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.

2038-04-26astronomy score per night — click a bar for that night2038-05-25

night of	weather	overall	best window	highest	dark h	Moon	Moon sep.
2038-04-26 Mon	—	unknown	—	72.5° 14:50	6.65	43%	105.4°
2038-04-27 Tue	—	unknown	—	72.5° 14:45	6.59	34%	93.1°
2038-04-28 Wed	—	unknown	—	72.5° 14:45	6.53	25%	81.1°
2038-04-29 Thu	—	unknown	—	72.5° 14:40	6.47	17%	69.2°
2038-04-30 Fri	—	unknown	—	72.5° 14:35	6.42	11%	57.5°
2038-05-01 Sat	—	unknown	—	72.5° 14:30	6.36	6%	45.8°
2038-05-02 Sun	—	unknown	—	72.5° 14:30	6.3	2%	34.3°
2038-05-03 Mon	—	unknown	—	72.5° 14:25	6.24	0%	22.9°
2038-05-04 Tue	—	unknown	—	72.5° 14:20	6.19	0%	12.3°
2038-05-05 Wed	—	unknown	—	72.5° 14:15	6.13	2%	7.8°
2038-05-06 Thu	—	unknown	—	72.5° 14:10	6.07	6%	16.2°
2038-05-07 Fri	—	unknown	—	72.5° 14:10	6.01	11%	27.6°
2038-05-08 Sat	—	unknown	—	72.5° 14:05	5.96	18%	39.7°
2038-05-09 Sun	—	unknown	—	72.5° 14:00	5.9	27%	52.2°
2038-05-10 Mon	—	unknown	—	72.5° 13:55	5.85	37%	65.1°
2038-05-11 Tue	—	unknown	—	72.5° 13:50	5.79	47%	78.2°
2038-05-12 Wed	—	unknown	—	72.5° 13:50	5.73	58%	91.8°
2038-05-13 Thu	—	unknown	—	72.5° 13:45	5.68	69%	105.7°
2038-05-14 Fri	—	unknown	—	72.5° 13:40	5.63	79%	120.0°
2038-05-15 Sat	—	unknown	—	72.5° 13:35	5.57	88%	134.5°
2038-05-16 Sun	—	unknown	—	72.5° 13:35	5.52	95%	149.1°
2038-05-17 Mon	—	unknown	—	72.5° 13:30	5.47	99%	163.3°
2038-05-18 Tue	—	unknown	—	72.5° 13:25	5.42	100%	172.5°
2038-05-19 Wed	—	unknown	—	72.5° 13:20	5.37	98%	163.3°
2038-05-20 Thu	—	unknown	—	72.5° 13:15	5.32	94%	149.7°
2038-05-21 Fri	—	unknown	—	72.5° 13:15	5.27	87%	136.0°
2038-05-22 Sat	—	unknown	—	72.5° 13:10	5.22	78%	122.5°
2038-05-23 Sun	—	unknown	—	72.5° 13:05	5.17	69%	109.5°
2038-05-24 Mon	—	unknown	—	72.5° 13:00	5.12	59%	96.9°
2038-05-25 Tue	—	unknown	—	72.5° 12:55	5.08	49%	84.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2038-04-26&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.