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.

2045-07-03astronomy score per night — click a bar for that night2045-08-01

night of	weather	overall	best window	highest	dark h	Moon	Moon sep.
2045-07-03 Mon	—	unknown	—	42.9° 12:10	4.59	82%	107.8°
2045-07-04 Tue	—	unknown	—	42.9° 12:05	4.62	74%	98.0°
2045-07-05 Wed	—	unknown	—	42.9° 12:00	4.65	65%	88.0°
2045-07-06 Thu	—	unknown	—	42.9° 12:00	4.68	55%	77.8°
2045-07-07 Fri	—	unknown	—	42.9° 11:50	4.71	45%	67.6°
2045-07-08 Sat	—	unknown	—	42.9° 11:50	4.74	35%	57.6°
2045-07-09 Sun	—	unknown	—	42.9° 11:45	4.78	26%	48.0°
2045-07-10 Mon	—	unknown	—	42.9° 11:40	4.81	17%	39.8°
2045-07-11 Tue	—	unknown	—	42.9° 11:35	4.85	9%	34.3°
2045-07-12 Wed	—	unknown	—	42.9° 11:30	4.89	3%	33.5°
2045-07-13 Thu	—	unknown	—	42.9° 11:30	4.93	0%	38.2°
2045-07-14 Fri	—	unknown	—	42.9° 11:25	4.97	0%	46.9°
2045-07-15 Sat	—	unknown	—	42.9° 11:20	5.02	3%	57.7°
2045-07-16 Sun	—	unknown	—	42.9° 11:15	5.06	9%	69.6°
2045-07-17 Mon	—	unknown	—	42.9° 11:10	5.1	17%	81.8°
2045-07-18 Tue	—	unknown	—	42.9° 11:10	5.15	27%	93.9°
2045-07-19 Wed	—	unknown	—	42.9° 11:05	5.2	38%	105.5°
2045-07-20 Thu	—	unknown	—	42.9° 11:00	5.24	48%	116.6°
2045-07-21 Fri	—	unknown	—	42.9° 10:55	5.29	59%	126.7°
2045-07-22 Sat	—	unknown	—	42.9° 10:55	5.34	69%	135.5°
2045-07-23 Sun	—	unknown	—	42.9° 10:50	5.39	78%	142.4°
2045-07-24 Mon	—	unknown	—	42.9° 10:45	5.44	86%	146.3°
2045-07-25 Tue	—	unknown	—	42.9° 10:40	5.49	92%	146.4°
2045-07-26 Wed	—	unknown	—	42.9° 10:35	5.55	96%	142.8°
2045-07-27 Thu	—	unknown	—	42.9° 10:35	5.6	99%	136.6°
2045-07-28 Fri	—	unknown	—	42.9° 10:30	5.65	100%	128.7°
2045-07-29 Sat	—	unknown	—	42.9° 10:25	5.71	99%	119.8°
2045-07-30 Sun	—	unknown	—	42.9° 10:20	5.76	96%	110.4°
2045-07-31 Mon	—	unknown	—	42.9° 10:15	5.81	92%	100.7°
2045-08-01 Tue	—	unknown	—	42.9° 10:15	5.87	86%	90.7°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2045-07-03&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.