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: 03-19 (1) — by astronomy; check the weather when the night is within four days.

2043-03-19astronomy score per night — click a bar for that night2043-04-17

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2043-03-19 Thu	1	—	unknown	—	89.7° 13:20	8.78	70%	83.2°
2043-03-20 Fri	0	—	unknown	—	89.8° 13:15	8.73	79%	94.4°
2043-03-21 Sat	0	—	unknown	—	89.8° 13:10	8.68	87%	105.4°
2043-03-22 Sun	0	—	unknown	—	89.6° 13:05	8.62	93%	115.9°
2043-03-23 Mon	0	—	unknown	—	89.5° 13:05	8.57	97%	125.8°
2043-03-24 Tue	0	—	unknown	—	89.7° 13:00	8.52	100%	134.8°
2043-03-25 Wed	0	—	unknown	—	89.8° 12:55	8.47	100%	142.2°
2043-03-26 Thu	0	—	unknown	—	89.7° 12:50	8.41	98%	147.1°
2043-03-27 Fri	0	—	unknown	—	89.6° 12:45	8.36	95%	148.5°
2043-03-28 Sat	0	—	unknown	—	89.6° 12:45	8.31	90%	145.9°
2043-03-29 Sun	0	—	unknown	—	89.8° 13:40	8.25	84%	140.3°
2043-03-30 Mon	0	—	unknown	—	89.8° 13:35	8.2	76%	132.6°
2043-03-31 Tue	0	—	unknown	—	89.7° 13:30	8.14	68%	123.8°
2043-04-01 Wed	0	—	unknown	—	89.5° 13:25	8.09	58%	114.1°
2043-04-02 Thu	0	—	unknown	—	89.7° 13:25	8.03	49%	103.8°
2043-04-03 Fri	0	—	unknown	—	89.8° 13:20	7.98	38%	93.1°
2043-04-04 Sat	0	—	unknown	—	89.8° 13:15	7.92	29%	82.1°
2043-04-05 Sun	0	—	unknown	—	89.6° 13:10	7.87	19%	70.7°
2043-04-06 Mon	0	—	unknown	—	89.5° 13:10	7.81	11%	59.3°
2043-04-07 Tue	0	—	unknown	—	89.7° 13:05	7.76	5%	48.4°
2043-04-08 Wed	0	—	unknown	—	89.8° 13:00	7.7	1%	38.8°
2043-04-09 Thu	0	—	unknown	—	89.7° 12:55	7.64	0%	32.6°
2043-04-10 Fri	0	—	unknown	—	89.6° 12:50	7.59	2%	32.0°
2043-04-11 Sat	0	—	unknown	—	89.6° 12:50	7.53	7%	37.3°
2043-04-12 Sun	0	—	unknown	—	89.8° 12:45	7.47	14%	46.4°
2043-04-13 Mon	0	—	unknown	—	89.8° 12:40	7.41	23%	57.3°
2043-04-14 Tue	0	—	unknown	—	89.7° 12:35	7.36	34%	68.7°
2043-04-15 Wed	0	—	unknown	—	89.5° 12:30	7.3	45%	80.3°
2043-04-16 Thu	0	—	unknown	—	89.7° 12:30	7.24	55%	91.7°
2043-04-17 Fri	0	—	unknown	—	89.8° 12:25	7.18	66%	102.8°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2043-03-19&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.