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.

2033-09-04astronomy score per night — click a bar for that night2033-10-03

night of	weather	overall	best window	highest	dark h	Moon	Moon sep.
2033-09-04 Sun	—	unknown	—	50.2° 14:55	7.79	78%	100.2°
2033-09-05 Mon	—	unknown	—	50.2° 14:50	7.85	86%	113.9°
2033-09-06 Tue	—	unknown	—	50.2° 14:50	7.9	93%	128.0°
2033-09-07 Wed	—	unknown	—	50.2° 14:45	7.96	98%	142.5°
2033-09-08 Thu	—	unknown	—	50.2° 14:40	8.01	100%	157.1°
2033-09-09 Fri	—	unknown	—	50.2° 14:35	8.07	99%	171.1°
2033-09-10 Sat	—	unknown	—	50.2° 14:35	8.12	95%	170.4°
2033-09-11 Sun	—	unknown	—	50.2° 14:30	8.18	88%	156.4°
2033-09-12 Mon	—	unknown	—	50.2° 14:25	8.23	80%	142.0°
2033-09-13 Tue	—	unknown	—	50.2° 14:20	8.28	70%	127.8°
2033-09-14 Wed	—	unknown	—	50.2° 14:15	8.34	59%	113.9°
2033-09-15 Thu	—	unknown	—	50.2° 14:15	8.39	48%	100.4°
2033-09-16 Fri	—	unknown	—	50.2° 14:10	8.44	37%	87.3°
2033-09-17 Sat	—	unknown	—	50.2° 14:05	8.49	28%	74.5°
2033-09-18 Sun	—	unknown	—	50.2° 14:00	8.54	19%	61.9°
2033-09-19 Mon	—	unknown	—	50.2° 13:55	8.6	12%	49.6°
2033-09-20 Tue	—	unknown	—	50.2° 13:55	8.65	6%	37.5°
2033-09-21 Wed	—	unknown	—	50.2° 13:50	8.7	2%	25.7°
2033-09-22 Thu	—	unknown	—	50.2° 13:45	8.75	0%	14.2°
2033-09-23 Fri	—	unknown	—	50.2° 13:40	8.8	0%	5.5°
2033-09-24 Sat	—	unknown	—	50.2° 13:40	8.85	2%	11.8°
2033-09-25 Sun	—	unknown	—	50.2° 13:35	8.9	5%	22.9°
2033-09-26 Mon	—	unknown	—	50.2° 13:30	8.95	10%	34.5°
2033-09-27 Tue	—	unknown	—	50.2° 13:25	9.0	16%	46.3°
2033-09-28 Wed	—	unknown	—	50.2° 13:20	9.05	24%	58.3°
2033-09-29 Thu	—	unknown	—	50.2° 13:20	9.1	32%	70.4°
2033-09-30 Fri	—	unknown	—	50.2° 13:15	9.15	42%	82.8°
2033-10-01 Sat	—	unknown	—	50.2° 13:10	9.19	52%	95.5°
2033-10-02 Sun	—	unknown	—	50.2° 13:05	9.24	63%	108.6°
2033-10-03 Mon	—	unknown	—	50.2° 13:00	9.29	73%	122.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2033-09-04&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.