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: 01-29 (91), 01-27 (90), 01-28 (90), 01-30 (90), 01-31 (86) — by astronomy; check the weather when the night is within four days.

2043-01-18astronomy score per night — click a bar for that night2043-02-16

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2043-01-18 Sun	42	—	unknown	19:00–23:55 (marginal, 4.92 h)	89.8° 17:15	11.16	56%	32.2°
2043-01-19 Mon	31	—	unknown	19:00–23:35 (marginal, 4.58 h)	89.8° 17:10	11.14	67%	36.7°
2043-01-20 Tue	26	—	unknown	19:00–23:20 (marginal, 4.33 h)	89.6° 17:05	11.11	78%	44.9°
2043-01-21 Wed	26	—	unknown	19:00–23:10 (marginal, 4.17 h)	89.5° 17:05	11.09	86%	55.1°
2043-01-22 Thu	31	—	unknown	19:05–23:10 (marginal, 4.08 h)	89.7° 17:00	11.06	93%	66.3°
2043-01-23 Fri	40	—	unknown	19:05–19:55 (good, 0.83 h)	89.8° 16:55	11.03	98%	77.9°
2043-01-24 Sat	51	—	unknown	19:05–21:05 (good, 2.0 h)	89.8° 16:50	11.0	100%	89.5°
2043-01-25 Sun	64	—	unknown	19:05–22:20 (good, 3.25 h)	89.6° 16:45	10.98	99%	101.0°
2043-01-26 Mon	76	—	unknown	19:05–22:30 (good, 3.42 h)	89.6° 16:45	10.95	97%	112.0°
2043-01-27 Tue	90	—	unknown	19:10–22:35 (good, 3.42 h)	89.7° 16:40	10.92	92%	122.3°
2043-01-28 Wed	90	—	unknown	19:10–22:35 (good, 3.42 h)	89.8° 16:35	10.89	86%	131.7°
2043-01-29 Thu	91	—	unknown	19:10–22:35 (good, 3.42 h)	89.7° 16:30	10.86	79%	139.7°
2043-01-30 Fri	90	—	unknown	19:10–22:35 (good, 3.42 h)	89.5° 16:25	10.83	70%	145.6°
2043-01-31 Sat	86	—	unknown	19:15–22:30 (good, 3.25 h)	89.6° 16:25	10.79	62%	148.2°
2043-02-01 Sun	84	—	unknown	19:15–22:30 (good, 3.25 h)	89.8° 16:20	10.76	52%	147.0°
2043-02-02 Mon	82	—	unknown	19:15–22:25 (good, 3.17 h)	89.8° 16:15	10.73	43%	142.4°
2043-02-03 Tue	79	—	unknown	19:15–22:20 (good, 3.08 h)	89.7° 16:10	10.69	34%	135.3°
2043-02-04 Wed	77	—	unknown	19:15–22:15 (good, 3.0 h)	89.5° 16:10	10.66	25%	126.6°
2043-02-05 Thu	73	—	unknown	19:20–22:15 (good, 2.92 h)	89.7° 16:05	10.63	17%	116.9°
2043-02-06 Fri	71	—	unknown	19:20–22:10 (good, 2.83 h)	89.8° 16:00	10.59	10%	106.4°
2043-02-07 Sat	69	—	unknown	19:20–22:05 (good, 2.75 h)	89.8° 15:55	10.55	5%	95.4°
2043-02-08 Sun	67	—	unknown	19:20–22:00 (good, 2.67 h)	89.6° 15:50	10.52	1%	84.0°
2043-02-09 Mon	64	—	unknown	19:25–21:55 (good, 2.5 h)	89.6° 15:50	10.48	0%	72.4°
2043-02-10 Tue	62	—	unknown	19:25–21:55 (good, 2.5 h)	89.7° 15:45	10.44	2%	60.9°
2043-02-11 Wed	58	—	unknown	19:25–21:50 (good, 2.42 h)	89.8° 15:40	10.41	5%	50.0°
2043-02-12 Thu	53	—	unknown	19:25–21:45 (good, 2.33 h)	89.7° 15:35	10.37	12%	40.4°
2043-02-13 Fri	44	—	unknown	19:30–21:30 (good, 2.0 h)	89.5° 15:30	10.33	20%	33.7°
2043-02-14 Sat	35	—	unknown	19:30–21:20 (good, 1.83 h)	89.6° 15:30	10.29	30%	31.6°
2043-02-15 Sun	26	—	unknown	19:30–20:50 (good, 1.33 h)	89.8° 15:25	10.25	41%	35.1°
2043-02-16 Mon	21	—	unknown	19:30–21:55 (marginal, 2.42 h)	89.8° 15:20	10.21	53%	42.7°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2043-01-18&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.