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.

2044-06-15astronomy score per night — click a bar for that night2044-07-14

night of	weather	overall	best window	highest	dark h	Moon	Moon sep.
2044-06-15 Wed	—	unknown	—	42.9° 13:20	4.45	76%	114.6°
2044-06-16 Thu	—	unknown	—	42.9° 13:15	4.44	68%	104.7°
2044-06-17 Fri	—	unknown	—	42.9° 13:15	4.43	58%	94.4°
2044-06-18 Sat	—	unknown	—	42.9° 13:10	4.42	48%	83.7°
2044-06-19 Sun	—	unknown	—	42.9° 13:05	4.42	37%	72.8°
2044-06-20 Mon	—	unknown	—	42.9° 13:00	4.42	27%	61.9°
2044-06-21 Tue	—	unknown	—	42.9° 13:00	4.42	17%	51.3°
2044-06-22 Wed	—	unknown	—	42.9° 12:55	4.43	9%	42.0°
2044-06-23 Thu	—	unknown	—	42.9° 12:50	4.43	4%	35.4°
2044-06-24 Fri	—	unknown	—	42.9° 12:45	4.44	1%	33.8°
2044-06-25 Sat	—	unknown	—	42.9° 12:40	4.45	0%	37.9°
2044-06-26 Sun	—	unknown	—	42.9° 12:40	4.46	4%	46.2°
2044-06-27 Mon	—	unknown	—	42.9° 12:35	4.48	9%	56.6°
2044-06-28 Tue	—	unknown	—	42.9° 12:30	4.49	17%	67.9°
2044-06-29 Wed	—	unknown	—	42.9° 12:25	4.51	26%	79.4°
2044-06-30 Thu	—	unknown	—	42.9° 12:20	4.53	37%	90.7°
2044-07-01 Fri	—	unknown	—	42.9° 12:20	4.55	47%	101.7°
2044-07-02 Sat	—	unknown	—	42.9° 12:15	4.58	57%	112.1°
2044-07-03 Sun	—	unknown	—	42.9° 12:10	4.6	67%	121.8°
2044-07-04 Mon	—	unknown	—	42.9° 12:05	4.63	76%	130.7°
2044-07-05 Tue	—	unknown	—	42.9° 12:00	4.66	84%	138.2°
2044-07-06 Wed	—	unknown	—	42.9° 11:55	4.69	90%	143.7°
2044-07-07 Thu	—	unknown	—	42.9° 11:50	4.72	95%	146.2°
2044-07-08 Fri	—	unknown	—	42.9° 11:45	4.75	98%	145.2°
2044-07-09 Sat	—	unknown	—	42.9° 11:45	4.79	100%	141.0°
2044-07-10 Sun	—	unknown	—	42.9° 11:40	4.82	100%	134.3°
2044-07-11 Mon	—	unknown	—	42.9° 11:35	4.86	97%	126.1°
2044-07-12 Tue	—	unknown	—	42.9° 11:30	4.9	94%	117.0°
2044-07-13 Wed	—	unknown	—	42.9° 11:25	4.94	88%	107.2°
2044-07-14 Thu	—	unknown	—	42.9° 11:25	4.98	81%	97.0°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2044-06-15&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.