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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: 06-28 (10), 06-29 (7), 06-30 (6), 07-01 (4), 07-02 (3) — by astronomy; check the weather when the night is within four days.
2044-06-28astronomy score per night — click a bar for that night2044-07-27
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2044-06-28 Tue 10 — unknown 22:20–23:45 (marginal, 1.42 h) 50.1° 19:25 4.49 17% 39.2°
2044-06-29 Wed 7 — unknown 22:20–23:00 (marginal, 0.67 h) 50.1° 19:20 4.51 26% 25.5°
2044-06-30 Thu 6 — unknown 23:10–23:35 (marginal, 0.42 h) 50.1° 19:15 4.53 37% 12.9°
2044-07-01 Fri 4 — unknown 23:10–23:30 (marginal, 0.33 h) 50.1° 19:10 4.55 47% 7.1°
2044-07-02 Sat 3 — unknown 23:10–23:25 (marginal, 0.25 h) 50.1° 19:05 4.58 57% 16.4°
2044-07-03 Sun 2 — unknown 23:10–23:15 (marginal, 0.08 h) 50.1° 19:05 4.6 67% 28.2°
2044-07-04 Mon 2 — unknown — 50.1° 19:00 4.63 76% 40.2°
2044-07-05 Tue 2 — unknown — 50.1° 18:55 4.66 84% 52.1°
2044-07-06 Wed 2 — unknown — 50.1° 18:50 4.69 90% 63.9°
2044-07-07 Thu 2 — unknown — 50.1° 18:45 4.72 95% 75.7°
2044-07-08 Fri 2 — unknown — 50.1° 18:45 4.75 98% 87.4°
2044-07-09 Sat 2 — unknown — 50.1° 18:40 4.79 100% 99.2°
2044-07-10 Sun 2 — unknown — 50.1° 18:35 4.82 100% 110.9°
2044-07-11 Mon 2 — unknown — 50.1° 18:30 4.86 97% 122.8°
2044-07-12 Tue 2 — unknown 22:15–22:20 (marginal, 0.08 h) 50.1° 18:30 4.9 94% 134.7°
2044-07-13 Wed 2 — unknown — 50.1° 18:25 4.94 88% 146.7°
2044-07-14 Thu 1 — unknown — 50.1° 18:20 4.98 81% 158.7°
2044-07-15 Fri 1 — unknown — 50.1° 18:15 5.03 72% 169.8°
2044-07-16 Sat 1 — unknown — 50.1° 18:10 5.07 62% 171.4°
2044-07-17 Sun 1 — unknown — 50.1° 18:10 5.11 52% 160.4°
2044-07-18 Mon 1 — unknown — 50.1° 18:05 5.16 41% 147.3°
2044-07-19 Tue 1 — unknown — 50.1° 18:00 5.21 30% 133.6°
2044-07-20 Wed 1 — unknown — 50.1° 17:55 5.26 20% 119.4°
2044-07-21 Thu 0 — unknown — 50.1° 17:50 5.3 12% 104.8°
2044-07-22 Fri 0 — unknown — 50.1° 17:50 5.35 5% 90.0°
2044-07-23 Sat 0 — unknown — 50.1° 17:45 5.4 1% 75.0°
2044-07-24 Sun 0 — unknown — 50.1° 17:40 5.45 0% 60.0°
2044-07-25 Mon 0 — unknown — 50.1° 17:35 5.51 2% 45.2°
2044-07-26 Tue 0 — unknown — 50.1° 17:35 5.56 7% 30.9°
2044-07-27 Wed 0 — unknown — 50.1° 17:30 5.61 14% 17.4°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2044-06-28&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.