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.

2039-06-06astronomy score per night — click a bar for that night2039-07-05

night of	weather	overall	best window	highest	dark h	Moon	Moon sep.
2039-06-06 Mon	—	unknown	—	72.5° 12:10	4.64	100%	161.1°
2039-06-07 Tue	—	unknown	—	72.5° 12:05	4.61	98%	146.4°
2039-06-08 Wed	—	unknown	—	72.5° 12:00	4.58	93%	131.6°
2039-06-09 Thu	—	unknown	—	72.5° 11:55	4.56	86%	117.2°
2039-06-10 Fri	—	unknown	—	72.5° 11:50	4.54	77%	103.1°
2039-06-11 Sat	—	unknown	—	72.5° 11:50	4.52	67%	89.5°
2039-06-12 Sun	—	unknown	—	72.5° 11:45	4.5	57%	76.4°
2039-06-13 Mon	—	unknown	—	72.5° 11:40	4.48	47%	63.7°
2039-06-14 Tue	—	unknown	—	72.5° 11:35	4.47	37%	51.3°
2039-06-15 Wed	—	unknown	—	72.5° 11:30	4.45	28%	39.2°
2039-06-16 Thu	—	unknown	—	72.5° 11:30	4.44	19%	27.4°
2039-06-17 Fri	—	unknown	—	72.5° 11:25	4.44	12%	16.0°
2039-06-18 Sat	—	unknown	—	72.5° 11:20	4.43	7%	6.8°
2039-06-19 Sun	—	unknown	—	72.5° 11:15	4.42	3%	10.7°
2039-06-20 Mon	—	unknown	—	72.5° 11:10	4.42	1%	21.5°
2039-06-21 Tue	—	unknown	—	72.5° 11:10	4.42	0%	33.0°
2039-06-22 Wed	—	unknown	—	72.5° 11:05	4.42	1%	44.9°
2039-06-23 Thu	—	unknown	—	72.5° 11:00	4.43	4%	56.9°
2039-06-24 Fri	—	unknown	—	72.5° 10:55	4.43	10%	69.0°
2039-06-25 Sat	—	unknown	—	72.5° 10:55	4.44	16%	81.4°
2039-06-26 Sun	—	unknown	—	72.5° 10:50	4.45	24%	94.0°
2039-06-27 Mon	—	unknown	—	72.5° 10:45	4.47	34%	106.8°
2039-06-28 Tue	—	unknown	—	72.5° 10:40	4.48	44%	119.9°
2039-06-29 Wed	—	unknown	—	72.5° 10:35	4.5	55%	133.4°
2039-06-30 Thu	—	unknown	—	72.5° 10:35	4.51	66%	147.1°
2039-07-01 Fri	—	unknown	—	72.5° 10:30	4.53	77%	160.9°
2039-07-02 Sat	—	unknown	—	72.5° 10:25	4.56	86%	173.0°
2039-07-03 Sun	—	unknown	—	72.5° 10:20	4.58	93%	167.0°
2039-07-04 Mon	—	unknown	—	72.5° 10:15	4.61	98%	152.9°
2039-07-05 Tue	—	unknown	—	72.5° 10:15	4.63	100%	138.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2039-06-06&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.