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.

2036-08-27astronomy score per night — click a bar for that night2036-09-25

night of	weather	overall	best window	highest	dark h	Moon	Moon sep.
2036-08-27 Wed	—	unknown	—	50.2° 15:25	7.36	43%	51.1°
2036-08-28 Thu	—	unknown	—	50.2° 15:25	7.42	53%	63.8°
2036-08-29 Fri	—	unknown	—	50.2° 15:20	7.48	63%	76.1°
2036-08-30 Sat	—	unknown	—	50.2° 15:15	7.53	72%	88.2°
2036-08-31 Sun	—	unknown	—	50.2° 15:10	7.59	80%	100.2°
2036-09-01 Mon	—	unknown	—	50.2° 15:05	7.64	87%	112.0°
2036-09-02 Tue	—	unknown	—	50.2° 15:05	7.7	93%	123.9°
2036-09-03 Wed	—	unknown	—	50.2° 15:00	7.75	97%	135.7°
2036-09-04 Thu	—	unknown	—	50.2° 14:55	7.81	99%	147.6°
2036-09-05 Fri	—	unknown	—	50.2° 14:50	7.86	100%	159.6°
2036-09-06 Sat	—	unknown	—	50.2° 14:45	7.92	99%	171.7°
2036-09-07 Sun	—	unknown	—	50.2° 14:45	7.97	96%	176.0°
2036-09-08 Mon	—	unknown	—	50.2° 14:40	8.03	91%	163.6°
2036-09-09 Tue	—	unknown	—	50.2° 14:35	8.08	84%	151.0°
2036-09-10 Wed	—	unknown	—	50.2° 14:30	8.14	76%	138.2°
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°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2036-08-27&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.