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.

2038-06-13astronomy score per night — click a bar for that night2038-07-12

night of	weather	overall	best window	highest	dark h	Moon	Moon sep.
2038-06-13 Sun	—	unknown	—	42.9° 13:30	4.48	86%	132.4°
2038-06-14 Mon	—	unknown	—	42.9° 13:25	4.46	93%	143.1°
2038-06-15 Tue	—	unknown	—	42.9° 13:25	4.45	98%	150.9°
2038-06-16 Wed	—	unknown	—	42.9° 13:20	4.44	100%	152.8°
2038-06-17 Thu	—	unknown	—	42.9° 13:15	4.43	99%	148.2°
2038-06-18 Fri	—	unknown	—	42.9° 13:10	4.43	96%	139.5°
2038-06-19 Sat	—	unknown	—	42.9° 13:05	4.42	90%	129.0°
2038-06-20 Sun	—	unknown	—	42.9° 13:05	4.42	83%	118.0°
2038-06-21 Mon	—	unknown	—	42.9° 13:00	4.42	74%	106.8°
2038-06-22 Tue	—	unknown	—	42.9° 12:55	4.43	65%	95.8°
2038-06-23 Wed	—	unknown	—	42.9° 12:50	4.43	56%	85.0°
2038-06-24 Thu	—	unknown	—	42.9° 12:50	4.44	46%	74.3°
2038-06-25 Fri	—	unknown	—	42.9° 12:45	4.45	37%	64.0°
2038-06-26 Sat	—	unknown	—	42.9° 12:40	4.46	28%	53.9°
2038-06-27 Sun	—	unknown	—	42.9° 12:35	4.47	20%	44.5°
2038-06-28 Mon	—	unknown	—	42.9° 12:30	4.48	13%	36.0°
2038-06-29 Tue	—	unknown	—	42.9° 12:30	4.5	7%	29.6°
2038-06-30 Wed	—	unknown	—	42.9° 12:25	4.52	3%	27.0°
2038-07-01 Thu	—	unknown	—	42.9° 12:20	4.54	0%	29.5°
2038-07-02 Fri	—	unknown	—	42.9° 12:15	4.56	0%	36.3°
2038-07-03 Sat	—	unknown	—	42.9° 12:10	4.59	2%	45.7°
2038-07-04 Sun	—	unknown	—	42.9° 12:10	4.61	6%	56.4°
2038-07-05 Mon	—	unknown	—	42.9° 12:00	4.64	13%	68.1°
2038-07-06 Tue	—	unknown	—	42.9° 12:00	4.67	21%	80.2°
2038-07-07 Wed	—	unknown	—	42.9° 11:55	4.7	31%	92.5°
2038-07-08 Thu	—	unknown	—	42.9° 11:50	4.73	42%	105.0°
2038-07-09 Fri	—	unknown	—	42.9° 11:45	4.77	53%	117.3°
2038-07-10 Sat	—	unknown	—	42.9° 11:40	4.8	64%	129.2°
2038-07-11 Sun	—	unknown	—	42.9° 11:35	4.84	75%	140.2°
2038-07-12 Mon	—	unknown	—	42.9° 11:35	4.88	84%	148.9°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2038-06-13&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.