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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: 07-02 (7), 07-03 (6), 07-04 (5), 07-05 (4), 07-06 (3) — by astronomy; check the weather when the night is within four days.
2038-07-02astronomy score per night — click a bar for that night2038-07-31
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2038-07-02 Fri 7 — unknown 22:20–23:00 (marginal, 0.67 h) 50.1° 19:10 4.56 0% 80.3°
2038-07-03 Sat 6 — unknown 22:20–22:55 (marginal, 0.58 h) 50.1° 19:05 4.59 2% 67.2°
2038-07-04 Sun 5 — unknown 22:20–22:55 (marginal, 0.58 h) 50.1° 19:00 4.61 6% 53.9°
2038-07-05 Mon 4 — unknown 22:20–22:45 (marginal, 0.42 h) 50.1° 18:55 4.64 13% 40.3°
2038-07-06 Tue 3 — unknown 22:15–22:35 (marginal, 0.33 h) 50.1° 18:55 4.67 21% 26.6°
2038-07-07 Wed 2 — unknown 22:15–22:25 (marginal, 0.17 h) 50.1° 18:50 4.7 31% 12.7°
2038-07-08 Thu 2 — unknown — 50.1° 18:45 4.73 42% 1.4°
2038-07-09 Fri 1 — unknown — 50.1° 18:40 4.77 53% 15.5°
2038-07-10 Sat 1 — unknown — 50.1° 18:35 4.8 64% 29.7°
2038-07-11 Sun 1 — unknown — 50.1° 18:35 4.84 75% 44.0°
2038-07-12 Mon 1 — unknown — 50.1° 18:30 4.88 84% 58.3°
2038-07-13 Tue 1 — unknown — 50.1° 18:25 4.92 92% 72.5°
2038-07-14 Wed 1 — unknown — 50.1° 18:20 4.96 97% 86.6°
2038-07-15 Thu 1 — unknown — 50.1° 18:20 5.0 100% 100.6°
2038-07-16 Fri 1 — unknown — 50.1° 18:15 5.05 100% 114.3°
2038-07-17 Sat 1 — unknown — 50.1° 18:10 5.09 98% 127.7°
2038-07-18 Sun 1 — unknown — 50.1° 18:05 5.14 93% 140.7°
2038-07-19 Mon 1 — unknown — 50.1° 18:00 5.18 87% 153.5°
2038-07-20 Tue 1 — unknown — 50.1° 18:00 5.23 80% 165.9°
2038-07-21 Wed 1 — unknown — 50.1° 17:55 5.28 71% 178.0°
2038-07-22 Thu 0 — unknown — 50.1° 17:50 5.33 62% 169.9°
2038-07-23 Fri 0 — unknown — 50.1° 17:45 5.38 53% 158.1°
2038-07-24 Sat 0 — unknown — 50.1° 17:40 5.43 43% 146.2°
2038-07-25 Sun 0 — unknown — 50.1° 17:40 5.48 34% 134.3°
2038-07-26 Mon 0 — unknown — 50.1° 17:35 5.53 25% 122.3°
2038-07-27 Tue 0 — unknown — 50.1° 17:30 5.58 17% 110.0°
2038-07-28 Wed 0 — unknown — 50.1° 17:25 5.64 10% 97.5°
2038-07-29 Thu 0 — unknown — 50.1° 17:25 5.69 5% 84.7°
2038-07-30 Fri 0 — unknown — 50.1° 17:20 5.74 1% 71.6°
2038-07-31 Sat 0 — unknown — 50.1° 17:15 5.8 0% 58.1°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2038-07-02&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.