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: 05-08 (2), 05-09 (2), 04-26 (1), 04-27 (1), 04-28 (1) — by astronomy; check the weather when the night is within four days.

2029-04-10astronomy score per night — click a bar for that night2029-05-09

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2029-04-10 Tue	0	—	unknown	—	89.7° 12:50	7.56	8%	46.1°
2029-04-11 Wed	0	—	unknown	—	89.7° 12:45	7.51	4%	37.9°
2029-04-12 Thu	0	—	unknown	—	89.6° 12:40	7.45	1%	31.7°
2029-04-13 Fri	0	—	unknown	—	89.5° 12:40	7.39	0%	28.7°
2029-04-14 Sat	0	—	unknown	—	89.7° 12:35	7.33	1%	30.0°
2029-04-15 Sun	0	—	unknown	—	89.7° 12:30	7.28	4%	35.2°
2029-04-16 Mon	0	—	unknown	—	89.7° 12:25	7.22	8%	43.0°
2029-04-17 Tue	0	—	unknown	—	89.5° 12:20	7.16	14%	52.2°
2029-04-18 Wed	0	—	unknown	—	89.6° 12:20	7.1	22%	62.3°
2029-04-19 Thu	0	—	unknown	—	89.7° 12:15	7.05	31%	73.0°
2029-04-20 Fri	0	—	unknown	—	89.7° 12:10	6.99	40%	84.2°
2029-04-21 Sat	0	—	unknown	—	89.6° 12:05	6.93	51%	95.8°
2029-04-22 Sun	0	—	unknown	—	89.6° 12:00	6.87	62%	107.7°
2029-04-23 Mon	0	—	unknown	—	89.7° 11:55	6.81	73%	119.6°
2029-04-24 Tue	0	—	unknown	—	89.7° 11:50	6.75	82%	131.3°
2029-04-25 Wed	0	—	unknown	—	89.6° 11:45	6.7	90%	141.8°
2029-04-26 Thu	1	—	unknown	—	89.5° 11:45	6.64	96%	149.4°
2029-04-27 Fri	1	—	unknown	—	89.7° 11:40	6.58	99%	151.1°
2029-04-28 Sat	1	—	unknown	—	89.7° 11:35	6.52	100%	146.1°
2029-04-29 Sun	1	—	unknown	—	89.7° 11:30	6.46	97%	136.8°
2029-04-30 Mon	1	—	unknown	—	89.5° 11:25	6.41	91%	125.5°
2029-05-01 Tue	1	—	unknown	—	89.6° 11:25	6.35	84%	113.7°
2029-05-02 Wed	1	—	unknown	—	89.7° 11:20	6.29	75%	101.9°
2029-05-03 Thu	1	—	unknown	—	89.7° 11:15	6.23	65%	90.3°
2029-05-04 Fri	1	—	unknown	—	89.6° 11:10	6.17	55%	79.0°
2029-05-05 Sat	1	—	unknown	—	89.5° 11:10	6.12	45%	68.2°
2029-05-06 Sun	1	—	unknown	—	89.6° 11:05	6.06	35%	58.0°
2029-05-07 Mon	1	—	unknown	—	89.7° 11:00	6.0	26%	48.4°
2029-05-08 Tue	2	—	unknown	—	89.7° 10:55	5.95	19%	39.8°
2029-05-09 Wed	2	—	unknown	04:55–05:00 (marginal, 0.08 h)	89.6° 10:50	5.89	12%	33.0°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2029-04-10&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.