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.

2047-05-15astronomy score per night — click a bar for that night2047-06-13

night of	weather	overall	best window	highest	dark h	Moon	Moon sep.
2047-05-15 Wed	—	unknown	—	42.9° 15:25	5.58	58%	123.2°
2047-05-16 Thu	—	unknown	—	42.9° 15:20	5.53	48%	112.9°
2047-05-17 Fri	—	unknown	—	42.9° 15:20	5.48	38%	102.6°
2047-05-18 Sat	—	unknown	—	42.9° 15:15	5.42	29%	92.2°
2047-05-19 Sun	—	unknown	—	42.9° 15:10	5.37	21%	81.9°
2047-05-20 Mon	—	unknown	—	42.9° 15:05	5.32	14%	71.9°
2047-05-21 Tue	—	unknown	—	42.9° 15:00	5.27	8%	62.1°
2047-05-22 Wed	—	unknown	—	42.9° 15:00	5.23	4%	52.7°
2047-05-23 Thu	—	unknown	—	42.9° 14:55	5.18	1%	44.0°
2047-05-24 Fri	—	unknown	—	42.9° 14:50	5.13	0%	36.7°
2047-05-25 Sat	—	unknown	—	42.9° 14:45	5.09	1%	31.8°
2047-05-26 Sun	—	unknown	—	42.9° 14:45	5.04	4%	30.7°
2047-05-27 Mon	—	unknown	—	42.9° 14:40	5.0	9%	34.0°
2047-05-28 Tue	—	unknown	—	42.9° 14:35	4.96	16%	40.7°
2047-05-29 Wed	—	unknown	—	42.9° 14:30	4.91	24%	49.5°
2047-05-30 Thu	—	unknown	—	42.9° 14:25	4.87	33%	59.8°
2047-05-31 Fri	—	unknown	—	42.9° 14:25	4.84	44%	70.8°
2047-06-01 Sat	—	unknown	—	42.9° 14:20	4.8	55%	82.5°
2047-06-02 Sun	—	unknown	—	42.9° 14:15	4.76	66%	94.6°
2047-06-03 Mon	—	unknown	—	42.9° 14:10	4.73	77%	106.9°
2047-06-04 Tue	—	unknown	—	42.9° 14:05	4.7	86%	119.2°
2047-06-05 Wed	—	unknown	—	42.9° 14:05	4.67	93%	130.8°
2047-06-06 Thu	—	unknown	—	42.9° 14:00	4.64	98%	140.8°
2047-06-07 Fri	—	unknown	—	42.9° 13:55	4.61	100%	147.7°
2047-06-08 Sat	—	unknown	—	42.9° 13:50	4.58	99%	149.2°
2047-06-09 Sun	—	unknown	—	42.9° 13:50	4.56	95%	144.9°
2047-06-10 Mon	—	unknown	—	42.9° 13:45	4.54	90%	136.8°
2047-06-11 Tue	—	unknown	—	42.9° 13:40	4.52	82%	127.0°
2047-06-12 Wed	—	unknown	—	42.9° 13:35	4.5	73%	116.6°
2047-06-13 Thu	—	unknown	—	42.9° 13:30	4.48	64%	106.0°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2047-05-15&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.