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: 12-21 (100), 12-22 (100), 12-23 (100), 12-24 (100), 12-25 (100) — by astronomy; check the weather when the night is within four days.

2046-12-21astronomy score per night — click a bar for that night2047-01-19

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2046-12-21 Fri	100	—	unknown	18:35–01:15 (good, 6.67 h)	89.8° 19:05	11.51	35%	150.2°
2046-12-22 Sat	100	—	unknown	18:35–01:10 (good, 6.58 h)	89.8° 19:00	11.51	25%	151.6°
2046-12-23 Sun	100	—	unknown	18:40–01:05 (good, 6.42 h)	89.6° 18:55	11.51	15%	146.8°
2046-12-24 Mon	100	—	unknown	18:40–01:00 (good, 6.33 h)	89.6° 18:55	11.5	8%	137.9°
2046-12-25 Tue	100	—	unknown	18:40–01:00 (good, 6.33 h)	89.7° 18:50	11.5	3%	127.0°
2046-12-26 Wed	100	—	unknown	18:40–00:55 (good, 6.25 h)	89.8° 18:45	11.5	0%	115.4°
2046-12-27 Thu	100	—	unknown	18:40–00:50 (good, 6.17 h)	89.7° 18:40	11.49	0%	103.5°
2046-12-28 Fri	100	—	unknown	18:40–00:45 (good, 6.08 h)	89.6° 18:35	11.48	3%	91.6°
2046-12-29 Sat	100	—	unknown	18:40–00:40 (good, 6.0 h)	89.6° 18:35	11.48	7%	80.1°
2046-12-30 Sun	100	—	unknown	18:40–00:40 (good, 6.0 h)	89.8° 18:30	11.47	13%	68.9°
2046-12-31 Mon	98	—	unknown	18:45–00:35 (good, 5.83 h)	89.8° 18:25	11.46	20%	58.3°
2047-01-01 Tue	90	—	unknown	18:45–00:30 (good, 5.75 h)	89.7° 18:20	11.45	29%	48.5°
2047-01-02 Wed	83	—	unknown	18:45–00:25 (good, 5.67 h)	89.5° 18:15	11.44	38%	39.7°
2047-01-03 Thu	71	—	unknown	18:45–00:00 (good, 5.25 h)	89.7° 18:15	11.43	47%	32.7°
2047-01-04 Fri	55	—	unknown	20:35–21:15 (good, 0.67 h)	89.8° 18:10	11.42	57%	28.6°
2047-01-05 Sat	39	—	unknown	18:45–00:40 (marginal, 5.92 h)	89.8° 18:05	11.4	66%	28.7°
2047-01-06 Sun	29	—	unknown	18:50–00:20 (marginal, 5.5 h)	89.6° 18:00	11.39	75%	33.1°
2047-01-07 Mon	26	—	unknown	18:50–00:05 (marginal, 5.25 h)	89.6° 18:00	11.37	83%	40.5°
2047-01-08 Tue	28	—	unknown	18:50–23:55 (marginal, 5.08 h)	89.7° 17:55	11.36	90%	49.8°
2047-01-09 Wed	34	—	unknown	18:50–23:50 (marginal, 5.0 h)	89.8° 17:50	11.34	95%	60.3°
2047-01-10 Thu	45	—	unknown	18:50–19:20 (good, 0.5 h)	89.7° 17:45	11.33	98%	71.5°
2047-01-11 Fri	60	—	unknown	18:50–21:15 (good, 2.42 h)	89.6° 17:40	11.31	100%	83.3°
2047-01-12 Sat	76	—	unknown	18:55–22:35 (good, 3.67 h)	89.6° 17:40	11.29	99%	95.4°
2047-01-13 Sun	100	—	unknown	18:55–23:20 (good, 4.42 h)	89.8° 17:35	11.27	96%	107.6°
2047-01-14 Mon	100	—	unknown	18:55–23:25 (good, 4.5 h)	89.8° 17:30	11.25	90%	119.7°
2047-01-15 Tue	100	—	unknown	18:55–23:25 (good, 4.5 h)	89.7° 17:25	11.23	82%	131.3°
2047-01-16 Wed	100	—	unknown	18:55–23:25 (good, 4.5 h)	89.5° 17:20	11.21	72%	141.6°
2047-01-17 Thu	100	—	unknown	19:00–23:25 (good, 4.42 h)	89.7° 17:20	11.18	61%	149.2°
2047-01-18 Fri	100	—	unknown	19:00–23:25 (good, 4.42 h)	89.8° 17:15	11.16	50%	151.9°
2047-01-19 Sat	100	—	unknown	19:00–23:20 (good, 4.33 h)	89.8° 17:10	11.13	39%	148.4°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2046-12-21&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.