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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 (8), 06-29 (7), 06-30 (7), 07-01 (7), 06-23 (6) — by astronomy; check the weather when the night is within four days.
2045-06-22astronomy score per night — click a bar for that night2045-07-21
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2045-06-22 Thu 8 — unknown 23:15–00:00 (marginal, 0.75 h) 50.1° 19:45 4.43 63% 13.9°
2045-06-23 Fri 6 — unknown 23:15–23:50 (marginal, 0.58 h) 50.1° 19:45 4.43 73% 25.9°
2045-06-24 Sat 5 — unknown 23:15–23:45 (marginal, 0.5 h) 50.1° 19:40 4.44 82% 38.5°
2045-06-25 Sun 5 — unknown 23:15–23:40 (marginal, 0.42 h) 50.1° 19:35 4.45 89% 51.1°
2045-06-26 Mon 5 — unknown 23:15–23:40 (marginal, 0.42 h) 50.1° 19:30 4.46 94% 63.5°
2045-06-27 Tue 6 — unknown 23:15–23:45 (marginal, 0.5 h) 50.1° 19:30 4.47 98% 75.8°
2045-06-28 Wed 6 — unknown 23:10–23:45 (marginal, 0.58 h) 50.1° 19:25 4.49 100% 88.0°
2045-06-29 Thu 7 — unknown 23:10–23:40 (marginal, 0.5 h) 50.1° 19:20 4.51 100% 100.0°
2045-06-30 Fri 7 — unknown 22:20–22:55 (marginal, 0.58 h) 50.1° 19:15 4.53 98% 111.8°
2045-07-01 Sat 7 — unknown 22:20–22:55 (marginal, 0.58 h) 50.1° 19:10 4.55 94% 123.6°
2045-07-02 Sun 6 — unknown 22:20–23:00 (marginal, 0.67 h) 50.1° 19:10 4.57 88% 135.2°
2045-07-03 Mon 6 — unknown 22:20–22:55 (marginal, 0.58 h) 50.1° 19:05 4.59 82% 146.7°
2045-07-04 Tue 5 — unknown 22:20–22:50 (marginal, 0.5 h) 50.1° 19:00 4.62 74% 158.0°
2045-07-05 Wed 4 — unknown 22:20–22:50 (marginal, 0.5 h) 50.1° 18:55 4.65 65% 168.2°
2045-07-06 Thu 4 — unknown 22:15–22:45 (marginal, 0.5 h) 50.1° 18:50 4.68 55% 170.9°
2045-07-07 Fri 4 — unknown 22:15–22:40 (marginal, 0.42 h) 50.1° 18:50 4.71 45% 161.9°
2045-07-08 Sat 3 — unknown 22:15–22:35 (marginal, 0.33 h) 50.1° 18:45 4.74 35% 150.0°
2045-07-09 Sun 3 — unknown 22:15–22:30 (marginal, 0.25 h) 50.1° 18:40 4.78 26% 137.2°
2045-07-10 Mon 2 — unknown 22:15–22:30 (marginal, 0.25 h) 50.1° 18:35 4.81 17% 123.8°
2045-07-11 Tue 2 — unknown 22:15–22:25 (marginal, 0.17 h) 50.1° 18:35 4.85 9% 109.9°
2045-07-12 Wed 2 — unknown 22:15–22:20 (marginal, 0.08 h) 50.1° 18:30 4.89 3% 95.5°
2045-07-13 Thu 2 — unknown — 50.1° 18:25 4.93 0% 80.8°
2045-07-14 Fri 2 — unknown 22:10–22:15 (marginal, 0.08 h) 50.1° 18:20 4.97 0% 65.9°
2045-07-15 Sat 1 — unknown — 50.1° 18:15 5.02 3% 50.9°
2045-07-16 Sun 1 — unknown — 50.1° 18:15 5.06 9% 36.3°
2045-07-17 Mon 1 — unknown — 50.1° 18:10 5.1 17% 22.2°
2045-07-18 Tue 1 — unknown — 50.1° 18:05 5.15 27% 10.4°
2045-07-19 Wed 1 — unknown — 50.1° 18:00 5.2 38% 11.4°
2045-07-20 Thu 0 — unknown — 50.1° 17:55 5.24 48% 23.0°
2045-07-21 Fri 0 — unknown — 50.1° 17:55 5.29 59% 35.6°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2045-06-22&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.