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: 09-12 (100), 09-13 (100), 09-14 (100), 09-15 (100), 09-16 (100) — by astronomy; check the weather when the night is within four days.

2047-09-05astronomy score per night — click a bar for that night2047-10-04

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2047-09-05 Thu	34	—	unknown	21:30–05:15 (marginal, 7.75 h)	89.7° 03:05	7.83	97%	37.7°
2047-09-06 Fri	35	—	unknown	21:25–05:20 (marginal, 7.92 h)	89.5° 03:00	7.88	93%	31.3°
2047-09-07 Sat	42	—	unknown	21:25–05:20 (marginal, 7.92 h)	89.7° 03:00	7.94	88%	28.5°
2047-09-08 Sun	54	—	unknown	20:50–05:20 (marginal, 8.5 h)	89.8° 02:55	7.99	81%	30.1°
2047-09-09 Mon	83	—	unknown	21:20–00:20 (good, 3.0 h)	89.8° 02:50	8.05	73%	35.5°
2047-09-10 Tue	88	—	unknown	21:20–03:05 (good, 5.75 h)	89.6° 02:45	8.1	64%	43.2°
2047-09-11 Wed	93	—	unknown	21:15–05:25 (good, 8.17 h)	89.5° 02:45	8.16	55%	52.3°
2047-09-12 Thu	100	—	unknown	21:15–05:25 (good, 8.17 h)	89.7° 02:40	8.21	46%	62.2°
2047-09-13 Fri	100	—	unknown	21:10–05:30 (good, 8.33 h)	89.8° 02:35	8.26	36%	72.7°
2047-09-14 Sat	100	—	unknown	21:10–05:30 (good, 8.33 h)	89.8° 02:30	8.32	27%	83.7°
2047-09-15 Sun	100	—	unknown	21:10–05:30 (good, 8.33 h)	89.6° 02:25	8.37	18%	95.2°
2047-09-16 Mon	100	—	unknown	21:05–05:30 (good, 8.42 h)	89.6° 02:25	8.42	10%	106.9°
2047-09-17 Tue	100	—	unknown	21:05–05:30 (good, 8.42 h)	89.8° 02:20	8.47	5%	118.7°
2047-09-18 Wed	100	—	unknown	21:00–05:35 (good, 8.58 h)	89.8° 02:15	8.52	1%	130.3°
2047-09-19 Thu	100	—	unknown	21:00–05:35 (good, 8.58 h)	89.7° 02:10	8.58	0%	140.9°
2047-09-20 Fri	100	—	unknown	21:00–05:35 (good, 8.58 h)	89.5° 02:05	8.63	2%	148.8°
2047-09-21 Sat	100	—	unknown	20:55–05:35 (good, 8.67 h)	89.7° 02:05	8.68	7%	151.5°
2047-09-22 Sun	100	—	unknown	20:55–05:40 (good, 8.75 h)	89.8° 02:00	8.73	14%	147.4°
2047-09-23 Mon	100	—	unknown	20:55–05:40 (good, 8.75 h)	89.8° 01:55	8.78	23%	138.8°
2047-09-24 Tue	100	—	unknown	20:50–05:40 (good, 8.83 h)	89.7° 01:50	8.83	34%	128.0°
2047-09-25 Wed	100	—	unknown	20:50–05:40 (good, 8.83 h)	89.5° 01:50	8.88	45%	116.4°
2047-09-26 Thu	100	—	unknown	20:45–05:45 (good, 9.0 h)	89.7° 01:45	8.93	56%	104.5°
2047-09-27 Fri	100	—	unknown	20:45–05:45 (good, 9.0 h)	89.8° 01:40	8.98	66%	92.7°
2047-09-28 Sat	100	—	unknown	20:45–05:45 (good, 9.0 h)	89.8° 01:35	9.03	76%	81.1°
2047-09-29 Sun	100	—	unknown	21:35–05:45 (good, 8.17 h)	89.6° 01:30	9.08	84%	69.9°
2047-09-30 Mon	97	—	unknown	01:35–05:50 (good, 4.25 h)	89.6° 01:30	9.13	91%	59.1°
2047-10-01 Tue	89	—	unknown	04:50–05:50 (good, 1.0 h)	89.8° 01:25	9.18	96%	49.0°
2047-10-02 Wed	51	—	unknown	20:35–05:50 (marginal, 9.25 h)	89.8° 01:20	9.22	99%	40.0°
2047-10-03 Thu	36	—	unknown	02:15–05:50 (marginal, 3.58 h)	89.7° 01:15	9.27	100%	32.9°
2047-10-04 Fri	33	—	unknown	20:35–23:40 (marginal, 3.08 h)	89.5° 01:10	9.32	99%	29.0°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2047-09-05&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.