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.

2035-08-21astronomy score per night — click a bar for that night2035-09-19

night of	weather	overall	best window	highest	dark h	Moon	Moon sep.
2035-08-21 Tue	—	unknown	—	50.2° 15:55	6.98	91%	176.0°
2035-08-22 Wed	—	unknown	—	50.2° 15:50	7.03	85%	170.0°
2035-08-23 Thu	—	unknown	—	50.2° 15:45	7.09	76%	156.7°
2035-08-24 Fri	—	unknown	—	50.2° 15:40	7.15	66%	143.2°
2035-08-25 Sat	—	unknown	—	50.2° 15:40	7.21	55%	129.4°
2035-08-26 Sun	—	unknown	—	50.2° 15:35	7.26	44%	115.4°
2035-08-27 Mon	—	unknown	—	50.2° 15:30	7.32	32%	101.1°
2035-08-28 Tue	—	unknown	—	50.2° 15:25	7.38	22%	86.7°
2035-08-29 Wed	—	unknown	—	50.2° 15:20	7.43	13%	72.2°
2035-08-30 Thu	—	unknown	—	50.2° 15:20	7.49	6%	57.7°
2035-08-31 Fri	—	unknown	—	50.2° 15:15	7.55	2%	43.2°
2035-09-01 Sat	—	unknown	—	50.2° 15:10	7.6	0%	28.9°
2035-09-02 Sun	—	unknown	—	50.2° 15:05	7.66	1%	14.9°
2035-09-03 Mon	—	unknown	—	50.2° 15:00	7.71	4%	2.3°
2035-09-04 Tue	—	unknown	—	50.2° 15:00	7.77	10%	12.5°
2035-09-05 Wed	—	unknown	—	50.2° 14:55	7.82	17%	25.4°
2035-09-06 Thu	—	unknown	—	50.2° 14:50	7.88	25%	38.0°
2035-09-07 Fri	—	unknown	—	50.2° 14:45	7.93	34%	50.3°
2035-09-08 Sat	—	unknown	—	50.2° 14:40	7.99	43%	62.4°
2035-09-09 Sun	—	unknown	—	50.2° 14:40	8.04	53%	74.3°
2035-09-10 Mon	—	unknown	—	50.2° 14:35	8.1	62%	86.1°
2035-09-11 Tue	—	unknown	—	50.2° 14:30	8.15	71%	98.0°
2035-09-12 Wed	—	unknown	—	50.2° 14:25	8.2	80%	109.9°
2035-09-13 Thu	—	unknown	—	50.2° 14:25	8.26	87%	122.0°
2035-09-14 Fri	—	unknown	—	50.2° 14:20	8.31	93%	134.3°
2035-09-15 Sat	—	unknown	—	50.2° 14:15	8.36	97%	146.8°
2035-09-16 Sun	—	unknown	—	50.2° 14:10	8.42	100%	159.6°
2035-09-17 Mon	—	unknown	—	50.2° 14:05	8.47	100%	172.5°
2035-09-18 Tue	—	unknown	—	50.2° 14:05	8.52	98%	173.5°
2035-09-19 Wed	—	unknown	—	50.2° 14:00	8.57	94%	160.2°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2035-08-21&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.