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: 12-26 (100), 12-27 (100), 12-28 (100), 12-29 (100), 12-30 (100) — by astronomy; check the weather when the night is within four days.

2045-12-21astronomy score per night — click a bar for that night2046-01-19

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2045-12-21 Thu	29	—	unknown	18:35–00:45 (marginal, 6.17 h)	89.7° 19:05	11.51	94%	43.4°
2045-12-22 Fri	38	—	unknown	18:35–00:45 (marginal, 6.17 h)	89.8° 19:00	11.51	98%	54.0°
2045-12-23 Sat	53	—	unknown	18:40–19:05 (good, 0.42 h)	89.8° 18:55	11.5	100%	65.8°
2045-12-24 Sun	73	—	unknown	18:40–21:55 (good, 3.25 h)	89.6° 18:50	11.5	99%	78.3°
2045-12-25 Mon	83	—	unknown	18:40–23:30 (good, 4.83 h)	89.6° 18:50	11.5	95%	91.2°
2045-12-26 Tue	100	—	unknown	18:40–00:30 (good, 5.83 h)	89.7° 18:45	11.49	89%	104.0°
2045-12-27 Wed	100	—	unknown	18:40–00:35 (good, 5.92 h)	89.8° 18:40	11.49	80%	116.6°
2045-12-28 Thu	100	—	unknown	18:40–00:35 (good, 5.92 h)	89.7° 18:35	11.48	70%	128.5°
2045-12-29 Fri	100	—	unknown	18:40–00:35 (good, 5.92 h)	89.6° 18:30	11.48	59%	139.2°
2045-12-30 Sat	100	—	unknown	18:40–00:35 (good, 5.92 h)	89.6° 18:30	11.47	48%	147.5°
2045-12-31 Sun	100	—	unknown	18:45–00:35 (good, 5.83 h)	89.8° 18:25	11.46	37%	151.5°
2046-01-01 Mon	100	—	unknown	18:45–00:30 (good, 5.75 h)	89.8° 18:20	11.45	27%	149.9°
2046-01-02 Tue	100	—	unknown	18:45–00:25 (good, 5.67 h)	89.7° 18:15	11.44	18%	143.6°
2046-01-03 Wed	100	—	unknown	18:45–00:20 (good, 5.58 h)	89.5° 18:15	11.43	11%	134.7°
2046-01-04 Thu	100	—	unknown	18:45–00:20 (good, 5.58 h)	89.7° 18:10	11.41	5%	124.5°
2046-01-05 Fri	100	—	unknown	18:45–00:15 (good, 5.5 h)	89.8° 18:05	11.4	2%	113.9°
2046-01-06 Sat	100	—	unknown	18:50–00:10 (good, 5.33 h)	89.8° 18:00	11.39	0%	103.0°
2046-01-07 Sun	100	—	unknown	18:50–00:05 (good, 5.25 h)	89.6° 17:55	11.37	1%	92.2°
2046-01-08 Mon	100	—	unknown	18:50–00:00 (good, 5.17 h)	89.6° 17:55	11.36	3%	81.5°
2046-01-09 Tue	100	—	unknown	18:50–00:00 (good, 5.17 h)	89.7° 17:50	11.34	7%	71.0°
2046-01-10 Wed	100	—	unknown	18:50–23:55 (good, 5.08 h)	89.8° 17:45	11.32	12%	60.9°
2046-01-11 Thu	92	—	unknown	18:50–23:50 (good, 5.0 h)	89.7° 17:40	11.3	19%	51.2°
2046-01-12 Fri	87	—	unknown	18:55–23:45 (good, 4.83 h)	89.6° 17:35	11.28	27%	42.3°
2046-01-13 Sat	79	—	unknown	18:55–23:25 (good, 4.5 h)	89.6° 17:35	11.26	36%	34.7°
2046-01-14 Sun	61	—	unknown	18:55–23:10 (good, 4.25 h)	89.8° 17:30	11.24	45%	29.5°
2046-01-15 Mon	45	—	unknown	18:55–00:05 (marginal, 5.17 h)	89.8° 17:25	11.22	55%	28.4°
2046-01-16 Tue	33	—	unknown	18:55–23:50 (marginal, 4.92 h)	89.7° 17:20	11.2	65%	32.1°
2046-01-17 Wed	27	—	unknown	19:00–23:35 (marginal, 4.58 h)	89.5° 17:15	11.18	75%	39.5°
2046-01-18 Thu	26	—	unknown	19:00–23:20 (marginal, 4.33 h)	89.7° 17:15	11.15	83%	49.3°
2046-01-19 Fri	29	—	unknown	19:00–23:15 (marginal, 4.25 h)	89.8° 17:10	11.13	91%	60.5°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2045-12-21&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.