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.

2029-06-19astronomy score per night — click a bar for that night2029-07-18

night of	weather	overall	best window	highest	dark h	Moon	Moon sep.
2029-06-19 Tue	—	unknown	—	42.9° 13:05	4.42	56%	98.6°
2029-06-20 Wed	—	unknown	—	42.9° 13:00	4.42	67%	110.9°
2029-06-21 Thu	—	unknown	—	42.9° 13:00	4.42	78%	122.8°
2029-06-22 Fri	—	unknown	—	42.9° 12:55	4.43	87%	134.0°
2029-06-23 Sat	—	unknown	—	42.9° 12:50	4.43	94%	143.4°
2029-06-24 Sun	—	unknown	—	42.9° 12:45	4.44	98%	149.4°
2029-06-25 Mon	—	unknown	—	42.9° 12:45	4.45	100%	149.8°
2029-06-26 Tue	—	unknown	—	42.9° 12:40	4.46	99%	144.8°
2029-06-27 Wed	—	unknown	—	42.9° 12:35	4.47	96%	136.4°
2029-06-28 Thu	—	unknown	—	42.9° 12:30	4.49	91%	126.5°
2029-06-29 Fri	—	unknown	—	42.9° 12:25	4.5	84%	116.1°
2029-06-30 Sat	—	unknown	—	42.9° 12:25	4.52	76%	105.4°
2029-07-01 Sun	—	unknown	—	42.9° 12:20	4.54	67%	94.8°
2029-07-02 Mon	—	unknown	—	42.9° 12:15	4.57	58%	84.4°
2029-07-03 Tue	—	unknown	—	42.9° 12:10	4.59	48%	74.1°
2029-07-04 Wed	—	unknown	—	42.9° 12:05	4.62	39%	64.1°
2029-07-05 Thu	—	unknown	—	42.9° 12:00	4.65	30%	54.4°
2029-07-06 Fri	—	unknown	—	42.9° 11:55	4.68	21%	45.3°
2029-07-07 Sat	—	unknown	—	42.9° 11:50	4.71	14%	37.3°
2029-07-08 Sun	—	unknown	—	42.9° 11:45	4.74	8%	31.5°
2029-07-09 Mon	—	unknown	—	42.9° 11:45	4.77	3%	29.6°
2029-07-10 Tue	—	unknown	—	42.9° 11:40	4.81	1%	32.6°
2029-07-11 Wed	—	unknown	—	42.9° 11:35	4.85	0%	39.5°
2029-07-12 Thu	—	unknown	—	42.9° 11:30	4.89	2%	49.0°
2029-07-13 Fri	—	unknown	—	42.9° 11:30	4.93	6%	59.8°
2029-07-14 Sat	—	unknown	—	42.9° 11:25	4.97	13%	71.5°
2029-07-15 Sun	—	unknown	—	42.9° 11:20	5.01	21%	83.6°
2029-07-16 Mon	—	unknown	—	42.9° 11:15	5.05	31%	95.9°
2029-07-17 Tue	—	unknown	—	42.9° 11:10	5.1	42%	108.1°
2029-07-18 Wed	—	unknown	—	42.9° 11:10	5.14	54%	120.0°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2029-06-19&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.