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: 10-06 (100), 10-07 (100), 10-08 (100), 10-09 (100), 10-10 (100) — by astronomy; check the weather when the night is within four days.

2031-09-30astronomy score per night — click a bar for that night2031-10-29

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2031-09-30 Tue	37	—	unknown	20:40–05:45 (marginal, 9.08 h)	89.5° 01:30	9.12	100%	34.7°
2031-10-01 Wed	36	—	unknown	20:40–00:35 (marginal, 3.92 h)	89.7° 01:25	9.17	98%	31.4°
2031-10-02 Thu	47	—	unknown	20:35–05:50 (marginal, 9.25 h)	89.7° 01:20	9.22	95%	33.2°
2031-10-03 Fri	58	—	unknown	20:00–05:50 (marginal, 9.83 h)	89.7° 01:15	9.27	89%	39.1°
2031-10-04 Sat	90	—	unknown	20:35–23:50 (good, 3.25 h)	89.6° 01:10	9.31	82%	47.3°
2031-10-05 Sun	97	—	unknown	20:30–02:55 (good, 6.42 h)	89.5° 01:10	9.36	73%	56.6°
2031-10-06 Mon	100	—	unknown	20:30–05:15 (good, 8.75 h)	89.7° 01:05	9.41	64%	66.4°
2031-10-07 Tue	100	—	unknown	20:30–05:55 (good, 9.42 h)	89.7° 01:00	9.45	55%	76.3°
2031-10-08 Wed	100	—	unknown	20:25–05:55 (good, 9.5 h)	89.7° 00:55	9.5	46%	86.4°
2031-10-09 Thu	100	—	unknown	20:25–05:55 (good, 9.5 h)	89.5° 00:50	9.54	36%	96.5°
2031-10-10 Fri	100	—	unknown	20:25–06:00 (good, 9.58 h)	89.6° 00:50	9.59	27%	106.6°
2031-10-11 Sat	100	—	unknown	20:20–06:00 (good, 9.67 h)	89.7° 00:45	9.64	19%	116.6°
2031-10-12 Sun	100	—	unknown	20:20–06:00 (good, 9.67 h)	89.7° 00:40	9.68	12%	126.3°
2031-10-13 Mon	100	—	unknown	20:20–06:00 (good, 9.67 h)	89.6° 00:35	9.72	6%	135.3°
2031-10-14 Tue	100	—	unknown	20:15–06:05 (good, 9.83 h)	89.5° 00:35	9.77	2%	143.0°
2031-10-15 Wed	100	—	unknown	20:15–06:05 (good, 9.83 h)	89.6° 00:30	9.81	0%	147.8°
2031-10-16 Thu	100	—	unknown	20:15–06:05 (good, 9.83 h)	89.7° 00:25	9.86	0%	148.2°
2031-10-17 Fri	100	—	unknown	20:10–06:05 (good, 9.92 h)	89.7° 00:20	9.9	3%	143.8°
2031-10-18 Sat	100	—	unknown	20:10–06:05 (good, 9.92 h)	89.6° 00:15	9.94	8%	135.7°
2031-10-19 Sun	100	—	unknown	20:10–06:10 (good, 10.0 h)	89.5° 00:15	9.98	15%	125.6°
2031-10-20 Mon	100	—	unknown	20:10–06:10 (good, 10.0 h)	89.7° 00:10	10.02	24%	114.4°
2031-10-21 Tue	100	—	unknown	20:05–06:10 (good, 10.08 h)	89.7° 00:05	10.07	34%	102.6°
2031-10-22 Wed	100	—	unknown	20:05–06:10 (good, 10.08 h)	89.7° 00:00	10.11	46%	90.5°
2031-10-23 Thu	100	—	unknown	20:05–06:05 (good, 10.0 h)	89.5° 23:55	10.15	57%	78.5°
2031-10-24 Fri	100	—	unknown	20:00–06:00 (good, 10.0 h)	89.6° 23:55	10.19	68%	66.6°
2031-10-25 Sat	94	—	unknown	22:20–05:00 (good, 7.67 h)	89.7° 23:50	10.23	78%	55.4°
2031-10-26 Sun	86	—	unknown	02:25–04:55 (good, 2.5 h)	89.7° 22:45	10.27	87%	45.1°
2031-10-27 Mon	68	—	unknown	04:35–04:50 (good, 0.25 h)	89.6° 22:40	10.31	93%	36.8°
2031-10-28 Tue	38	—	unknown	23:45–04:55 (marginal, 5.17 h)	89.5° 22:40	10.34	98%	32.0°
2031-10-29 Wed	35	—	unknown	18:55–21:45 (marginal, 2.83 h)	89.6° 22:35	10.38	100%	31.9°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2031-09-30&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.