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.

2030-07-13astronomy score per night — click a bar for that night2030-08-11

night of	weather	overall	best window	highest	dark h	Moon	Moon sep.
2030-07-13 Sat	—	unknown	—	42.9° 11:30	4.92	98%	150.5°
2030-07-14 Sun	—	unknown	—	42.9° 11:25	4.96	100%	143.4°
2030-07-15 Mon	—	unknown	—	42.9° 11:20	5.0	99%	133.1°
2030-07-16 Tue	—	unknown	—	42.9° 11:15	5.04	95%	121.6°
2030-07-17 Wed	—	unknown	—	42.9° 11:15	5.09	89%	109.8°
2030-07-18 Thu	—	unknown	—	42.9° 11:10	5.13	82%	98.1°
2030-07-19 Fri	—	unknown	—	42.9° 11:05	5.18	73%	86.6°
2030-07-20 Sat	—	unknown	—	42.9° 11:00	5.23	64%	75.4°
2030-07-21 Sun	—	unknown	—	42.9° 10:55	5.27	54%	64.8°
2030-07-22 Mon	—	unknown	—	42.9° 10:55	5.32	44%	54.6°
2030-07-23 Tue	—	unknown	—	42.9° 10:50	5.37	35%	45.2°
2030-07-24 Wed	—	unknown	—	42.9° 10:45	5.42	26%	37.0°
2030-07-25 Thu	—	unknown	—	42.9° 10:40	5.48	18%	30.7°
2030-07-26 Fri	—	unknown	—	42.9° 10:40	5.53	12%	27.9°
2030-07-27 Sat	—	unknown	—	42.9° 10:35	5.58	6%	29.6°
2030-07-28 Sun	—	unknown	—	42.9° 10:30	5.63	2%	35.4°
2030-07-29 Mon	—	unknown	—	42.9° 10:25	5.69	0%	43.7°
2030-07-30 Tue	—	unknown	—	42.9° 10:20	5.74	0%	53.5°
2030-07-31 Wed	—	unknown	—	42.9° 10:20	5.79	2%	64.2°
2030-08-01 Thu	—	unknown	—	42.9° 10:15	5.85	7%	75.5°
2030-08-02 Fri	—	unknown	—	42.9° 10:10	5.9	13%	87.2°
2030-08-03 Sat	—	unknown	—	42.9° 10:05	5.96	21%	99.1°
2030-08-04 Sun	—	unknown	—	42.9° 10:00	6.02	31%	111.1°
2030-08-05 Mon	—	unknown	—	42.9° 10:00	6.07	41%	122.9°
2030-08-06 Tue	—	unknown	—	42.9° 09:55	6.13	53%	134.1°
2030-08-07 Wed	—	unknown	—	42.9° 09:50	6.19	64%	144.0°
2030-08-08 Thu	—	unknown	—	42.9° 09:45	6.24	75%	150.7°
2030-08-09 Fri	—	unknown	—	42.9° 09:45	6.3	84%	151.8°
2030-08-10 Sat	—	unknown	—	42.9° 09:40	6.36	92%	146.6°
2030-08-11 Sun	—	unknown	—	42.9° 09:35	6.41	97%	137.4°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2030-07-13&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.