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.

2037-07-26astronomy score per night — click a bar for that night2037-08-24

night of	weather	overall	best window	highest	dark h	Moon	Moon sep.
2037-07-26 Sun	—	unknown	—	50.2° 17:35	5.54	100%	115.6°
2037-07-27 Mon	—	unknown	—	50.2° 17:30	5.6	99%	127.9°
2037-07-28 Tue	—	unknown	—	50.2° 17:25	5.65	97%	140.0°
2037-07-29 Wed	—	unknown	—	50.2° 17:20	5.7	93%	152.0°
2037-07-30 Thu	—	unknown	—	50.1° 17:20	5.76	87%	163.9°
2037-07-31 Fri	—	unknown	—	50.2° 17:15	5.81	80%	175.7°
2037-08-01 Sat	—	unknown	—	50.2° 17:10	5.87	72%	172.5°
2037-08-02 Sun	—	unknown	—	50.2° 17:05	5.92	63%	160.5°
2037-08-03 Mon	—	unknown	—	50.1° 17:00	5.98	54%	148.5°
2037-08-04 Tue	—	unknown	—	50.1° 17:00	6.03	44%	136.2°
2037-08-05 Wed	—	unknown	—	50.2° 16:55	6.09	34%	123.6°
2037-08-06 Thu	—	unknown	—	50.2° 16:50	6.15	25%	110.6°
2037-08-07 Fri	—	unknown	—	50.2° 16:45	6.2	16%	97.2°
2037-08-08 Sat	—	unknown	—	50.1° 16:40	6.26	9%	83.4°
2037-08-09 Sun	—	unknown	—	50.2° 16:40	6.32	3%	69.0°
2037-08-10 Mon	—	unknown	—	50.2° 16:35	6.37	0%	54.4°
2037-08-11 Tue	—	unknown	—	50.2° 16:30	6.43	0%	39.4°
2037-08-12 Wed	—	unknown	—	50.1° 16:25	6.49	3%	24.4°
2037-08-13 Thu	—	unknown	—	50.1° 16:25	6.55	9%	9.4°
2037-08-14 Fri	—	unknown	—	50.2° 16:20	6.6	17%	5.4°
2037-08-15 Sat	—	unknown	—	50.2° 16:15	6.66	27%	19.9°
2037-08-16 Sun	—	unknown	—	50.2° 16:10	6.72	38%	34.1°
2037-08-17 Mon	—	unknown	—	50.1° 16:05	6.78	49%	47.9°
2037-08-18 Tue	—	unknown	—	50.1° 16:05	6.83	60%	61.4°
2037-08-19 Wed	—	unknown	—	50.2° 16:00	6.89	70%	74.5°
2037-08-20 Thu	—	unknown	—	50.2° 15:55	6.95	79%	87.4°
2037-08-21 Fri	—	unknown	—	50.2° 15:50	7.01	86%	100.0°
2037-08-22 Sat	—	unknown	—	50.1° 15:45	7.06	92%	112.4°
2037-08-23 Sun	—	unknown	—	50.2° 15:45	7.12	97%	124.6°
2037-08-24 Mon	—	unknown	—	50.2° 15:40	7.18	99%	136.7°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2037-07-26&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.