:50 (good, 3.17 h) 50.1° 21:55 5.29 42% 153.2°
2044-05-21 Sat 74 — unknown 22:45–01:45 (good, 3.0 h) 50.1° 21:50 5.24 32% 165.3°
2044-05-22 Sun 73 — unknown 22:45–01:40 (good, 2.92 h) 50.1° 21:50 5.19 23% 173.6°
2044-05-23 Mon 71 — unknown 22:45–01:35 (good, 2.83 h) 50.1° 21:45 5.14 14% 164.7°
2044-05-24 Tue 69 — unknown 22:45–01:30 (good, 2.75 h) 50.1° 21:40 5.1 7% 151.2°
2044-05-25 Wed 66 — unknown 22:50–01:30 (good, 2.67 h) 50.1° 21:35 5.05 2% 136.8°
2044-05-26 Thu 64 — unknown 22:50–01:25 (good, 2.58 h) 50.1° 21:35 5.01 0% 122.0°
2044-05-27 Fri 63 — unknown 22:50–01:20 (good, 2.5 h) 50.1° 21:30 4.97 1% 107.0°
2044-05-28 Sat 60 — unknown 22:55–01:15 (good, 2.33 h) 50.1° 21:25 4.92 5% 92.0°
2044-05-29 Sun 56 — unknown 22:55–01:10 (good, 2.25 h) 50.1° 21:20 4.88 11% 77.1°
2044-05-30 Mon 50 — unknown 22:55–01:10 (good, 2.25 h) 50.1° 21:15 4.85 20% 62.5°
2044-05-31 Tue 42 — unknown 22:55–00:55 (good, 2.0 h) 50.1° 21:15 4.81 30% 48.3°
2044-06-01 Wed 32 — unknown 23:00–00:40 (good, 1.67 h) 50.1° 21:10 4.77 41% 34.5°
2044-06-02 Thu 25 — unknown 23:00–23:35 (good, 0.58 h) 50.1° 21:05 4.74 52% 21.4°
2044-06-03 Fri 19 — unknown 23:00–01:15 (marginal, 2.25 h) 50.1° 21:00 4.7 62% 9.8°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2044-05-05&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.