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: 10-18 (100), 10-19 (100), 10-20 (100), 10-21 (100), 10-22 (100) — by astronomy; check the weather when the night is within four days.

2038-10-16astronomy score per night — click a bar for that night2038-11-14

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2038-10-16 Sat	93	—	unknown	20:15–22:50 (good, 2.58 h)	89.7° 00:25	9.87	88%	49.6°
2038-10-17 Sun	97	—	unknown	20:10–00:55 (good, 4.75 h)	89.8° 00:20	9.91	81%	57.2°
2038-10-18 Mon	100	—	unknown	20:10–03:40 (good, 7.5 h)	89.7° 00:15	9.95	73%	65.8°
2038-10-19 Tue	100	—	unknown	20:10–05:05 (good, 8.92 h)	89.5° 00:10	10.0	64%	75.0°
2038-10-20 Wed	100	—	unknown	20:05–05:50 (good, 9.75 h)	89.6° 00:10	10.04	54%	84.7°
2038-10-21 Thu	100	—	unknown	20:05–06:00 (good, 9.92 h)	89.7° 00:05	10.08	44%	94.8°
2038-10-22 Fri	100	—	unknown	20:05–06:00 (good, 9.92 h)	89.8° 00:00	10.12	34%	105.0°
2038-10-23 Sat	100	—	unknown	20:05–06:00 (good, 9.92 h)	89.7° 23:55	10.16	24%	115.3°
2038-10-24 Sun	100	—	unknown	20:00–06:00 (good, 10.0 h)	89.5° 23:50	10.2	15%	125.2°
2038-10-25 Mon	100	—	unknown	20:00–05:55 (good, 9.92 h)	89.7° 23:50	10.24	8%	133.9°
2038-10-26 Tue	100	—	unknown	20:00–05:55 (good, 9.92 h)	89.8° 23:45	10.28	3%	140.0°
2038-10-27 Wed	100	—	unknown	20:00–05:50 (good, 9.83 h)	89.8° 23:40	10.32	0%	142.0°
2038-10-28 Thu	100	—	unknown	19:55–05:45 (good, 9.83 h)	89.6° 23:35	10.36	1%	139.0°
2038-10-29 Fri	100	—	unknown	19:55–05:40 (good, 9.75 h)	89.5° 23:35	10.39	5%	131.9°
2038-10-30 Sat	100	—	unknown	19:55–04:40 (good, 9.75 h)	89.7° 23:30	10.43	11%	122.5°
2038-10-31 Sun	100	—	unknown	18:55–04:35 (good, 9.67 h)	89.8° 22:25	10.47	20%	112.0°
2038-11-01 Mon	100	—	unknown	18:50–04:30 (good, 9.67 h)	89.7° 22:20	10.5	29%	101.2°
2038-11-02 Tue	100	—	unknown	18:50–04:25 (good, 9.58 h)	89.6° 22:15	10.54	40%	90.5°
2038-11-03 Wed	100	—	unknown	18:50–04:20 (good, 9.5 h)	89.6° 22:15	10.58	50%	80.1°
2038-11-04 Thu	100	—	unknown	18:50–04:20 (good, 9.5 h)	89.7° 22:10	10.61	60%	70.2°
2038-11-05 Fri	97	—	unknown	18:50–04:15 (good, 9.42 h)	89.8° 22:05	10.65	70%	61.0°
2038-11-06 Sat	89	—	unknown	21:45–04:10 (good, 6.42 h)	89.7° 22:00	10.68	79%	52.7°
2038-11-07 Sun	81	—	unknown	03:20–04:05 (good, 0.75 h)	89.5° 21:55	10.71	86%	45.7°
2038-11-08 Mon	51	—	unknown	18:45–04:35 (marginal, 9.83 h)	89.6° 21:55	10.75	92%	40.6°
2038-11-09 Tue	47	—	unknown	18:45–04:10 (marginal, 9.42 h)	89.8° 21:50	10.78	96%	38.1°
2038-11-10 Wed	45	—	unknown	18:45–03:50 (marginal, 9.08 h)	89.8° 21:45	10.81	99%	38.7°
2038-11-11 Thu	49	—	unknown	18:45–03:30 (marginal, 8.75 h)	89.6° 21:40	10.84	100%	42.1°
2038-11-12 Fri	60	—	unknown	18:40–03:25 (marginal, 8.75 h)	89.5° 21:40	10.87	99%	47.8°
2038-11-13 Sat	67	—	unknown	18:40–20:10 (good, 1.5 h)	89.7° 21:35	10.9	96%	55.1°
2038-11-14 Sun	100	—	unknown	18:40–22:05 (good, 3.42 h)	89.8° 21:30	10.93	92%	63.5°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2038-10-16&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.