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.

2043-07-15astronomy score per night — click a bar for that night2043-08-13

night of	weather	overall	best window	highest	dark h	Moon	Moon sep.
2043-07-15 Wed	—	unknown	—	42.9° 11:20	4.99	67%	130.5°
2043-07-16 Thu	—	unknown	—	42.9° 11:20	5.04	76%	138.0°
2043-07-17 Fri	—	unknown	—	42.9° 11:15	5.08	84%	143.5°
2043-07-18 Sat	—	unknown	—	42.9° 11:10	5.13	90%	146.2°
2043-07-19 Sun	—	unknown	—	42.9° 11:05	5.17	95%	145.3°
2043-07-20 Mon	—	unknown	—	42.9° 11:05	5.22	98%	140.8°
2043-07-21 Tue	—	unknown	—	42.9° 11:00	5.27	100%	133.6°
2043-07-22 Wed	—	unknown	—	42.9° 10:55	5.32	99%	124.7°
2043-07-23 Thu	—	unknown	—	42.9° 10:50	5.37	96%	114.7°
2043-07-24 Fri	—	unknown	—	42.9° 10:45	5.42	92%	104.1°
2043-07-25 Sat	—	unknown	—	42.9° 10:45	5.47	85%	92.9°
2043-07-26 Sun	—	unknown	—	42.9° 10:40	5.52	76%	81.6°
2043-07-27 Mon	—	unknown	—	42.9° 10:35	5.57	66%	70.3°
2043-07-28 Tue	—	unknown	—	42.9° 10:30	5.62	55%	59.3°
2043-07-29 Wed	—	unknown	—	42.9° 10:25	5.68	43%	49.0°
2043-07-30 Thu	—	unknown	—	42.9° 10:25	5.73	32%	40.4°
2043-07-31 Fri	—	unknown	—	42.9° 10:20	5.79	22%	34.9°
2043-08-01 Sat	—	unknown	—	42.9° 10:15	5.84	13%	34.0°
2043-08-02 Sun	—	unknown	—	42.9° 10:10	5.9	6%	38.3°
2043-08-03 Mon	—	unknown	—	42.9° 10:05	5.95	2%	46.2°
2043-08-04 Tue	—	unknown	—	42.9° 10:05	6.01	0%	55.9°
2043-08-05 Wed	—	unknown	—	42.9° 10:00	6.06	1%	66.6°
2043-08-06 Thu	—	unknown	—	42.9° 09:55	6.12	4%	77.5°
2043-08-07 Fri	—	unknown	—	42.9° 09:50	6.18	9%	88.3°
2043-08-08 Sat	—	unknown	—	42.9° 09:50	6.23	16%	98.9°
2043-08-09 Sun	—	unknown	—	42.9° 09:45	6.29	24%	109.1°
2043-08-10 Mon	—	unknown	—	42.9° 09:40	6.35	33%	118.7°
2043-08-11 Tue	—	unknown	—	42.9° 09:35	6.41	42%	127.7°
2043-08-12 Wed	—	unknown	—	42.9° 09:30	6.46	51%	135.6°
2043-08-13 Thu	—	unknown	—	42.9° 09:30	6.52	61%	141.8°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2043-07-15&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.