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.

2034-09-15astronomy score per night — click a bar for that night2034-10-14

night of	weather	overall	best window	highest	dark h	Moon	Moon sep.
2034-09-15 Fri	—	unknown	—	50.2° 14:15	8.38	10%	24.2°
2034-09-16 Sat	—	unknown	—	50.2° 14:10	8.43	17%	36.1°
2034-09-17 Sun	—	unknown	—	50.2° 14:05	8.48	24%	47.9°
2034-09-18 Mon	—	unknown	—	50.2° 14:00	8.53	33%	59.7°
2034-09-19 Tue	—	unknown	—	50.2° 14:00	8.58	42%	71.5°
2034-09-20 Wed	—	unknown	—	50.2° 13:55	8.64	51%	83.4°
2034-09-21 Thu	—	unknown	—	50.2° 13:50	8.69	61%	95.5°
2034-09-22 Fri	—	unknown	—	50.2° 13:45	8.74	71%	107.9°
2034-09-23 Sat	—	unknown	—	50.2° 13:40	8.79	79%	120.7°
2034-09-24 Sun	—	unknown	—	50.2° 13:40	8.84	87%	133.8°
2034-09-25 Mon	—	unknown	—	50.2° 13:35	8.89	94%	147.4°
2034-09-26 Tue	—	unknown	—	50.2° 13:30	8.94	98%	161.2°
2034-09-27 Wed	—	unknown	—	50.2° 13:25	8.99	100%	174.5°
2034-09-28 Thu	—	unknown	—	50.2° 13:25	9.04	99%	168.8°
2034-09-29 Fri	—	unknown	—	50.2° 13:20	9.09	95%	154.4°
2034-09-30 Sat	—	unknown	—	50.2° 13:15	9.13	89%	139.6°
2034-10-01 Sun	—	unknown	—	50.2° 13:10	9.18	80%	125.0°
2034-10-02 Mon	—	unknown	—	50.2° 13:05	9.23	70%	110.5°
2034-10-03 Tue	—	unknown	—	50.2° 13:05	9.28	59%	96.3°
2034-10-04 Wed	—	unknown	—	50.2° 13:00	9.33	48%	82.4°
2034-10-05 Thu	—	unknown	—	50.2° 12:55	9.37	37%	68.8°
2034-10-06 Fri	—	unknown	—	50.2° 12:50	9.42	27%	55.4°
2034-10-07 Sat	—	unknown	—	50.2° 12:45	9.47	18%	42.4°
2034-10-08 Sun	—	unknown	—	50.2° 12:45	9.51	11%	29.6°
2034-10-09 Mon	—	unknown	—	50.2° 12:40	9.56	6%	17.1°
2034-10-10 Tue	—	unknown	—	50.2° 12:35	9.6	2%	5.6°
2034-10-11 Wed	—	unknown	—	50.2° 12:30	9.65	0%	8.9°
2034-10-12 Thu	—	unknown	—	50.2° 12:30	9.69	0%	20.6°
2034-10-13 Fri	—	unknown	—	50.2° 12:25	9.74	2%	32.5°
2034-10-14 Sat	—	unknown	—	50.2° 12:20	9.78	6%	44.3°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2034-09-15&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.