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: 12-18 (100), 12-19 (100), 12-31 (100), 01-01 (100), 01-02 (100) — by astronomy; check the weather when the night is within four days.

2031-12-18astronomy score per night — click a bar for that night2032-01-16

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
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°
2032-01-04 Sun	100	—	unknown	18:45–02:20 (good, 7.58 h)	72.5° 21:15	11.42	60%	123.3°
2032-01-05 Mon	100	—	unknown	18:45–02:15 (good, 7.5 h)	72.5° 21:10	11.41	50%	135.6°
2032-01-06 Tue	100	—	unknown	18:45–02:15 (good, 7.5 h)	72.5° 21:05	11.39	40%	148.2°
2032-01-07 Wed	100	—	unknown	18:50–02:15 (good, 7.42 h)	72.5° 21:00	11.38	30%	161.1°
2032-01-08 Thu	100	—	unknown	18:50–02:10 (good, 7.33 h)	72.5° 21:00	11.36	20%	173.1°
2032-01-09 Fri	100	—	unknown	18:50–02:05 (good, 7.25 h)	72.5° 20:55	11.35	12%	169.1°
2032-01-10 Sat	100	—	unknown	18:50–02:00 (good, 7.17 h)	72.5° 20:50	11.33	5%	155.2°
2032-01-11 Sun	100	—	unknown	18:50–01:55 (good, 7.08 h)	72.5° 20:45	11.31	1%	140.5°
2032-01-12 Mon	100	—	unknown	18:55–01:55 (good, 7.0 h)	72.5° 20:40	11.3	0%	125.4°
2032-01-13 Tue	100	—	unknown	18:55–01:50 (good, 6.92 h)	72.5° 20:40	11.28	2%	110.2°
2032-01-14 Wed	100	—	unknown	18:55–01:45 (good, 6.83 h)	72.5° 20:35	11.26	7%	95.1°
2032-01-15 Thu	100	—	unknown	18:55–01:40 (good, 6.75 h)	72.5° 20:30	11.23	14%	80.3°
2032-01-16 Fri	100	—	unknown	18:55–01:35 (good, 6.67 h)	72.5° 20:25	11.21	23%	65.9°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2031-12-18&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.