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.

2042-08-06astronomy score per night — click a bar for that night2042-09-04

night of	weather	overall	best window	highest	dark h	Moon	Moon sep.
2042-08-06 Wed	—	unknown	—	50.1° 16:50	6.13	67%	160.5°
2042-08-07 Thu	—	unknown	—	50.1° 16:45	6.19	56%	146.4°
2042-08-08 Fri	—	unknown	—	50.1° 16:45	6.25	44%	132.4°
2042-08-09 Sat	—	unknown	—	50.1° 16:40	6.3	34%	118.6°
2042-08-10 Sun	—	unknown	—	50.1° 16:35	6.36	24%	105.1°
2042-08-11 Mon	—	unknown	—	50.1° 16:30	6.42	15%	91.7°
2042-08-12 Tue	—	unknown	—	50.1° 16:30	6.48	8%	78.5°
2042-08-13 Wed	—	unknown	—	50.1° 16:25	6.53	4%	65.6°
2042-08-14 Thu	—	unknown	—	50.1° 16:20	6.59	1%	52.9°
2042-08-15 Fri	—	unknown	—	50.1° 16:15	6.65	0%	40.4°
2042-08-16 Sat	—	unknown	—	50.1° 16:10	6.71	2%	28.1°
2042-08-17 Sun	—	unknown	—	50.1° 16:10	6.76	5%	16.2°
2042-08-18 Mon	—	unknown	—	50.1° 16:05	6.82	9%	5.2°
2042-08-19 Tue	—	unknown	—	50.1° 16:00	6.88	16%	8.9°
2042-08-20 Wed	—	unknown	—	50.1° 15:55	6.94	23%	20.3°
2042-08-21 Thu	—	unknown	—	50.1° 15:50	6.99	32%	32.0°
2042-08-22 Fri	—	unknown	—	50.1° 15:50	7.05	41%	43.8°
2042-08-23 Sat	—	unknown	—	50.1° 15:45	7.11	50%	55.8°
2042-08-24 Sun	—	unknown	—	50.1° 15:40	7.17	60%	68.1°
2042-08-25 Mon	—	unknown	—	50.1° 15:35	7.22	70%	80.7°
2042-08-26 Tue	—	unknown	—	50.1° 15:35	7.28	79%	93.7°
2042-08-27 Wed	—	unknown	—	50.1° 15:30	7.34	87%	107.1°
2042-08-28 Thu	—	unknown	—	50.1° 15:25	7.39	94%	120.9°
2042-08-29 Fri	—	unknown	—	50.1° 15:20	7.45	98%	135.2°
2042-08-30 Sat	—	unknown	—	50.1° 15:15	7.51	100%	149.7°
2042-08-31 Sun	—	unknown	—	50.1° 15:15	7.56	99%	164.4°
2042-09-01 Mon	—	unknown	—	50.1° 15:10	7.62	95%	176.4°
2042-09-02 Tue	—	unknown	—	50.1° 15:05	7.67	88%	164.9°
2042-09-03 Wed	—	unknown	—	50.1° 15:00	7.73	80%	150.4°
2042-09-04 Thu	—	unknown	—	50.1° 14:55	7.78	70%	136.0°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2042-08-06&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.