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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: 04-06 (93), 04-07 (93), 04-08 (93), 04-09 (93), 04-10 (93) — by astronomy; check the weather when the night is within four days.
2026-03-28astronomy score per night — click a bar for that night2026-04-26
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2026-03-28 Sat 54 6 3 — 50.2° 00:25 8.3 82% 47.6°
2026-03-29 Sun 36 0 0 — 50.2° 01:20 8.25 90% 34.5°
2026-03-30 Mon 27 2 1 — 50.2° 01:20 8.19 95% 21.8°
2026-03-31 Tue 24 4 1 — 50.2° 01:15 8.14 99% 10.5°
2026-04-01 Wed 24 0 0 — 50.2° 01:10 8.08 100% 8.7°
2026-04-02 Thu 30 0 0 — 50.2° 01:05 8.03 99% 19.0°
2026-04-03 Fri 65 0 0 — 50.2° 01:05 7.97 96% 30.7°
2026-04-04 Sat 86 28 24 00:00–01:00 (marginal, 1.0 h) 50.2° 01:00 7.92 92% 42.6°
2026-04-05 Sun 91 73 66 21:30–23:00 (good, 1.5 h) 50.2° 00:55 7.86 86% 54.4°
2026-04-06 Mon 93 73 68 00:00–03:45 (good, 3.75 h) 50.2° 00:50 7.8 79% 66.2°
2026-04-07 Tue 93 38 36 00:00–01:00 (good, 1.0 h) 50.2° 00:45 7.75 71% 77.9°
2026-04-08 Wed 93 35 32 21:35–00:00 (good, 2.42 h) 50.2° 00:45 7.69 62% 89.6°
2026-04-09 Thu 93 59 55 22:00–02:00 (good, 4.0 h) 50.2° 00:40 7.64 53% 101.5°
2026-04-10 Fri 93 0 0 — 50.2° 00:35 7.58 43% 113.5°
2026-04-11 Sat 93 51 48 22:00–02:00 (good, 4.0 h) 50.2° 00:30 7.52 33% 125.8°
2026-04-12 Sun 93 34 32 22:00–00:00 (good, 2.0 h) 50.2° 00:25 7.47 24% 138.3°
2026-04-13 Mon 93 2 2 — 50.2° 00:25 7.41 16% 151.1°
2026-04-14 Tue 93 16 15 02:00–03:00 (good, 1.0 h) 50.2° 00:20 7.35 9% 163.9°
2026-04-15 Wed 93 0 0 — 50.2° 00:15 7.29 3% 172.8°
2026-04-16 Thu 93 6 5 — 50.2° 00:10 7.24 0% 164.3°
2026-04-17 Fri 93 97 90 21:45–04:00 (good, 6.25 h) 50.2° 00:05 7.18 0% 150.6°
2026-04-18 Sat 93 88 82 21:50–03:55 (good, 6.08 h) 50.2° 00:05 7.12 3% 136.1°
2026-04-19 Sun 93 72 67 01:00–03:50 (good, 2.83 h) 50.2° 00:00 7.06 9% 121.4°
2026-04-20 Mon 93 52 48 01:00–03:50 (good, 2.83 h) 50.2° 23:55 7.0 16% 106.7°
2026-04-21 Tue 90 0 0 — 50.2° 23:50 6.95 26% 92.3°
2026-04-22 Wed 85 0 0 — 50.2° 23:50 6.89 37% 78.1°
2026-04-23 Thu 80 96 77 21:55–03:35 (good, 5.67 h) 50.2° 23:45 6.83 48% 64.2°
2026-04-24 Fri 65 68 44 02:00–03:00 (good, 1.0 h) 50.2° 23:40 6.77 59% 50.7°
2026-04-25 Sat 45 79 35 00:00–03:55 (marginal, 3.92 h) 50.2° 23:35 6.71 69% 37.6°
2026-04-26 Sun 32 100 32 22:00–03:45 (marginal, 5.75 h) 50.2° 23:30 6.65 78% 24.9°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2026-03-28&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.