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: 09-03 (100), 09-04 (100), 09-05 (100), 09-06 (100), 09-07 (100) — by astronomy; check the weather when the night is within four days.

2043-09-03astronomy score per night — click a bar for that night2043-10-02

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2043-09-03 Thu	100	—	unknown	21:30–05:15 (good, 7.75 h)	89.7° 03:15	7.72	0%	127.5°
2043-09-04 Fri	100	—	unknown	21:30–05:15 (good, 7.75 h)	89.8° 03:10	7.77	2%	136.8°
2043-09-05 Sat	100	—	unknown	21:30–05:15 (good, 7.75 h)	89.7° 03:05	7.83	6%	144.2°
2043-09-06 Sun	100	—	unknown	21:25–05:20 (good, 7.92 h)	89.5° 03:00	7.88	11%	148.5°
2043-09-07 Mon	100	—	unknown	21:25–05:20 (good, 7.92 h)	89.6° 03:00	7.94	18%	148.9°
2043-09-08 Tue	100	—	unknown	21:20–05:20 (good, 8.0 h)	89.8° 02:55	7.99	26%	145.3°
2043-09-09 Wed	100	—	unknown	21:20–05:20 (good, 8.0 h)	89.8° 02:50	8.05	35%	138.8°
2043-09-10 Thu	100	—	unknown	21:20–05:25 (good, 8.08 h)	89.7° 02:45	8.1	44%	130.6°
2043-09-11 Fri	100	—	unknown	21:15–05:25 (good, 8.17 h)	89.5° 02:45	8.15	54%	121.4°
2043-09-12 Sat	100	—	unknown	21:15–05:25 (good, 8.17 h)	89.7° 02:40	8.21	63%	111.6°
2043-09-13 Sun	100	—	unknown	21:10–05:25 (good, 8.25 h)	89.8° 02:35	8.26	72%	101.3°
2043-09-14 Mon	100	—	unknown	21:10–05:30 (good, 8.33 h)	89.8° 02:30	8.31	81%	90.5°
2043-09-15 Tue	100	—	unknown	21:20–05:30 (good, 8.17 h)	89.6° 02:25	8.37	88%	79.5°
2043-09-16 Wed	100	—	unknown	23:15–05:30 (good, 6.25 h)	89.6° 02:25	8.42	94%	68.2°
2043-09-17 Thu	65	—	unknown	04:00–05:30 (good, 1.5 h)	89.7° 02:20	8.47	98%	57.1°
2043-09-18 Fri	53	—	unknown	21:00–05:35 (marginal, 8.58 h)	89.8° 02:15	8.52	100%	46.5°
2043-09-19 Sat	40	—	unknown	21:00–05:35 (marginal, 8.58 h)	89.7° 02:10	8.57	99%	37.5°
2043-09-20 Sun	39	—	unknown	21:00–05:35 (marginal, 8.58 h)	89.5° 02:05	8.63	95%	31.7°
2043-09-21 Mon	49	—	unknown	20:55–05:35 (marginal, 8.67 h)	89.6° 02:05	8.68	89%	31.4°
2043-09-22 Tue	84	—	unknown	20:55–21:05 (good, 0.17 h)	89.8° 02:00	8.73	81%	36.7°
2043-09-23 Wed	89	—	unknown	20:55–01:35 (good, 4.67 h)	89.8° 01:55	8.78	71%	45.6°
2043-09-24 Thu	95	—	unknown	20:50–05:30 (good, 8.67 h)	89.7° 01:50	8.83	60%	56.3°
2043-09-25 Fri	100	—	unknown	20:50–05:40 (good, 8.83 h)	89.5° 01:50	8.88	48%	67.8°
2043-09-26 Sat	100	—	unknown	20:45–05:45 (good, 9.0 h)	89.7° 01:45	8.93	37%	79.5°
2043-09-27 Sun	100	—	unknown	20:45–05:45 (good, 9.0 h)	89.8° 01:40	8.98	27%	91.2°
2043-09-28 Mon	100	—	unknown	20:45–05:45 (good, 9.0 h)	89.8° 01:35	9.03	18%	102.7°
2043-09-29 Tue	100	—	unknown	20:40–05:45 (good, 9.08 h)	89.6° 01:30	9.08	10%	113.9°
2043-09-30 Wed	100	—	unknown	20:40–05:45 (good, 9.08 h)	89.6° 01:30	9.13	5%	124.4°
2043-10-01 Thu	100	—	unknown	20:40–05:50 (good, 9.17 h)	89.7° 01:25	9.17	2%	134.0°
2043-10-02 Fri	100	—	unknown	20:35–05:50 (good, 9.25 h)	89.8° 01:20	9.22	0%	142.0°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2043-09-03&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.