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.

2030-07-01astronomy score per night — click a bar for that night2030-07-30

night of	weather	overall	best window	highest	dark h	Moon	Moon sep.
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°
2030-07-17 Wed	—	unknown	—	42.9° 11:15	5.09	89%	109.8°
2030-07-18 Thu	—	unknown	—	42.9° 11:10	5.13	82%	98.1°
2030-07-19 Fri	—	unknown	—	42.9° 11:05	5.18	73%	86.6°
2030-07-20 Sat	—	unknown	—	42.9° 11:00	5.23	64%	75.4°
2030-07-21 Sun	—	unknown	—	42.9° 10:55	5.27	54%	64.8°
2030-07-22 Mon	—	unknown	—	42.9° 10:55	5.32	44%	54.6°
2030-07-23 Tue	—	unknown	—	42.9° 10:50	5.37	35%	45.2°
2030-07-24 Wed	—	unknown	—	42.9° 10:45	5.42	26%	37.0°
2030-07-25 Thu	—	unknown	—	42.9° 10:40	5.48	18%	30.7°
2030-07-26 Fri	—	unknown	—	42.9° 10:40	5.53	12%	27.9°
2030-07-27 Sat	—	unknown	—	42.9° 10:35	5.58	6%	29.6°
2030-07-28 Sun	—	unknown	—	42.9° 10:30	5.63	2%	35.4°
2030-07-29 Mon	—	unknown	—	42.9° 10:25	5.69	0%	43.7°
2030-07-30 Tue	—	unknown	—	42.9° 10:20	5.74	0%	53.5°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2030-07-01&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.