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.

2046-05-13astronomy score per night — click a bar for that night2046-06-11

night of	weather	overall	best window	highest	dark h	Moon	Moon sep.
2046-05-13 Sun	—	unknown	—	42.9° 15:35	5.68	56%	68.8°
2046-05-14 Mon	—	unknown	—	42.9° 15:30	5.62	67%	80.7°
2046-05-15 Tue	—	unknown	—	42.9° 15:25	5.57	77%	92.9°
2046-05-16 Wed	—	unknown	—	42.9° 15:20	5.52	86%	105.1°
2046-05-17 Thu	—	unknown	—	42.9° 15:15	5.46	93%	117.0°
2046-05-18 Fri	—	unknown	—	42.9° 15:15	5.41	98%	128.2°
2046-05-19 Sat	—	unknown	—	42.9° 15:10	5.36	100%	137.9°
2046-05-20 Sun	—	unknown	—	42.9° 15:05	5.31	99%	145.0°
2046-05-21 Mon	—	unknown	—	42.9° 15:00	5.26	96%	147.9°
2046-05-22 Tue	—	unknown	—	42.9° 14:55	5.21	91%	145.9°
2046-05-23 Wed	—	unknown	—	42.9° 14:55	5.17	84%	140.1°
2046-05-24 Thu	—	unknown	—	42.9° 14:50	5.12	76%	132.1°
2046-05-25 Fri	—	unknown	—	42.9° 14:45	5.07	67%	123.0°
2046-05-26 Sat	—	unknown	—	42.9° 14:40	5.03	57%	113.3°
2046-05-27 Sun	—	unknown	—	42.9° 14:40	4.99	48%	103.5°
2046-05-28 Mon	—	unknown	—	42.9° 14:35	4.94	39%	93.5°
2046-05-29 Tue	—	unknown	—	42.9° 14:30	4.9	30%	83.4°
2046-05-30 Wed	—	unknown	—	42.9° 14:25	4.86	21%	73.4°
2046-05-31 Thu	—	unknown	—	42.9° 14:20	4.83	14%	63.5°
2046-06-01 Fri	—	unknown	—	42.9° 14:20	4.79	8%	53.8°
2046-06-02 Sat	—	unknown	—	42.9° 14:15	4.75	3%	44.9°
2046-06-03 Sun	—	unknown	—	42.9° 14:10	4.72	1%	37.4°
2046-06-04 Mon	—	unknown	—	42.9° 14:05	4.69	0%	32.8°
2046-06-05 Tue	—	unknown	—	42.9° 14:00	4.66	2%	32.5°
2046-06-06 Wed	—	unknown	—	42.9° 14:00	4.63	6%	37.0°
2046-06-07 Thu	—	unknown	—	42.9° 13:55	4.6	12%	45.0°
2046-06-08 Fri	—	unknown	—	42.9° 13:50	4.58	21%	55.0°
2046-06-09 Sat	—	unknown	—	42.9° 13:45	4.55	31%	66.1°
2046-06-10 Sun	—	unknown	—	42.9° 13:45	4.53	42%	77.9°
2046-06-11 Mon	—	unknown	—	42.9° 13:40	4.51	53%	89.8°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2046-05-13&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.