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: 10-12 (100), 10-13 (100), 10-14 (100), 10-15 (100), 10-16 (100) — by astronomy; check the weather when the night is within four days.

2031-10-12astronomy score per night — click a bar for that night2031-11-10

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2031-10-12 Sun	100	—	unknown	20:20–06:00 (good, 9.67 h)	89.7° 00:40	9.68	12%	126.3°
2031-10-13 Mon	100	—	unknown	20:20–06:00 (good, 9.67 h)	89.6° 00:35	9.72	6%	135.3°
2031-10-14 Tue	100	—	unknown	20:15–06:05 (good, 9.83 h)	89.5° 00:35	9.77	2%	143.0°
2031-10-15 Wed	100	—	unknown	20:15–06:05 (good, 9.83 h)	89.6° 00:30	9.81	0%	147.8°
2031-10-16 Thu	100	—	unknown	20:15–06:05 (good, 9.83 h)	89.7° 00:25	9.86	0%	148.2°
2031-10-17 Fri	100	—	unknown	20:10–06:05 (good, 9.92 h)	89.7° 00:20	9.9	3%	143.8°
2031-10-18 Sat	100	—	unknown	20:10–06:05 (good, 9.92 h)	89.6° 00:15	9.94	8%	135.7°
2031-10-19 Sun	100	—	unknown	20:10–06:10 (good, 10.0 h)	89.5° 00:15	9.98	15%	125.6°
2031-10-20 Mon	100	—	unknown	20:10–06:10 (good, 10.0 h)	89.7° 00:10	10.02	24%	114.4°
2031-10-21 Tue	100	—	unknown	20:05–06:10 (good, 10.08 h)	89.7° 00:05	10.07	34%	102.6°
2031-10-22 Wed	100	—	unknown	20:05–06:10 (good, 10.08 h)	89.7° 00:00	10.11	46%	90.5°
2031-10-23 Thu	100	—	unknown	20:05–06:05 (good, 10.0 h)	89.5° 23:55	10.15	57%	78.5°
2031-10-24 Fri	100	—	unknown	20:00–06:00 (good, 10.0 h)	89.6° 23:55	10.19	68%	66.6°
2031-10-25 Sat	94	—	unknown	22:20–05:00 (good, 7.67 h)	89.7° 23:50	10.23	78%	55.4°
2031-10-26 Sun	86	—	unknown	02:25–04:55 (good, 2.5 h)	89.7° 22:45	10.27	87%	45.1°
2031-10-27 Mon	68	—	unknown	04:35–04:50 (good, 0.25 h)	89.6° 22:40	10.31	93%	36.8°
2031-10-28 Tue	38	—	unknown	23:45–04:55 (marginal, 5.17 h)	89.5° 22:40	10.34	98%	32.0°
2031-10-29 Wed	35	—	unknown	18:55–21:45 (marginal, 2.83 h)	89.6° 22:35	10.38	100%	31.9°
2031-10-30 Thu	43	—	unknown	18:55–23:20 (marginal, 4.42 h)	89.7° 22:30	10.42	100%	36.5°
2031-10-31 Fri	57	—	unknown	18:55–04:10 (marginal, 9.25 h)	89.7° 22:25	10.46	97%	44.0°
2031-11-01 Sat	66	—	unknown	18:55–20:55 (good, 2.0 h)	89.6° 22:20	10.49	93%	53.1°
2031-11-02 Sun	100	—	unknown	18:50–23:20 (good, 4.5 h)	89.5° 22:20	10.53	87%	62.8°
2031-11-03 Mon	100	—	unknown	18:50–01:50 (good, 7.0 h)	89.7° 22:15	10.57	80%	72.9°
2031-11-04 Tue	100	—	unknown	18:50–03:15 (good, 8.42 h)	89.7° 22:10	10.6	72%	83.0°
2031-11-05 Wed	100	—	unknown	18:50–03:50 (good, 9.0 h)	89.7° 22:05	10.64	63%	93.1°
2031-11-06 Thu	100	—	unknown	18:45–03:55 (good, 9.17 h)	89.5° 22:00	10.67	54%	103.2°
2031-11-07 Fri	100	—	unknown	18:45–04:00 (good, 9.25 h)	89.6° 22:00	10.7	44%	113.1°
2031-11-08 Sat	100	—	unknown	18:45–04:00 (good, 9.25 h)	89.7° 21:55	10.74	35%	122.8°
2031-11-09 Sun	100	—	unknown	18:45–03:55 (good, 9.17 h)	89.7° 21:50	10.77	26%	132.1°
2031-11-10 Mon	100	—	unknown	18:45–03:55 (good, 9.17 h)	89.6° 21:45	10.8	17%	140.3°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2031-10-12&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.