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: 05-11 (3), 05-12 (3), 05-09 (2), 05-10 (2), 04-26 (1) — by astronomy; check the weather when the night is within four days.

2045-04-13astronomy score per night — click a bar for that night2045-05-12

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2045-04-13 Thu	0	—	unknown	—	89.6° 12:40	7.39	12%	51.6°
2045-04-14 Fri	0	—	unknown	—	89.8° 12:35	7.33	6%	42.3°
2045-04-15 Sat	0	—	unknown	—	89.8° 12:30	7.27	2%	34.5°
2045-04-16 Sun	0	—	unknown	—	89.7° 12:25	7.21	0%	29.7°
2045-04-17 Mon	0	—	unknown	—	89.5° 12:25	7.15	1%	29.7°
2045-04-18 Tue	0	—	unknown	—	89.7° 12:20	7.1	3%	34.8°
2045-04-19 Wed	0	—	unknown	—	89.8° 12:15	7.04	8%	43.3°
2045-04-20 Thu	0	—	unknown	—	89.8° 12:10	6.98	15%	53.8°
2045-04-21 Fri	0	—	unknown	—	89.6° 12:05	6.92	24%	65.4°
2045-04-22 Sat	0	—	unknown	—	89.7° 12:00	6.86	35%	77.5°
2045-04-23 Sun	0	—	unknown	—	89.8° 11:55	6.81	46%	89.8°
2045-04-24 Mon	0	—	unknown	—	89.7° 11:50	6.75	57%	102.1°
2045-04-25 Tue	0	—	unknown	—	89.5° 11:45	6.69	68%	114.3°
2045-04-26 Wed	1	—	unknown	—	89.6° 11:45	6.63	78%	126.0°
2045-04-27 Thu	1	—	unknown	—	89.8° 11:40	6.57	87%	136.7°
2045-04-28 Fri	1	—	unknown	—	89.8° 11:35	6.51	94%	145.4°
2045-04-29 Sat	1	—	unknown	—	89.7° 11:30	6.46	98%	150.4°
2045-04-30 Sun	1	—	unknown	—	89.5° 11:30	6.4	100%	150.1°
2045-05-01 Mon	1	—	unknown	—	89.7° 11:25	6.34	99%	144.7°
2045-05-02 Tue	1	—	unknown	—	89.8° 11:20	6.28	97%	136.4°
2045-05-03 Wed	1	—	unknown	—	89.8° 11:15	6.22	92%	126.8°
2045-05-04 Thu	1	—	unknown	—	89.6° 11:10	6.17	86%	116.5°
2045-05-05 Fri	1	—	unknown	—	89.6° 11:10	6.11	78%	106.1°
2045-05-06 Sat	1	—	unknown	—	89.7° 11:05	6.05	70%	95.7°
2045-05-07 Sun	1	—	unknown	—	89.8° 11:00	6.0	61%	85.3°
2045-05-08 Mon	1	—	unknown	—	89.7° 10:55	5.94	52%	75.0°
2045-05-09 Tue	2	—	unknown	—	89.6° 10:50	5.88	42%	64.8°
2045-05-10 Wed	2	—	unknown	04:10–04:15 (marginal, 0.08 h)	89.6° 10:50	5.83	33%	54.8°
2045-05-11 Thu	3	—	unknown	04:05–04:15 (marginal, 0.17 h)	89.8° 10:45	5.77	24%	45.4°
2045-05-12 Fri	3	—	unknown	04:45–04:55 (marginal, 0.17 h)	89.8° 10:40	5.72	16%	37.0°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2045-04-13&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.