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 Triangulum Pinwheel: 01-10 (100), 01-11 (100), 01-12 (100), 01-13 (100), 01-14 (100) — by astronomy; check the weather when the night is within four days.

2031-01-03astronomy score per night — click a bar for that night2031-02-01

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2031-01-03 Fri	25	—	unknown	18:45–00:35 (marginal, 5.83 h)	79.1° 19:05	11.43	81%	25.0°
2031-01-04 Sat	23	—	unknown	18:45–00:15 (marginal, 5.5 h)	79.1° 19:00	11.42	88%	34.7°
2031-01-05 Sun	27	—	unknown	18:45–00:10 (marginal, 5.42 h)	79.1° 18:55	11.4	93%	45.4°
2031-01-06 Mon	35	—	unknown	18:50–00:10 (marginal, 5.33 h)	79.1° 18:50	11.39	97%	56.4°
2031-01-07 Tue	48	—	unknown	18:50–19:20 (good, 0.5 h)	79.1° 18:50	11.38	99%	67.6°
2031-01-08 Wed	63	—	unknown	18:50–21:30 (good, 2.67 h)	79.1° 18:45	11.36	100%	79.0°
2031-01-09 Thu	80	—	unknown	18:50–22:40 (good, 3.83 h)	79.1° 18:40	11.34	99%	90.5°
2031-01-10 Fri	100	—	unknown	18:50–23:45 (good, 4.92 h)	79.1° 18:35	11.33	96%	102.2°
2031-01-11 Sat	100	—	unknown	18:50–23:50 (good, 5.0 h)	79.1° 18:35	11.31	91%	113.9°
2031-01-12 Sun	100	—	unknown	18:55–23:50 (good, 4.92 h)	79.1° 18:30	11.29	84%	125.7°
2031-01-13 Mon	100	—	unknown	18:55–23:50 (good, 4.92 h)	79.1° 18:25	11.27	76%	137.4°
2031-01-14 Tue	100	—	unknown	18:55–23:50 (good, 4.92 h)	79.1° 18:20	11.25	67%	148.7°
2031-01-15 Wed	100	—	unknown	18:55–23:50 (good, 4.92 h)	79.1° 18:15	11.23	56%	158.6°
2031-01-16 Thu	100	—	unknown	18:55–23:45 (good, 4.83 h)	79.1° 18:15	11.21	46%	163.5°
2031-01-17 Fri	100	—	unknown	19:00–23:40 (good, 4.67 h)	79.1° 18:10	11.19	35%	158.7°
2031-01-18 Sat	100	—	unknown	19:00–23:35 (good, 4.58 h)	79.1° 18:05	11.16	24%	147.9°
2031-01-19 Sun	100	—	unknown	19:00–23:35 (good, 4.58 h)	79.1° 18:00	11.14	15%	135.0°
2031-01-20 Mon	100	—	unknown	19:00–23:30 (good, 4.5 h)	79.1° 17:55	11.11	7%	121.1°
2031-01-21 Tue	100	—	unknown	19:00–23:25 (good, 4.42 h)	79.1° 17:55	11.09	2%	106.8°
2031-01-22 Wed	100	—	unknown	19:05–23:20 (good, 4.25 h)	79.1° 17:50	11.06	0%	92.4°
2031-01-23 Thu	100	—	unknown	19:05–23:20 (good, 4.25 h)	79.1° 17:45	11.03	1%	78.2°
2031-01-24 Fri	100	—	unknown	19:05–23:15 (good, 4.17 h)	79.1° 17:40	11.01	4%	64.2°
2031-01-25 Sat	96	—	unknown	19:05–23:10 (good, 4.08 h)	79.1° 17:40	10.98	10%	50.9°
2031-01-26 Sun	90	—	unknown	19:05–23:05 (good, 4.0 h)	79.1° 17:35	10.95	18%	38.3°
2031-01-27 Mon	74	—	unknown	19:10–23:00 (good, 3.83 h)	79.1° 17:30	10.92	27%	27.1°
2031-01-28 Tue	59	—	unknown	19:10–22:40 (good, 3.5 h)	79.1° 17:25	10.89	36%	18.8°
2031-01-29 Wed	45	—	unknown	19:10–22:00 (good, 2.83 h)	79.1° 17:20	10.86	46%	17.0°
2031-01-30 Thu	34	—	unknown	19:10–23:10 (marginal, 4.0 h)	79.1° 17:20	10.83	56%	22.8°
2031-01-31 Fri	25	—	unknown	19:15–23:00 (marginal, 3.75 h)	79.1° 17:15	10.8	65%	32.0°
2031-02-01 Sat	23	—	unknown	19:15–22:50 (marginal, 3.58 h)	79.1° 17:10	10.76	74%	42.4°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2031-01-03&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.