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.

2029-09-12astronomy score per night — click a bar for that night2029-10-11

night of	weather	overall	best window	highest	dark h	Moon	Moon sep.
2029-09-12 Wed	—	unknown	—	50.2° 14:25	8.23	27%	47.3°
2029-09-13 Thu	—	unknown	—	50.2° 14:20	8.28	37%	61.2°
2029-09-14 Fri	—	unknown	—	50.2° 14:15	8.33	48%	74.9°
2029-09-15 Sat	—	unknown	—	50.2° 14:15	8.39	60%	88.4°
2029-09-16 Sun	—	unknown	—	50.2° 14:10	8.44	70%	101.5°
2029-09-17 Mon	—	unknown	—	50.2° 14:05	8.49	79%	114.3°
2029-09-18 Tue	—	unknown	—	50.2° 14:00	8.54	86%	126.9°
2029-09-19 Wed	—	unknown	—	50.2° 13:55	8.59	93%	139.1°
2029-09-20 Thu	—	unknown	—	50.2° 13:55	8.65	97%	151.0°
2029-09-21 Fri	—	unknown	—	50.2° 13:50	8.7	99%	162.0°
2029-09-22 Sat	—	unknown	—	50.2° 13:45	8.75	100%	169.8°
2029-09-23 Sun	—	unknown	—	50.2° 13:40	8.8	98%	166.8°
2029-09-24 Mon	—	unknown	—	50.2° 13:35	8.85	95%	157.2°
2029-09-25 Tue	—	unknown	—	50.2° 13:35	8.9	91%	146.1°
2029-09-26 Wed	—	unknown	—	50.2° 13:30	8.95	84%	134.8°
2029-09-27 Thu	—	unknown	—	50.2° 13:25	9.0	77%	123.2°
2029-09-28 Fri	—	unknown	—	50.2° 13:20	9.05	69%	111.5°
2029-09-29 Sat	—	unknown	—	50.2° 13:20	9.1	59%	99.5°
2029-09-30 Sun	—	unknown	—	50.2° 13:15	9.14	50%	87.3°
2029-10-01 Mon	—	unknown	—	50.2° 13:10	9.19	39%	74.8°
2029-10-02 Tue	—	unknown	—	50.2° 13:05	9.24	29%	61.9°
2029-10-03 Wed	—	unknown	—	50.2° 13:00	9.29	20%	48.7°
2029-10-04 Thu	—	unknown	—	50.2° 13:00	9.34	12%	35.1°
2029-10-05 Fri	—	unknown	—	50.2° 12:55	9.38	5%	21.6°
2029-10-06 Sat	—	unknown	—	50.2° 12:50	9.43	1%	10.7°
2029-10-07 Sun	—	unknown	—	50.2° 12:45	9.48	0%	14.4°
2029-10-08 Mon	—	unknown	—	50.2° 12:40	9.52	2%	27.5°
2029-10-09 Tue	—	unknown	—	50.2° 12:40	9.57	7%	41.9°
2029-10-10 Wed	—	unknown	—	50.2° 12:35	9.61	14%	56.4°
2029-10-11 Thu	—	unknown	—	50.2° 12:30	9.66	23%	70.7°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2029-09-12&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.