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.

2033-08-20astronomy score per night — click a bar for that night2033-09-18

night of	weather	overall	best window	highest	dark h	Moon	Moon sep.
2033-08-20 Sat	—	unknown	—	50.2° 15:55	6.95	16%	84.2°
2033-08-21 Sun	—	unknown	—	50.2° 15:50	7.0	9%	71.4°
2033-08-22 Mon	—	unknown	—	50.2° 15:45	7.06	4%	58.9°
2033-08-23 Tue	—	unknown	—	50.2° 15:45	7.12	1%	46.5°
2033-08-24 Wed	—	unknown	—	50.2° 15:40	7.18	0%	34.4°
2033-08-25 Thu	—	unknown	—	50.2° 15:35	7.23	1%	22.5°
2033-08-26 Fri	—	unknown	—	50.2° 15:30	7.29	4%	11.3°
2033-08-27 Sat	—	unknown	—	50.2° 15:30	7.35	8%	5.7°
2033-08-28 Sun	—	unknown	—	50.2° 15:25	7.4	14%	14.7°
2033-08-29 Mon	—	unknown	—	50.2° 15:20	7.46	21%	26.1°
2033-08-30 Tue	—	unknown	—	50.2° 15:15	7.52	30%	37.8°
2033-08-31 Wed	—	unknown	—	50.2° 15:10	7.57	39%	49.7°
2033-09-01 Thu	—	unknown	—	50.2° 15:10	7.63	48%	61.8°
2033-09-02 Fri	—	unknown	—	50.2° 15:05	7.68	58%	74.2°
2033-09-03 Sat	—	unknown	—	50.2° 15:00	7.74	68%	87.0°
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°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2033-08-20&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.