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.

2027-11-15astronomy score per night — click a bar for that night2027-12-14

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2027-11-15 Mon	65	—	unknown	18:40–19:45 (good, 1.08 h)	89.6° 21:25	10.95	96%	53.8°
2027-11-16 Tue	100	—	unknown	18:40–22:35 (good, 3.92 h)	89.5° 21:25	10.98	90%	65.5°
2027-11-17 Wed	100	—	unknown	18:40–01:15 (good, 6.58 h)	89.6° 21:20	11.01	83%	77.8°
2027-11-18 Thu	100	—	unknown	18:40–02:50 (good, 8.17 h)	89.7° 21:15	11.04	73%	90.3°
2027-11-19 Fri	100	—	unknown	18:35–03:00 (good, 8.42 h)	89.7° 21:10	11.06	63%	102.8°
2027-11-20 Sat	100	—	unknown	18:35–03:05 (good, 8.5 h)	89.5° 21:05	11.09	51%	115.1°
2027-11-21 Sun	100	—	unknown	18:35–03:05 (good, 8.5 h)	89.6° 21:05	11.11	40%	126.8°
2027-11-22 Mon	100	—	unknown	18:35–03:05 (good, 8.5 h)	89.7° 21:00	11.14	29%	137.5°
2027-11-23 Tue	100	—	unknown	18:35–03:05 (good, 8.5 h)	89.7° 20:55	11.16	20%	146.2°
2027-11-24 Wed	100	—	unknown	18:35–03:00 (good, 8.42 h)	89.6° 20:50	11.19	12%	151.2°
2027-11-25 Thu	100	—	unknown	18:35–02:55 (good, 8.33 h)	89.5° 20:45	11.21	6%	150.7°
2027-11-26 Fri	100	—	unknown	18:35–02:50 (good, 8.25 h)	89.6° 20:45	11.23	2%	145.1°
2027-11-27 Sat	100	—	unknown	18:35–02:50 (good, 8.25 h)	89.7° 20:40	11.25	0%	136.5°
2027-11-28 Sun	100	—	unknown	18:35–02:45 (good, 8.17 h)	89.7° 20:35	11.27	1%	126.6°
2027-11-29 Mon	100	—	unknown	18:35–02:40 (good, 8.08 h)	89.6° 20:30	11.29	3%	116.1°
2027-11-30 Tue	100	—	unknown	18:35–02:35 (good, 8.0 h)	89.5° 20:30	11.31	8%	105.4°
2027-12-01 Wed	100	—	unknown	18:35–02:30 (good, 7.92 h)	89.6° 20:25	11.33	14%	94.7°
2027-12-02 Thu	100	—	unknown	18:35–02:30 (good, 7.92 h)	89.7° 20:20	11.34	21%	84.1°
2027-12-03 Fri	100	—	unknown	18:35–02:25 (good, 7.83 h)	89.7° 20:15	11.36	29%	73.7°
2027-12-04 Sat	100	—	unknown	18:35–02:20 (good, 7.75 h)	89.5° 20:10	11.38	38%	63.5°
2027-12-05 Sun	93	—	unknown	18:35–02:15 (good, 7.67 h)	89.5° 20:10	11.39	47%	53.7°
2027-12-06 Mon	86	—	unknown	18:35–02:15 (good, 7.67 h)	89.7° 20:05	11.4	57%	44.4°
2027-12-07 Tue	73	—	unknown	22:15–01:00 (good, 2.75 h)	89.7° 20:00	11.42	66%	36.2°
2027-12-08 Wed	49	—	unknown	18:35–02:30 (marginal, 7.92 h)	89.6° 19:55	11.43	75%	30.2°
2027-12-09 Thu	33	—	unknown	18:35–02:10 (marginal, 7.58 h)	89.5° 19:50	11.44	83%	28.3°
2027-12-10 Fri	26	—	unknown	18:35–01:45 (marginal, 7.17 h)	89.6° 19:50	11.45	90%	31.6°
2027-12-11 Sat	28	—	unknown	18:35–23:10 (marginal, 4.58 h)	89.7° 19:45	11.46	96%	39.2°
2027-12-12 Sun	38	—	unknown	18:35–01:20 (marginal, 6.75 h)	89.7° 19:40	11.47	99%	49.5°
2027-12-13 Mon	56	—	unknown	18:35–18:55 (good, 0.33 h)	89.6° 19:35	11.48	100%	61.2°
2027-12-14 Tue	72	—	unknown	18:35–21:50 (good, 3.25 h)	89.5° 19:35	11.48	98%	73.7°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2027-11-15&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.