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.

2039-05-24astronomy score per night — click a bar for that night2039-06-22

night of	weather	overall	best window	highest	dark h	Moon	Moon sep.
2039-05-24 Tue	—	unknown	—	42.9° 14:50	5.13	3%	28.9°
2039-05-25 Wed	—	unknown	—	42.9° 14:45	5.09	7%	32.3°
2039-05-26 Thu	—	unknown	—	42.9° 14:45	5.04	13%	38.9°
2039-05-27 Fri	—	unknown	—	42.9° 14:40	5.0	20%	47.5°
2039-05-28 Sat	—	unknown	—	42.9° 14:35	4.96	28%	57.2°
2039-05-29 Sun	—	unknown	—	42.9° 14:30	4.92	38%	67.7°
2039-05-30 Mon	—	unknown	—	42.9° 14:25	4.88	48%	78.8°
2039-05-31 Tue	—	unknown	—	42.9° 14:25	4.84	59%	90.4°
2039-06-01 Wed	—	unknown	—	42.9° 14:20	4.8	69%	102.4°
2039-06-02 Thu	—	unknown	—	42.9° 14:15	4.77	79%	114.5°
2039-06-03 Fri	—	unknown	—	42.9° 14:10	4.73	88%	126.6°
2039-06-04 Sat	—	unknown	—	42.9° 14:05	4.7	95%	137.9°
2039-06-05 Sun	—	unknown	—	42.9° 14:05	4.67	99%	147.0°
2039-06-06 Mon	—	unknown	—	42.9° 14:00	4.64	100%	151.3°
2039-06-07 Tue	—	unknown	—	42.9° 13:55	4.61	98%	148.7°
2039-06-08 Wed	—	unknown	—	42.9° 13:50	4.58	93%	140.7°
2039-06-09 Thu	—	unknown	—	42.9° 13:50	4.56	86%	130.1°
2039-06-10 Fri	—	unknown	—	42.9° 13:45	4.54	77%	118.6°
2039-06-11 Sat	—	unknown	—	42.9° 13:40	4.52	67%	107.0°
2039-06-12 Sun	—	unknown	—	42.9° 13:35	4.5	57%	95.4°
2039-06-13 Mon	—	unknown	—	42.9° 13:30	4.48	47%	84.2°
2039-06-14 Tue	—	unknown	—	42.9° 13:30	4.47	37%	73.3°
2039-06-15 Wed	—	unknown	—	42.9° 13:25	4.45	28%	62.9°
2039-06-16 Thu	—	unknown	—	42.9° 13:20	4.44	19%	53.0°
2039-06-17 Fri	—	unknown	—	42.9° 13:15	4.44	12%	43.8°
2039-06-18 Sat	—	unknown	—	42.9° 13:10	4.43	7%	36.0°
2039-06-19 Sun	—	unknown	—	42.9° 13:10	4.42	3%	30.5°
2039-06-20 Mon	—	unknown	—	42.9° 13:05	4.42	1%	28.6°
2039-06-21 Tue	—	unknown	—	42.9° 13:00	4.42	0%	31.1°
2039-06-22 Wed	—	unknown	—	42.9° 12:55	4.42	1%	37.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2039-05-24&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.