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: 10-10 (100), 10-11 (100), 10-12 (100), 10-13 (100), 10-14 (100) — by astronomy; check the weather when the night is within four days.

2026-10-10astronomy score per night — click a bar for that night2026-11-08

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2026-10-10 Sat	100	98	98	20:25–06:00 (good, 9.58 h)	89.5° 00:45	9.6	0%	149.9°
2026-10-11 Sun	100	0	0	—	89.6° 00:45	9.64	2%	150.8°
2026-10-12 Mon	100	0	0	—	89.7° 00:40	9.69	6%	146.9°
2026-10-13 Tue	100	0	0	03:00–06:00 (good, 3.0 h)	89.7° 00:35	9.73	11%	139.8°
2026-10-14 Wed	100	—	unknown	20:15–06:05 (good, 9.83 h)	89.6° 00:30	9.78	17%	131.2°
2026-10-15 Thu	100	—	unknown	20:15–06:05 (good, 9.83 h)	89.5° 00:30	9.82	25%	121.6°
2026-10-16 Fri	100	—	unknown	20:15–06:05 (good, 9.83 h)	89.6° 00:25	9.86	34%	111.7°
2026-10-17 Sat	100	—	unknown	20:10–06:05 (good, 9.92 h)	89.7° 00:20	9.91	43%	101.5°
2026-10-18 Sun	100	—	unknown	20:10–06:05 (good, 9.92 h)	89.7° 00:15	9.95	52%	91.1°
2026-10-19 Mon	100	—	unknown	20:10–06:10 (good, 10.0 h)	89.6° 00:10	9.99	62%	80.6°
2026-10-20 Tue	100	—	unknown	20:10–06:10 (good, 10.0 h)	89.5° 00:10	10.03	71%	69.9°
2026-10-21 Wed	96	—	unknown	20:50–06:10 (good, 9.33 h)	89.7° 00:05	10.08	80%	59.3°
2026-10-22 Thu	88	—	unknown	02:15–06:10 (good, 3.92 h)	89.7° 00:00	10.12	87%	49.0°
2026-10-23 Fri	80	—	unknown	05:30–06:05 (good, 0.58 h)	89.7° 23:55	10.16	94%	39.4°
2026-10-24 Sat	39	—	unknown	00:50–05:15 (marginal, 5.42 h)	89.5° 23:50	10.2	98%	32.0°
2026-10-25 Sun	32	—	unknown	19:00–21:25 (marginal, 2.42 h)	89.6° 22:50	10.24	100%	29.0°
2026-10-26 Mon	37	—	unknown	19:00–22:15 (marginal, 3.25 h)	89.7° 22:45	10.28	99%	32.0°
2026-10-27 Tue	54	—	unknown	19:00–02:20 (marginal, 7.33 h)	89.7° 22:40	10.31	96%	40.0°
2026-10-28 Wed	65	—	unknown	18:55–20:55 (good, 2.0 h)	89.6° 22:35	10.35	90%	50.6°
2026-10-29 Thu	98	—	unknown	18:55–00:20 (good, 5.42 h)	89.5° 22:35	10.39	81%	62.5°
2026-10-30 Fri	100	—	unknown	18:55–02:50 (good, 7.92 h)	89.6° 22:30	10.43	71%	74.9°
2026-10-31 Sat	100	—	unknown	18:55–04:05 (good, 9.17 h)	89.7° 22:25	10.47	60%	87.3°
2026-11-01 Sun	100	—	unknown	18:50–04:15 (good, 9.42 h)	89.7° 22:20	10.5	49%	99.6°
2026-11-02 Mon	100	—	unknown	18:50–04:20 (good, 9.5 h)	89.6° 22:15	10.54	38%	111.6°
2026-11-03 Tue	100	—	unknown	18:50–04:20 (good, 9.5 h)	89.5° 22:15	10.57	28%	122.9°
2026-11-04 Wed	100	—	unknown	18:50–04:15 (good, 9.42 h)	89.7° 22:10	10.61	19%	133.4°
2026-11-05 Thu	100	—	unknown	18:50–04:15 (good, 9.42 h)	89.7° 22:05	10.64	12%	142.4°
2026-11-06 Fri	100	—	unknown	18:45–04:10 (good, 9.42 h)	89.7° 22:00	10.68	6%	148.8°
2026-11-07 Sat	100	—	unknown	18:45–04:05 (good, 9.33 h)	89.5° 21:55	10.71	2%	151.1°
2026-11-08 Sun	100	—	unknown	18:45–04:00 (good, 9.25 h)	89.6° 21:55	10.74	0%	148.5°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2026-10-10&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.