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.

2039-09-30astronomy score per night — click a bar for that night2039-10-29

night of	weather	overall	best window	highest	dark h	Moon	Moon sep.
2039-09-30 Fri	—	unknown	—	50.1° 13:15	9.12	98%	165.0°
2039-10-01 Sat	—	unknown	—	50.1° 13:10	9.17	100%	178.1°
2039-10-02 Sun	—	unknown	—	50.1° 13:10	9.22	100%	169.0°
2039-10-03 Mon	—	unknown	—	50.1° 13:05	9.27	97%	156.3°
2039-10-04 Tue	—	unknown	—	50.1° 13:00	9.32	93%	143.9°
2039-10-05 Wed	—	unknown	—	50.1° 12:55	9.36	87%	131.8°
2039-10-06 Thu	—	unknown	—	50.1° 12:50	9.41	80%	119.7°
2039-10-07 Fri	—	unknown	—	50.1° 12:50	9.46	72%	107.9°
2039-10-08 Sat	—	unknown	—	50.1° 12:45	9.5	64%	96.0°
2039-10-09 Sun	—	unknown	—	50.1° 12:40	9.55	54%	84.2°
2039-10-10 Mon	—	unknown	—	50.1° 12:35	9.59	45%	72.2°
2039-10-11 Tue	—	unknown	—	50.1° 12:35	9.64	35%	60.0°
2039-10-12 Wed	—	unknown	—	50.1° 12:30	9.68	26%	47.6°
2039-10-13 Thu	—	unknown	—	50.1° 12:25	9.73	18%	34.8°
2039-10-14 Fri	—	unknown	—	50.1° 12:20	9.77	10%	21.7°
2039-10-15 Sat	—	unknown	—	50.1° 12:15	9.81	5%	8.1°
2039-10-16 Sun	—	unknown	—	50.1° 12:15	9.86	1%	5.8°
2039-10-17 Mon	—	unknown	—	50.1° 12:10	9.9	0%	20.1°
2039-10-18 Tue	—	unknown	—	50.1° 12:05	9.94	2%	34.7°
2039-10-19 Wed	—	unknown	—	50.1° 12:00	9.99	6%	49.4°
2039-10-20 Thu	—	unknown	—	50.1° 11:55	10.03	13%	64.1°
2039-10-21 Fri	—	unknown	—	50.1° 11:50	10.07	22%	78.7°
2039-10-22 Sat	—	unknown	—	50.1° 11:45	10.11	32%	93.1°
2039-10-23 Sun	—	unknown	—	50.1° 11:40	10.15	44%	107.3°
2039-10-24 Mon	—	unknown	—	50.1° 11:40	10.19	55%	121.2°
2039-10-25 Tue	—	unknown	—	50.1° 11:35	10.23	66%	134.8°
2039-10-26 Wed	—	unknown	—	50.1° 11:30	10.27	75%	148.3°
2039-10-27 Thu	—	unknown	—	50.1° 11:25	10.31	84%	161.4°
2039-10-28 Fri	—	unknown	—	50.1° 11:20	10.35	91%	174.4°
2039-10-29 Sat	—	unknown	—	50.1° 10:20	10.38	96%	172.8°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2039-09-30&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.