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.

2042-06-26astronomy score per night — click a bar for that night2042-07-25

night of	weather	overall	best window	highest	dark h	Moon	Moon sep.
2042-06-26 Thu	—	unknown	—	42.9° 12:40	4.46	64%	114.7°
2042-06-27 Fri	—	unknown	—	42.9° 12:35	4.47	72%	124.0°
2042-06-28 Sat	—	unknown	—	42.9° 12:30	4.48	81%	132.7°
2042-06-29 Sun	—	unknown	—	42.9° 12:30	4.5	88%	140.1°
2042-06-30 Mon	—	unknown	—	42.9° 12:25	4.52	94%	145.4°
2042-07-01 Tue	—	unknown	—	42.9° 12:20	4.54	98%	147.0°
2042-07-02 Wed	—	unknown	—	42.9° 12:15	4.56	100%	144.2°
2042-07-03 Thu	—	unknown	—	42.9° 12:10	4.59	99%	137.7°
2042-07-04 Fri	—	unknown	—	42.9° 12:10	4.61	97%	128.7°
2042-07-05 Sat	—	unknown	—	42.9° 12:00	4.64	92%	118.2°
2042-07-06 Sun	—	unknown	—	42.9° 12:00	4.67	84%	106.8°
2042-07-07 Mon	—	unknown	—	42.9° 11:55	4.7	75%	95.0°
2042-07-08 Tue	—	unknown	—	42.9° 11:50	4.73	65%	83.1°
2042-07-09 Wed	—	unknown	—	42.9° 11:45	4.77	54%	71.4°
2042-07-10 Thu	—	unknown	—	42.9° 11:40	4.8	42%	60.0°
2042-07-11 Fri	—	unknown	—	42.9° 11:35	4.84	31%	49.6°
2042-07-12 Sat	—	unknown	—	42.9° 11:35	4.88	21%	40.7°
2042-07-13 Sun	—	unknown	—	42.9° 11:30	4.92	13%	34.7°
2042-07-14 Mon	—	unknown	—	42.9° 11:25	4.96	6%	33.1°
2042-07-15 Tue	—	unknown	—	42.9° 11:20	5.0	2%	36.2°
2042-07-16 Wed	—	unknown	—	42.9° 11:15	5.05	0%	43.0°
2042-07-17 Thu	—	unknown	—	42.9° 11:15	5.09	1%	51.7°
2042-07-18 Fri	—	unknown	—	42.9° 11:10	5.14	3%	61.4°
2042-07-19 Sat	—	unknown	—	42.9° 11:05	5.18	8%	71.4°
2042-07-20 Sun	—	unknown	—	42.9° 11:00	5.23	14%	81.6°
2042-07-21 Mon	—	unknown	—	42.9° 11:00	5.28	21%	91.7°
2042-07-22 Tue	—	unknown	—	42.9° 10:55	5.33	29%	101.7°
2042-07-23 Wed	—	unknown	—	42.9° 10:50	5.38	38%	111.4°
2042-07-24 Thu	—	unknown	—	42.9° 10:45	5.43	47%	120.8°
2042-07-25 Fri	—	unknown	—	42.9° 10:40	5.48	57%	129.7°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2042-06-26&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.