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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: 06-22 (11), 06-23 (9), 06-24 (6), 06-25 (5), 07-01 (5) — by astronomy; check the weather when the night is within four days.
2034-06-22astronomy score per night — click a bar for that night2034-07-21
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2034-06-22 Thu 11 — unknown 22:20–00:10 (marginal, 1.83 h) 50.2° 19:50 4.43 43% 13.0°
2034-06-23 Fri 9 — unknown 23:15–00:05 (marginal, 0.83 h) 50.2° 19:45 4.43 53% 4.1°
2034-06-24 Sat 6 — unknown 23:15–23:55 (marginal, 0.67 h) 50.2° 19:40 4.44 63% 12.6°
2034-06-25 Sun 5 — unknown 23:15–23:40 (marginal, 0.42 h) 50.2° 19:35 4.45 72% 24.1°
2034-06-26 Mon 4 — unknown 23:15–23:30 (marginal, 0.25 h) 50.2° 19:30 4.46 80% 35.9°
2034-06-27 Tue 4 — unknown 23:15–23:30 (marginal, 0.25 h) 50.2° 19:30 4.47 87% 47.6°
2034-06-28 Wed 4 — unknown 23:15–23:30 (marginal, 0.25 h) 50.2° 19:25 4.48 92% 59.5°
2034-06-29 Thu 4 — unknown 23:10–23:30 (marginal, 0.33 h) 50.2° 19:20 4.5 97% 71.5°
2034-06-30 Fri 4 — unknown 23:10–23:35 (marginal, 0.42 h) 50.2° 19:15 4.52 99% 83.7°
2034-07-01 Sat 5 — unknown 23:10–23:35 (marginal, 0.42 h) 50.2° 19:15 4.54 100% 96.1°
2034-07-02 Sun 5 — unknown 22:20–22:45 (marginal, 0.42 h) 50.2° 19:10 4.56 98% 108.6°
2034-07-03 Mon 5 — unknown 22:20–22:50 (marginal, 0.5 h) 50.2° 19:05 4.59 95% 121.4°
2034-07-04 Tue 5 — unknown 22:20–22:45 (marginal, 0.42 h) 50.2° 19:00 4.61 89% 134.4°
2034-07-05 Wed 4 — unknown 22:20–22:50 (marginal, 0.5 h) 50.2° 18:55 4.64 82% 147.5°
2034-07-06 Thu 4 — unknown 22:15–22:45 (marginal, 0.5 h) 50.2° 18:55 4.67 73% 160.8°
2034-07-07 Fri 3 — unknown 22:15–22:40 (marginal, 0.42 h) 50.2° 18:50 4.7 63% 173.5°
2034-07-08 Sat 3 — unknown 22:15–22:35 (marginal, 0.33 h) 50.2° 18:45 4.73 52% 170.5°
2034-07-09 Sun 3 — unknown 22:15–22:35 (marginal, 0.33 h) 50.2° 18:40 4.77 40% 156.9°
2034-07-10 Mon 2 — unknown 22:15–22:30 (marginal, 0.25 h) 50.2° 18:35 4.8 29% 142.7°
2034-07-11 Tue 2 — unknown 22:15–22:25 (marginal, 0.17 h) 50.2° 18:35 4.84 19% 128.3°
2034-07-12 Wed 2 — unknown 22:15–22:20 (marginal, 0.08 h) 50.2° 18:30 4.88 11% 113.8°
2034-07-13 Thu 2 — unknown — 50.2° 18:25 4.92 5% 99.3°
2034-07-14 Fri 2 — unknown 22:10–22:15 (marginal, 0.08 h) 50.2° 18:20 4.96 1% 84.8°
2034-07-15 Sat 1 — unknown — 50.2° 18:20 5.0 0% 70.6°
2034-07-16 Sun 1 — unknown — 50.2° 18:15 5.04 2% 56.6°
2034-07-17 Mon 1 — unknown — 50.2° 18:10 5.09 6% 43.0°
2034-07-18 Tue 1 — unknown — 50.2° 18:05 5.13 12% 29.8°
2034-07-19 Wed 1 — unknown — 50.2° 18:00 5.18 19% 17.2°
2034-07-20 Thu 1 — unknown — 50.2° 18:00 5.23 28% 5.7°
2034-07-21 Fri 0 — unknown — 50.2° 17:55 5.28 37% 8.9°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2034-06-22&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.