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.

2039-08-03astronomy score per night — click a bar for that night2039-09-01

night of	weather	overall	best window	highest	dark h	Moon	Moon sep.
2039-08-03 Wed	—	unknown	—	50.1° 17:05	5.95	100%	119.3°
2039-08-04 Thu	—	unknown	—	50.1° 17:00	6.01	100%	133.7°
2039-08-05 Fri	—	unknown	—	50.1° 16:55	6.06	97%	147.7°
2039-08-06 Sat	—	unknown	—	50.1° 16:50	6.12	92%	161.5°
2039-08-07 Sun	—	unknown	—	50.1° 16:50	6.18	85%	174.8°
2039-08-08 Mon	—	unknown	—	50.1° 16:45	6.23	77%	172.3°
2039-08-09 Tue	—	unknown	—	50.1° 16:40	6.29	68%	159.8°
2039-08-10 Wed	—	unknown	—	50.1° 16:35	6.35	58%	147.5°
2039-08-11 Thu	—	unknown	—	50.1° 16:35	6.4	49%	135.5°
2039-08-12 Fri	—	unknown	—	50.1° 16:30	6.46	40%	123.6°
2039-08-13 Sat	—	unknown	—	50.1° 16:25	6.52	30%	111.8°
2039-08-14 Sun	—	unknown	—	50.1° 16:20	6.58	22%	99.9°
2039-08-15 Mon	—	unknown	—	50.1° 16:15	6.63	15%	87.9°
2039-08-16 Tue	—	unknown	—	50.1° 16:15	6.69	9%	75.8°
2039-08-17 Wed	—	unknown	—	50.1° 16:10	6.75	4%	63.5°
2039-08-18 Thu	—	unknown	—	50.1° 16:05	6.81	1%	50.9°
2039-08-19 Fri	—	unknown	—	50.1° 16:00	6.86	0%	38.1°
2039-08-20 Sat	—	unknown	—	50.1° 15:55	6.92	1%	25.1°
2039-08-21 Sun	—	unknown	—	50.1° 15:55	6.98	5%	11.8°
2039-08-22 Mon	—	unknown	—	50.1° 15:50	7.04	11%	1.7°
2039-08-23 Tue	—	unknown	—	50.1° 15:45	7.09	18%	15.3°
2039-08-24 Wed	—	unknown	—	50.1° 15:40	7.15	28%	29.2°
2039-08-25 Thu	—	unknown	—	50.1° 15:40	7.21	38%	43.1°
2039-08-26 Fri	—	unknown	—	50.1° 15:35	7.26	50%	57.2°
2039-08-27 Sat	—	unknown	—	50.1° 15:30	7.32	61%	71.4°
2039-08-28 Sun	—	unknown	—	50.1° 15:25	7.38	72%	85.6°
2039-08-29 Mon	—	unknown	—	50.1° 15:20	7.43	82%	99.9°
2039-08-30 Tue	—	unknown	—	50.1° 15:20	7.49	90%	114.2°
2039-08-31 Wed	—	unknown	—	50.1° 15:15	7.55	95%	128.3°
2039-09-01 Thu	—	unknown	—	50.1° 15:10	7.6	99%	142.3°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2039-08-03&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.