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.

2044-08-27astronomy score per night — click a bar for that night2044-09-25

night of	weather	overall	best window	highest	dark h	Moon	Moon sep.
2044-08-27 Sat	—	unknown	—	50.1° 15:25	7.37	27%	32.7°
2044-08-28 Sun	—	unknown	—	50.1° 15:25	7.42	36%	45.0°
2044-08-29 Mon	—	unknown	—	50.1° 15:20	7.48	46%	57.0°
2044-08-30 Tue	—	unknown	—	50.1° 15:15	7.54	55%	68.9°
2044-08-31 Wed	—	unknown	—	50.1° 15:10	7.59	64%	80.7°
2044-09-01 Thu	—	unknown	—	50.1° 15:05	7.65	73%	92.5°
2044-09-02 Fri	—	unknown	—	50.1° 15:05	7.7	81%	104.2°
2044-09-03 Sat	—	unknown	—	50.1° 15:00	7.76	88%	116.1°
2044-09-04 Sun	—	unknown	—	50.1° 14:55	7.81	94%	128.1°
2044-09-05 Mon	—	unknown	—	50.1° 14:50	7.87	98%	140.2°
2044-09-06 Tue	—	unknown	—	50.1° 14:50	7.92	100%	152.4°
2044-09-07 Wed	—	unknown	—	50.1° 14:45	7.98	100%	164.3°
2044-09-08 Thu	—	unknown	—	50.1° 14:40	8.03	98%	173.0°
2044-09-09 Fri	—	unknown	—	50.1° 14:35	8.09	94%	166.1°
2044-09-10 Sat	—	unknown	—	50.1° 14:30	8.14	87%	153.7°
2044-09-11 Sun	—	unknown	—	50.1° 14:30	8.19	79%	140.5°
2044-09-12 Mon	—	unknown	—	50.1° 14:25	8.25	69%	126.9°
2044-09-13 Tue	—	unknown	—	50.1° 14:20	8.3	58%	113.1°
2044-09-14 Wed	—	unknown	—	50.1° 14:15	8.35	47%	99.2°
2044-09-15 Thu	—	unknown	—	50.1° 14:10	8.41	36%	85.1°
2044-09-16 Fri	—	unknown	—	50.1° 14:10	8.46	25%	70.9°
2044-09-17 Sat	—	unknown	—	50.1° 14:05	8.51	16%	56.7°
2044-09-18 Sun	—	unknown	—	50.1° 14:00	8.56	8%	42.5°
2044-09-19 Mon	—	unknown	—	50.1° 13:55	8.61	3%	28.5°
2044-09-20 Tue	—	unknown	—	50.1° 13:55	8.67	0%	15.3°
2044-09-21 Wed	—	unknown	—	50.1° 13:50	8.72	0%	6.9°
2044-09-22 Thu	—	unknown	—	50.1° 13:45	8.77	3%	15.4°
2044-09-23 Fri	—	unknown	—	50.1° 13:40	8.82	7%	27.8°
2044-09-24 Sat	—	unknown	—	50.1° 13:35	8.87	13%	40.3°
2044-09-25 Sun	—	unknown	—	50.1° 13:35	8.92	21%	52.7°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2044-08-27&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.