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: 08-23 (100), 08-24 (100), 08-25 (100), 08-26 (100), 08-27 (100) — by astronomy; check the weather when the night is within four days.

2030-08-20astronomy score per night — click a bar for that night2030-09-18

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2030-08-20 Tue	87	—	unknown	22:05–04:55 (good, 6.83 h)	89.5° 04:10	6.93	51%	41.8°
2030-08-21 Wed	93	—	unknown	22:00–04:55 (good, 6.92 h)	89.7° 04:05	6.99	42%	50.3°
2030-08-22 Thu	99	—	unknown	21:55–05:00 (good, 7.08 h)	89.7° 04:00	7.05	33%	59.8°
2030-08-23 Fri	100	—	unknown	21:55–05:00 (good, 7.08 h)	89.7° 03:55	7.1	24%	69.8°
2030-08-24 Sat	100	—	unknown	21:50–05:00 (good, 7.17 h)	89.5° 03:50	7.16	16%	80.2°
2030-08-25 Sun	100	—	unknown	21:50–05:00 (good, 7.17 h)	89.6° 03:50	7.22	10%	90.8°
2030-08-26 Mon	100	—	unknown	21:45–05:05 (good, 7.33 h)	89.7° 03:45	7.27	5%	101.7°
2030-08-27 Tue	100	—	unknown	21:45–05:05 (good, 7.33 h)	89.7° 03:40	7.33	1%	112.7°
2030-08-28 Wed	100	—	unknown	21:45–05:05 (good, 7.33 h)	89.6° 03:35	7.39	0%	123.6°
2030-08-29 Thu	100	—	unknown	21:40–05:10 (good, 7.5 h)	89.5° 03:30	7.44	1%	133.9°
2030-08-30 Fri	100	—	unknown	21:40–05:10 (good, 7.5 h)	89.6° 03:30	7.5	5%	142.9°
2030-08-31 Sat	100	—	unknown	21:35–05:10 (good, 7.58 h)	89.7° 03:25	7.56	11%	148.9°
2030-09-01 Sun	100	—	unknown	21:35–05:10 (good, 7.58 h)	89.7° 03:20	7.61	18%	149.9°
2030-09-02 Mon	100	—	unknown	21:35–05:15 (good, 7.67 h)	89.6° 03:15	7.67	28%	145.3°
2030-09-03 Tue	100	—	unknown	21:30–05:15 (good, 7.75 h)	89.5° 03:15	7.72	39%	136.8°
2030-09-04 Wed	100	—	unknown	21:30–05:15 (good, 7.75 h)	89.7° 03:10	7.78	50%	126.3°
2030-09-05 Thu	100	—	unknown	21:25–05:15 (good, 7.83 h)	89.7° 03:05	7.83	62%	114.7°
2030-09-06 Fri	100	—	unknown	21:25–05:20 (good, 7.92 h)	89.7° 03:00	7.89	72%	102.7°
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°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2030-08-20&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.