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: 12-22 (100), 12-23 (100), 12-24 (100), 12-25 (100), 12-26 (100) — by astronomy; check the weather when the night is within four days.

2029-12-15astronomy score per night — click a bar for that night2030-01-13

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2029-12-15 Sat	36	—	unknown	18:35–01:50 (marginal, 7.25 h)	89.6° 19:25	11.49	79%	29.0°
2029-12-16 Sun	28	—	unknown	18:35–01:30 (marginal, 6.92 h)	89.5° 19:25	11.5	86%	32.1°
2029-12-17 Mon	28	—	unknown	18:35–01:10 (marginal, 6.58 h)	89.7° 19:20	11.5	92%	38.4°
2029-12-18 Tue	33	—	unknown	18:35–01:00 (marginal, 6.42 h)	89.7° 19:15	11.5	96%	46.8°
2029-12-19 Wed	44	—	unknown	18:35–01:05 (marginal, 6.5 h)	89.7° 19:10	11.51	99%	56.3°
2029-12-20 Thu	59	—	unknown	18:35–19:30 (good, 0.92 h)	89.5° 19:05	11.51	100%	66.5°
2029-12-21 Fri	73	—	unknown	18:35–21:55 (good, 3.33 h)	89.6° 19:05	11.51	99%	77.2°
2029-12-22 Sat	100	—	unknown	18:35–23:15 (good, 4.67 h)	89.7° 19:00	11.51	96%	88.2°
2029-12-23 Sun	100	—	unknown	18:40–00:35 (good, 5.92 h)	89.7° 18:55	11.51	91%	99.4°
2029-12-24 Mon	100	—	unknown	18:40–00:40 (good, 6.0 h)	89.6° 18:50	11.5	84%	110.7°
2029-12-25 Tue	100	—	unknown	18:40–00:45 (good, 6.08 h)	89.5° 18:50	11.5	76%	121.8°
2029-12-26 Wed	100	—	unknown	18:40–00:45 (good, 6.08 h)	89.6° 18:45	11.49	66%	132.5°
2029-12-27 Thu	100	—	unknown	18:40–00:45 (good, 6.08 h)	89.7° 18:40	11.49	55%	142.0°
2029-12-28 Fri	100	—	unknown	18:40–00:45 (good, 6.08 h)	89.7° 18:35	11.48	44%	149.0°
2029-12-29 Sat	100	—	unknown	18:40–00:40 (good, 6.0 h)	89.6° 18:30	11.48	33%	151.1°
2029-12-30 Sun	100	—	unknown	18:40–00:35 (good, 5.92 h)	89.5° 18:30	11.47	23%	147.1°
2029-12-31 Mon	100	—	unknown	18:45–00:35 (good, 5.83 h)	89.7° 18:25	11.46	14%	138.5°
2030-01-01 Tue	100	—	unknown	18:45–00:30 (good, 5.75 h)	89.7° 18:20	11.45	6%	127.6°
2030-01-02 Wed	100	—	unknown	18:45–00:25 (good, 5.67 h)	89.7° 18:15	11.44	2%	115.6°
2030-01-03 Thu	100	—	unknown	18:45–00:20 (good, 5.58 h)	89.5° 18:10	11.43	0%	103.1°
2030-01-04 Fri	100	—	unknown	18:45–00:15 (good, 5.5 h)	89.6° 18:10	11.42	1%	90.6°
2030-01-05 Sat	100	—	unknown	18:45–00:15 (good, 5.5 h)	89.7° 18:05	11.4	4%	78.4°
2030-01-06 Sun	100	—	unknown	18:50–00:10 (good, 5.33 h)	89.7° 18:00	11.39	10%	66.7°
2030-01-07 Mon	97	—	unknown	18:50–00:05 (good, 5.25 h)	89.6° 17:55	11.37	17%	55.8°
2030-01-08 Tue	89	—	unknown	18:50–00:00 (good, 5.17 h)	89.5° 17:50	11.36	25%	45.8°
2030-01-09 Wed	81	—	unknown	18:50–23:55 (good, 5.08 h)	89.6° 17:50	11.34	34%	37.4°
2030-01-10 Thu	69	—	unknown	18:50–23:30 (good, 4.67 h)	89.7° 17:45	11.32	44%	31.3°
2030-01-11 Fri	52	—	unknown	18:50–21:30 (good, 2.67 h)	89.7° 17:40	11.3	53%	28.9°
2030-01-12 Sat	38	—	unknown	18:55–00:10 (marginal, 5.25 h)	89.6° 17:35	11.29	63%	30.8°
2030-01-13 Sun	31	—	unknown	18:55–23:55 (marginal, 5.0 h)	89.5° 17:35	11.27	71%	36.3°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2029-12-15&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.