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: 02-12 (58), 02-13 (57), 02-14 (51), 02-15 (46), 02-16 (39) — by astronomy; check the weather when the night is within four days.

2040-02-12astronomy score per night — click a bar for that night2040-03-12

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2040-02-12 Sun	58	—	unknown	19:25–21:45 (good, 2.33 h)	89.6° 15:35	10.38	0%	67.9°
2040-02-13 Mon	57	—	unknown	19:25–21:40 (good, 2.25 h)	89.6° 15:35	10.34	3%	57.2°
2040-02-14 Tue	51	—	unknown	19:30–21:40 (good, 2.17 h)	89.7° 15:30	10.3	7%	48.0°
2040-02-15 Wed	46	—	unknown	19:30–21:35 (good, 2.08 h)	89.8° 15:25	10.26	14%	41.0°
2040-02-16 Thu	39	—	unknown	19:30–21:20 (good, 1.83 h)	89.7° 15:20	10.22	22%	37.1°
2040-02-17 Fri	32	—	unknown	19:30–21:05 (good, 1.58 h)	89.5° 15:15	10.18	31%	37.0°
2040-02-18 Sat	25	—	unknown	19:35–20:50 (good, 1.25 h)	89.6° 15:15	10.14	41%	40.5°
2040-02-19 Sun	20	—	unknown	19:35–21:50 (marginal, 2.25 h)	89.8° 15:10	10.1	50%	46.4°
2040-02-20 Mon	17	—	unknown	19:35–21:40 (marginal, 2.08 h)	89.8° 15:05	10.06	60%	53.9°
2040-02-21 Tue	15	—	unknown	19:35–21:30 (marginal, 1.92 h)	89.6° 15:00	10.02	69%	62.3°
2040-02-22 Wed	15	—	unknown	19:35–21:25 (marginal, 1.83 h)	89.5° 15:00	9.97	77%	71.3°
2040-02-23 Thu	15	—	unknown	19:40–21:25 (marginal, 1.75 h)	89.7° 14:55	9.93	84%	80.6°
2040-02-24 Fri	16	—	unknown	19:40–21:25 (marginal, 1.75 h)	89.8° 14:50	9.89	91%	90.2°
2040-02-25 Sat	18	—	unknown	19:40–20:20 (good, 0.67 h)	89.7° 14:45	9.84	96%	99.9°
2040-02-26 Sun	21	—	unknown	19:40–20:30 (good, 0.83 h)	89.6° 14:40	9.8	99%	109.6°
2040-02-27 Mon	22	—	unknown	19:45–20:35 (good, 0.83 h)	89.6° 14:40	9.75	100%	119.1°
2040-02-28 Tue	22	—	unknown	19:45–20:30 (good, 0.75 h)	89.7° 14:35	9.71	99%	128.0°
2040-02-29 Wed	24	—	unknown	19:45–20:30 (good, 0.75 h)	89.8° 14:30	9.66	96%	135.7°
2040-03-01 Thu	24	—	unknown	19:45–20:35 (good, 0.83 h)	89.7° 14:25	9.62	91%	141.3°
2040-03-02 Fri	22	—	unknown	19:50–20:30 (good, 0.67 h)	89.5° 14:20	9.57	84%	143.5°
2040-03-03 Sat	21	—	unknown	19:50–20:25 (good, 0.58 h)	89.6° 14:20	9.53	75%	141.6°
2040-03-04 Sun	19	—	unknown	19:50–20:25 (good, 0.58 h)	89.8° 14:15	9.48	65%	135.9°
2040-03-05 Mon	17	—	unknown	19:50–20:20 (good, 0.5 h)	89.8° 14:10	9.43	54%	127.6°
2040-03-06 Tue	14	—	unknown	19:55–20:15 (good, 0.33 h)	89.6° 14:05	9.39	43%	117.7°
2040-03-07 Wed	13	—	unknown	19:55–20:10 (good, 0.25 h)	89.5° 14:05	9.34	32%	106.8°
2040-03-08 Thu	11	—	unknown	19:55–20:10 (good, 0.25 h)	89.7° 14:00	9.29	22%	95.4°
2040-03-09 Fri	10	—	unknown	19:55–20:05 (good, 0.17 h)	89.8° 13:55	9.24	13%	83.8°
2040-03-10 Sat	9	—	unknown	19:55–20:00 (good, 0.08 h)	89.7° 13:50	9.19	6%	72.4°
2040-03-11 Sun	7	—	unknown	20:00–20:30 (marginal, 0.5 h)	89.6° 13:45	9.15	2%	61.5°
2040-03-12 Mon	6	—	unknown	20:00–20:25 (marginal, 0.42 h)	89.6° 13:45	9.1	0%	51.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2040-02-12&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.