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.

2044-05-26astronomy score per night — click a bar for that night2044-06-24

night of	weather	overall	best window	highest	dark h	Moon	Moon sep.
2044-05-26 Thu	—	unknown	—	42.9° 14:40	5.01	0%	38.6°
2044-05-27 Fri	—	unknown	—	42.9° 14:35	4.97	1%	34.0°
2044-05-28 Sat	—	unknown	—	42.9° 14:30	4.92	5%	35.0°
2044-05-29 Sun	—	unknown	—	42.9° 14:30	4.88	11%	41.1°
2044-05-30 Mon	—	unknown	—	42.9° 14:25	4.85	20%	50.2°
2044-05-31 Tue	—	unknown	—	42.9° 14:20	4.81	30%	60.8°
2044-06-01 Wed	—	unknown	—	42.9° 14:15	4.77	41%	71.9°
2044-06-02 Thu	—	unknown	—	42.9° 14:10	4.74	52%	83.0°
2044-06-03 Fri	—	unknown	—	42.9° 14:10	4.7	62%	93.9°
2044-06-04 Sat	—	unknown	—	42.9° 14:05	4.67	72%	104.5°
2044-06-05 Sun	—	unknown	—	42.9° 14:00	4.64	80%	114.7°
2044-06-06 Mon	—	unknown	—	42.9° 13:55	4.62	88%	124.2°
2044-06-07 Tue	—	unknown	—	42.9° 13:55	4.59	93%	132.8°
2044-06-08 Wed	—	unknown	—	42.9° 13:50	4.56	97%	139.9°
2044-06-09 Thu	—	unknown	—	42.9° 13:45	4.54	99%	144.7°
2044-06-10 Fri	—	unknown	—	42.9° 13:40	4.52	100%	146.4°
2044-06-11 Sat	—	unknown	—	42.9° 13:35	4.5	98%	144.5°
2044-06-12 Sun	—	unknown	—	42.9° 13:35	4.48	95%	139.5°
2044-06-13 Mon	—	unknown	—	42.9° 13:30	4.47	90%	132.4°
2044-06-14 Tue	—	unknown	—	42.9° 13:25	4.46	84%	123.9°
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°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2044-05-26&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.