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.

2035-06-21astronomy score per night — click a bar for that night2035-07-20

night of	weather	overall	best window	highest	dark h	Moon	Moon sep.
2035-06-21 Thu	—	unknown	—	42.9° 13:00	4.42	99%	149.2°
2035-06-22 Fri	—	unknown	—	42.9° 12:55	4.42	96%	140.9°
2035-06-23 Sat	—	unknown	—	42.9° 12:50	4.43	91%	131.2°
2035-06-24 Sun	—	unknown	—	42.9° 12:50	4.43	85%	120.7°
2035-06-25 Mon	—	unknown	—	42.9° 12:45	4.44	78%	109.7°
2035-06-26 Tue	—	unknown	—	42.9° 12:40	4.45	69%	98.4°
2035-06-27 Wed	—	unknown	—	42.9° 12:35	4.47	59%	86.7°
2035-06-28 Thu	—	unknown	—	42.9° 12:35	4.48	48%	74.7°
2035-06-29 Fri	—	unknown	—	42.9° 12:30	4.5	38%	62.6°
2035-06-30 Sat	—	unknown	—	42.9° 12:25	4.51	27%	50.4°
2035-07-01 Sun	—	unknown	—	42.9° 12:20	4.53	17%	38.7°
2035-07-02 Mon	—	unknown	—	42.9° 12:15	4.56	9%	28.8°
2035-07-03 Tue	—	unknown	—	42.9° 12:15	4.58	4%	23.8°
2035-07-04 Wed	—	unknown	—	42.9° 12:10	4.61	0%	27.1°
2035-07-05 Thu	—	unknown	—	42.9° 12:05	4.63	0%	36.6°
2035-07-06 Fri	—	unknown	—	42.9° 12:00	4.66	4%	48.6°
2035-07-07 Sat	—	unknown	—	42.9° 11:55	4.69	9%	61.4°
2035-07-08 Sun	—	unknown	—	42.9° 11:50	4.73	17%	74.2°
2035-07-09 Mon	—	unknown	—	42.9° 11:45	4.76	26%	86.9°
2035-07-10 Tue	—	unknown	—	42.9° 11:40	4.79	36%	99.1°
2035-07-11 Wed	—	unknown	—	42.9° 11:40	4.83	46%	110.8°
2035-07-12 Thu	—	unknown	—	42.9° 11:35	4.87	56%	122.0°
2035-07-13 Fri	—	unknown	—	42.9° 11:30	4.91	66%	132.6°
2035-07-14 Sat	—	unknown	—	42.9° 11:25	4.95	75%	142.3°
2035-07-15 Sun	—	unknown	—	42.9° 11:20	4.99	82%	150.3°
2035-07-16 Mon	—	unknown	—	42.9° 11:20	5.03	89%	155.4°
2035-07-17 Tue	—	unknown	—	42.9° 11:15	5.08	94%	155.7°
2035-07-18 Wed	—	unknown	—	42.9° 11:10	5.12	98%	151.0°
2035-07-19 Thu	—	unknown	—	42.9° 11:05	5.17	100%	143.1°
2035-07-20 Fri	—	unknown	—	42.9° 11:00	5.22	100%	133.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2035-06-21&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.