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.

2036-05-17astronomy score per night — click a bar for that night2036-06-15

night of	weather	overall	best window	highest	dark h	Moon	Moon sep.
2036-05-17 Sat	—	unknown	—	42.9° 15:15	5.44	54%	116.0°
2036-05-18 Sun	—	unknown	—	42.9° 15:10	5.39	45%	105.3°
2036-05-19 Mon	—	unknown	—	42.9° 15:05	5.34	35%	94.3°
2036-05-20 Tue	—	unknown	—	42.9° 15:05	5.29	26%	83.0°
2036-05-21 Wed	—	unknown	—	42.9° 15:00	5.24	18%	71.4°
2036-05-22 Thu	—	unknown	—	42.9° 14:55	5.19	10%	59.8°
2036-05-23 Fri	—	unknown	—	42.9° 14:50	5.15	5%	48.2°
2036-05-24 Sat	—	unknown	—	42.9° 14:45	5.1	1%	37.2°
2036-05-25 Sun	—	unknown	—	42.9° 14:45	5.06	0%	28.3°
2036-05-26 Mon	—	unknown	—	42.9° 14:40	5.01	2%	24.4°
2036-05-27 Tue	—	unknown	—	42.9° 14:35	4.97	6%	28.1°
2036-05-28 Wed	—	unknown	—	42.9° 14:30	4.93	13%	37.2°
2036-05-29 Thu	—	unknown	—	42.9° 14:30	4.89	22%	48.8°
2036-05-30 Fri	—	unknown	—	42.9° 14:25	4.85	33%	61.2°
2036-05-31 Sat	—	unknown	—	42.9° 14:20	4.81	44%	73.9°
2036-06-01 Sun	—	unknown	—	42.9° 14:15	4.78	55%	86.6°
2036-06-02 Mon	—	unknown	—	42.9° 14:10	4.74	66%	99.1°
2036-06-03 Tue	—	unknown	—	42.9° 14:10	4.71	76%	111.2°
2036-06-04 Wed	—	unknown	—	42.9° 14:05	4.68	84%	123.0°
2036-06-05 Thu	—	unknown	—	42.9° 14:00	4.65	91%	134.0°
2036-06-06 Fri	—	unknown	—	42.9° 13:55	4.62	96%	143.9°
2036-06-07 Sat	—	unknown	—	42.9° 13:50	4.59	99%	151.7°
2036-06-08 Sun	—	unknown	—	42.9° 13:50	4.57	100%	155.5°
2036-06-09 Mon	—	unknown	—	42.9° 13:45	4.54	99%	153.8°
2036-06-10 Tue	—	unknown	—	42.9° 13:40	4.52	96%	147.6°
2036-06-11 Wed	—	unknown	—	42.9° 13:35	4.5	91%	139.0°
2036-06-12 Thu	—	unknown	—	42.9° 13:35	4.49	85%	129.4°
2036-06-13 Fri	—	unknown	—	42.9° 13:30	4.47	78%	119.1°
2036-06-14 Sat	—	unknown	—	42.9° 13:25	4.46	70%	108.6°
2036-06-15 Sun	—	unknown	—	42.9° 13:20	4.45	61%	97.7°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2036-05-17&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.