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.

2047-09-15astronomy score per night — click a bar for that night2047-10-14

night of	weather	overall	best window	highest	dark h	Moon	Moon sep.
2047-09-15 Sun	—	unknown	—	50.1° 14:15	8.37	18%	63.2°
2047-09-16 Mon	—	unknown	—	50.1° 14:10	8.42	10%	50.1°
2047-09-17 Tue	—	unknown	—	50.1° 14:05	8.47	5%	36.7°
2047-09-18 Wed	—	unknown	—	50.1° 14:05	8.52	1%	23.3°
2047-09-19 Thu	—	unknown	—	50.1° 14:00	8.58	0%	11.8°
2047-09-20 Fri	—	unknown	—	50.1° 13:55	8.63	2%	12.6°
2047-09-21 Sat	—	unknown	—	50.1° 13:50	8.68	7%	24.8°
2047-09-22 Sun	—	unknown	—	50.1° 13:50	8.73	14%	38.8°
2047-09-23 Mon	—	unknown	—	50.1° 13:45	8.78	23%	53.0°
2047-09-24 Tue	—	unknown	—	50.1° 13:40	8.83	34%	67.2°
2047-09-25 Wed	—	unknown	—	50.1° 13:35	8.88	45%	81.0°
2047-09-26 Thu	—	unknown	—	50.1° 13:30	8.93	56%	94.6°
2047-09-27 Fri	—	unknown	—	50.1° 13:30	8.98	66%	107.9°
2047-09-28 Sat	—	unknown	—	50.1° 13:25	9.03	76%	120.8°
2047-09-29 Sun	—	unknown	—	50.1° 13:20	9.08	84%	133.5°
2047-09-30 Mon	—	unknown	—	50.1° 13:15	9.13	91%	145.8°
2047-10-01 Tue	—	unknown	—	50.1° 13:10	9.18	96%	157.4°
2047-10-02 Wed	—	unknown	—	50.1° 13:10	9.22	99%	167.4°
2047-10-03 Thu	—	unknown	—	50.1° 13:05	9.27	100%	169.4°
2047-10-04 Fri	—	unknown	—	50.1° 13:00	9.32	99%	161.2°
2047-10-05 Sat	—	unknown	—	50.1° 12:55	9.37	96%	150.4°
2047-10-06 Sun	—	unknown	—	50.1° 12:55	9.41	92%	139.1°
2047-10-07 Mon	—	unknown	—	50.1° 12:50	9.46	86%	127.6°
2047-10-08 Tue	—	unknown	—	50.1° 12:45	9.5	79%	116.0°
2047-10-09 Wed	—	unknown	—	50.1° 12:40	9.55	71%	104.3°
2047-10-10 Thu	—	unknown	—	50.1° 12:35	9.6	62%	92.4°
2047-10-11 Fri	—	unknown	—	50.1° 12:35	9.64	53%	80.4°
2047-10-12 Sat	—	unknown	—	50.1° 12:30	9.69	43%	68.0°
2047-10-13 Sun	—	unknown	—	50.1° 12:25	9.73	33%	55.4°
2047-10-14 Mon	—	unknown	—	50.1° 12:20	9.77	23%	42.4°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2047-09-15&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.