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.

2033-09-20astronomy score per night — click a bar for that night2033-10-19

night of	weather	overall	best window	highest	dark h	Moon	Moon sep.
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°
2033-10-04 Tue	—	unknown	—	50.2° 13:00	9.34	83%	136.1°
2033-10-05 Wed	—	unknown	—	50.2° 12:55	9.38	91%	150.4°
2033-10-06 Thu	—	unknown	—	50.2° 12:50	9.43	96%	164.8°
2033-10-07 Fri	—	unknown	—	50.2° 12:45	9.48	100%	174.6°
2033-10-08 Sat	—	unknown	—	50.2° 12:45	9.52	100%	162.9°
2033-10-09 Sun	—	unknown	—	50.2° 12:40	9.57	97%	148.1°
2033-10-10 Mon	—	unknown	—	50.2° 12:35	9.61	91%	133.3°
2033-10-11 Tue	—	unknown	—	50.2° 12:30	9.66	83%	118.8°
2033-10-12 Wed	—	unknown	—	50.2° 12:25	9.7	74%	104.7°
2033-10-13 Thu	—	unknown	—	50.2° 12:25	9.75	63%	91.1°
2033-10-14 Fri	—	unknown	—	50.2° 12:20	9.79	53%	77.9°
2033-10-15 Sat	—	unknown	—	50.2° 12:15	9.83	43%	65.1°
2033-10-16 Sun	—	unknown	—	50.2° 12:10	9.88	33%	52.7°
2033-10-17 Mon	—	unknown	—	50.2° 12:05	9.92	24%	40.5°
2033-10-18 Tue	—	unknown	—	50.2° 12:00	9.96	16%	28.6°
2033-10-19 Wed	—	unknown	—	50.2° 11:55	10.0	10%	17.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2033-09-20&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.