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: 12-14 (100), 12-15 (100), 12-16 (100), 12-17 (100), 12-18 (100) — by astronomy; check the weather when the night is within four days.

2038-12-05astronomy score per night — click a bar for that night2039-01-03

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2038-12-05 Sun	62	—	unknown	02:10–02:15 (good, 0.08 h)	89.5° 20:05	11.39	72%	41.8°
2038-12-06 Mon	50	—	unknown	18:35–02:40 (marginal, 8.08 h)	89.6° 20:05	11.41	80%	38.6°
2038-12-07 Tue	41	—	unknown	18:35–02:20 (marginal, 7.75 h)	89.8° 20:00	11.42	87%	38.3°
2038-12-08 Wed	37	—	unknown	18:35–02:00 (marginal, 7.42 h)	89.8° 19:55	11.43	93%	41.0°
2038-12-09 Thu	39	—	unknown	18:35–01:45 (marginal, 7.17 h)	89.6° 19:50	11.44	97%	46.2°
2038-12-10 Fri	47	—	unknown	18:35–01:40 (marginal, 7.08 h)	89.5° 19:50	11.45	99%	53.2°
2038-12-11 Sat	59	—	unknown	18:35–19:05 (good, 0.5 h)	89.7° 19:45	11.46	100%	61.3°
2038-12-12 Sun	70	—	unknown	18:35–21:00 (good, 2.42 h)	89.8° 19:40	11.47	99%	70.3°
2038-12-13 Mon	78	—	unknown	18:35–23:00 (good, 4.42 h)	89.7° 19:35	11.48	96%	79.8°
2038-12-14 Tue	100	—	unknown	18:35–00:15 (good, 5.67 h)	89.6° 19:30	11.49	90%	89.6°
2038-12-15 Wed	100	—	unknown	18:35–01:10 (good, 6.58 h)	89.6° 19:30	11.49	84%	99.5°
2038-12-16 Thu	100	—	unknown	18:35–01:15 (good, 6.67 h)	89.7° 19:25	11.5	75%	109.5°
2038-12-17 Fri	100	—	unknown	18:35–01:20 (good, 6.75 h)	89.8° 19:20	11.5	66%	119.1°
2038-12-18 Sat	100	—	unknown	18:35–01:20 (good, 6.75 h)	89.7° 19:15	11.5	55%	128.1°
2038-12-19 Sun	100	—	unknown	18:35–01:15 (good, 6.67 h)	89.5° 19:10	11.51	44%	135.7°
2038-12-20 Mon	100	—	unknown	18:35–01:15 (good, 6.67 h)	89.6° 19:10	11.51	33%	140.7°
2038-12-21 Tue	100	—	unknown	18:35–01:15 (good, 6.67 h)	89.8° 19:05	11.51	23%	141.8°
2038-12-22 Wed	100	—	unknown	18:35–01:10 (good, 6.58 h)	89.8° 19:00	11.51	14%	138.4°
2038-12-23 Thu	100	—	unknown	18:40–01:05 (good, 6.42 h)	89.6° 18:55	11.51	6%	131.2°
2038-12-24 Fri	100	—	unknown	18:40–01:00 (good, 6.33 h)	89.5° 18:55	11.5	2%	121.7°
2038-12-25 Sat	100	—	unknown	18:40–01:00 (good, 6.33 h)	89.7° 18:50	11.5	0%	110.9°
2038-12-26 Sun	100	—	unknown	18:40–00:55 (good, 6.25 h)	89.8° 18:45	11.5	1%	99.6°
2038-12-27 Mon	100	—	unknown	18:40–00:50 (good, 6.17 h)	89.7° 18:40	11.49	5%	88.4°
2038-12-28 Tue	100	—	unknown	18:40–00:45 (good, 6.08 h)	89.6° 18:35	11.48	11%	77.5°
2038-12-29 Wed	100	—	unknown	18:40–00:40 (good, 6.0 h)	89.6° 18:35	11.48	18%	67.2°
2038-12-30 Thu	95	—	unknown	18:40–00:40 (good, 6.0 h)	89.7° 18:30	11.47	27%	57.9°
2038-12-31 Fri	87	—	unknown	18:45–00:35 (good, 5.83 h)	89.8° 18:25	11.46	37%	49.7°
2039-01-01 Sat	77	—	unknown	18:45–00:30 (good, 5.75 h)	89.7° 18:20	11.45	46%	43.3°
2039-01-02 Sun	66	—	unknown	18:45–23:55 (good, 5.17 h)	89.5° 18:15	11.44	56%	39.2°
2039-01-03 Mon	50	—	unknown	18:45–00:50 (marginal, 6.08 h)	89.6° 18:15	11.43	65%	38.0°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2038-12-05&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.