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 North America Nebula: 12-14 (92), 12-13 (91), 12-15 (91), 12-12 (89), 12-16 (89) — by astronomy; check the weather when the night is within four days.

2030-12-11astronomy score per night — click a bar for that night2031-01-09

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2030-12-11 Wed	74	—	unknown	18:35–21:55 (good, 3.33 h)	87.2° 16:00	11.46	96%	109.1°
2030-12-12 Thu	89	—	unknown	18:35–22:00 (good, 3.42 h)	87.2° 15:55	11.47	92%	115.2°
2030-12-13 Fri	91	—	unknown	18:35–22:00 (good, 3.42 h)	87.2° 15:50	11.48	86%	120.6°
2030-12-14 Sat	92	—	unknown	18:35–22:00 (good, 3.42 h)	87.2° 15:50	11.49	79%	124.7°
2030-12-15 Sun	91	—	unknown	18:35–22:05 (good, 3.5 h)	87.2° 15:45	11.49	70%	127.2°
2030-12-16 Mon	89	—	unknown	18:35–22:00 (good, 3.42 h)	87.2° 15:40	11.5	61%	127.7°
2030-12-17 Tue	87	—	unknown	18:35–21:55 (good, 3.33 h)	87.2° 15:35	11.5	51%	126.1°
2030-12-18 Wed	85	—	unknown	18:35–21:50 (good, 3.25 h)	87.2° 15:30	11.5	40%	122.4°
2030-12-19 Thu	84	—	unknown	18:35–21:50 (good, 3.25 h)	87.2° 15:30	11.51	30%	116.7°
2030-12-20 Fri	81	—	unknown	18:35–21:45 (good, 3.17 h)	87.2° 15:25	11.51	20%	109.5°
2030-12-21 Sat	78	—	unknown	18:35–21:40 (good, 3.08 h)	87.2° 15:20	11.51	11%	101.2°
2030-12-22 Sun	76	—	unknown	18:35–21:35 (good, 3.0 h)	87.2° 15:15	11.51	5%	92.2°
2030-12-23 Mon	74	—	unknown	18:40–21:30 (good, 2.83 h)	87.2° 15:10	11.51	1%	82.9°
2030-12-24 Tue	72	—	unknown	18:40–21:30 (good, 2.83 h)	87.2° 15:10	11.5	0%	73.9°
2030-12-25 Wed	70	—	unknown	18:40–21:25 (good, 2.75 h)	87.2° 15:05	11.5	2%	65.8°
2030-12-26 Thu	65	—	unknown	18:40–21:20 (good, 2.67 h)	87.2° 15:00	11.5	7%	59.1°
2030-12-27 Fri	59	—	unknown	18:40–21:15 (good, 2.58 h)	87.2° 14:55	11.49	14%	54.5°
2030-12-28 Sat	52	—	unknown	18:40–21:05 (good, 2.42 h)	87.2° 14:55	11.48	23%	52.4°
2030-12-29 Sun	43	—	unknown	18:40–20:50 (good, 2.17 h)	87.2° 14:50	11.48	33%	52.9°
2030-12-30 Mon	36	—	unknown	18:40–20:40 (good, 2.0 h)	87.2° 14:45	11.47	44%	55.6°
2030-12-31 Tue	29	—	unknown	18:45–20:00 (good, 1.25 h)	87.2° 14:40	11.46	54%	60.0°
2031-01-01 Wed	25	—	unknown	18:45–19:00 (good, 0.25 h)	87.2° 14:35	11.45	64%	65.7°
2031-01-02 Thu	23	—	unknown	18:45–21:20 (marginal, 2.58 h)	87.2° 14:35	11.44	72%	72.1°
2031-01-03 Fri	23	—	unknown	18:45–21:15 (marginal, 2.5 h)	87.2° 14:30	11.43	81%	79.0°
2031-01-04 Sat	23	—	unknown	18:45–19:00 (good, 0.25 h)	87.2° 14:25	11.42	88%	86.2°
2031-01-05 Sun	25	—	unknown	18:45–19:30 (good, 0.75 h)	87.2° 14:20	11.4	93%	93.4°
2031-01-06 Mon	26	—	unknown	18:50–20:00 (good, 1.17 h)	87.2° 14:15	11.39	97%	100.6°
2031-01-07 Tue	29	—	unknown	18:50–20:10 (good, 1.33 h)	87.2° 14:15	11.38	99%	107.4°
2031-01-08 Wed	32	—	unknown	18:50–20:10 (good, 1.33 h)	87.2° 14:10	11.36	100%	113.8°
2031-01-09 Thu	34	—	unknown	18:50–20:15 (good, 1.42 h)	87.2° 14:05	11.34	99%	119.3°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2030-12-11&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.