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.

2037-06-10astronomy score per night — click a bar for that night2037-07-09

night of	weather	overall	best window	highest	dark h	Moon	Moon sep.
2037-06-10 Wed	—	unknown	—	42.9° 13:40	4.53	9%	42.1°
2037-06-11 Thu	—	unknown	—	42.9° 13:40	4.51	4%	33.1°
2037-06-12 Fri	—	unknown	—	42.9° 13:35	4.49	1%	26.8°
2037-06-13 Sat	—	unknown	—	42.9° 13:30	4.47	0%	26.0°
2037-06-14 Sun	—	unknown	—	42.9° 13:25	4.46	2%	31.3°
2037-06-15 Mon	—	unknown	—	42.9° 13:20	4.45	6%	40.7°
2037-06-16 Tue	—	unknown	—	42.9° 13:20	4.44	13%	52.0°
2037-06-17 Wed	—	unknown	—	42.9° 13:15	4.43	21%	64.2°
2037-06-18 Thu	—	unknown	—	42.9° 13:10	4.43	32%	76.9°
2037-06-19 Fri	—	unknown	—	42.9° 13:05	4.42	43%	89.8°
2037-06-20 Sat	—	unknown	—	42.9° 13:00	4.42	54%	102.5°
2037-06-21 Sun	—	unknown	—	42.9° 13:00	4.42	65%	115.1°
2037-06-22 Mon	—	unknown	—	42.9° 12:55	4.43	76%	127.1°
2037-06-23 Tue	—	unknown	—	42.9° 12:50	4.43	85%	138.3°
2037-06-24 Wed	—	unknown	—	42.9° 12:45	4.44	92%	147.7°
2037-06-25 Thu	—	unknown	—	42.9° 12:45	4.45	97%	153.6°
2037-06-26 Fri	—	unknown	—	42.9° 12:40	4.46	99%	153.8°
2037-06-27 Sat	—	unknown	—	42.9° 12:35	4.47	100%	148.5°
2037-06-28 Sun	—	unknown	—	42.9° 12:30	4.49	98%	140.0°
2037-06-29 Mon	—	unknown	—	42.9° 12:25	4.51	95%	130.1°
2037-06-30 Tue	—	unknown	—	42.9° 12:25	4.52	89%	119.7°
2037-07-01 Wed	—	unknown	—	42.9° 12:20	4.55	83%	109.0°
2037-07-02 Thu	—	unknown	—	42.9° 12:15	4.57	75%	98.3°
2037-07-03 Fri	—	unknown	—	42.9° 12:10	4.59	66%	87.6°
2037-07-04 Sat	—	unknown	—	42.9° 12:05	4.62	57%	77.0°
2037-07-05 Sun	—	unknown	—	42.9° 12:00	4.65	47%	66.3°
2037-07-06 Mon	—	unknown	—	42.9° 11:55	4.68	38%	55.8°
2037-07-07 Tue	—	unknown	—	42.9° 11:50	4.71	28%	45.6°
2037-07-08 Wed	—	unknown	—	42.9° 11:50	4.74	20%	36.2°
2037-07-09 Thu	—	unknown	—	42.9° 11:45	4.78	12%	28.7°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2037-06-10&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.