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.

2034-08-12astronomy score per night — click a bar for that night2034-09-10

night of	weather	overall	best window	highest	dark h	Moon	Moon sep.
2034-08-12 Sat	—	unknown	—	50.2° 16:30	6.47	2%	61.7°
2034-08-13 Sun	—	unknown	—	50.2° 16:25	6.53	0%	48.1°
2034-08-14 Mon	—	unknown	—	50.2° 16:20	6.59	1%	34.8°
2034-08-15 Tue	—	unknown	—	50.2° 16:15	6.65	4%	21.8°
2034-08-16 Wed	—	unknown	—	50.2° 16:10	6.7	8%	9.5°
2034-08-17 Thu	—	unknown	—	50.2° 16:10	6.76	15%	5.3°
2034-08-18 Fri	—	unknown	—	50.2° 16:05	6.82	22%	16.4°
2034-08-19 Sat	—	unknown	—	50.2° 16:00	6.88	31%	28.2°
2034-08-20 Sun	—	unknown	—	50.2° 15:55	6.93	40%	40.0°
2034-08-21 Mon	—	unknown	—	50.2° 15:50	6.99	49%	51.8°
2034-08-22 Tue	—	unknown	—	50.2° 15:50	7.05	58%	63.6°
2034-08-23 Wed	—	unknown	—	50.2° 15:45	7.11	68%	75.6°
2034-08-24 Thu	—	unknown	—	50.2° 15:40	7.16	77%	87.8°
2034-08-25 Fri	—	unknown	—	50.2° 15:35	7.22	84%	100.2°
2034-08-26 Sat	—	unknown	—	50.2° 15:35	7.28	91%	112.9°
2034-08-27 Sun	—	unknown	—	50.2° 15:30	7.33	96%	126.0°
2034-08-28 Mon	—	unknown	—	50.2° 15:25	7.39	99%	139.4°
2034-08-29 Tue	—	unknown	—	50.2° 15:20	7.45	100%	153.1°
2034-08-30 Wed	—	unknown	—	50.2° 15:15	7.5	98%	166.8°
2034-08-31 Thu	—	unknown	—	50.2° 15:15	7.56	94%	176.0°
2034-09-01 Fri	—	unknown	—	50.2° 15:10	7.61	87%	163.7°
2034-09-02 Sat	—	unknown	—	50.2° 15:05	7.67	78%	149.5°
2034-09-03 Sun	—	unknown	—	50.2° 15:00	7.73	68%	135.2°
2034-09-04 Mon	—	unknown	—	50.2° 14:55	7.78	56%	121.0°
2034-09-05 Tue	—	unknown	—	50.2° 14:55	7.84	45%	106.9°
2034-09-06 Wed	—	unknown	—	50.2° 14:50	7.89	34%	93.0°
2034-09-07 Thu	—	unknown	—	50.2° 14:45	7.95	24%	79.2°
2034-09-08 Fri	—	unknown	—	50.2° 14:40	8.0	15%	65.6°
2034-09-09 Sat	—	unknown	—	50.2° 14:40	8.05	8%	52.2°
2034-09-10 Sun	—	unknown	—	50.2° 14:35	8.11	3%	39.0°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2034-08-12&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.