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.

2036-05-27astronomy score per night — click a bar for that night2036-06-25

night of	weather	overall	best window	highest	dark h	Moon	Moon sep.
2036-05-27 Tue	—	unknown	—	72.5° 12:45	4.97	6%	37.1°
2036-05-28 Wed	—	unknown	—	72.5° 12:45	4.93	13%	51.4°
2036-05-29 Thu	—	unknown	—	72.5° 12:40	4.89	22%	65.7°
2036-05-30 Fri	—	unknown	—	72.5° 12:35	4.85	33%	79.9°
2036-05-31 Sat	—	unknown	—	72.5° 12:30	4.81	44%	94.0°
2036-06-01 Sun	—	unknown	—	72.5° 12:30	4.78	55%	107.8°
2036-06-02 Mon	—	unknown	—	72.5° 12:25	4.74	66%	121.3°
2036-06-03 Tue	—	unknown	—	72.5° 12:20	4.71	76%	134.5°
2036-06-04 Wed	—	unknown	—	72.5° 12:15	4.68	84%	147.3°
2036-06-05 Thu	—	unknown	—	72.5° 12:10	4.65	91%	159.4°
2036-06-06 Fri	—	unknown	—	72.5° 12:10	4.62	96%	169.3°
2036-06-07 Sat	—	unknown	—	72.5° 12:00	4.59	99%	168.6°
2036-06-08 Sun	—	unknown	—	72.5° 12:00	4.57	100%	158.7°
2036-06-09 Mon	—	unknown	—	72.5° 11:50	4.54	99%	147.2°
2036-06-10 Tue	—	unknown	—	72.5° 11:50	4.52	96%	135.6°
2036-06-11 Wed	—	unknown	—	72.5° 11:45	4.5	91%	123.9°
2036-06-12 Thu	—	unknown	—	72.5° 11:40	4.49	85%	112.2°
2036-06-13 Fri	—	unknown	—	72.5° 11:35	4.47	78%	100.5°
2036-06-14 Sat	—	unknown	—	72.5° 11:35	4.46	70%	88.8°
2036-06-15 Sun	—	unknown	—	72.5° 11:30	4.45	61%	77.0°
2036-06-16 Mon	—	unknown	—	72.5° 11:25	4.44	51%	65.0°
2036-06-17 Tue	—	unknown	—	72.5° 11:20	4.43	41%	52.9°
2036-06-18 Wed	—	unknown	—	72.5° 11:15	4.43	31%	40.5°
2036-06-19 Thu	—	unknown	—	72.5° 11:15	4.42	22%	27.9°
2036-06-20 Fri	—	unknown	—	72.5° 11:10	4.42	14%	15.8°
2036-06-21 Sat	—	unknown	—	72.5° 11:05	4.42	7%	9.2°
2036-06-22 Sun	—	unknown	—	72.5° 11:00	4.43	2%	17.9°
2036-06-23 Mon	—	unknown	—	72.5° 10:55	4.43	0%	31.5°
2036-06-24 Tue	—	unknown	—	72.5° 10:55	4.44	1%	45.9°
2036-06-25 Wed	—	unknown	—	72.5° 10:50	4.45	5%	60.7°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2036-05-27&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.