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: 12-13 (100), 12-14 (100), 12-15 (100), 12-16 (100), 12-17 (100) — by astronomy; check the weather when the night is within four days.

2031-12-13astronomy score per night — click a bar for that night2032-01-11

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2031-12-13 Sat	100	—	unknown	18:35–01:45 (good, 7.17 h)	89.6° 19:35	11.48	0%	122.7°
2031-12-14 Sun	100	—	unknown	18:35–01:40 (good, 7.08 h)	89.5° 19:35	11.48	0%	110.6°
2031-12-15 Mon	100	—	unknown	18:35–01:40 (good, 7.08 h)	89.7° 19:30	11.49	4%	98.0°
2031-12-16 Tue	100	—	unknown	18:35–01:35 (good, 7.0 h)	89.7° 19:25	11.5	10%	85.3°
2031-12-17 Wed	100	—	unknown	18:35–01:30 (good, 6.92 h)	89.7° 19:20	11.5	18%	72.7°
2031-12-18 Thu	100	—	unknown	18:35–01:25 (good, 6.83 h)	89.5° 19:15	11.5	27%	60.8°
2031-12-19 Fri	91	—	unknown	18:35–01:20 (good, 6.75 h)	89.6° 19:15	11.51	38%	49.8°
2031-12-20 Sat	83	—	unknown	18:35–01:20 (good, 6.75 h)	89.7° 19:10	11.51	49%	40.5°
2031-12-21 Sun	63	—	unknown	20:45–00:00 (good, 3.25 h)	89.7° 19:05	11.51	60%	33.9°
2031-12-22 Mon	47	—	unknown	18:35–01:35 (marginal, 7.0 h)	89.6° 19:00	11.51	70%	31.4°
2031-12-23 Tue	34	—	unknown	18:40–01:20 (marginal, 6.67 h)	89.5° 18:55	11.51	79%	33.6°
2031-12-24 Wed	31	—	unknown	18:40–01:00 (marginal, 6.33 h)	89.6° 18:55	11.5	87%	39.6°
2031-12-25 Thu	33	—	unknown	18:40–00:50 (marginal, 6.17 h)	89.7° 18:50	11.5	93%	47.7°
2031-12-26 Fri	41	—	unknown	18:40–00:45 (marginal, 6.08 h)	89.7° 18:45	11.5	97%	56.9°
2031-12-27 Sat	53	—	unknown	18:40–19:10 (good, 0.5 h)	89.6° 18:40	11.49	99%	66.7°
2031-12-28 Sun	68	—	unknown	18:40–21:25 (good, 2.75 h)	89.5° 18:40	11.49	100%	76.8°
2031-12-29 Mon	78	—	unknown	18:40–22:35 (good, 3.92 h)	89.7° 18:35	11.48	98%	86.9°
2031-12-30 Tue	100	—	unknown	18:40–23:45 (good, 5.08 h)	89.7° 18:30	11.47	96%	97.1°
2031-12-31 Wed	100	—	unknown	18:45–00:10 (good, 5.42 h)	89.7° 18:25	11.46	91%	107.0°
2032-01-01 Thu	100	—	unknown	18:45–00:15 (good, 5.5 h)	89.6° 18:20	11.45	85%	116.8°
2032-01-02 Fri	100	—	unknown	18:45–00:15 (good, 5.5 h)	89.6° 18:20	11.44	77%	126.2°
2032-01-03 Sat	100	—	unknown	18:45–00:15 (good, 5.5 h)	89.7° 18:15	11.43	69%	134.8°
2032-01-04 Sun	100	—	unknown	18:45–00:15 (good, 5.5 h)	89.7° 18:10	11.42	60%	142.2°
2032-01-05 Mon	100	—	unknown	18:45–00:15 (good, 5.5 h)	89.7° 18:05	11.41	50%	147.2°
2032-01-06 Tue	100	—	unknown	18:45–00:10 (good, 5.42 h)	89.5° 18:00	11.39	40%	148.3°
2032-01-07 Wed	100	—	unknown	18:50–00:05 (good, 5.25 h)	89.6° 18:00	11.38	30%	144.9°
2032-01-08 Thu	100	—	unknown	18:50–00:05 (good, 5.25 h)	89.7° 17:55	11.36	20%	137.6°
2032-01-09 Fri	100	—	unknown	18:50–00:00 (good, 5.17 h)	89.7° 17:50	11.35	12%	127.7°
2032-01-10 Sat	100	—	unknown	18:50–23:55 (good, 5.08 h)	89.6° 17:45	11.33	5%	116.2°
2032-01-11 Sun	100	—	unknown	18:50–23:50 (good, 5.0 h)	89.5° 17:45	11.31	1%	103.8°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2031-12-13&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.