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.

2043-06-10astronomy score per night — click a bar for that night2043-07-09

night of	weather	overall	best window	highest	dark h	Moon	Moon sep.
2043-06-10 Wed	—	unknown	—	42.9° 13:45	4.54	16%	54.0°
2043-06-11 Thu	—	unknown	—	42.9° 13:40	4.52	25%	64.4°
2043-06-12 Fri	—	unknown	—	42.9° 13:35	4.5	35%	75.0°
2043-06-13 Sat	—	unknown	—	42.9° 13:30	4.48	45%	85.6°
2043-06-14 Sun	—	unknown	—	42.9° 13:30	4.47	55%	95.9°
2043-06-15 Mon	—	unknown	—	42.9° 13:25	4.45	64%	105.9°
2043-06-16 Tue	—	unknown	—	42.9° 13:20	4.44	73%	115.6°
2043-06-17 Wed	—	unknown	—	42.9° 13:15	4.43	81%	124.7°
2043-06-18 Thu	—	unknown	—	42.9° 13:10	4.43	88%	133.0°
2043-06-19 Fri	—	unknown	—	42.9° 13:10	4.42	93%	140.0°
2043-06-20 Sat	—	unknown	—	42.9° 13:05	4.42	97%	144.8°
2043-06-21 Sun	—	unknown	—	42.9° 13:00	4.42	99%	146.4°
2043-06-22 Mon	—	unknown	—	42.9° 12:55	4.42	100%	144.4°
2043-06-23 Tue	—	unknown	—	42.9° 12:55	4.43	98%	139.0°
2043-06-24 Wed	—	unknown	—	42.9° 12:50	4.43	94%	131.3°
2043-06-25 Thu	—	unknown	—	42.9° 12:45	4.44	89%	122.2°
2043-06-26 Fri	—	unknown	—	42.9° 12:40	4.45	82%	112.1°
2043-06-27 Sat	—	unknown	—	42.9° 12:35	4.47	73%	101.4°
2043-06-28 Sun	—	unknown	—	42.9° 12:35	4.48	63%	90.3°
2043-06-29 Mon	—	unknown	—	42.9° 12:30	4.5	52%	79.0°
2043-06-30 Tue	—	unknown	—	42.9° 12:25	4.51	41%	67.6°
2043-07-01 Wed	—	unknown	—	42.9° 12:20	4.53	30%	56.5°
2043-07-02 Thu	—	unknown	—	42.9° 12:15	4.56	20%	46.4°
2043-07-03 Fri	—	unknown	—	42.9° 12:15	4.58	11%	38.2°
2043-07-04 Sat	—	unknown	—	42.9° 12:10	4.61	5%	33.9°
2043-07-05 Sun	—	unknown	—	42.9° 12:05	4.63	1%	34.9°
2043-07-06 Mon	—	unknown	—	42.9° 12:00	4.66	0%	40.9°
2043-07-07 Tue	—	unknown	—	42.9° 11:55	4.69	2%	49.8°
2043-07-08 Wed	—	unknown	—	42.9° 11:50	4.73	6%	60.1°
2043-07-09 Thu	—	unknown	—	42.9° 11:45	4.76	13%	70.9°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2043-06-10&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.