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.

2034-08-26astronomy score per night — click a bar for that night2034-09-24

night of	weather	overall	best window	highest	dark h	Moon	Moon sep.
2034-08-26 Sat	—	unknown	—	50.2° 15:35	7.28	91%	112.9°
2034-08-27 Sun	—	unknown	—	50.2° 15:30	7.33	96%	126.0°
2034-08-28 Mon	—	unknown	—	50.2° 15:25	7.39	99%	139.4°
2034-08-29 Tue	—	unknown	—	50.2° 15:20	7.45	100%	153.1°
2034-08-30 Wed	—	unknown	—	50.2° 15:15	7.5	98%	166.8°
2034-08-31 Thu	—	unknown	—	50.2° 15:15	7.56	94%	176.0°
2034-09-01 Fri	—	unknown	—	50.2° 15:10	7.61	87%	163.7°
2034-09-02 Sat	—	unknown	—	50.2° 15:05	7.67	78%	149.5°
2034-09-03 Sun	—	unknown	—	50.2° 15:00	7.73	68%	135.2°
2034-09-04 Mon	—	unknown	—	50.2° 14:55	7.78	56%	121.0°
2034-09-05 Tue	—	unknown	—	50.2° 14:55	7.84	45%	106.9°
2034-09-06 Wed	—	unknown	—	50.2° 14:50	7.89	34%	93.0°
2034-09-07 Thu	—	unknown	—	50.2° 14:45	7.95	24%	79.2°
2034-09-08 Fri	—	unknown	—	50.2° 14:40	8.0	15%	65.6°
2034-09-09 Sat	—	unknown	—	50.2° 14:40	8.05	8%	52.2°
2034-09-10 Sun	—	unknown	—	50.2° 14:35	8.11	3%	39.0°
2034-09-11 Mon	—	unknown	—	50.2° 14:30	8.16	1%	26.1°
2034-09-12 Tue	—	unknown	—	50.2° 14:25	8.22	0%	13.6°
2034-09-13 Wed	—	unknown	—	50.2° 14:20	8.27	2%	3.7°
2034-09-14 Thu	—	unknown	—	50.2° 14:20	8.32	5%	12.4°
2034-09-15 Fri	—	unknown	—	50.2° 14:15	8.38	10%	24.2°
2034-09-16 Sat	—	unknown	—	50.2° 14:10	8.43	17%	36.1°
2034-09-17 Sun	—	unknown	—	50.2° 14:05	8.48	24%	47.9°
2034-09-18 Mon	—	unknown	—	50.2° 14:00	8.53	33%	59.7°
2034-09-19 Tue	—	unknown	—	50.2° 14:00	8.58	42%	71.5°
2034-09-20 Wed	—	unknown	—	50.2° 13:55	8.64	51%	83.4°
2034-09-21 Thu	—	unknown	—	50.2° 13:50	8.69	61%	95.5°
2034-09-22 Fri	—	unknown	—	50.2° 13:45	8.74	71%	107.9°
2034-09-23 Sat	—	unknown	—	50.2° 13:40	8.79	79%	120.7°
2034-09-24 Sun	—	unknown	—	50.2° 13:40	8.84	87%	133.8°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2034-08-26&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.