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.

2038-04-03astronomy score per night — click a bar for that night2038-05-02

night of	weather	overall	best window	highest	dark h	Moon	Moon sep.
2038-04-03 Sat	—	unknown	—	79.2° 14:10	7.97	1%	36.2°
2038-04-04 Sun	—	unknown	—	79.2° 14:05	7.91	0%	28.7°
2038-04-05 Mon	—	unknown	—	79.2° 14:00	7.86	2%	24.5°
2038-04-06 Tue	—	unknown	—	79.2° 14:00	7.8	5%	25.2°
2038-04-07 Wed	—	unknown	—	79.2° 13:55	7.74	9%	30.6°
2038-04-08 Thu	—	unknown	—	79.2° 13:50	7.69	16%	38.8°
2038-04-09 Fri	—	unknown	—	79.2° 13:45	7.63	23%	48.6°
2038-04-10 Sat	—	unknown	—	79.2° 13:40	7.57	32%	59.2°
2038-04-11 Sun	—	unknown	—	79.2° 13:40	7.52	42%	70.4°
2038-04-12 Mon	—	unknown	—	79.2° 13:35	7.46	52%	82.1°
2038-04-13 Tue	—	unknown	—	79.2° 13:30	7.4	62%	94.3°
2038-04-14 Wed	—	unknown	—	79.2° 13:25	7.35	73%	106.8°
2038-04-15 Thu	—	unknown	—	79.2° 13:20	7.29	82%	119.6°
2038-04-16 Fri	—	unknown	—	79.2° 13:20	7.23	90%	132.3°
2038-04-17 Sat	—	unknown	—	79.2° 13:15	7.17	96%	144.1°
2038-04-18 Sun	—	unknown	—	79.2° 13:10	7.11	99%	153.1°
2038-04-19 Mon	—	unknown	—	79.2° 13:05	7.06	100%	155.8°
2038-04-20 Tue	—	unknown	—	79.2° 13:05	7.0	96%	150.2°
2038-04-21 Wed	—	unknown	—	79.2° 13:00	6.94	91%	140.0°
2038-04-22 Thu	—	unknown	—	79.2° 12:55	6.88	83%	128.1°
2038-04-23 Fri	—	unknown	—	79.2° 12:50	6.82	74%	115.9°
2038-04-24 Sat	—	unknown	—	79.2° 12:45	6.77	64%	103.7°
2038-04-25 Sun	—	unknown	—	79.2° 12:45	6.71	53%	91.8°
2038-04-26 Mon	—	unknown	—	79.2° 12:40	6.65	43%	80.3°
2038-04-27 Tue	—	unknown	—	79.2° 12:35	6.59	34%	69.1°
2038-04-28 Wed	—	unknown	—	79.2° 12:30	6.53	25%	58.3°
2038-04-29 Thu	—	unknown	—	79.2° 12:25	6.47	17%	48.0°
2038-04-30 Fri	—	unknown	—	79.2° 12:25	6.42	11%	38.5°
2038-05-01 Sat	—	unknown	—	79.2° 12:20	6.36	6%	30.4°
2038-05-02 Sun	—	unknown	—	79.2° 12:15	6.3	2%	25.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2038-04-03&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.