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: 10-24 (100), 10-25 (100), 10-26 (100), 10-27 (100), 10-28 (100) — by astronomy; check the weather when the night is within four days.

2040-10-20astronomy score per night — click a bar for that night2040-11-18

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2040-10-20 Sat	46	—	unknown	20:05–01:10 (marginal, 5.08 h)	89.7° 00:05	10.06	99%	36.0°
2040-10-21 Sun	55	—	unknown	20:05–05:50 (marginal, 9.75 h)	89.5° 00:00	10.1	97%	39.8°
2040-10-22 Mon	62	—	unknown	20:05–21:30 (good, 1.42 h)	89.6° 00:00	10.14	92%	46.5°
2040-10-23 Tue	94	—	unknown	20:05–23:30 (good, 3.42 h)	89.8° 23:55	10.18	86%	54.8°
2040-10-24 Wed	100	—	unknown	20:00–02:35 (good, 6.58 h)	89.8° 23:50	10.22	78%	63.8°
2040-10-25 Thu	100	—	unknown	20:00–04:05 (good, 8.08 h)	89.6° 23:45	10.26	69%	73.2°
2040-10-26 Fri	100	—	unknown	20:00–05:20 (good, 9.33 h)	89.5° 23:45	10.3	60%	82.8°
2040-10-27 Sat	100	—	unknown	19:55–04:30 (good, 9.58 h)	89.7° 23:40	10.34	51%	92.4°
2040-10-28 Sun	100	—	unknown	18:55–04:35 (good, 9.67 h)	89.8° 22:35	10.38	42%	102.0°
2040-10-29 Mon	100	—	unknown	18:55–04:35 (good, 9.67 h)	89.7° 22:30	10.41	32%	111.5°
2040-10-30 Tue	100	—	unknown	18:55–04:35 (good, 9.67 h)	89.6° 22:25	10.45	24%	120.7°
2040-10-31 Wed	100	—	unknown	18:55–04:30 (good, 9.58 h)	89.6° 22:25	10.49	16%	129.3°
2040-11-01 Thu	100	—	unknown	18:50–04:25 (good, 9.58 h)	89.7° 22:20	10.52	9%	136.8°
2040-11-02 Fri	100	—	unknown	18:50–04:25 (good, 9.58 h)	89.8° 22:15	10.56	4%	142.3°
2040-11-03 Sat	100	—	unknown	18:50–04:20 (good, 9.5 h)	89.7° 22:10	10.59	1%	144.4°
2040-11-04 Sun	100	—	unknown	18:50–04:15 (good, 9.42 h)	89.5° 22:05	10.63	0%	142.2°
2040-11-05 Mon	100	—	unknown	18:45–04:10 (good, 9.42 h)	89.6° 22:05	10.66	2%	136.2°
2040-11-06 Tue	100	—	unknown	18:45–04:10 (good, 9.42 h)	89.8° 22:00	10.7	6%	127.5°
2040-11-07 Wed	100	—	unknown	18:45–04:05 (good, 9.33 h)	89.8° 21:55	10.73	12%	117.2°
2040-11-08 Thu	100	—	unknown	18:45–04:00 (good, 9.25 h)	89.6° 21:50	10.76	21%	106.1°
2040-11-09 Fri	100	—	unknown	18:45–03:55 (good, 9.17 h)	89.5° 21:50	10.8	31%	94.6°
2040-11-10 Sat	100	—	unknown	18:45–03:55 (good, 9.17 h)	89.7° 21:45	10.83	42%	83.1°
2040-11-11 Sun	100	—	unknown	18:40–03:50 (good, 9.17 h)	89.8° 21:40	10.86	53%	71.7°
2040-11-12 Mon	97	—	unknown	18:40–03:45 (good, 9.08 h)	89.7° 21:35	10.89	64%	60.9°
2040-11-13 Tue	87	—	unknown	18:40–03:40 (good, 9.0 h)	89.6° 21:30	10.92	75%	51.1°
2040-11-14 Wed	75	—	unknown	03:10–03:35 (good, 0.42 h)	89.6° 21:30	10.95	84%	42.9°
2040-11-15 Thu	47	—	unknown	18:40–03:55 (marginal, 9.25 h)	89.7° 21:25	10.98	91%	37.3°
2040-11-16 Fri	39	—	unknown	18:40–03:30 (marginal, 8.83 h)	89.8° 21:20	11.0	96%	35.6°
2040-11-17 Sat	39	—	unknown	18:40–00:35 (marginal, 5.92 h)	89.7° 21:15	11.03	99%	38.1°
2040-11-18 Sun	47	—	unknown	18:35–01:20 (marginal, 6.75 h)	89.5° 21:10	11.06	100%	43.9°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2040-10-20&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.