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: 11-16 (100), 11-17 (100), 11-18 (100), 11-19 (100), 11-20 (100) — by astronomy; check the weather when the night is within four days.

2038-11-16astronomy score per night — click a bar for that night2038-12-15

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2038-11-16 Tue	100	—	unknown	18:40–01:55 (good, 7.25 h)	89.6° 21:20	10.99	79%	82.1°
2038-11-17 Wed	100	—	unknown	18:40–03:00 (good, 8.33 h)	89.6° 21:20	11.02	70%	91.9°
2038-11-18 Thu	100	—	unknown	18:40–03:05 (good, 8.42 h)	89.7° 21:15	11.04	60%	101.9°
2038-11-19 Fri	100	—	unknown	18:35–03:10 (good, 8.58 h)	89.8° 21:10	11.07	50%	111.8°
2038-11-20 Sat	100	—	unknown	18:35–03:10 (good, 8.58 h)	89.7° 21:05	11.1	39%	121.6°
2038-11-21 Sun	100	—	unknown	18:35–03:10 (good, 8.58 h)	89.5° 21:00	11.12	29%	130.5°
2038-11-22 Mon	100	—	unknown	18:35–03:05 (good, 8.5 h)	89.6° 21:00	11.15	19%	137.7°
2038-11-23 Tue	100	—	unknown	18:35–03:05 (good, 8.5 h)	89.8° 20:55	11.17	10%	141.7°
2038-11-24 Wed	100	—	unknown	18:35–03:00 (good, 8.42 h)	89.8° 20:50	11.19	4%	141.0°
2038-11-25 Thu	100	—	unknown	18:35–02:55 (good, 8.33 h)	89.6° 20:45	11.21	1%	135.7°
2038-11-26 Fri	100	—	unknown	18:35–02:50 (good, 8.25 h)	89.5° 20:45	11.24	0%	127.1°
2038-11-27 Sat	100	—	unknown	18:35–02:50 (good, 8.25 h)	89.7° 20:40	11.26	3%	116.8°
2038-11-28 Sun	100	—	unknown	18:35–02:45 (good, 8.17 h)	89.8° 20:35	11.28	8%	105.8°
2038-11-29 Mon	100	—	unknown	18:35–02:40 (good, 8.08 h)	89.7° 20:30	11.3	15%	94.6°
2038-11-30 Tue	100	—	unknown	18:35–02:35 (good, 8.0 h)	89.6° 20:25	11.31	24%	83.7°
2038-12-01 Wed	100	—	unknown	18:35–02:30 (good, 7.92 h)	89.6° 20:25	11.33	34%	73.3°
2038-12-02 Thu	99	—	unknown	18:35–02:30 (good, 7.92 h)	89.7° 20:20	11.35	44%	63.7°
2038-12-03 Fri	91	—	unknown	18:35–02:25 (good, 7.83 h)	89.8° 20:15	11.37	54%	54.9°
2038-12-04 Sat	84	—	unknown	18:35–02:20 (good, 7.75 h)	89.7° 20:10	11.38	64%	47.5°
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°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2038-11-16&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.