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.

2029-04-30astronomy score per night — click a bar for that night2029-05-29

night of	weather	overall	best window	highest	dark h	Moon	Moon sep.
2029-04-30 Mon	—	unknown	—	72.5° 14:35	6.41	91%	164.2°
2029-05-01 Tue	—	unknown	—	72.5° 14:30	6.35	84%	150.1°
2029-05-02 Wed	—	unknown	—	72.5° 14:25	6.29	75%	136.4°
2029-05-03 Thu	—	unknown	—	72.5° 14:25	6.23	65%	123.1°
2029-05-04 Fri	—	unknown	—	72.5° 14:20	6.17	55%	110.3°
2029-05-05 Sat	—	unknown	—	72.5° 14:15	6.12	45%	97.8°
2029-05-06 Sun	—	unknown	—	72.5° 14:10	6.06	35%	85.7°
2029-05-07 Mon	—	unknown	—	72.5° 14:05	6.0	26%	73.7°
2029-05-08 Tue	—	unknown	—	72.5° 14:05	5.95	19%	61.8°
2029-05-09 Wed	—	unknown	—	72.5° 14:00	5.89	12%	50.0°
2029-05-10 Thu	—	unknown	—	72.5° 13:55	5.83	6%	38.2°
2029-05-11 Fri	—	unknown	—	72.5° 13:50	5.78	3%	26.3°
2029-05-12 Sat	—	unknown	—	72.5° 13:45	5.72	0%	14.4°
2029-05-13 Sun	—	unknown	—	72.5° 13:45	5.67	0%	2.6°
2029-05-14 Mon	—	unknown	—	72.5° 13:40	5.62	2%	10.0°
2029-05-15 Tue	—	unknown	—	72.5° 13:35	5.56	5%	22.3°
2029-05-16 Wed	—	unknown	—	72.5° 13:30	5.51	11%	34.9°
2029-05-17 Thu	—	unknown	—	72.5° 13:30	5.46	18%	47.7°
2029-05-18 Fri	—	unknown	—	72.5° 13:25	5.41	26%	60.7°
2029-05-19 Sat	—	unknown	—	72.5° 13:20	5.36	36%	74.0°
2029-05-20 Sun	—	unknown	—	72.5° 13:15	5.31	47%	87.5°
2029-05-21 Mon	—	unknown	—	72.5° 13:10	5.26	58%	101.4°
2029-05-22 Tue	—	unknown	—	72.5° 13:10	5.21	70%	115.6°
2029-05-23 Wed	—	unknown	—	72.5° 13:05	5.16	80%	130.1°
2029-05-24 Thu	—	unknown	—	72.5° 13:00	5.11	88%	144.8°
2029-05-25 Fri	—	unknown	—	72.5° 12:55	5.07	95%	159.7°
2029-05-26 Sat	—	unknown	—	72.5° 12:50	5.03	99%	174.5°
2029-05-27 Sun	—	unknown	—	72.5° 12:50	4.98	100%	170.6°
2029-05-28 Mon	—	unknown	—	72.5° 12:45	4.94	98%	156.1°
2029-05-29 Tue	—	unknown	—	72.5° 12:40	4.9	94%	142.0°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2029-04-30&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.