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: 01-13 (100), 01-14 (100), 01-15 (100), 01-16 (100), 01-17 (100) — by astronomy; check the weather when the night is within four days.

2028-01-09astronomy score per night — click a bar for that night2028-02-07

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2028-01-09 Sun	31	—	unknown	18:50–23:50 (marginal, 5.0 h)	89.7° 17:50	11.35	93%	55.8°
2028-01-10 Mon	41	—	unknown	18:50–23:55 (marginal, 5.08 h)	89.6° 17:45	11.33	98%	68.1°
2028-01-11 Tue	56	—	unknown	18:50–21:00 (good, 2.17 h)	89.5° 17:45	11.31	100%	81.0°
2028-01-12 Wed	75	—	unknown	18:55–22:25 (good, 3.5 h)	89.6° 17:40	11.3	99%	94.3°
2028-01-13 Thu	100	—	unknown	18:55–23:20 (good, 4.42 h)	89.7° 17:35	11.28	95%	107.6°
2028-01-14 Fri	100	—	unknown	18:55–23:30 (good, 4.58 h)	89.7° 17:30	11.26	89%	120.4°
2028-01-15 Sat	100	—	unknown	18:55–23:25 (good, 4.5 h)	89.6° 17:25	11.24	80%	132.3°
2028-01-16 Sun	100	—	unknown	18:55–23:25 (good, 4.5 h)	89.5° 17:25	11.21	70%	142.6°
2028-01-17 Mon	100	—	unknown	19:00–23:30 (good, 4.5 h)	89.7° 17:20	11.19	60%	149.8°
2028-01-18 Tue	100	—	unknown	19:00–23:25 (good, 4.42 h)	89.7° 17:15	11.17	49%	151.9°
2028-01-19 Wed	100	—	unknown	19:00–23:20 (good, 4.33 h)	89.7° 17:10	11.14	38%	148.4°
2028-01-20 Thu	100	—	unknown	19:00–23:15 (good, 4.25 h)	89.5° 17:05	11.12	28%	141.1°
2028-01-21 Fri	100	—	unknown	19:00–23:10 (good, 4.17 h)	89.6° 17:05	11.09	20%	131.9°
2028-01-22 Sat	100	—	unknown	19:05–23:10 (good, 4.08 h)	89.7° 17:00	11.07	12%	121.8°
2028-01-23 Sun	100	—	unknown	19:05–23:05 (good, 4.0 h)	89.7° 16:55	11.04	7%	111.4°
2028-01-24 Mon	100	—	unknown	19:05–23:00 (good, 3.92 h)	89.6° 16:50	11.01	3%	100.8°
2028-01-25 Tue	100	—	unknown	19:05–22:55 (good, 3.83 h)	89.5° 16:50	10.99	0%	90.2°
2028-01-26 Wed	99	—	unknown	19:05–22:50 (good, 3.75 h)	89.6° 16:45	10.96	0%	79.7°
2028-01-27 Thu	96	—	unknown	19:10–22:50 (good, 3.67 h)	89.7° 16:40	10.93	2%	69.3°
2028-01-28 Fri	93	—	unknown	19:10–22:45 (good, 3.58 h)	89.7° 16:35	10.9	5%	59.2°
2028-01-29 Sat	87	—	unknown	19:10–22:40 (good, 3.5 h)	89.6° 16:30	10.87	10%	49.6°
2028-01-30 Sun	79	—	unknown	19:10–22:35 (good, 3.42 h)	89.5° 16:30	10.84	16%	40.8°
2028-01-31 Mon	66	—	unknown	19:15–22:35 (good, 3.33 h)	89.7° 16:25	10.81	23%	33.4°
2028-02-01 Tue	53	—	unknown	19:15–22:10 (good, 2.92 h)	89.7° 16:20	10.77	32%	28.8°
2028-02-02 Wed	42	—	unknown	19:15–21:55 (good, 2.67 h)	89.7° 16:15	10.74	41%	28.6°
2028-02-03 Thu	32	—	unknown	19:15–19:25 (good, 0.17 h)	89.5° 16:10	10.71	51%	33.0°
2028-02-04 Fri	26	—	unknown	19:15–22:35 (marginal, 3.33 h)	89.6° 16:10	10.67	62%	40.9°
2028-02-05 Sat	22	—	unknown	19:20–22:25 (marginal, 3.08 h)	89.7° 16:05	10.64	72%	51.1°
2028-02-06 Sun	22	—	unknown	19:20–22:20 (marginal, 3.0 h)	89.7° 16:00	10.6	81%	62.6°
2028-02-07 Mon	25	—	unknown	19:20–22:20 (marginal, 3.0 h)	89.6° 15:55	10.57	90%	75.0°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2028-01-09&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.