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.

2044-05-23astronomy score per night — click a bar for that night2044-06-21

night of	weather	overall	best window	highest	dark h	Moon	Moon sep.
2044-05-23 Mon	—	unknown	—	72.6° 13:05	5.14	14%	40.5°
2044-05-24 Tue	—	unknown	—	72.6° 13:00	5.1	7%	26.3°
2044-05-25 Wed	—	unknown	—	72.6° 12:55	5.05	2%	11.6°
2044-05-26 Thu	—	unknown	—	72.6° 12:50	5.01	0%	3.4°
2044-05-27 Fri	—	unknown	—	72.5° 12:50	4.97	1%	18.5°
2044-05-28 Sat	—	unknown	—	72.6° 12:45	4.92	5%	33.6°
2044-05-29 Sun	—	unknown	—	72.6° 12:40	4.88	11%	48.6°
2044-05-30 Mon	—	unknown	—	72.6° 12:35	4.85	20%	63.3°
2044-05-31 Tue	—	unknown	—	72.6° 12:30	4.81	30%	77.7°
2044-06-01 Wed	—	unknown	—	72.6° 12:30	4.77	41%	91.6°
2044-06-02 Thu	—	unknown	—	72.6° 12:25	4.74	52%	105.1°
2044-06-03 Fri	—	unknown	—	72.6° 12:20	4.7	62%	118.3°
2044-06-04 Sat	—	unknown	—	72.6° 12:15	4.67	72%	131.1°
2044-06-05 Sun	—	unknown	—	72.5° 12:10	4.64	80%	143.7°
2044-06-06 Mon	—	unknown	—	72.6° 12:10	4.62	88%	156.0°
2044-06-07 Tue	—	unknown	—	72.6° 12:00	4.59	93%	168.2°
2044-06-08 Wed	—	unknown	—	72.6° 12:00	4.56	97%	179.3°
2044-06-09 Thu	—	unknown	—	72.5° 11:55	4.54	99%	167.8°
2044-06-10 Fri	—	unknown	—	72.6° 11:50	4.52	100%	155.9°
2044-06-11 Sat	—	unknown	—	72.6° 11:45	4.5	98%	144.1°
2044-06-12 Sun	—	unknown	—	72.6° 11:40	4.48	95%	132.3°
2044-06-13 Mon	—	unknown	—	72.6° 11:35	4.47	90%	120.4°
2044-06-14 Tue	—	unknown	—	72.6° 11:35	4.46	84%	108.4°
2044-06-15 Wed	—	unknown	—	72.6° 11:30	4.45	76%	96.4°
2044-06-16 Thu	—	unknown	—	72.6° 11:25	4.44	68%	84.1°
2044-06-17 Fri	—	unknown	—	72.6° 11:20	4.43	58%	71.6°
2044-06-18 Sat	—	unknown	—	72.5° 11:15	4.42	48%	58.8°
2044-06-19 Sun	—	unknown	—	72.6° 11:15	4.42	37%	45.5°
2044-06-20 Mon	—	unknown	—	72.6° 11:10	4.42	27%	31.8°
2044-06-21 Tue	—	unknown	—	72.6° 11:05	4.42	17%	17.7°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2044-05-23&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.