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.

Best nights for Seven Sisters: 12-24 (100), 12-25 (100), 12-26 (100), 12-27 (100), 12-28 (100) — by astronomy; check the weather when the night is within four days.

2029-12-17astronomy score per night — click a bar for that night2030-01-15

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2029-12-17 Mon	31	—	unknown	22:55–03:35 (marginal, 4.67 h)	72.5° 22:20	11.5	92%	6.9°
2029-12-18 Tue	23	—	unknown	18:35–20:10 (marginal, 1.58 h)	72.5° 22:20	11.5	96%	5.6°
2029-12-19 Wed	23	—	unknown	18:35–20:35 (marginal, 2.0 h)	72.5° 22:15	11.51	99%	17.4°
2029-12-20 Thu	27	—	unknown	18:35–21:20 (marginal, 2.75 h)	72.5° 22:10	11.51	100%	29.7°
2029-12-21 Fri	46	—	unknown	18:35–00:50 (marginal, 6.25 h)	72.5° 22:05	11.51	99%	42.1°
2029-12-22 Sat	89	—	unknown	18:35–20:35 (good, 2.0 h)	72.5° 22:05	11.51	96%	54.7°
2029-12-23 Sun	98	—	unknown	18:40–23:30 (good, 4.83 h)	72.5° 22:00	11.51	91%	67.5°
2029-12-24 Mon	100	—	unknown	18:40–01:30 (good, 6.83 h)	72.5° 21:55	11.5	84%	80.5°
2029-12-25 Tue	100	—	unknown	18:40–02:40 (good, 8.0 h)	72.5° 21:50	11.5	76%	93.7°
2029-12-26 Wed	100	—	unknown	18:40–02:45 (good, 8.08 h)	72.5° 21:45	11.49	66%	107.1°
2029-12-27 Thu	100	—	unknown	18:40–02:50 (good, 8.17 h)	72.5° 21:45	11.49	55%	120.8°
2029-12-28 Fri	100	—	unknown	18:40–02:45 (good, 8.08 h)	72.5° 21:40	11.48	44%	134.7°
2029-12-29 Sat	100	—	unknown	18:40–02:45 (good, 8.08 h)	72.5° 21:35	11.48	33%	148.8°
2029-12-30 Sun	100	—	unknown	18:40–02:40 (good, 8.0 h)	72.5° 21:30	11.47	23%	163.2°
2029-12-31 Mon	100	—	unknown	18:45–02:40 (good, 7.92 h)	72.5° 21:25	11.46	14%	177.2°
2030-01-01 Tue	100	—	unknown	18:45–02:35 (good, 7.83 h)	72.5° 21:25	11.45	6%	167.4°
2030-01-02 Wed	100	—	unknown	18:45–02:30 (good, 7.75 h)	72.5° 21:20	11.44	2%	152.8°
2030-01-03 Thu	100	—	unknown	18:45–02:25 (good, 7.67 h)	72.5° 21:15	11.43	0%	138.3°
2030-01-04 Fri	100	—	unknown	18:45–02:20 (good, 7.58 h)	72.5° 21:10	11.42	1%	124.0°
2030-01-05 Sat	100	—	unknown	18:45–02:20 (good, 7.58 h)	72.5° 21:10	11.4	4%	110.1°
2030-01-06 Sun	100	—	unknown	18:50–02:15 (good, 7.42 h)	72.5° 21:05	11.39	10%	96.5°
2030-01-07 Mon	100	—	unknown	18:50–02:10 (good, 7.33 h)	72.5° 21:00	11.37	17%	83.3°
2030-01-08 Tue	100	—	unknown	18:50–02:05 (good, 7.25 h)	72.5° 20:55	11.36	25%	70.6°
2030-01-09 Wed	97	—	unknown	18:50–02:05 (good, 7.25 h)	72.5° 20:50	11.34	34%	58.2°
2030-01-10 Thu	89	—	unknown	18:50–02:00 (good, 7.17 h)	72.5° 20:50	11.32	44%	46.0°
2030-01-11 Fri	81	—	unknown	18:50–01:55 (good, 7.08 h)	72.5° 20:45	11.3	53%	34.1°
2030-01-12 Sat	60	—	unknown	18:55–02:20 (marginal, 7.42 h)	72.5° 20:40	11.29	63%	22.3°
2030-01-13 Sun	45	—	unknown	18:55–02:05 (marginal, 7.17 h)	72.5° 20:35	11.27	71%	10.6°
2030-01-14 Mon	31	—	unknown	18:55–01:50 (marginal, 6.92 h)	72.5° 20:30	11.25	80%	2.4°
2030-01-15 Tue	23	—	unknown	18:55–01:30 (marginal, 6.58 h)	72.5° 20:30	11.22	87%	13.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2029-12-17&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.