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.

2045-07-18astronomy score per night — click a bar for that night2045-08-16

night of	weather	overall	best window	highest	dark h	Moon	Moon sep.
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°
2045-08-02 Wed	—	unknown	—	42.9° 10:10	5.93	79%	80.7°
2045-08-03 Thu	—	unknown	—	42.9° 10:05	5.98	70%	70.6°
2045-08-04 Fri	—	unknown	—	42.9° 10:00	6.04	61%	60.7°
2045-08-05 Sat	—	unknown	—	42.9° 10:00	6.09	51%	51.2°
2045-08-06 Sun	—	unknown	—	42.9° 09:55	6.15	40%	42.6°
2045-08-07 Mon	—	unknown	—	42.9° 09:50	6.21	30%	36.0°
2045-08-08 Tue	—	unknown	—	42.9° 09:45	6.26	20%	33.2°
2045-08-09 Wed	—	unknown	—	42.9° 09:40	6.32	11%	35.6°
2045-08-10 Thu	—	unknown	—	42.9° 09:40	6.38	5%	42.7°
2045-08-11 Fri	—	unknown	—	42.9° 09:35	6.44	1%	52.7°
2045-08-12 Sat	—	unknown	—	42.9° 09:30	6.49	0%	64.3°
2045-08-13 Sun	—	unknown	—	42.9° 09:25	6.55	2%	76.7°
2045-08-14 Mon	—	unknown	—	42.9° 09:20	6.61	7%	89.2°
2045-08-15 Tue	—	unknown	—	42.9° 09:20	6.67	14%	101.4°
2045-08-16 Wed	—	unknown	—	42.9° 09:15	6.72	24%	113.0°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2045-07-18&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.