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

2030-03-16astronomy score per night — click a bar for that night2030-04-14

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2030-03-16 Sat	2	—	unknown	20:05–20:10 (marginal, 0.08 h)	89.7° 13:30	8.92	90%	110.4°
2030-03-17 Sun	1	—	unknown	—	89.7° 13:25	8.87	96%	121.9°
2030-03-18 Mon	1	—	unknown	—	89.7° 13:20	8.82	99%	133.0°
2030-03-19 Tue	1	—	unknown	—	89.5° 13:15	8.77	100%	142.7°
2030-03-20 Wed	1	—	unknown	—	89.6° 13:15	8.72	98%	149.3°
2030-03-21 Thu	1	—	unknown	—	89.7° 13:10	8.67	93%	150.2°
2030-03-22 Fri	0	—	unknown	—	89.7° 13:05	8.62	86%	145.0°
2030-03-23 Sat	0	—	unknown	—	89.6° 13:00	8.56	77%	135.8°
2030-03-24 Sun	0	—	unknown	—	89.5° 13:00	8.51	66%	124.8°
2030-03-25 Mon	0	—	unknown	—	89.6° 12:55	8.46	55%	113.1°
2030-03-26 Tue	0	—	unknown	—	89.7° 12:50	8.41	44%	101.3°
2030-03-27 Wed	0	—	unknown	—	89.7° 12:45	8.35	34%	89.5°
2030-03-28 Thu	0	—	unknown	—	89.6° 12:40	8.3	24%	77.9°
2030-03-29 Fri	0	—	unknown	—	89.5° 12:40	8.24	16%	66.7°
2030-03-30 Sat	0	—	unknown	—	89.7° 12:35	8.19	9%	56.0°
2030-03-31 Sun	0	—	unknown	—	89.7° 13:30	8.14	4%	46.2°
2030-04-01 Mon	0	—	unknown	—	89.7° 13:25	8.08	1%	37.8°
2030-04-02 Tue	0	—	unknown	—	89.5° 13:20	8.03	0%	31.8°
2030-04-03 Wed	0	—	unknown	—	89.6° 13:20	7.97	1%	29.4°
2030-04-04 Thu	0	—	unknown	—	89.7° 13:15	7.91	4%	31.4°
2030-04-05 Fri	0	—	unknown	—	89.7° 13:10	7.86	8%	36.9°
2030-04-06 Sat	0	—	unknown	—	89.6° 13:05	7.8	14%	44.6°
2030-04-07 Sun	0	—	unknown	—	89.5° 13:05	7.75	21%	53.6°
2030-04-08 Mon	0	—	unknown	—	89.6° 13:00	7.69	29%	63.3°
2030-04-09 Tue	0	—	unknown	—	89.7° 12:55	7.63	38%	73.5°
2030-04-10 Wed	0	—	unknown	—	89.7° 12:50	7.58	48%	84.0°
2030-04-11 Thu	0	—	unknown	—	89.6° 12:45	7.52	58%	94.9°
2030-04-12 Fri	0	—	unknown	—	89.5° 12:45	7.46	68%	106.0°
2030-04-13 Sat	0	—	unknown	—	89.7° 12:40	7.41	77%	117.2°
2030-04-14 Sun	0	—	unknown	—	89.7° 12:35	7.35	86%	128.3°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2030-03-16&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.