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.

2029-08-29astronomy score per night — click a bar for that night2029-09-27

night of	weather	overall	best window	highest	dark h	Moon	Moon sep.
2029-08-29 Wed	—	unknown	—	50.2° 15:20	7.46	71%	142.8°
2029-08-30 Thu	—	unknown	—	50.2° 15:15	7.51	62%	131.3°
2029-08-31 Fri	—	unknown	—	50.2° 15:10	7.57	52%	119.6°
2029-09-01 Sat	—	unknown	—	50.2° 15:10	7.63	43%	107.6°
2029-09-02 Sun	—	unknown	—	50.2° 15:05	7.68	33%	95.4°
2029-09-03 Mon	—	unknown	—	50.2° 15:00	7.74	24%	82.8°
2029-09-04 Tue	—	unknown	—	50.2° 14:55	7.79	16%	69.8°
2029-09-05 Wed	—	unknown	—	50.2° 14:50	7.85	8%	56.4°
2029-09-06 Thu	—	unknown	—	50.2° 14:50	7.9	3%	42.7°
2029-09-07 Fri	—	unknown	—	50.2° 14:45	7.96	0%	29.0°
2029-09-08 Sat	—	unknown	—	50.2° 14:40	8.01	0%	16.0°
2029-09-09 Sun	—	unknown	—	50.2° 14:35	8.07	3%	10.0°
2029-09-10 Mon	—	unknown	—	50.2° 14:35	8.12	9%	19.6°
2029-09-11 Tue	—	unknown	—	50.2° 14:30	8.17	17%	33.2°
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°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2029-08-29&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.