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: 01-19 (100), 01-20 (100), 01-21 (100), 01-22 (100), 01-23 (100) — by astronomy; check the weather when the night is within four days.

2028-01-19astronomy score per night — click a bar for that night2028-02-17

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
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°
2028-02-08 Tue	31	—	unknown	19:20–20:05 (good, 0.75 h)	89.5° 15:50	10.53	96%	88.0°
2028-02-09 Wed	38	—	unknown	19:25–21:20 (good, 1.92 h)	89.6° 15:50	10.49	99%	101.4°
2028-02-10 Thu	46	—	unknown	19:25–21:35 (good, 2.17 h)	89.7° 15:45	10.46	100%	114.6°
2028-02-11 Fri	50	—	unknown	19:25–21:35 (good, 2.17 h)	89.7° 15:40	10.42	97%	127.4°
2028-02-12 Sat	56	—	unknown	19:25–21:35 (good, 2.17 h)	89.6° 15:35	10.38	92%	138.8°
2028-02-13 Sun	56	—	unknown	19:25–21:40 (good, 2.25 h)	89.5° 15:35	10.34	84%	147.6°
2028-02-14 Mon	53	—	unknown	19:30–21:40 (good, 2.17 h)	89.7° 15:30	10.3	75%	151.8°
2028-02-15 Tue	51	—	unknown	19:30–21:35 (good, 2.08 h)	89.7° 15:25	10.27	65%	149.8°
2028-02-16 Wed	50	—	unknown	19:30–21:30 (good, 2.0 h)	89.7° 15:20	10.23	54%	143.2°
2028-02-17 Thu	48	—	unknown	19:30–21:25 (good, 1.92 h)	89.5° 15:15	10.18	44%	134.2°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2028-01-19&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.