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: 10-08 (100), 10-09 (100), 10-10 (100), 10-11 (100), 10-12 (100) — by astronomy; check the weather when the night is within four days.

2040-10-08astronomy score per night — click a bar for that night2040-11-06

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2040-10-08 Mon	100	—	unknown	20:25–05:55 (good, 9.5 h)	89.6° 00:55	9.54	8%	140.6°
2040-10-09 Tue	100	—	unknown	20:25–06:00 (good, 9.58 h)	89.8° 00:50	9.58	15%	133.8°
2040-10-10 Wed	100	—	unknown	20:20–06:00 (good, 9.67 h)	89.8° 00:45	9.63	24%	124.7°
2040-10-11 Thu	100	—	unknown	20:20–06:00 (good, 9.67 h)	89.6° 00:40	9.67	34%	114.4°
2040-10-12 Fri	100	—	unknown	20:20–06:00 (good, 9.67 h)	89.5° 00:40	9.72	45%	103.4°
2040-10-13 Sat	100	—	unknown	20:15–06:05 (good, 9.83 h)	89.7° 00:35	9.76	56%	92.0°
2040-10-14 Sun	100	—	unknown	20:15–06:05 (good, 9.83 h)	89.8° 00:30	9.8	68%	80.4°
2040-10-15 Mon	100	—	unknown	20:15–06:05 (good, 9.83 h)	89.7° 00:25	9.85	78%	69.1°
2040-10-16 Tue	93	—	unknown	23:45–06:05 (good, 6.33 h)	89.6° 00:20	9.89	87%	58.3°
2040-10-17 Wed	85	—	unknown	05:10–06:05 (good, 0.92 h)	89.6° 00:20	9.93	93%	48.6°
2040-10-18 Thu	49	—	unknown	20:10–06:10 (marginal, 10.0 h)	89.7° 00:15	9.98	98%	40.8°
2040-10-19 Fri	45	—	unknown	20:10–06:10 (marginal, 10.0 h)	89.8° 00:10	10.02	100%	36.3°
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°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2040-10-08&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.