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.

2031-06-01astronomy score per night — click a bar for that night2031-06-30

night of	weather	overall	best window	highest	dark h	Moon	Moon sep.
2031-06-01 Sun	—	unknown	—	72.5° 12:30	4.8	83%	143.3°
2031-06-02 Mon	—	unknown	—	72.5° 12:25	4.77	91%	157.2°
2031-06-03 Tue	—	unknown	—	72.5° 12:25	4.73	96%	170.9°
2031-06-04 Wed	—	unknown	—	72.5° 12:20	4.7	100%	172.0°
2031-06-05 Thu	—	unknown	—	72.5° 12:15	4.67	100%	157.8°
2031-06-06 Fri	—	unknown	—	72.5° 12:10	4.64	97%	142.8°
2031-06-07 Sat	—	unknown	—	72.5° 12:05	4.61	91%	127.9°
2031-06-08 Sun	—	unknown	—	72.5° 12:00	4.59	83%	113.1°
2031-06-09 Mon	—	unknown	—	72.5° 11:55	4.56	74%	98.6°
2031-06-10 Tue	—	unknown	—	72.5° 11:50	4.54	63%	84.5°
2031-06-11 Wed	—	unknown	—	72.5° 11:45	4.52	52%	70.8°
2031-06-12 Thu	—	unknown	—	72.5° 11:45	4.5	41%	57.5°
2031-06-13 Fri	—	unknown	—	72.5° 11:40	4.48	31%	44.6°
2031-06-14 Sat	—	unknown	—	72.5° 11:35	4.47	22%	31.9°
2031-06-15 Sun	—	unknown	—	72.5° 11:30	4.46	14%	19.6°
2031-06-16 Mon	—	unknown	—	72.5° 11:30	4.44	8%	8.1°
2031-06-17 Tue	—	unknown	—	72.5° 11:25	4.44	4%	6.7°
2031-06-18 Wed	—	unknown	—	72.5° 11:20	4.43	1%	17.8°
2031-06-19 Thu	—	unknown	—	72.5° 11:15	4.43	0%	29.4°
2031-06-20 Fri	—	unknown	—	72.5° 11:10	4.42	1%	41.2°
2031-06-21 Sat	—	unknown	—	72.5° 11:10	4.42	4%	52.9°
2031-06-22 Sun	—	unknown	—	72.5° 11:05	4.42	8%	64.7°
2031-06-23 Mon	—	unknown	—	72.5° 11:00	4.43	14%	76.6°
2031-06-24 Tue	—	unknown	—	72.5° 10:55	4.43	21%	88.5°
2031-06-25 Wed	—	unknown	—	72.5° 10:50	4.44	30%	100.6°
2031-06-26 Thu	—	unknown	—	72.5° 10:50	4.45	39%	112.9°
2031-06-27 Fri	—	unknown	—	72.5° 10:45	4.46	49%	125.5°
2031-06-28 Sat	—	unknown	—	72.5° 10:40	4.48	60%	138.5°
2031-06-29 Sun	—	unknown	—	72.5° 10:35	4.5	70%	151.8°
2031-06-30 Mon	—	unknown	—	72.5° 10:35	4.51	80%	165.4°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2031-06-01&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.