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.

2045-06-18astronomy score per night — click a bar for that night2045-07-17

night of	weather	overall	best window	highest	dark h	Moon	Moon sep.
2045-06-18 Sun	—	unknown	—	42.9° 13:10	4.43	20%	62.1°
2045-06-19 Mon	—	unknown	—	42.9° 13:05	4.42	30%	73.8°
2045-06-20 Tue	—	unknown	—	42.9° 13:00	4.42	41%	85.6°
2045-06-21 Wed	—	unknown	—	42.9° 13:00	4.42	52%	97.2°
2045-06-22 Thu	—	unknown	—	42.9° 12:55	4.43	63%	108.5°
2045-06-23 Fri	—	unknown	—	42.9° 12:50	4.43	73%	119.2°
2045-06-24 Sat	—	unknown	—	42.9° 12:45	4.44	82%	129.0°
2045-06-25 Sun	—	unknown	—	42.9° 12:45	4.45	89%	137.4°
2045-06-26 Mon	—	unknown	—	42.9° 12:40	4.46	94%	143.7°
2045-06-27 Tue	—	unknown	—	42.9° 12:35	4.47	98%	146.7°
2045-06-28 Wed	—	unknown	—	42.9° 12:30	4.49	100%	145.9°
2045-06-29 Thu	—	unknown	—	42.9° 12:25	4.51	100%	141.5°
2045-06-30 Fri	—	unknown	—	42.9° 12:25	4.53	98%	134.6°
2045-07-01 Sat	—	unknown	—	42.9° 12:20	4.55	94%	126.4°
2045-07-02 Sun	—	unknown	—	42.9° 12:15	4.57	88%	117.4°
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°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2045-06-18&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.