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 Andromeda Galaxy: 01-25 (95), 01-26 (84), 01-27 (69), 02-09 (60), 02-10 (60) — by astronomy; check the weather when the night is within four days.

2031-01-25astronomy score per night — click a bar for that night2031-02-23

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2031-01-25 Sat	95	—	unknown	19:05–22:55 (good, 3.83 h)	89.6° 16:45	10.98	10%	50.3°
2031-01-26 Sun	84	—	unknown	19:05–22:50 (good, 3.75 h)	89.5° 16:45	10.95	18%	40.6°
2031-01-27 Mon	69	—	unknown	19:10–22:35 (good, 3.42 h)	89.7° 16:40	10.92	27%	33.5°
2031-01-28 Tue	55	—	unknown	19:10–22:20 (good, 3.17 h)	89.7° 16:35	10.89	36%	30.3°
2031-01-29 Wed	43	—	unknown	19:10–21:25 (good, 2.25 h)	89.7° 16:30	10.86	46%	31.7°
2031-01-30 Thu	34	—	unknown	19:10–23:05 (marginal, 3.92 h)	89.6° 16:25	10.83	56%	36.9°
2031-01-31 Fri	28	—	unknown	19:15–22:50 (marginal, 3.58 h)	89.6° 16:25	10.8	65%	44.4°
2031-02-01 Sat	25	—	unknown	19:15–22:40 (marginal, 3.42 h)	89.7° 16:20	10.76	74%	53.2°
2031-02-02 Sun	25	—	unknown	19:15–22:35 (marginal, 3.33 h)	89.7° 16:15	10.73	82%	62.7°
2031-02-03 Mon	28	—	unknown	19:15–22:35 (marginal, 3.33 h)	89.7° 16:10	10.7	88%	72.6°
2031-02-04 Tue	33	—	unknown	19:15–19:55 (good, 0.67 h)	89.5° 16:05	10.66	94%	82.8°
2031-02-05 Wed	38	—	unknown	19:20–20:50 (good, 1.5 h)	89.6° 16:05	10.63	97%	93.2°
2031-02-06 Thu	45	—	unknown	19:20–21:40 (good, 2.33 h)	89.7° 16:00	10.59	100%	103.7°
2031-02-07 Fri	51	—	unknown	19:20–21:45 (good, 2.42 h)	89.7° 15:55	10.56	100%	114.2°
2031-02-08 Sat	56	—	unknown	19:20–21:50 (good, 2.5 h)	89.6° 15:50	10.52	98%	124.4°
2031-02-09 Sun	60	—	unknown	19:25–21:45 (good, 2.33 h)	89.5° 15:50	10.48	94%	134.0°
2031-02-10 Mon	60	—	unknown	19:25–21:45 (good, 2.33 h)	89.7° 15:45	10.45	88%	142.4°
2031-02-11 Tue	59	—	unknown	19:25–21:50 (good, 2.42 h)	89.7° 15:40	10.41	81%	148.1°
2031-02-12 Wed	58	—	unknown	19:25–21:45 (good, 2.33 h)	89.7° 15:35	10.37	72%	149.5°
2031-02-13 Thu	56	—	unknown	19:25–21:40 (good, 2.25 h)	89.6° 15:30	10.33	61%	145.8°
2031-02-14 Fri	53	—	unknown	19:30–21:35 (good, 2.08 h)	89.5° 15:30	10.29	50%	138.1°
2031-02-15 Sat	50	—	unknown	19:30–21:35 (good, 2.08 h)	89.7° 15:25	10.25	39%	128.0°
2031-02-16 Sun	49	—	unknown	19:30–21:30 (good, 2.0 h)	89.7° 15:20	10.21	28%	116.5°
2031-02-17 Mon	48	—	unknown	19:30–21:25 (good, 1.92 h)	89.7° 15:15	10.17	18%	104.3°
2031-02-18 Tue	45	—	unknown	19:35–21:20 (good, 1.75 h)	89.5° 15:10	10.13	10%	91.8°
2031-02-19 Wed	43	—	unknown	19:35–21:15 (good, 1.67 h)	89.6° 15:10	10.09	4%	79.2°
2031-02-20 Thu	41	—	unknown	19:35–21:15 (good, 1.67 h)	89.7° 15:05	10.05	1%	66.8°
2031-02-21 Fri	39	—	unknown	19:35–21:10 (good, 1.58 h)	89.7° 15:00	10.01	0%	55.2°
2031-02-22 Sat	37	—	unknown	19:40–21:05 (good, 1.42 h)	89.6° 14:55	9.96	2%	44.7°
2031-02-23 Sun	34	—	unknown	19:40–21:00 (good, 1.33 h)	89.5° 14:55	9.92	7%	36.2°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2031-01-25&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.