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.

2029-05-12astronomy score per night — click a bar for that night2029-06-10

night of	weather	overall	best window	highest	dark h	Moon	Moon sep.
2029-05-12 Sat	—	unknown	—	42.9° 15:35	5.72	0%	48.7°
2029-05-13 Sun	—	unknown	—	42.9° 15:30	5.67	0%	40.2°
2029-05-14 Mon	—	unknown	—	42.9° 15:30	5.62	2%	33.5°
2029-05-15 Tue	—	unknown	—	42.9° 15:25	5.56	5%	29.9°
2029-05-16 Wed	—	unknown	—	42.9° 15:20	5.51	11%	30.7°
2029-05-17 Thu	—	unknown	—	42.9° 15:15	5.46	18%	36.0°
2029-05-18 Fri	—	unknown	—	42.9° 15:10	5.41	26%	44.2°
2029-05-19 Sat	—	unknown	—	42.9° 15:10	5.36	36%	54.2°
2029-05-20 Sun	—	unknown	—	42.9° 15:05	5.31	47%	65.3°
2029-05-21 Mon	—	unknown	—	42.9° 15:00	5.26	58%	77.1°
2029-05-22 Tue	—	unknown	—	42.9° 14:55	5.21	70%	89.4°
2029-05-23 Wed	—	unknown	—	42.9° 14:50	5.16	80%	102.0°
2029-05-24 Thu	—	unknown	—	42.9° 14:50	5.11	88%	114.6°
2029-05-25 Fri	—	unknown	—	42.9° 14:45	5.07	95%	126.7°
2029-05-26 Sat	—	unknown	—	42.9° 14:40	5.03	99%	137.7°
2029-05-27 Sun	—	unknown	—	42.9° 14:35	4.98	100%	146.3°
2029-05-28 Mon	—	unknown	—	42.9° 14:35	4.94	98%	150.3°
2029-05-29 Tue	—	unknown	—	42.9° 14:30	4.9	94%	148.4°
2029-05-30 Wed	—	unknown	—	42.9° 14:25	4.86	88%	141.7°
2029-05-31 Thu	—	unknown	—	42.9° 14:20	4.82	80%	132.7°
2029-06-01 Fri	—	unknown	—	42.9° 14:15	4.79	70%	122.6°
2029-06-02 Sat	—	unknown	—	42.9° 14:15	4.75	61%	112.2°
2029-06-03 Sun	—	unknown	—	42.9° 14:10	4.72	51%	101.8°
2029-06-04 Mon	—	unknown	—	42.9° 14:05	4.68	42%	91.4°
2029-06-05 Tue	—	unknown	—	42.9° 14:00	4.65	32%	81.1°
2029-06-06 Wed	—	unknown	—	42.9° 13:55	4.63	24%	70.9°
2029-06-07 Thu	—	unknown	—	42.9° 13:55	4.6	16%	60.9°
2029-06-08 Fri	—	unknown	—	42.9° 13:50	4.57	10%	51.4°
2029-06-09 Sat	—	unknown	—	42.9° 13:45	4.55	5%	42.5°
2029-06-10 Sun	—	unknown	—	42.9° 13:40	4.53	2%	35.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2029-05-12&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.