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: 09-21 (100), 09-22 (100), 09-23 (100), 09-24 (100), 09-25 (100) — by astronomy; check the weather when the night is within four days.

2042-09-21astronomy score per night — click a bar for that night2042-10-20

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2042-09-21 Sun	100	—	unknown	20:55–05:35 (good, 8.67 h)	89.5° 02:00	8.69	44%	122.4°
2042-09-22 Mon	100	—	unknown	20:55–05:40 (good, 8.75 h)	89.6° 02:00	8.74	54%	112.4°
2042-09-23 Tue	100	—	unknown	20:50–05:40 (good, 8.83 h)	89.8° 01:55	8.79	64%	101.7°
2042-09-24 Wed	100	—	unknown	20:50–05:40 (good, 8.83 h)	89.8° 01:50	8.84	74%	90.4°
2042-09-25 Thu	100	—	unknown	20:50–05:40 (good, 8.83 h)	89.6° 01:45	8.89	83%	78.8°
2042-09-26 Fri	100	—	unknown	22:20–05:45 (good, 7.42 h)	89.5° 01:45	8.94	91%	67.0°
2042-09-27 Sat	91	—	unknown	03:35–05:45 (good, 2.17 h)	89.7° 01:40	8.99	96%	55.4°
2042-09-28 Sun	52	—	unknown	20:45–05:45 (marginal, 9.0 h)	89.8° 01:35	9.04	100%	44.7°
2042-09-29 Mon	41	—	unknown	20:40–05:45 (marginal, 9.08 h)	89.8° 01:30	9.09	100%	36.3°
2042-09-30 Tue	42	—	unknown	20:40–01:45 (marginal, 5.08 h)	89.6° 01:25	9.14	97%	32.4°
2042-10-01 Wed	53	—	unknown	20:40–05:50 (marginal, 9.17 h)	89.6° 01:25	9.19	91%	34.5°
2042-10-02 Thu	87	—	unknown	20:35–22:45 (good, 2.17 h)	89.7° 01:20	9.23	83%	41.5°
2042-10-03 Fri	92	—	unknown	20:35–01:40 (good, 5.08 h)	89.8° 01:15	9.28	73%	51.0°
2042-10-04 Sat	98	—	unknown	20:35–05:00 (good, 8.42 h)	89.7° 01:10	9.33	63%	61.7°
2042-10-05 Sun	100	—	unknown	20:30–05:55 (good, 9.42 h)	89.5° 01:05	9.38	52%	72.7°
2042-10-06 Mon	100	—	unknown	20:30–05:55 (good, 9.42 h)	89.6° 01:05	9.42	41%	83.6°
2042-10-07 Tue	100	—	unknown	20:25–05:55 (good, 9.5 h)	89.8° 01:00	9.47	32%	94.4°
2042-10-08 Wed	100	—	unknown	20:25–05:55 (good, 9.5 h)	89.8° 00:55	9.51	23%	104.9°
2042-10-09 Thu	100	—	unknown	20:25–06:00 (good, 9.58 h)	89.7° 00:50	9.56	15%	115.0°
2042-10-10 Fri	100	—	unknown	20:25–06:00 (good, 9.58 h)	89.5° 00:50	9.61	9%	124.5°
2042-10-11 Sat	100	—	unknown	20:20–06:00 (good, 9.67 h)	89.7° 00:45	9.65	4%	133.1°
2042-10-12 Sun	100	—	unknown	20:20–06:00 (good, 9.67 h)	89.8° 00:40	9.69	1%	140.5°
2042-10-13 Mon	100	—	unknown	20:20–06:00 (good, 9.67 h)	89.8° 00:35	9.74	0%	145.7°
2042-10-14 Tue	100	—	unknown	20:15–06:05 (good, 9.83 h)	89.6° 00:30	9.78	1%	147.7°
2042-10-15 Wed	100	—	unknown	20:15–06:05 (good, 9.83 h)	89.6° 00:30	9.83	3%	146.0°
2042-10-16 Thu	100	—	unknown	20:15–06:05 (good, 9.83 h)	89.7° 00:25	9.87	7%	140.9°
2042-10-17 Fri	100	—	unknown	20:10–06:05 (good, 9.92 h)	89.8° 00:20	9.91	13%	133.7°
2042-10-18 Sat	100	—	unknown	20:10–06:05 (good, 9.92 h)	89.7° 00:15	9.95	20%	124.9°
2042-10-19 Sun	100	—	unknown	20:10–06:10 (good, 10.0 h)	89.5° 00:10	10.0	28%	115.3°
2042-10-20 Mon	100	—	unknown	20:05–06:10 (good, 10.08 h)	89.6° 00:10	10.04	38%	105.0°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2042-09-21&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.