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: 05-10 (3), 05-05 (2), 05-06 (2), 05-07 (2), 05-08 (2) — by astronomy; check the weather when the night is within four days.

2030-04-11astronomy score per night — click a bar for that night2030-05-10

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
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°
2030-04-15 Mon	0	—	unknown	—	89.7° 12:30	7.29	93%	138.7°
2030-04-16 Tue	0	—	unknown	—	89.5° 12:25	7.23	98%	146.9°
2030-04-17 Wed	0	—	unknown	—	89.6° 12:25	7.18	100%	150.6°
2030-04-18 Thu	0	—	unknown	—	89.7° 12:20	7.12	99%	147.6°
2030-04-19 Fri	0	—	unknown	—	89.7° 12:15	7.06	95%	139.5°
2030-04-20 Sat	0	—	unknown	—	89.6° 12:10	7.0	89%	128.6°
2030-04-21 Sun	0	—	unknown	—	89.5° 12:05	6.94	80%	116.7°
2030-04-22 Mon	0	—	unknown	—	89.7° 12:00	6.89	70%	104.4°
2030-04-23 Tue	0	—	unknown	—	89.7° 12:00	6.83	59%	92.3°
2030-04-24 Wed	0	—	unknown	—	89.6° 11:50	6.77	48%	80.5°
2030-04-25 Thu	0	—	unknown	—	89.5° 11:50	6.71	38%	69.1°
2030-04-26 Fri	0	—	unknown	—	89.7° 11:45	6.65	28%	58.3°
2030-04-27 Sat	1	—	unknown	—	89.7° 11:40	6.59	20%	48.4°
2030-04-28 Sun	1	—	unknown	—	89.7° 11:35	6.54	12%	39.6°
2030-04-29 Mon	1	—	unknown	—	89.5° 11:30	6.48	7%	33.0°
2030-04-30 Tue	1	—	unknown	—	89.6° 11:30	6.42	3%	29.6°
2030-05-01 Wed	1	—	unknown	—	89.7° 11:25	6.36	0%	30.5°
2030-05-02 Thu	1	—	unknown	—	89.7° 11:20	6.3	0%	35.2°
2030-05-03 Fri	1	—	unknown	—	89.6° 11:15	6.25	2%	42.5°
2030-05-04 Sat	1	—	unknown	—	89.5° 11:10	6.19	5%	51.2°
2030-05-05 Sun	2	—	unknown	—	89.6° 11:10	6.13	10%	60.7°
2030-05-06 Mon	2	—	unknown	05:00–05:05 (marginal, 0.08 h)	89.7° 11:05	6.07	16%	70.7°
2030-05-07 Tue	2	—	unknown	04:55–05:05 (marginal, 0.17 h)	89.7° 11:00	6.02	24%	81.1°
2030-05-08 Wed	2	—	unknown	04:55–05:00 (marginal, 0.08 h)	89.6° 10:55	5.96	32%	91.7°
2030-05-09 Thu	2	—	unknown	04:50–05:00 (marginal, 0.17 h)	89.5° 10:55	5.9	42%	102.5°
2030-05-10 Fri	3	—	unknown	04:45–05:00 (marginal, 0.25 h)	89.7° 10:50	5.85	52%	113.4°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2030-04-11&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.