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: 12-05 (100), 12-06 (100), 12-07 (100), 12-08 (100), 12-09 (100) — by astronomy; check the weather when the night is within four days.

2031-12-05astronomy score per night — click a bar for that night2032-01-03

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2031-12-05 Fri	100	—	unknown	18:35–04:00 (good, 9.42 h)	72.5° 23:10	11.39	62%	90.8°
2031-12-06 Sat	100	—	unknown	18:35–04:05 (good, 9.5 h)	72.5° 23:10	11.4	52%	102.7°
2031-12-07 Sun	100	—	unknown	18:35–04:10 (good, 9.58 h)	72.5° 23:05	11.42	42%	114.9°
2031-12-08 Mon	100	—	unknown	18:35–04:05 (good, 9.5 h)	72.5° 23:00	11.43	33%	127.3°
2031-12-09 Tue	100	—	unknown	18:35–04:05 (good, 9.5 h)	72.5° 22:55	11.44	23%	140.1°
2031-12-10 Wed	100	—	unknown	18:35–04:05 (good, 9.5 h)	72.5° 22:50	11.45	15%	153.2°
2031-12-11 Thu	100	—	unknown	18:35–04:00 (good, 9.42 h)	72.5° 22:50	11.46	8%	166.5°
2031-12-12 Fri	100	—	unknown	18:35–03:55 (good, 9.33 h)	72.5° 22:45	11.47	3%	174.7°
2031-12-13 Sat	100	—	unknown	18:35–03:50 (good, 9.25 h)	72.5° 22:40	11.48	0%	163.0°
2031-12-14 Sun	100	—	unknown	18:35–03:45 (good, 9.17 h)	72.5° 22:35	11.48	0%	148.6°
2031-12-15 Mon	100	—	unknown	18:35–03:45 (good, 9.17 h)	72.5° 22:30	11.49	4%	133.7°
2031-12-16 Tue	100	—	unknown	18:35–03:40 (good, 9.08 h)	72.5° 22:30	11.5	10%	118.9°
2031-12-17 Wed	100	—	unknown	18:35–03:35 (good, 9.0 h)	72.5° 22:25	11.5	18%	104.1°
2031-12-18 Thu	100	—	unknown	18:35–03:30 (good, 8.92 h)	72.5° 22:20	11.5	27%	89.6°
2031-12-19 Fri	100	—	unknown	18:35–03:25 (good, 8.83 h)	72.5° 22:15	11.51	38%	75.5°
2031-12-20 Sat	99	—	unknown	18:35–03:25 (good, 8.83 h)	72.5° 22:10	11.51	49%	61.6°
2031-12-21 Sun	91	—	unknown	19:25–03:20 (good, 7.92 h)	72.5° 22:10	11.51	60%	48.2°
2031-12-22 Mon	82	—	unknown	23:40–03:15 (good, 3.58 h)	72.5° 22:05	11.51	70%	35.1°
2031-12-23 Tue	51	—	unknown	18:40–03:40 (marginal, 9.0 h)	72.5° 22:00	11.51	79%	22.4°
2031-12-24 Wed	37	—	unknown	18:40–03:20 (marginal, 8.67 h)	72.5° 21:55	11.5	87%	10.5°
2031-12-25 Thu	26	—	unknown	23:20–02:55 (marginal, 3.58 h)	72.5° 21:55	11.5	93%	6.1°
2031-12-26 Fri	23	—	unknown	18:40–20:35 (marginal, 1.92 h)	72.5° 21:50	11.5	97%	16.5°
2031-12-27 Sat	25	—	unknown	18:40–21:00 (marginal, 2.33 h)	72.5° 21:45	11.49	99%	28.3°
2031-12-28 Sun	39	—	unknown	18:40–23:55 (marginal, 5.25 h)	72.5° 21:40	11.49	100%	40.2°
2031-12-29 Mon	60	—	unknown	18:40–19:10 (good, 0.5 h)	72.5° 21:35	11.48	98%	52.1°
2031-12-30 Tue	96	—	unknown	18:40–21:50 (good, 3.17 h)	72.5° 21:35	11.47	96%	63.9°
2031-12-31 Wed	100	—	unknown	18:45–00:15 (good, 5.5 h)	72.5° 21:30	11.46	91%	75.7°
2032-01-01 Thu	100	—	unknown	18:45–01:35 (good, 6.83 h)	72.5° 21:25	11.45	85%	87.4°
2032-01-02 Fri	100	—	unknown	18:45–02:10 (good, 7.42 h)	72.5° 21:20	11.44	77%	99.2°
2032-01-03 Sat	100	—	unknown	18:45–02:15 (good, 7.5 h)	72.5° 21:15	11.43	69%	111.2°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2031-12-05&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.