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.

2044-04-24astronomy score per night — click a bar for that night2044-05-23

night of	weather	overall	best window	highest	dark h	Moon	Moon sep.
2044-04-24 Sun	—	unknown	—	72.5° 14:55	6.73	11%	62.4°
2044-04-25 Mon	—	unknown	—	72.6° 14:55	6.67	5%	48.6°
2044-04-26 Tue	—	unknown	—	72.6° 14:50	6.62	1%	34.4°
2044-04-27 Wed	—	unknown	—	72.6° 14:45	6.56	0%	19.9°
2044-04-28 Thu	—	unknown	—	72.6° 14:40	6.5	2%	5.2°
2044-04-29 Fri	—	unknown	—	72.5° 14:40	6.44	6%	9.7°
2044-04-30 Sat	—	unknown	—	72.6° 14:35	6.38	14%	24.5°
2044-05-01 Sun	—	unknown	—	72.6° 14:30	6.33	23%	39.1°
2044-05-02 Mon	—	unknown	—	72.6° 14:25	6.27	33%	53.5°
2044-05-03 Tue	—	unknown	—	72.6° 14:20	6.21	44%	67.6°
2044-05-04 Wed	—	unknown	—	72.6° 14:20	6.15	56%	81.5°
2044-05-05 Thu	—	unknown	—	72.6° 14:15	6.1	66%	95.0°
2044-05-06 Fri	—	unknown	—	72.6° 14:10	6.04	76%	108.2°
2044-05-07 Sat	—	unknown	—	72.6° 14:05	5.98	84%	121.2°
2044-05-08 Sun	—	unknown	—	72.5° 14:00	5.93	91%	134.0°
2044-05-09 Mon	—	unknown	—	72.6° 14:00	5.87	96%	146.6°
2044-05-10 Tue	—	unknown	—	72.6° 13:55	5.81	99%	159.0°
2044-05-11 Wed	—	unknown	—	72.6° 13:50	5.76	100%	171.2°
2044-05-12 Thu	—	unknown	—	72.6° 13:45	5.7	99%	176.6°
2044-05-13 Fri	—	unknown	—	72.5° 13:45	5.65	96%	164.7°
2044-05-14 Sat	—	unknown	—	72.6° 13:40	5.6	92%	152.8°
2044-05-15 Sun	—	unknown	—	72.6° 13:35	5.54	86%	141.0°
2044-05-16 Mon	—	unknown	—	72.6° 13:30	5.49	79%	129.2°
2044-05-17 Tue	—	unknown	—	72.6° 13:25	5.44	71%	117.3°
2044-05-18 Wed	—	unknown	—	72.6° 13:25	5.39	62%	105.3°
2044-05-19 Thu	—	unknown	—	72.6° 13:20	5.34	52%	93.0°
2044-05-20 Fri	—	unknown	—	72.6° 13:15	5.29	42%	80.5°
2044-05-21 Sat	—	unknown	—	72.6° 13:10	5.24	32%	67.6°
2044-05-22 Sun	—	unknown	—	72.5° 13:05	5.19	23%	54.3°
2044-05-23 Mon	—	unknown	—	72.6° 13:05	5.14	14%	40.5°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2044-04-24&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.