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.

2028-07-31astronomy score per night — click a bar for that night2028-08-29

night of	weather	overall	best window	highest	dark h	Moon	Moon sep.
2028-07-31 Mon	—	unknown	—	50.2° 17:15	5.82	82%	73.3°
2028-08-01 Tue	—	unknown	—	50.2° 17:10	5.88	89%	85.8°
2028-08-02 Wed	—	unknown	—	50.2° 17:05	5.93	94%	98.2°
2028-08-03 Thu	—	unknown	—	50.2° 17:00	5.99	98%	110.4°
2028-08-04 Fri	—	unknown	—	50.2° 16:55	6.04	100%	122.4°
2028-08-05 Sat	—	unknown	—	50.2° 16:55	6.1	100%	134.2°
2028-08-06 Sun	—	unknown	—	50.2° 16:50	6.16	98%	145.7°
2028-08-07 Mon	—	unknown	—	50.2° 16:45	6.21	94%	156.8°
2028-08-08 Tue	—	unknown	—	50.2° 16:40	6.27	88%	166.5°
2028-08-09 Wed	—	unknown	—	50.2° 16:35	6.33	82%	169.9°
2028-08-10 Thu	—	unknown	—	50.2° 16:35	6.38	74%	162.7°
2028-08-11 Fri	—	unknown	—	50.2° 16:30	6.44	65%	152.0°
2028-08-12 Sat	—	unknown	—	50.2° 16:25	6.5	56%	140.4°
2028-08-13 Sun	—	unknown	—	50.2° 16:20	6.56	46%	128.3°
2028-08-14 Mon	—	unknown	—	50.2° 16:20	6.61	35%	115.7°
2028-08-15 Tue	—	unknown	—	50.2° 16:15	6.67	26%	102.7°
2028-08-16 Wed	—	unknown	—	50.2° 16:10	6.73	16%	89.2°
2028-08-17 Thu	—	unknown	—	50.2° 16:05	6.79	9%	75.2°
2028-08-18 Fri	—	unknown	—	50.2° 16:00	6.84	3%	60.8°
2028-08-19 Sat	—	unknown	—	50.2° 16:00	6.9	0%	46.2°
2028-08-20 Sun	—	unknown	—	50.2° 15:55	6.96	0%	31.6°
2028-08-21 Mon	—	unknown	—	50.2° 15:50	7.02	4%	17.9°
2028-08-22 Tue	—	unknown	—	50.2° 15:45	7.07	9%	9.7°
2028-08-23 Wed	—	unknown	—	50.2° 15:40	7.13	17%	17.6°
2028-08-24 Thu	—	unknown	—	50.2° 15:40	7.19	27%	30.6°
2028-08-25 Fri	—	unknown	—	50.2° 15:35	7.25	38%	44.0°
2028-08-26 Sat	—	unknown	—	50.2° 15:30	7.3	49%	57.3°
2028-08-27 Sun	—	unknown	—	50.2° 15:25	7.36	59%	70.2°
2028-08-28 Mon	—	unknown	—	50.2° 15:25	7.42	69%	82.9°
2028-08-29 Tue	—	unknown	—	50.2° 15:20	7.47	78%	95.3°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2028-07-31&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.