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: 09-25 (100), 09-26 (100), 09-27 (100), 09-28 (100), 09-29 (100) — by astronomy; check the weather when the night is within four days.

2043-09-18astronomy score per night — click a bar for that night2043-10-17

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
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°
2043-10-03 Sat	100	—	unknown	20:35–05:50 (good, 9.25 h)	89.7° 01:15	9.27	1%	147.5°
2043-10-04 Sun	100	—	unknown	20:35–05:50 (good, 9.25 h)	89.5° 01:10	9.32	3%	149.2°
2043-10-05 Mon	100	—	unknown	20:30–05:55 (good, 9.42 h)	89.6° 01:10	9.36	7%	146.8°
2043-10-06 Tue	100	—	unknown	20:30–05:55 (good, 9.42 h)	89.8° 01:05	9.41	13%	141.1°
2043-10-07 Wed	100	—	unknown	20:30–05:55 (good, 9.42 h)	89.8° 01:00	9.46	20%	133.4°
2043-10-08 Thu	100	—	unknown	20:25–05:55 (good, 9.5 h)	89.7° 00:55	9.5	28%	124.5°
2043-10-09 Fri	100	—	unknown	20:25–05:55 (good, 9.5 h)	89.5° 00:55	9.55	37%	115.0°
2043-10-10 Sat	100	—	unknown	20:25–06:00 (good, 9.58 h)	89.7° 00:50	9.59	46%	104.9°
2043-10-11 Sun	100	—	unknown	20:20–06:00 (good, 9.67 h)	89.8° 00:45	9.64	56%	94.5°
2043-10-12 Mon	100	—	unknown	20:20–06:00 (good, 9.67 h)	89.8° 00:40	9.68	66%	83.8°
2043-10-13 Tue	100	—	unknown	20:20–06:00 (good, 9.67 h)	89.6° 00:35	9.73	75%	72.8°
2043-10-14 Wed	98	—	unknown	21:15–06:05 (good, 8.83 h)	89.6° 00:35	9.77	84%	61.8°
2043-10-15 Thu	88	—	unknown	02:45–06:05 (good, 3.33 h)	89.7° 00:30	9.82	91%	51.0°
2043-10-16 Fri	80	—	unknown	06:00–06:05 (good, 0.08 h)	89.8° 00:25	9.86	96%	41.1°
2043-10-17 Sat	39	—	unknown	01:10–06:05 (marginal, 4.92 h)	89.7° 00:20	9.9	100%	33.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2043-09-18&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.