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.

2029-05-18astronomy score per night — click a bar for that night2029-06-16

night of	weather	overall	best window	highest	dark h	Moon	Moon sep.
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°
2029-05-30 Wed	—	unknown	—	72.5° 12:35	4.86	88%	128.2°
2029-05-31 Thu	—	unknown	—	72.5° 12:35	4.82	80%	114.9°
2029-06-01 Fri	—	unknown	—	72.5° 12:30	4.79	70%	102.0°
2029-06-02 Sat	—	unknown	—	72.5° 12:25	4.75	61%	89.5°
2029-06-03 Sun	—	unknown	—	72.5° 12:20	4.72	51%	77.3°
2029-06-04 Mon	—	unknown	—	72.5° 12:15	4.68	42%	65.3°
2029-06-05 Tue	—	unknown	—	72.5° 12:15	4.65	32%	53.4°
2029-06-06 Wed	—	unknown	—	72.5° 12:10	4.63	24%	41.6°
2029-06-07 Thu	—	unknown	—	72.5° 12:05	4.6	16%	29.7°
2029-06-08 Fri	—	unknown	—	72.5° 12:00	4.57	10%	17.8°
2029-06-09 Sat	—	unknown	—	72.5° 11:55	4.55	5%	5.8°
2029-06-10 Sun	—	unknown	—	72.5° 11:50	4.53	2%	6.6°
2029-06-11 Mon	—	unknown	—	72.5° 11:45	4.51	0%	19.0°
2029-06-12 Tue	—	unknown	—	72.5° 11:40	4.49	1%	31.7°
2029-06-13 Wed	—	unknown	—	72.5° 11:35	4.48	3%	44.5°
2029-06-14 Thu	—	unknown	—	72.5° 11:35	4.46	8%	57.6°
2029-06-15 Fri	—	unknown	—	72.5° 11:30	4.45	15%	71.0°
2029-06-16 Sat	—	unknown	—	72.5° 11:25	4.44	24%	84.5°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2029-05-18&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.