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.

2028-06-25astronomy score per night — click a bar for that night2028-07-24

night of	weather	overall	best window	highest	dark h	Moon	Moon sep.
2028-06-25 Sun	—	unknown	—	42.9° 12:40	4.45	13%	57.8°
2028-06-26 Mon	—	unknown	—	42.9° 12:40	4.46	22%	69.6°
2028-06-27 Tue	—	unknown	—	42.9° 12:35	4.47	32%	81.7°
2028-06-28 Wed	—	unknown	—	42.9° 12:30	4.49	43%	93.9°
2028-06-29 Thu	—	unknown	—	42.9° 12:25	4.51	55%	105.9°
2028-06-30 Fri	—	unknown	—	42.9° 12:20	4.53	66%	117.4°
2028-07-01 Sat	—	unknown	—	42.9° 12:20	4.55	76%	128.2°
2028-07-02 Sun	—	unknown	—	42.9° 12:15	4.57	85%	137.7°
2028-07-03 Mon	—	unknown	—	42.9° 12:10	4.6	92%	144.9°
2028-07-04 Tue	—	unknown	—	42.9° 12:05	4.62	96%	148.6°
2028-07-05 Wed	—	unknown	—	42.9° 12:00	4.65	99%	147.6°
2028-07-06 Thu	—	unknown	—	42.9° 11:55	4.68	100%	142.6°
2028-07-07 Fri	—	unknown	—	42.9° 11:50	4.71	99%	135.0°
2028-07-08 Sat	—	unknown	—	42.9° 11:45	4.75	95%	126.1°
2028-07-09 Sun	—	unknown	—	42.9° 11:45	4.78	90%	116.5°
2028-07-10 Mon	—	unknown	—	42.9° 11:40	4.82	84%	106.6°
2028-07-11 Tue	—	unknown	—	42.9° 11:35	4.86	77%	96.6°
2028-07-12 Wed	—	unknown	—	42.9° 11:30	4.9	68%	86.5°
2028-07-13 Thu	—	unknown	—	42.9° 11:25	4.94	59%	76.4°
2028-07-14 Fri	—	unknown	—	42.9° 11:25	4.98	49%	66.3°
2028-07-15 Sat	—	unknown	—	42.9° 11:20	5.02	40%	56.5°
2028-07-16 Sun	—	unknown	—	42.9° 11:15	5.06	30%	47.1°
2028-07-17 Mon	—	unknown	—	42.9° 11:10	5.11	21%	38.8°
2028-07-18 Tue	—	unknown	—	42.9° 11:05	5.15	13%	32.9°
2028-07-19 Wed	—	unknown	—	42.9° 11:05	5.2	6%	31.4°
2028-07-20 Thu	—	unknown	—	42.9° 11:00	5.25	2%	35.1°
2028-07-21 Fri	—	unknown	—	42.9° 10:55	5.3	0%	43.1°
2028-07-22 Sat	—	unknown	—	42.9° 10:50	5.35	1%	53.7°
2028-07-23 Sun	—	unknown	—	42.9° 10:45	5.4	5%	65.6°
2028-07-24 Mon	—	unknown	—	42.9° 10:45	5.45	11%	78.0°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2028-06-25&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.