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: 09-30 (100), 10-01 (100), 10-02 (100), 10-03 (100), 10-04 (100) — by astronomy; check the weather when the night is within four days.

2038-09-30astronomy score per night — click a bar for that night2038-10-29

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2038-09-30 Thu	100	—	unknown	20:40–05:50 (good, 9.17 h)	89.6° 01:25	9.14	7%	141.2°
2038-10-01 Fri	100	—	unknown	20:40–05:50 (good, 9.17 h)	89.6° 01:25	9.18	14%	136.3°
2038-10-02 Sat	100	—	unknown	20:35–05:50 (good, 9.25 h)	89.7° 01:20	9.23	23%	128.3°
2038-10-03 Sun	100	—	unknown	20:35–05:50 (good, 9.25 h)	89.8° 01:15	9.28	34%	118.7°
2038-10-04 Mon	100	—	unknown	20:35–05:50 (good, 9.25 h)	89.7° 01:10	9.33	45%	108.4°
2038-10-05 Tue	100	—	unknown	20:30–05:55 (good, 9.42 h)	89.5° 01:05	9.37	56%	97.9°
2038-10-06 Wed	100	—	unknown	20:30–05:55 (good, 9.42 h)	89.6° 01:05	9.42	66%	87.6°
2038-10-07 Thu	100	—	unknown	20:25–05:55 (good, 9.5 h)	89.8° 01:00	9.47	75%	77.4°
2038-10-08 Fri	100	—	unknown	20:40–05:55 (good, 9.25 h)	89.8° 00:55	9.51	83%	67.8°
2038-10-09 Sat	94	—	unknown	00:55–06:00 (good, 5.08 h)	89.7° 00:50	9.56	90%	58.8°
2038-10-10 Sun	86	—	unknown	05:25–06:00 (good, 0.58 h)	89.5° 00:50	9.6	95%	50.7°
2038-10-11 Mon	52	—	unknown	20:20–06:00 (marginal, 9.67 h)	89.7° 00:45	9.65	98%	44.2°
2038-10-12 Tue	48	—	unknown	20:20–06:00 (marginal, 9.67 h)	89.8° 00:40	9.69	100%	39.6°
2038-10-13 Wed	50	—	unknown	20:20–06:00 (marginal, 9.67 h)	89.7° 00:35	9.74	99%	37.9°
2038-10-14 Thu	54	—	unknown	20:15–06:05 (marginal, 9.83 h)	89.6° 00:30	9.78	97%	39.3°
2038-10-15 Fri	59	—	unknown	19:45–06:05 (marginal, 10.33 h)	89.5° 00:30	9.82	93%	43.4°
2038-10-16 Sat	93	—	unknown	20:15–22:50 (good, 2.58 h)	89.7° 00:25	9.87	88%	49.6°
2038-10-17 Sun	97	—	unknown	20:10–00:55 (good, 4.75 h)	89.8° 00:20	9.91	81%	57.2°
2038-10-18 Mon	100	—	unknown	20:10–03:40 (good, 7.5 h)	89.7° 00:15	9.95	73%	65.8°
2038-10-19 Tue	100	—	unknown	20:10–05:05 (good, 8.92 h)	89.5° 00:10	10.0	64%	75.0°
2038-10-20 Wed	100	—	unknown	20:05–05:50 (good, 9.75 h)	89.6° 00:10	10.04	54%	84.7°
2038-10-21 Thu	100	—	unknown	20:05–06:00 (good, 9.92 h)	89.7° 00:05	10.08	44%	94.8°
2038-10-22 Fri	100	—	unknown	20:05–06:00 (good, 9.92 h)	89.8° 00:00	10.12	34%	105.0°
2038-10-23 Sat	100	—	unknown	20:05–06:00 (good, 9.92 h)	89.7° 23:55	10.16	24%	115.3°
2038-10-24 Sun	100	—	unknown	20:00–06:00 (good, 10.0 h)	89.5° 23:50	10.2	15%	125.2°
2038-10-25 Mon	100	—	unknown	20:00–05:55 (good, 9.92 h)	89.7° 23:50	10.24	8%	133.9°
2038-10-26 Tue	100	—	unknown	20:00–05:55 (good, 9.92 h)	89.8° 23:45	10.28	3%	140.0°
2038-10-27 Wed	100	—	unknown	20:00–05:50 (good, 9.83 h)	89.8° 23:40	10.32	0%	142.0°
2038-10-28 Thu	100	—	unknown	19:55–05:45 (good, 9.83 h)	89.6° 23:35	10.36	1%	139.0°
2038-10-29 Fri	100	—	unknown	19:55–05:40 (good, 9.75 h)	89.5° 23:35	10.39	5%	131.9°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2038-09-30&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.