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.

2028-05-26astronomy score per night — click a bar for that night2028-06-24

night of	weather	overall	best window	highest	dark h	Moon	Moon sep.
2028-05-26 Fri	—	unknown	—	42.9° 14:40	5.01	8%	33.6°
2028-05-27 Sat	—	unknown	—	42.9° 14:35	4.97	15%	40.4°
2028-05-28 Sun	—	unknown	—	42.9° 14:30	4.93	24%	49.9°
2028-05-29 Mon	—	unknown	—	42.9° 14:30	4.89	34%	60.8°
2028-05-30 Tue	—	unknown	—	42.9° 14:25	4.85	46%	72.5°
2028-05-31 Wed	—	unknown	—	42.9° 14:20	4.81	57%	84.5°
2028-06-01 Thu	—	unknown	—	42.9° 14:15	4.78	68%	96.6°
2028-06-02 Fri	—	unknown	—	42.9° 14:10	4.74	78%	108.6°
2028-06-03 Sat	—	unknown	—	42.9° 14:10	4.71	87%	120.1°
2028-06-04 Sun	—	unknown	—	42.9° 14:05	4.68	93%	130.8°
2028-06-05 Mon	—	unknown	—	42.9° 14:00	4.65	98%	140.0°
2028-06-06 Tue	—	unknown	—	42.9° 13:55	4.62	100%	146.4°
2028-06-07 Wed	—	unknown	—	42.9° 13:50	4.59	99%	148.8°
2028-06-08 Thu	—	unknown	—	42.9° 13:50	4.57	97%	146.4°
2028-06-09 Fri	—	unknown	—	42.9° 13:45	4.54	92%	140.4°
2028-06-10 Sat	—	unknown	—	42.9° 13:40	4.52	86%	132.2°
2028-06-11 Sun	—	unknown	—	42.9° 13:35	4.5	79%	123.1°
2028-06-12 Mon	—	unknown	—	42.9° 13:35	4.49	71%	113.4°
2028-06-13 Tue	—	unknown	—	42.9° 13:30	4.47	62%	103.4°
2028-06-14 Wed	—	unknown	—	42.9° 13:25	4.46	52%	93.3°
2028-06-15 Thu	—	unknown	—	42.9° 13:20	4.45	43%	83.2°
2028-06-16 Fri	—	unknown	—	42.9° 13:15	4.44	34%	73.0°
2028-06-17 Sat	—	unknown	—	42.9° 13:15	4.43	25%	62.8°
2028-06-18 Sun	—	unknown	—	42.9° 13:10	4.43	16%	53.0°
2028-06-19 Mon	—	unknown	—	42.9° 13:05	4.42	10%	43.7°
2028-06-20 Tue	—	unknown	—	42.9° 13:00	4.42	4%	36.1°
2028-06-21 Wed	—	unknown	—	42.9° 12:55	4.42	1%	31.6°
2028-06-22 Thu	—	unknown	—	42.9° 12:55	4.43	0%	32.2°
2028-06-23 Fri	—	unknown	—	42.9° 12:50	4.43	2%	37.9°
2028-06-24 Sat	—	unknown	—	42.9° 12:45	4.44	6%	46.9°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2028-05-26&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.