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.

2046-04-25astronomy score per night — click a bar for that night2046-05-24

night of	weather	overall	best window	highest	dark h	Moon	Moon sep.
2046-04-25 Wed	—	unknown	—	42.9° 16:45	6.7	70%	143.8°
2046-04-26 Thu	—	unknown	—	42.9° 16:40	6.64	60%	137.2°
2046-04-27 Fri	—	unknown	—	42.9° 16:35	6.59	50%	128.8°
2046-04-28 Sat	—	unknown	—	42.9° 16:30	6.53	41%	119.6°
2046-04-29 Sun	—	unknown	—	42.9° 16:30	6.47	32%	110.0°
2046-04-30 Mon	—	unknown	—	42.9° 16:25	6.41	23%	100.2°
2046-05-01 Tue	—	unknown	—	42.9° 16:20	6.35	16%	90.2°
2046-05-02 Wed	—	unknown	—	42.9° 16:15	6.3	10%	80.2°
2046-05-03 Thu	—	unknown	—	42.9° 16:10	6.24	5%	70.1°
2046-05-04 Fri	—	unknown	—	42.9° 16:10	6.18	2%	60.3°
2046-05-05 Sat	—	unknown	—	42.9° 16:05	6.12	0%	50.9°
2046-05-06 Sun	—	unknown	—	42.9° 16:00	6.07	1%	42.3°
2046-05-07 Mon	—	unknown	—	42.9° 15:55	6.01	4%	35.7°
2046-05-08 Tue	—	unknown	—	42.9° 15:55	5.95	8%	32.3°
2046-05-09 Wed	—	unknown	—	42.9° 15:50	5.9	15%	33.4°
2046-05-10 Thu	—	unknown	—	42.9° 15:45	5.84	24%	38.9°
2046-05-11 Fri	—	unknown	—	42.9° 15:40	5.79	33%	47.3°
2046-05-12 Sat	—	unknown	—	42.9° 15:35	5.73	44%	57.6°
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°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2046-04-25&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.