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.

2035-07-21astronomy score per night — click a bar for that night2035-08-19

night of	weather	overall	best window	highest	dark h	Moon	Moon sep.
2035-07-21 Sat	—	unknown	—	42.9° 11:00	5.26	98%	123.2°
2035-07-22 Sun	—	unknown	—	42.9° 10:55	5.31	94%	112.3°
2035-07-23 Mon	—	unknown	—	42.9° 10:50	5.36	89%	100.9°
2035-07-24 Tue	—	unknown	—	42.9° 10:45	5.41	82%	89.4°
2035-07-25 Wed	—	unknown	—	42.9° 10:45	5.46	73%	77.6°
2035-07-26 Thu	—	unknown	—	42.9° 10:40	5.52	63%	65.7°
2035-07-27 Fri	—	unknown	—	42.9° 10:35	5.57	52%	53.7°
2035-07-28 Sat	—	unknown	—	42.9° 10:30	5.62	41%	42.2°
2035-07-29 Sun	—	unknown	—	42.9° 10:25	5.67	30%	31.8°
2035-07-30 Mon	—	unknown	—	42.9° 10:25	5.73	20%	24.7°
2035-07-31 Tue	—	unknown	—	42.9° 10:20	5.78	11%	24.7°
2035-08-01 Wed	—	unknown	—	42.9° 10:15	5.84	5%	32.1°
2035-08-02 Thu	—	unknown	—	42.9° 10:10	5.89	1%	43.2°
2035-08-03 Fri	—	unknown	—	42.9° 10:05	5.95	0%	55.8°
2035-08-04 Sat	—	unknown	—	42.9° 10:05	6.0	2%	68.8°
2035-08-05 Sun	—	unknown	—	42.9° 10:00	6.06	7%	81.8°
2035-08-06 Mon	—	unknown	—	42.9° 09:55	6.12	13%	94.5°
2035-08-07 Tue	—	unknown	—	42.9° 09:50	6.17	22%	106.8°
2035-08-08 Wed	—	unknown	—	42.9° 09:50	6.23	31%	118.5°
2035-08-09 Thu	—	unknown	—	42.9° 09:45	6.29	40%	129.5°
2035-08-10 Fri	—	unknown	—	42.9° 09:40	6.34	50%	139.6°
2035-08-11 Sat	—	unknown	—	42.9° 09:35	6.4	60%	148.3°
2035-08-12 Sun	—	unknown	—	42.9° 09:30	6.46	69%	154.5°
2035-08-13 Mon	—	unknown	—	42.9° 09:30	6.52	77%	156.3°
2035-08-14 Tue	—	unknown	—	42.9° 09:25	6.57	85%	152.8°
2035-08-15 Wed	—	unknown	—	42.9° 09:20	6.63	91%	145.6°
2035-08-16 Thu	—	unknown	—	42.9° 09:15	6.69	96%	136.4°
2035-08-17 Fri	—	unknown	—	42.9° 09:10	6.75	99%	126.1°
2035-08-18 Sat	—	unknown	—	42.9° 09:10	6.8	100%	115.2°
2035-08-19 Sun	—	unknown	—	42.9° 09:05	6.86	99%	103.9°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2035-07-21&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.