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: 10-14 (100), 10-15 (100), 10-16 (100), 10-17 (100), 10-18 (100) — by astronomy; check the weather when the night is within four days.

2041-10-09astronomy score per night — click a bar for that night2041-11-07

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2041-10-09 Wed	43	—	unknown	20:25–06:00 (marginal, 9.58 h)	89.8° 00:50	9.57	100%	35.8°
2041-10-10 Thu	45	—	unknown	20:20–01:20 (marginal, 5.0 h)	89.6° 00:45	9.62	98%	34.1°
2041-10-11 Fri	55	—	unknown	20:20–06:00 (marginal, 9.67 h)	89.5° 00:45	9.66	94%	37.6°
2041-10-12 Sat	88	—	unknown	20:20–22:20 (good, 2.0 h)	89.7° 00:40	9.71	87%	44.9°
2041-10-13 Sun	94	—	unknown	20:15–00:50 (good, 4.58 h)	89.8° 00:35	9.75	78%	54.0°
2041-10-14 Mon	100	—	unknown	20:15–04:00 (good, 7.75 h)	89.7° 00:30	9.79	69%	63.9°
2041-10-15 Tue	100	—	unknown	20:15–05:35 (good, 9.33 h)	89.6° 00:25	9.84	60%	74.1°
2041-10-16 Wed	100	—	unknown	20:15–06:05 (good, 9.83 h)	89.6° 00:25	9.88	50%	84.3°
2041-10-17 Thu	100	—	unknown	20:10–06:05 (good, 9.92 h)	89.7° 00:20	9.92	40%	94.3°
2041-10-18 Fri	100	—	unknown	20:10–06:10 (good, 10.0 h)	89.8° 00:15	9.97	31%	104.2°
2041-10-19 Sat	100	—	unknown	20:10–06:10 (good, 10.0 h)	89.7° 00:10	10.01	22%	113.7°
2041-10-20 Sun	100	—	unknown	20:05–06:10 (good, 10.08 h)	89.5° 00:05	10.05	15%	122.8°
2041-10-21 Mon	100	—	unknown	20:05–06:10 (good, 10.08 h)	89.6° 00:05	10.09	9%	131.2°
2041-10-22 Tue	100	—	unknown	20:05–06:10 (good, 10.08 h)	89.8° 00:00	10.13	4%	138.5°
2041-10-23 Wed	100	—	unknown	20:05–06:05 (good, 10.0 h)	89.8° 23:55	10.17	1%	143.8°
2041-10-24 Thu	100	—	unknown	20:00–06:00 (good, 10.0 h)	89.6° 23:50	10.21	0%	146.0°
2041-10-25 Fri	100	—	unknown	20:00–05:55 (good, 9.92 h)	89.5° 23:50	10.25	1%	144.4°
2041-10-26 Sat	100	—	unknown	20:00–04:55 (good, 9.92 h)	89.7° 23:45	10.29	3%	139.3°
2041-10-27 Sun	100	—	unknown	19:00–04:50 (good, 9.83 h)	89.8° 22:40	10.33	8%	131.7°
2041-10-28 Mon	100	—	unknown	18:55–04:45 (good, 9.83 h)	89.7° 22:35	10.37	15%	122.4°
2041-10-29 Tue	100	—	unknown	18:55–04:40 (good, 9.75 h)	89.6° 22:30	10.4	23%	112.2°
2041-10-30 Wed	100	—	unknown	18:55–04:35 (good, 9.67 h)	89.6° 22:30	10.44	33%	101.3°
2041-10-31 Thu	100	—	unknown	18:55–04:35 (good, 9.67 h)	89.7° 22:25	10.48	44%	90.0°
2041-11-01 Fri	100	—	unknown	18:50–04:30 (good, 9.67 h)	89.8° 22:20	10.51	55%	78.5°
2041-11-02 Sat	100	—	unknown	18:50–04:25 (good, 9.58 h)	89.7° 22:15	10.55	66%	67.0°
2041-11-03 Sun	92	—	unknown	18:50–04:20 (good, 9.5 h)	89.5° 22:10	10.59	76%	56.0°
2041-11-04 Mon	83	—	unknown	03:15–04:15 (good, 1.0 h)	89.6° 22:10	10.62	86%	45.9°
2041-11-05 Tue	48	—	unknown	18:50–04:45 (marginal, 9.92 h)	89.8° 22:05	10.66	93%	38.1°
2041-11-06 Wed	39	—	unknown	18:45–04:10 (marginal, 9.42 h)	89.8° 22:00	10.69	98%	34.1°
2041-11-07 Thu	38	—	unknown	18:45–22:20 (marginal, 3.58 h)	89.7° 21:55	10.72	100%	35.5°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2041-10-09&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.