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: 01-20 (100), 01-21 (100), 01-22 (100), 01-23 (100), 01-24 (100) — by astronomy; check the weather when the night is within four days.

2039-01-20astronomy score per night — click a bar for that night2039-02-18

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2039-01-20 Thu	100	—	unknown	19:00–23:15 (good, 4.25 h)	89.7° 17:05	11.11	17%	125.3°
2039-01-21 Fri	100	—	unknown	19:00–23:10 (good, 4.17 h)	89.5° 17:05	11.09	9%	115.2°
2039-01-22 Sat	100	—	unknown	19:05–23:05 (good, 4.0 h)	89.7° 17:00	11.06	4%	104.3°
2039-01-23 Sun	100	—	unknown	19:05–23:05 (good, 4.0 h)	89.8° 16:55	11.03	1%	93.1°
2039-01-24 Mon	100	—	unknown	19:05–23:00 (good, 3.92 h)	89.7° 16:50	11.01	0%	82.0°
2039-01-25 Tue	100	—	unknown	19:05–22:55 (good, 3.83 h)	89.6° 16:45	10.98	2%	71.4°
2039-01-26 Wed	97	—	unknown	19:05–22:50 (good, 3.75 h)	89.6° 16:45	10.95	7%	61.5°
2039-01-27 Thu	89	—	unknown	19:10–22:50 (good, 3.67 h)	89.7° 16:40	10.92	13%	52.6°
2039-01-28 Fri	79	—	unknown	19:10–22:45 (good, 3.58 h)	89.8° 16:35	10.89	20%	45.3°
2039-01-29 Sat	66	—	unknown	19:10–22:30 (good, 3.33 h)	89.7° 16:30	10.86	29%	40.2°
2039-01-30 Sun	54	—	unknown	19:10–22:15 (good, 3.08 h)	89.5° 16:25	10.83	38%	38.0°
2039-01-31 Mon	42	—	unknown	19:15–21:40 (good, 2.42 h)	89.6° 16:25	10.79	48%	38.9°
2039-02-01 Tue	33	—	unknown	19:15–19:35 (good, 0.33 h)	89.8° 16:20	10.76	57%	42.6°
2039-02-02 Wed	28	—	unknown	19:15–22:45 (marginal, 3.5 h)	89.8° 16:15	10.73	66%	48.6°
2039-02-03 Thu	25	—	unknown	19:15–22:35 (marginal, 3.33 h)	89.7° 16:10	10.7	75%	56.1°
2039-02-04 Fri	25	—	unknown	19:15–22:30 (marginal, 3.25 h)	89.5° 16:10	10.66	83%	64.6°
2039-02-05 Sat	26	—	unknown	19:20–22:25 (marginal, 3.08 h)	89.7° 16:05	10.63	89%	73.8°
2039-02-06 Sun	30	—	unknown	19:20–19:50 (good, 0.5 h)	89.8° 16:00	10.59	95%	83.6°
2039-02-07 Mon	36	—	unknown	19:20–20:45 (good, 1.42 h)	89.8° 15:55	10.56	98%	93.8°
2039-02-08 Tue	43	—	unknown	19:20–21:30 (good, 2.17 h)	89.6° 15:50	10.52	100%	104.1°
2039-02-09 Wed	48	—	unknown	19:25–21:40 (good, 2.25 h)	89.5° 15:50	10.48	99%	114.3°
2039-02-10 Thu	52	—	unknown	19:25–21:40 (good, 2.25 h)	89.7° 15:45	10.45	96%	124.0°
2039-02-11 Fri	57	—	unknown	19:25–21:40 (good, 2.25 h)	89.8° 15:40	10.41	91%	132.5°
2039-02-12 Sat	58	—	unknown	19:25–21:45 (good, 2.33 h)	89.7° 15:35	10.37	83%	139.0°
2039-02-13 Sun	56	—	unknown	19:25–21:40 (good, 2.25 h)	89.6° 15:30	10.33	74%	142.1°
2039-02-14 Mon	53	—	unknown	19:30–21:35 (good, 2.08 h)	89.6° 15:30	10.29	63%	140.9°
2039-02-15 Tue	51	—	unknown	19:30–21:35 (good, 2.08 h)	89.7° 15:25	10.25	52%	135.7°
2039-02-16 Wed	49	—	unknown	19:30–21:30 (good, 2.0 h)	89.8° 15:20	10.21	41%	127.7°
2039-02-17 Thu	48	—	unknown	19:30–21:25 (good, 1.92 h)	89.7° 15:15	10.17	30%	118.1°
2039-02-18 Fri	45	—	unknown	19:35–21:20 (good, 1.75 h)	89.5° 15:10	10.13	20%	107.7°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2039-01-20&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.