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: 09-07 (100), 09-08 (100), 09-09 (100), 09-19 (100), 09-20 (100) — by astronomy; check the weather when the night is within four days.

2030-09-07astronomy score per night — click a bar for that night2030-10-06

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2030-09-07 Sat	100	—	unknown	21:25–05:20 (good, 7.92 h)	89.5° 02:55	7.94	82%	90.6°
2030-09-08 Sun	100	—	unknown	22:30–05:20 (good, 6.83 h)	89.6° 02:55	8.0	90%	78.5°
2030-09-09 Mon	100	—	unknown	01:15–05:25 (good, 4.17 h)	89.7° 02:50	8.05	95%	66.7°
2030-09-10 Tue	64	—	unknown	04:35–05:25 (good, 0.83 h)	89.7° 02:45	8.11	99%	55.6°
2030-09-11 Wed	50	—	unknown	21:15–05:25 (marginal, 8.17 h)	89.6° 02:40	8.16	100%	45.4°
2030-09-12 Thu	36	—	unknown	21:15–05:25 (marginal, 8.17 h)	89.5° 02:35	8.21	99%	36.9°
2030-09-13 Fri	35	—	unknown	21:10–05:30 (marginal, 8.33 h)	89.6° 02:35	8.27	95%	31.4°
2030-09-14 Sat	43	—	unknown	21:10–05:30 (marginal, 8.33 h)	89.7° 02:30	8.32	90%	30.0°
2030-09-15 Sun	55	—	unknown	20:35–05:30 (marginal, 8.92 h)	89.7° 02:25	8.37	84%	33.0°
2030-09-16 Mon	86	—	unknown	21:05–00:10 (good, 3.08 h)	89.6° 02:20	8.43	76%	39.3°
2030-09-17 Tue	91	—	unknown	21:05–03:00 (good, 5.92 h)	89.5° 02:20	8.48	68%	47.5°
2030-09-18 Wed	97	—	unknown	21:00–05:35 (good, 8.58 h)	89.7° 02:15	8.53	58%	56.7°
2030-09-19 Thu	100	—	unknown	21:00–05:35 (good, 8.58 h)	89.7° 02:10	8.58	49%	66.4°
2030-09-20 Fri	100	—	unknown	21:00–05:35 (good, 8.58 h)	89.7° 02:05	8.63	40%	76.6°
2030-09-21 Sat	100	—	unknown	20:55–05:35 (good, 8.67 h)	89.5° 02:00	8.69	30%	87.0°
2030-09-22 Sun	100	—	unknown	20:55–05:40 (good, 8.75 h)	89.6° 02:00	8.74	22%	97.8°
2030-09-23 Mon	100	—	unknown	20:50–05:40 (good, 8.83 h)	89.7° 01:55	8.79	14%	108.6°
2030-09-24 Tue	100	—	unknown	20:50–05:40 (good, 8.83 h)	89.7° 01:50	8.84	8%	119.6°
2030-09-25 Wed	100	—	unknown	20:50–05:40 (good, 8.83 h)	89.6° 01:45	8.89	3%	130.2°
2030-09-26 Thu	100	—	unknown	20:45–05:45 (good, 9.0 h)	89.5° 01:40	8.94	0%	139.9°
2030-09-27 Fri	100	—	unknown	20:45–05:45 (good, 9.0 h)	89.6° 01:40	8.99	0%	147.2°
2030-09-28 Sat	100	—	unknown	20:45–05:45 (good, 9.0 h)	89.7° 01:35	9.04	3%	150.1°
2030-09-29 Sun	100	—	unknown	20:40–05:45 (good, 9.08 h)	89.7° 01:30	9.08	8%	147.0°
2030-09-30 Mon	100	—	unknown	20:40–05:50 (good, 9.17 h)	89.6° 01:25	9.13	16%	139.2°
2030-10-01 Tue	100	—	unknown	20:40–05:50 (good, 9.17 h)	89.5° 01:25	9.18	25%	128.8°
2030-10-02 Wed	100	—	unknown	20:35–05:50 (good, 9.25 h)	89.7° 01:20	9.23	36%	117.3°
2030-10-03 Thu	100	—	unknown	20:35–05:50 (good, 9.25 h)	89.7° 01:15	9.28	47%	105.4°
2030-10-04 Fri	100	—	unknown	20:35–05:50 (good, 9.25 h)	89.7° 01:10	9.32	58%	93.3°
2030-10-05 Sat	100	—	unknown	20:30–05:55 (good, 9.42 h)	89.5° 01:05	9.37	69%	81.4°
2030-10-06 Sun	100	—	unknown	20:45–05:55 (good, 9.17 h)	89.6° 01:05	9.42	79%	69.7°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2030-09-07&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.