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: 05-05 (2), 05-06 (2), 05-07 (2), 05-08 (2), 05-09 (2) — by astronomy; check the weather when the night is within four days.

2038-04-10astronomy score per night — click a bar for that night2038-05-09

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2038-04-10 Sat	0	—	unknown	—	89.7° 12:50	7.57	32%	67.6°
2038-04-11 Sun	0	—	unknown	—	89.6° 12:45	7.52	42%	77.2°
2038-04-12 Mon	0	—	unknown	—	89.6° 12:45	7.46	52%	87.3°
2038-04-13 Tue	0	—	unknown	—	89.7° 12:40	7.4	62%	97.7°
2038-04-14 Wed	0	—	unknown	—	89.8° 12:35	7.35	73%	108.4°
2038-04-15 Thu	0	—	unknown	—	89.7° 12:30	7.29	82%	118.9°
2038-04-16 Fri	0	—	unknown	—	89.5° 12:25	7.23	90%	128.6°
2038-04-17 Sat	0	—	unknown	—	89.6° 12:25	7.17	96%	136.6°
2038-04-18 Sun	0	—	unknown	—	89.8° 12:20	7.11	99%	141.2°
2038-04-19 Mon	0	—	unknown	—	89.8° 12:15	7.06	100%	141.1°
2038-04-20 Tue	0	—	unknown	—	89.6° 12:10	7.0	96%	136.2°
2038-04-21 Wed	0	—	unknown	—	89.5° 12:10	6.94	91%	128.2°
2038-04-22 Thu	0	—	unknown	—	89.8° 12:00	6.88	83%	118.5°
2038-04-23 Fri	0	—	unknown	—	89.8° 12:00	6.82	74%	108.2°
2038-04-24 Sat	0	—	unknown	—	89.6° 11:50	6.77	64%	97.8°
2038-04-25 Sun	0	—	unknown	—	89.6° 11:50	6.71	53%	87.5°
2038-04-26 Mon	0	—	unknown	—	89.7° 11:45	6.65	43%	77.6°
2038-04-27 Tue	1	—	unknown	—	89.8° 11:40	6.59	34%	68.2°
2038-04-28 Wed	1	—	unknown	—	89.7° 11:35	6.53	25%	59.4°
2038-04-29 Thu	1	—	unknown	—	89.5° 11:30	6.47	17%	51.6°
2038-04-30 Fri	1	—	unknown	—	89.6° 11:30	6.42	11%	45.0°
2038-05-01 Sat	1	—	unknown	—	89.8° 11:25	6.36	6%	40.3°
2038-05-02 Sun	1	—	unknown	—	89.8° 11:20	6.3	2%	38.3°
2038-05-03 Mon	1	—	unknown	—	89.6° 11:15	6.24	0%	39.2°
2038-05-04 Tue	1	—	unknown	—	89.5° 11:15	6.19	0%	43.0°
2038-05-05 Wed	2	—	unknown	—	89.7° 11:10	6.13	2%	49.0°
2038-05-06 Thu	2	—	unknown	05:00–05:05 (marginal, 0.08 h)	89.8° 11:05	6.07	6%	56.7°
2038-05-07 Fri	2	—	unknown	04:55–05:00 (marginal, 0.08 h)	89.7° 11:00	6.01	11%	65.3°
2038-05-08 Sat	2	—	unknown	04:55–05:00 (marginal, 0.08 h)	89.6° 10:55	5.96	18%	74.7°
2038-05-09 Sun	2	—	unknown	04:50–05:00 (marginal, 0.17 h)	89.6° 10:55	5.9	27%	84.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2038-04-10&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.