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.

2045-04-02astronomy score per night — click a bar for that night2045-05-01

night of	weather	overall	best window	highest	dark h	Moon	Moon sep.
2045-04-02 Sun	—	unknown	—	79.2° 14:15	8.01	98%	164.3°
2045-04-03 Mon	—	unknown	—	79.2° 14:10	7.95	94%	163.1°
2045-04-04 Tue	—	unknown	—	79.2° 14:05	7.89	88%	154.1°
2045-04-05 Wed	—	unknown	—	79.2° 14:00	7.84	81%	142.9°
2045-04-06 Thu	—	unknown	—	79.2° 13:55	7.78	72%	131.4°
2045-04-07 Fri	—	unknown	—	79.2° 13:55	7.73	63%	119.8°
2045-04-08 Sat	—	unknown	—	79.2° 13:50	7.67	54%	108.3°
2045-04-09 Sun	—	unknown	—	79.2° 13:45	7.61	44%	96.8°
2045-04-10 Mon	—	unknown	—	79.2° 13:40	7.56	35%	85.4°
2045-04-11 Tue	—	unknown	—	79.2° 13:35	7.5	26%	73.9°
2045-04-12 Wed	—	unknown	—	79.2° 13:35	7.44	18%	62.4°
2045-04-13 Thu	—	unknown	—	79.2° 13:30	7.39	12%	50.8°
2045-04-14 Fri	—	unknown	—	79.2° 13:25	7.33	6%	39.2°
2045-04-15 Sat	—	unknown	—	79.2° 13:20	7.27	2%	28.0°
2045-04-16 Sun	—	unknown	—	79.2° 13:20	7.21	0%	18.5°
2045-04-17 Mon	—	unknown	—	79.2° 13:15	7.15	1%	15.0°
2045-04-18 Tue	—	unknown	—	79.2° 13:10	7.1	3%	21.4°
2045-04-19 Wed	—	unknown	—	79.2° 13:05	7.04	8%	32.5°
2045-04-20 Thu	—	unknown	—	79.2° 13:00	6.98	15%	45.1°
2045-04-21 Fri	—	unknown	—	79.2° 13:00	6.92	24%	58.3°
2045-04-22 Sat	—	unknown	—	79.2° 12:55	6.86	35%	71.8°
2045-04-23 Sun	—	unknown	—	79.2° 12:50	6.81	46%	85.4°
2045-04-24 Mon	—	unknown	—	79.2° 12:45	6.75	57%	99.1°
2045-04-25 Tue	—	unknown	—	79.2° 12:40	6.69	68%	112.8°
2045-04-26 Wed	—	unknown	—	79.2° 12:40	6.63	78%	126.3°
2045-04-27 Thu	—	unknown	—	79.2° 12:35	6.57	87%	139.5°
2045-04-28 Fri	—	unknown	—	79.2° 12:30	6.51	94%	151.9°
2045-04-29 Sat	—	unknown	—	79.2° 12:25	6.46	98%	162.0°
2045-04-30 Sun	—	unknown	—	79.2° 12:25	6.4	100%	164.8°
2045-05-01 Mon	—	unknown	—	79.2° 12:20	6.34	99%	157.9°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2045-04-02&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.