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.

2030-06-17astronomy score per night — click a bar for that night2030-07-16

night of	weather	overall	best window	highest	dark h	Moon	Moon sep.
2030-06-17 Mon	—	unknown	—	42.9° 13:15	4.43	93%	139.2°
2030-06-18 Tue	—	unknown	—	42.9° 13:10	4.43	86%	128.4°
2030-06-19 Wed	—	unknown	—	42.9° 13:05	4.42	78%	116.9°
2030-06-20 Thu	—	unknown	—	42.9° 13:05	4.42	68%	105.4°
2030-06-21 Fri	—	unknown	—	42.9° 13:00	4.42	58%	94.0°
2030-06-22 Sat	—	unknown	—	42.9° 12:55	4.42	48%	82.9°
2030-06-23 Sun	—	unknown	—	42.9° 12:50	4.43	38%	72.1°
2030-06-24 Mon	—	unknown	—	42.9° 12:45	4.44	29%	61.7°
2030-06-25 Tue	—	unknown	—	42.9° 12:45	4.44	21%	51.9°
2030-06-26 Wed	—	unknown	—	42.9° 12:40	4.46	14%	42.8°
2030-06-27 Thu	—	unknown	—	42.9° 12:35	4.47	8%	35.0°
2030-06-28 Fri	—	unknown	—	42.9° 12:30	4.48	4%	29.6°
2030-06-29 Sat	—	unknown	—	42.9° 12:30	4.5	1%	28.0°
2030-06-30 Sun	—	unknown	—	42.9° 12:25	4.52	0%	30.9°
2030-07-01 Mon	—	unknown	—	42.9° 12:20	4.54	1%	37.4°
2030-07-02 Tue	—	unknown	—	42.9° 12:15	4.56	4%	46.2°
2030-07-03 Wed	—	unknown	—	42.9° 12:10	4.58	9%	56.1°
2030-07-04 Thu	—	unknown	—	42.9° 12:10	4.61	16%	66.9°
2030-07-05 Fri	—	unknown	—	42.9° 12:00	4.64	24%	78.2°
2030-07-06 Sat	—	unknown	—	42.9° 12:00	4.67	34%	89.8°
2030-07-07 Sun	—	unknown	—	42.9° 11:50	4.7	44%	101.7°
2030-07-08 Mon	—	unknown	—	42.9° 11:50	4.73	55%	113.7°
2030-07-09 Tue	—	unknown	—	42.9° 11:45	4.77	66%	125.6°
2030-07-10 Wed	—	unknown	—	42.9° 11:40	4.8	77%	136.8°
2030-07-11 Thu	—	unknown	—	42.9° 11:35	4.84	86%	146.3°
2030-07-12 Fri	—	unknown	—	42.9° 11:35	4.88	93%	151.7°
2030-07-13 Sat	—	unknown	—	42.9° 11:30	4.92	98%	150.5°
2030-07-14 Sun	—	unknown	—	42.9° 11:25	4.96	100%	143.4°
2030-07-15 Mon	—	unknown	—	42.9° 11:20	5.0	99%	133.1°
2030-07-16 Tue	—	unknown	—	42.9° 11:15	5.04	95%	121.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2030-06-17&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.