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: 09-23 (100), 09-24 (100), 09-25 (100), 09-26 (100), 09-27 (100) — by astronomy; check the weather when the night is within four days.

2046-09-14astronomy score per night — click a bar for that night2046-10-13

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2046-09-14 Fri	55	—	unknown	21:10–05:30 (marginal, 8.33 h)	89.8° 02:30	8.33	100%	47.2°
2046-09-15 Sat	40	—	unknown	21:05–05:30 (marginal, 8.42 h)	89.7° 02:25	8.38	100%	38.8°
2046-09-16 Sun	34	—	unknown	21:05–01:45 (marginal, 4.67 h)	89.6° 02:20	8.43	97%	32.1°
2046-09-17 Mon	37	—	unknown	21:05–02:15 (marginal, 5.17 h)	89.6° 02:20	8.49	94%	28.5°
2046-09-18 Tue	46	—	unknown	21:00–05:35 (marginal, 8.58 h)	89.8° 02:15	8.54	88%	29.3°
2046-09-19 Wed	57	—	unknown	20:25–05:35 (marginal, 9.17 h)	89.8° 02:10	8.59	82%	34.1°
2046-09-20 Thu	86	—	unknown	21:00–00:40 (good, 3.67 h)	89.7° 02:05	8.64	73%	41.7°
2046-09-21 Fri	92	—	unknown	20:55–04:40 (good, 7.75 h)	89.5° 02:00	8.69	64%	50.9°
2046-09-22 Sat	99	—	unknown	20:55–05:40 (good, 8.75 h)	89.7° 02:00	8.74	54%	61.3°
2046-09-23 Sun	100	—	unknown	20:50–05:40 (good, 8.83 h)	89.8° 01:55	8.79	44%	72.3°
2046-09-24 Mon	100	—	unknown	20:50–05:40 (good, 8.83 h)	89.8° 01:50	8.84	33%	84.0°
2046-09-25 Tue	100	—	unknown	20:50–05:40 (good, 8.83 h)	89.6° 01:45	8.89	23%	96.2°
2046-09-26 Wed	100	—	unknown	20:45–05:45 (good, 9.0 h)	89.5° 01:45	8.94	14%	108.7°
2046-09-27 Thu	100	—	unknown	20:45–05:45 (good, 9.0 h)	89.7° 01:40	8.99	7%	121.2°
2046-09-28 Fri	100	—	unknown	20:45–05:45 (good, 9.0 h)	89.8° 01:35	9.04	2%	133.3°
2046-09-29 Sat	100	—	unknown	20:40–05:45 (good, 9.08 h)	89.8° 01:30	9.09	0%	143.8°
2046-09-30 Sun	100	—	unknown	20:40–05:50 (good, 9.17 h)	89.6° 01:25	9.14	1%	150.6°
2046-10-01 Mon	100	—	unknown	20:40–05:50 (good, 9.17 h)	89.6° 01:25	9.19	5%	150.9°
2046-10-02 Tue	100	—	unknown	20:35–05:50 (good, 9.25 h)	89.8° 01:20	9.24	12%	144.9°
2046-10-03 Wed	100	—	unknown	20:35–05:50 (good, 9.25 h)	89.8° 01:15	9.28	20%	135.4°
2046-10-04 Thu	100	—	unknown	20:30–05:50 (good, 9.33 h)	89.7° 01:10	9.33	30%	124.5°
2046-10-05 Fri	100	—	unknown	20:30–05:55 (good, 9.42 h)	89.5° 01:05	9.38	40%	113.2°
2046-10-06 Sat	100	—	unknown	20:30–05:55 (good, 9.42 h)	89.7° 01:05	9.42	51%	101.9°
2046-10-07 Sun	100	—	unknown	20:25–05:55 (good, 9.5 h)	89.8° 01:00	9.47	61%	90.8°
2046-10-08 Mon	100	—	unknown	20:25–05:55 (good, 9.5 h)	89.8° 00:55	9.52	70%	79.9°
2046-10-09 Tue	100	—	unknown	20:25–06:00 (good, 9.58 h)	89.6° 00:50	9.56	78%	69.4°
2046-10-10 Wed	97	—	unknown	23:55–06:00 (good, 6.08 h)	89.5° 00:50	9.61	86%	59.2°
2046-10-11 Thu	89	—	unknown	03:10–06:00 (good, 2.83 h)	89.7° 00:45	9.65	92%	49.6°
2046-10-12 Fri	82	—	unknown	05:55–06:00 (good, 0.08 h)	89.8° 00:40	9.7	96%	40.8°
2046-10-13 Sat	42	—	unknown	20:20–06:00 (marginal, 9.67 h)	89.8° 00:35	9.74	99%	33.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2046-09-14&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.