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.

2036-09-11astronomy score per night — click a bar for that night2036-10-10

night of	weather	overall	best window	highest	dark h	Moon	Moon sep.
2036-09-11 Thu	—	unknown	—	50.2° 14:30	8.19	66%	125.2°
2036-09-12 Fri	—	unknown	—	50.2° 14:25	8.24	56%	111.8°
2036-09-13 Sat	—	unknown	—	50.2° 14:20	8.3	44%	98.2°
2036-09-14 Sun	—	unknown	—	50.2° 14:15	8.35	34%	84.2°
2036-09-15 Mon	—	unknown	—	50.2° 14:10	8.4	23%	69.8°
2036-09-16 Tue	—	unknown	—	50.2° 14:10	8.45	14%	55.2°
2036-09-17 Wed	—	unknown	—	50.2° 14:05	8.51	7%	40.3°
2036-09-18 Thu	—	unknown	—	50.2° 14:00	8.56	2%	25.4°
2036-09-19 Fri	—	unknown	—	50.2° 13:55	8.61	0%	10.5°
2036-09-20 Sat	—	unknown	—	50.2° 13:50	8.66	1%	4.3°
2036-09-21 Sun	—	unknown	—	50.2° 13:50	8.71	5%	18.7°
2036-09-22 Mon	—	unknown	—	50.2° 13:45	8.76	11%	32.7°
2036-09-23 Tue	—	unknown	—	50.2° 13:40	8.81	19%	46.3°
2036-09-24 Wed	—	unknown	—	50.2° 13:35	8.86	27%	59.4°
2036-09-25 Thu	—	unknown	—	50.2° 13:35	8.91	37%	72.1°
2036-09-26 Fri	—	unknown	—	50.2° 13:30	8.96	47%	84.5°
2036-09-27 Sat	—	unknown	—	50.2° 13:25	9.01	56%	96.6°
2036-09-28 Sun	—	unknown	—	50.2° 13:20	9.06	66%	108.6°
2036-09-29 Mon	—	unknown	—	50.2° 13:15	9.11	74%	120.4°
2036-09-30 Tue	—	unknown	—	50.2° 13:15	9.16	82%	132.2°
2036-10-01 Wed	—	unknown	—	50.2° 13:10	9.21	89%	144.1°
2036-10-02 Thu	—	unknown	—	50.2° 13:05	9.25	94%	156.1°
2036-10-03 Fri	—	unknown	—	50.2° 13:00	9.3	98%	168.2°
2036-10-04 Sat	—	unknown	—	50.2° 12:55	9.35	100%	179.0°
2036-10-05 Sun	—	unknown	—	50.2° 12:55	9.4	100%	166.9°
2036-10-06 Mon	—	unknown	—	50.2° 12:50	9.44	98%	154.2°
2036-10-07 Tue	—	unknown	—	50.2° 12:45	9.49	93%	141.3°
2036-10-08 Wed	—	unknown	—	50.2° 12:40	9.53	87%	128.2°
2036-10-09 Thu	—	unknown	—	50.2° 12:40	9.58	79%	114.9°
2036-10-10 Fri	—	unknown	—	50.2° 12:35	9.63	70%	101.4°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2036-09-11&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.