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.

2046-09-16astronomy score per night — click a bar for that night2046-10-15

night of	weather	overall	best window	highest	dark h	Moon	Moon sep.
2046-09-16 Sun	—	unknown	—	50.1° 14:10	8.43	97%	168.6°
2046-09-17 Mon	—	unknown	—	50.1° 14:05	8.49	94%	159.4°
2046-09-18 Tue	—	unknown	—	50.1° 14:00	8.54	88%	148.4°
2046-09-19 Wed	—	unknown	—	50.1° 14:00	8.59	82%	136.8°
2046-09-20 Thu	—	unknown	—	50.1° 13:55	8.64	73%	125.0°
2046-09-21 Fri	—	unknown	—	50.1° 13:50	8.69	64%	112.9°
2046-09-22 Sat	—	unknown	—	50.1° 13:45	8.74	54%	100.4°
2046-09-23 Sun	—	unknown	—	50.1° 13:45	8.79	44%	87.7°
2046-09-24 Mon	—	unknown	—	50.1° 13:40	8.84	33%	74.5°
2046-09-25 Tue	—	unknown	—	50.1° 13:35	8.89	23%	60.9°
2046-09-26 Wed	—	unknown	—	50.1° 13:30	8.94	14%	46.9°
2046-09-27 Thu	—	unknown	—	50.1° 13:25	8.99	7%	32.6°
2046-09-28 Fri	—	unknown	—	50.1° 13:25	9.04	2%	18.8°
2046-09-29 Sat	—	unknown	—	50.1° 13:20	9.09	0%	9.3°
2046-09-30 Sun	—	unknown	—	50.1° 13:15	9.14	1%	16.9°
2046-10-01 Mon	—	unknown	—	50.1° 13:10	9.19	5%	30.6°
2046-10-02 Tue	—	unknown	—	50.1° 13:05	9.24	12%	44.8°
2046-10-03 Wed	—	unknown	—	50.1° 13:05	9.28	20%	58.9°
2046-10-04 Thu	—	unknown	—	50.1° 13:00	9.33	30%	72.6°
2046-10-05 Fri	—	unknown	—	50.1° 12:55	9.38	40%	85.9°
2046-10-06 Sat	—	unknown	—	50.1° 12:50	9.42	51%	98.8°
2046-10-07 Sun	—	unknown	—	50.1° 12:50	9.47	61%	111.2°
2046-10-08 Mon	—	unknown	—	50.1° 12:45	9.52	70%	123.4°
2046-10-09 Tue	—	unknown	—	50.1° 12:40	9.56	78%	135.3°
2046-10-10 Wed	—	unknown	—	50.1° 12:35	9.61	86%	146.8°
2046-10-11 Thu	—	unknown	—	50.1° 12:30	9.65	92%	157.9°
2046-10-12 Fri	—	unknown	—	50.1° 12:30	9.7	96%	167.6°
2046-10-13 Sat	—	unknown	—	50.1° 12:25	9.74	99%	170.0°
2046-10-14 Sun	—	unknown	—	50.1° 12:20	9.78	100%	162.0°
2046-10-15 Mon	—	unknown	—	50.1° 12:15	9.83	99%	151.2°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2046-09-16&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.