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: 03-16 (3), 03-17 (2), 03-18 (1), 03-19 (1), 03-20 (1) — by astronomy; check the weather when the night is within four days.

2047-03-16astronomy score per night — click a bar for that night2047-04-14

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2047-03-16 Sat	3	—	unknown	20:05–20:15 (marginal, 0.17 h)	89.8° 13:30	8.93	69%	135.3°
2047-03-17 Sun	2	—	unknown	20:05–20:10 (marginal, 0.08 h)	89.7° 13:25	8.88	58%	124.3°
2047-03-18 Mon	1	—	unknown	—	89.5° 13:25	8.83	47%	112.9°
2047-03-19 Tue	1	—	unknown	—	89.7° 13:20	8.78	37%	101.4°
2047-03-20 Wed	1	—	unknown	—	89.8° 13:15	8.73	27%	90.0°
2047-03-21 Thu	1	—	unknown	—	89.8° 13:10	8.67	18%	78.8°
2047-03-22 Fri	0	—	unknown	—	89.6° 13:05	8.62	12%	68.0°
2047-03-23 Sat	0	—	unknown	—	89.6° 13:05	8.57	6%	57.6°
2047-03-24 Sun	0	—	unknown	—	89.7° 13:00	8.52	2%	47.9°
2047-03-25 Mon	0	—	unknown	—	89.8° 12:55	8.46	0%	39.3°
2047-03-26 Tue	0	—	unknown	—	89.7° 12:50	8.41	0%	32.4°
2047-03-27 Wed	0	—	unknown	—	89.6° 12:45	8.36	2%	28.7°
2047-03-28 Thu	0	—	unknown	—	89.6° 12:45	8.3	6%	29.2°
2047-03-29 Fri	0	—	unknown	—	89.8° 12:40	8.25	10%	33.7°
2047-03-30 Sat	0	—	unknown	—	89.8° 12:35	8.2	17%	41.0°
2047-03-31 Sun	0	—	unknown	—	89.7° 13:30	8.14	25%	49.8°
2047-04-01 Mon	0	—	unknown	—	89.5° 13:30	8.09	33%	59.7°
2047-04-02 Tue	0	—	unknown	—	89.7° 13:25	8.03	43%	70.2°
2047-04-03 Wed	0	—	unknown	—	89.8° 13:20	7.98	53%	81.3°
2047-04-04 Thu	0	—	unknown	—	89.8° 13:15	7.92	63%	92.8°
2047-04-05 Fri	0	—	unknown	—	89.6° 13:10	7.87	74%	104.6°
2047-04-06 Sat	0	—	unknown	—	89.6° 13:10	7.81	83%	116.7°
2047-04-07 Sun	0	—	unknown	—	89.7° 13:05	7.75	91%	128.6°
2047-04-08 Mon	0	—	unknown	—	89.8° 13:00	7.7	96%	139.7°
2047-04-09 Tue	0	—	unknown	—	89.7° 12:55	7.64	99%	148.3°
2047-04-10 Wed	0	—	unknown	—	89.6° 12:50	7.58	99%	151.6°
2047-04-11 Thu	0	—	unknown	—	89.6° 12:50	7.53	96%	147.8°
2047-04-12 Fri	0	—	unknown	—	89.8° 12:45	7.47	91%	139.1°
2047-04-13 Sat	0	—	unknown	—	89.8° 12:40	7.41	83%	128.1°
2047-04-14 Sun	0	—	unknown	—	89.7° 12:35	7.36	73%	116.4°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2047-03-16&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.