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: 10-20 (100), 10-21 (100), 10-22 (100), 10-23 (100), 10-24 (100) — by astronomy; check the weather when the night is within four days.

2039-10-20astronomy score per night — click a bar for that night2039-11-18

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2039-10-20 Thu	100	—	unknown	20:10–06:10 (good, 10.0 h)	89.7° 00:10	10.03	13%	128.1°
2039-10-21 Fri	100	—	unknown	20:05–06:10 (good, 10.08 h)	89.8° 00:05	10.07	22%	118.0°
2039-10-22 Sat	100	—	unknown	20:05–06:10 (good, 10.08 h)	89.7° 00:00	10.11	32%	107.1°
2039-10-23 Sun	100	—	unknown	20:05–06:05 (good, 10.0 h)	89.5° 23:55	10.15	44%	95.9°
2039-10-24 Mon	100	—	unknown	20:00–06:00 (good, 10.0 h)	89.6° 23:55	10.19	55%	84.8°
2039-10-25 Tue	100	—	unknown	20:00–06:00 (good, 10.0 h)	89.8° 23:50	10.23	66%	74.0°
2039-10-26 Wed	98	—	unknown	20:00–05:55 (good, 9.92 h)	89.8° 23:45	10.27	75%	63.8°
2039-10-27 Thu	90	—	unknown	00:10–05:50 (good, 5.67 h)	89.6° 23:40	10.31	84%	54.4°
2039-10-28 Fri	82	—	unknown	04:55–05:45 (good, 0.83 h)	89.5° 23:40	10.35	91%	46.4°
2039-10-29 Sat	51	—	unknown	19:55–05:15 (marginal, 10.33 h)	89.7° 23:35	10.38	96%	40.4°
2039-10-30 Sun	46	—	unknown	18:55–04:45 (marginal, 9.83 h)	89.8° 22:30	10.42	99%	37.3°
2039-10-31 Mon	46	—	unknown	18:55–04:25 (marginal, 9.5 h)	89.7° 22:25	10.46	100%	37.6°
2039-11-01 Tue	54	—	unknown	18:50–04:10 (marginal, 9.33 h)	89.6° 22:20	10.5	99%	41.2°
2039-11-02 Wed	61	—	unknown	18:50–19:30 (good, 0.67 h)	89.6° 22:20	10.53	96%	47.2°
2039-11-03 Thu	95	—	unknown	18:50–21:10 (good, 2.33 h)	89.7° 22:15	10.57	92%	54.7°
2039-11-04 Fri	100	—	unknown	18:50–23:25 (good, 4.58 h)	89.8° 22:10	10.6	86%	63.2°
2039-11-05 Sat	100	—	unknown	18:50–01:40 (good, 6.83 h)	89.7° 22:05	10.64	79%	72.1°
2039-11-06 Sun	100	—	unknown	18:45–03:00 (good, 8.25 h)	89.5° 22:00	10.67	71%	81.4°
2039-11-07 Mon	100	—	unknown	18:45–03:40 (good, 8.92 h)	89.6° 22:00	10.71	62%	90.9°
2039-11-08 Tue	100	—	unknown	18:45–03:50 (good, 9.08 h)	89.8° 21:55	10.74	52%	100.6°
2039-11-09 Wed	100	—	unknown	18:45–03:50 (good, 9.08 h)	89.8° 21:50	10.77	42%	110.2°
2039-11-10 Thu	100	—	unknown	18:45–03:50 (good, 9.08 h)	89.6° 21:45	10.8	33%	119.7°
2039-11-11 Fri	100	—	unknown	18:45–03:50 (good, 9.08 h)	89.5° 21:45	10.83	23%	128.6°
2039-11-12 Sat	100	—	unknown	18:40–03:45 (good, 9.08 h)	89.7° 21:40	10.87	15%	136.4°
2039-11-13 Sun	100	—	unknown	18:40–03:45 (good, 9.08 h)	89.8° 21:35	10.9	8%	141.6°
2039-11-14 Mon	100	—	unknown	18:40–03:40 (good, 9.0 h)	89.7° 21:30	10.93	3%	142.8°
2039-11-15 Tue	100	—	unknown	18:40–03:35 (good, 8.92 h)	89.6° 21:25	10.95	0%	139.3°
2039-11-16 Wed	100	—	unknown	18:40–03:30 (good, 8.83 h)	89.6° 21:25	10.98	1%	131.8°
2039-11-17 Thu	100	—	unknown	18:40–03:30 (good, 8.83 h)	89.7° 21:20	11.01	4%	122.0°
2039-11-18 Fri	100	—	unknown	18:40–03:25 (good, 8.75 h)	89.8° 21:15	11.04	10%	110.9°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2039-10-20&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.