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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: 07-03 (6), 07-04 (5), 07-05 (4), 07-06 (4), 07-07 (3) — by astronomy; check the weather when the night is within four days.
2029-07-03astronomy score per night — click a bar for that night2029-08-01
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2029-07-03 Tue 6 — unknown 22:20–22:55 (marginal, 0.58 h) 50.2° 19:05 4.59 48% 167.0°
2029-07-04 Wed 5 — unknown 22:20–22:50 (marginal, 0.5 h) 50.2° 19:00 4.62 39% 157.5°
2029-07-05 Thu 4 — unknown 22:20–22:50 (marginal, 0.5 h) 50.2° 18:55 4.65 30% 146.5°
2029-07-06 Fri 4 — unknown 22:15–22:45 (marginal, 0.5 h) 50.2° 18:50 4.68 21% 135.0°
2029-07-07 Sat 3 — unknown 22:15–22:40 (marginal, 0.42 h) 50.2° 18:50 4.71 14% 123.2°
2029-07-08 Sun 3 — unknown 22:15–22:35 (marginal, 0.33 h) 50.2° 18:45 4.74 8% 111.0°
2029-07-09 Mon 3 — unknown 22:15–22:30 (marginal, 0.25 h) 50.2° 18:40 4.77 3% 98.6°
2029-07-10 Tue 2 — unknown 22:15–22:30 (marginal, 0.25 h) 50.2° 18:35 4.81 1% 85.8°
2029-07-11 Wed 2 — unknown 22:15–22:25 (marginal, 0.17 h) 50.2° 18:30 4.85 0% 72.8°
2029-07-12 Thu 2 — unknown 22:15–22:20 (marginal, 0.08 h) 50.2° 18:30 4.89 2% 59.6°
2029-07-13 Fri 2 — unknown — 50.2° 18:25 4.93 6% 46.2°
2029-07-14 Sat 1 — unknown — 50.2° 18:20 4.97 13% 32.8°
2029-07-15 Sun 1 — unknown — 50.2° 18:15 5.01 21% 20.0°
2029-07-16 Mon 1 — unknown — 50.2° 18:15 5.05 31% 10.5°
2029-07-17 Tue 1 — unknown — 50.2° 18:10 5.1 42% 14.8°
2029-07-18 Wed 0 — unknown — 50.2° 18:05 5.14 54% 26.9°
2029-07-19 Thu 0 — unknown — 50.2° 18:00 5.19 65% 40.4°
2029-07-20 Fri 0 — unknown — 50.2° 17:55 5.24 76% 54.1°
2029-07-21 Sat 0 — unknown — 50.2° 17:55 5.29 85% 67.8°
2029-07-22 Sun 0 — unknown — 50.2° 17:50 5.34 92% 81.5°
2029-07-23 Mon 0 — unknown — 50.2° 17:45 5.39 97% 95.1°
2029-07-24 Tue 0 — unknown — 50.2° 17:40 5.44 100% 108.4°
2029-07-25 Wed 0 — unknown — 50.2° 17:35 5.49 100% 121.5°
2029-07-26 Thu 0 — unknown — 50.2° 17:35 5.54 98% 134.1°
2029-07-27 Fri 0 — unknown — 50.2° 17:30 5.59 94% 146.4°
2029-07-28 Sat 0 — unknown — 50.2° 17:25 5.65 88% 157.9°
2029-07-29 Sun 0 — unknown — 50.2° 17:20 5.7 81% 167.5°
2029-07-30 Mon 0 — unknown — 50.2° 17:20 5.75 73% 169.1°
2029-07-31 Tue 0 — unknown — 50.2° 17:15 5.81 64% 161.0°
2029-08-01 Wed 0 — unknown — 50.2° 17:10 5.86 55% 150.3°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2029-07-03&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.