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.

2041-07-04astronomy score per night — click a bar for that night2041-08-02

night of	weather	overall	best window	highest	dark h	Moon	Moon sep.
2041-07-04 Thu	—	unknown	—	42.9° 12:05	4.62	34%	93.6°
2041-07-05 Fri	—	unknown	—	42.9° 12:00	4.65	44%	103.7°
2041-07-06 Sat	—	unknown	—	42.9° 12:00	4.68	53%	113.8°
2041-07-07 Sun	—	unknown	—	42.9° 11:50	4.71	63%	123.7°
2041-07-08 Mon	—	unknown	—	42.9° 11:50	4.74	73%	133.0°
2041-07-09 Tue	—	unknown	—	42.9° 11:45	4.78	82%	141.2°
2041-07-10 Wed	—	unknown	—	42.9° 11:40	4.81	89%	146.8°
2041-07-11 Thu	—	unknown	—	42.9° 11:35	4.85	95%	147.9°
2041-07-12 Fri	—	unknown	—	42.9° 11:30	4.89	99%	143.7°
2041-07-13 Sat	—	unknown	—	42.9° 11:30	4.93	100%	135.3°
2041-07-14 Sun	—	unknown	—	42.9° 11:25	4.97	98%	124.5°
2041-07-15 Mon	—	unknown	—	42.9° 11:20	5.01	93%	112.6°
2041-07-16 Tue	—	unknown	—	42.9° 11:15	5.06	86%	100.2°
2041-07-17 Wed	—	unknown	—	42.9° 11:10	5.1	77%	87.8°
2041-07-18 Thu	—	unknown	—	42.9° 11:10	5.15	66%	75.6°
2041-07-19 Fri	—	unknown	—	42.9° 11:05	5.19	55%	64.0°
2041-07-20 Sat	—	unknown	—	42.9° 11:00	5.24	44%	53.3°
2041-07-21 Sun	—	unknown	—	42.9° 10:55	5.29	34%	43.9°
2041-07-22 Mon	—	unknown	—	42.9° 10:55	5.34	24%	36.5°
2041-07-23 Tue	—	unknown	—	42.9° 10:50	5.39	16%	32.4°
2041-07-24 Wed	—	unknown	—	42.9° 10:45	5.44	9%	32.5°
2041-07-25 Thu	—	unknown	—	42.9° 10:40	5.49	4%	36.6°
2041-07-26 Fri	—	unknown	—	42.9° 10:35	5.54	1%	43.5°
2041-07-27 Sat	—	unknown	—	42.9° 10:35	5.6	0%	51.9°
2041-07-28 Sun	—	unknown	—	42.9° 10:30	5.65	1%	61.1°
2041-07-29 Mon	—	unknown	—	42.9° 10:25	5.7	3%	70.8°
2041-07-30 Tue	—	unknown	—	42.9° 10:20	5.76	8%	80.7°
2041-07-31 Wed	—	unknown	—	42.9° 10:15	5.81	13%	90.7°
2041-08-01 Thu	—	unknown	—	42.9° 10:15	5.87	20%	100.7°
2041-08-02 Fri	—	unknown	—	42.9° 10:10	5.92	28%	110.7°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2041-07-04&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.