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: 01-17 (100), 01-18 (100), 01-19 (100), 01-20 (100), 01-21 (100) — by astronomy; check the weather when the night is within four days.

2031-01-17astronomy score per night — click a bar for that night2031-02-15

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
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°
2031-02-02 Sun	23	—	unknown	19:15–22:40 (marginal, 3.42 h)	79.1° 17:05	10.73	82%	53.3°
2031-02-03 Mon	26	—	unknown	19:15–22:40 (marginal, 3.42 h)	79.1° 17:00	10.7	88%	64.5°
2031-02-04 Tue	32	—	unknown	19:15–19:40 (good, 0.42 h)	79.1° 17:00	10.66	94%	75.8°
2031-02-05 Wed	38	—	unknown	19:20–20:40 (good, 1.33 h)	79.1° 16:55	10.63	97%	87.4°
2031-02-06 Thu	47	—	unknown	19:20–21:40 (good, 2.33 h)	79.1° 16:50	10.59	100%	99.0°
2031-02-07 Fri	56	—	unknown	19:20–22:00 (good, 2.67 h)	79.1° 16:45	10.56	100%	110.9°
2031-02-08 Sat	63	—	unknown	19:20–22:05 (good, 2.75 h)	79.1° 16:45	10.52	98%	122.7°
2031-02-09 Sun	68	—	unknown	19:25–22:00 (good, 2.58 h)	79.1° 16:40	10.48	94%	134.6°
2031-02-10 Mon	68	—	unknown	19:25–22:00 (good, 2.58 h)	79.1° 16:35	10.45	88%	146.1°
2031-02-11 Tue	67	—	unknown	19:25–22:05 (good, 2.67 h)	79.1° 16:30	10.41	81%	156.5°
2031-02-12 Wed	66	—	unknown	19:25–22:00 (good, 2.58 h)	79.1° 16:25	10.37	72%	162.9°
2031-02-13 Thu	63	—	unknown	19:25–21:55 (good, 2.5 h)	79.1° 16:25	10.33	61%	160.4°
2031-02-14 Fri	60	—	unknown	19:30–21:50 (good, 2.33 h)	79.1° 16:20	10.29	50%	151.0°
2031-02-15 Sat	57	—	unknown	19:30–21:45 (good, 2.25 h)	79.1° 16:15	10.25	39%	138.9°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2031-01-17&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.