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: 11-17 (100), 11-18 (100), 11-19 (100), 11-20 (100), 11-21 (100) — by astronomy; check the weather when the night is within four days.

2030-11-17astronomy score per night — click a bar for that night2030-12-16

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2030-11-17 Sun	100	—	unknown	19:15–05:10 (good, 9.92 h)	72.5° 00:20	11.02	54%	81.3°
2030-11-18 Mon	100	—	unknown	19:10–05:15 (good, 10.08 h)	72.5° 00:15	11.04	44%	93.8°
2030-11-19 Tue	100	—	unknown	19:10–05:20 (good, 10.17 h)	72.5° 00:15	11.07	34%	106.7°
2030-11-20 Wed	100	—	unknown	19:05–05:20 (good, 10.25 h)	72.5° 00:10	11.1	24%	120.0°
2030-11-21 Thu	100	—	unknown	19:00–05:15 (good, 10.25 h)	72.5° 00:05	11.12	16%	133.9°
2030-11-22 Fri	100	—	unknown	18:55–05:10 (good, 10.25 h)	72.5° 00:00	11.14	8%	148.1°
2030-11-23 Sat	100	—	unknown	18:50–05:10 (good, 10.33 h)	72.5° 00:00	11.17	3%	162.7°
2030-11-24 Sun	100	—	unknown	18:50–05:05 (good, 10.25 h)	72.5° 23:55	11.19	0%	176.1°
2030-11-25 Mon	100	—	unknown	18:45–05:00 (good, 10.25 h)	72.5° 23:50	11.21	1%	166.3°
2030-11-26 Tue	100	—	unknown	18:40–04:55 (good, 10.25 h)	72.5° 23:45	11.24	4%	151.3°
2030-11-27 Wed	100	—	unknown	18:35–04:55 (good, 10.33 h)	72.5° 23:40	11.26	10%	136.3°
2030-11-28 Thu	100	—	unknown	18:35–04:50 (good, 10.25 h)	72.5° 23:40	11.28	18%	121.6°
2030-11-29 Fri	100	—	unknown	18:35–04:45 (good, 10.17 h)	72.5° 23:35	11.3	28%	107.3°
2030-11-30 Sat	100	—	unknown	18:35–04:40 (good, 10.08 h)	72.5° 23:30	11.31	39%	93.5°
2030-12-01 Sun	100	—	unknown	18:40–04:35 (good, 9.92 h)	72.5° 23:25	11.33	50%	80.1°
2030-12-02 Mon	100	—	unknown	19:10–04:35 (good, 9.42 h)	72.5° 23:20	11.35	60%	67.0°
2030-12-03 Tue	94	—	unknown	21:00–04:30 (good, 7.5 h)	72.5° 23:20	11.36	70%	54.3°
2030-12-04 Wed	86	—	unknown	00:45–04:25 (good, 3.67 h)	72.5° 23:15	11.38	78%	41.9°
2030-12-05 Thu	66	—	unknown	04:10–04:20 (good, 0.17 h)	72.5° 23:10	11.39	86%	29.7°
2030-12-06 Fri	39	—	unknown	22:25–04:30 (marginal, 6.08 h)	72.5° 23:05	11.41	92%	17.8°
2030-12-07 Sat	28	—	unknown	00:50–04:10 (marginal, 3.33 h)	72.5° 23:05	11.42	96%	6.4°
2030-12-08 Sun	24	—	unknown	18:35–20:20 (marginal, 1.75 h)	72.5° 23:00	11.43	99%	7.3°
2030-12-09 Mon	27	—	unknown	18:35–21:20 (marginal, 2.75 h)	72.5° 22:55	11.44	100%	18.6°
2030-12-10 Tue	34	—	unknown	18:35–22:20 (marginal, 3.75 h)	72.5° 22:50	11.45	99%	30.3°
2030-12-11 Wed	54	—	unknown	18:35–02:20 (marginal, 7.75 h)	72.5° 22:45	11.46	96%	42.1°
2030-12-12 Thu	89	—	unknown	18:35–21:30 (good, 2.92 h)	72.5° 22:45	11.47	92%	54.0°
2030-12-13 Fri	97	—	unknown	18:35–00:35 (good, 6.0 h)	72.5° 22:40	11.48	86%	65.9°
2030-12-14 Sat	100	—	unknown	18:35–02:15 (good, 7.67 h)	72.5° 22:35	11.49	79%	78.0°
2030-12-15 Sun	100	—	unknown	18:35–03:20 (good, 8.75 h)	72.5° 22:30	11.49	70%	90.3°
2030-12-16 Mon	100	—	unknown	18:35–03:25 (good, 8.83 h)	72.5° 22:25	11.5	61%	102.8°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2030-11-17&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.