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: 02-18 (42), 02-19 (42), 02-20 (40), 02-16 (39), 02-17 (38) — by astronomy; check the weather when the night is within four days.

2041-02-16astronomy score per night — click a bar for that night2041-03-17

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2041-02-16 Sat	39	—	unknown	19:30–21:15 (good, 1.75 h)	89.6° 15:20	10.19	99%	119.3°
2041-02-17 Sun	38	—	unknown	19:35–21:10 (good, 1.58 h)	89.8° 15:15	10.15	97%	127.9°
2041-02-18 Mon	42	—	unknown	19:35–21:10 (good, 1.58 h)	89.8° 15:10	10.11	93%	135.6°
2041-02-19 Tue	42	—	unknown	19:35–21:15 (good, 1.67 h)	89.6° 15:05	10.07	87%	141.5°
2041-02-20 Wed	40	—	unknown	19:35–21:10 (good, 1.58 h)	89.5° 15:05	10.03	80%	144.7°
2041-02-21 Thu	38	—	unknown	19:35–21:10 (good, 1.58 h)	89.7° 15:00	9.98	71%	144.3°
2041-02-22 Fri	36	—	unknown	19:40–21:05 (good, 1.42 h)	89.8° 14:55	9.94	61%	140.1°
2041-02-23 Sat	35	—	unknown	19:40–21:00 (good, 1.33 h)	89.7° 14:50	9.9	51%	133.0°
2041-02-24 Sun	33	—	unknown	19:40–20:55 (good, 1.25 h)	89.6° 14:45	9.85	40%	123.9°
2041-02-25 Mon	31	—	unknown	19:40–20:50 (good, 1.17 h)	89.6° 14:45	9.81	29%	113.3°
2041-02-26 Tue	29	—	unknown	19:45–20:50 (good, 1.08 h)	89.7° 14:40	9.77	20%	101.9°
2041-02-27 Wed	27	—	unknown	19:45–20:45 (good, 1.0 h)	89.8° 14:35	9.72	11%	89.8°
2041-02-28 Thu	26	—	unknown	19:45–20:40 (good, 0.92 h)	89.7° 14:30	9.68	5%	77.5°
2041-03-01 Fri	25	—	unknown	19:45–20:35 (good, 0.83 h)	89.5° 14:25	9.63	1%	65.5°
2041-03-02 Sat	22	—	unknown	19:50–20:30 (good, 0.67 h)	89.6° 14:25	9.58	0%	54.1°
2041-03-03 Sun	21	—	unknown	19:50–20:30 (good, 0.67 h)	89.8° 14:20	9.54	3%	44.4°
2041-03-04 Mon	18	—	unknown	19:50–20:20 (good, 0.5 h)	89.8° 14:15	9.49	8%	37.5°
2041-03-05 Tue	15	—	unknown	19:50–20:15 (good, 0.42 h)	89.6° 14:10	9.45	15%	34.9°
2041-03-06 Wed	12	—	unknown	19:50–20:00 (good, 0.17 h)	89.5° 14:10	9.4	23%	37.0°
2041-03-07 Thu	8	—	unknown	19:55–20:45 (marginal, 0.83 h)	89.7° 14:05	9.35	33%	42.8°
2041-03-08 Fri	6	—	unknown	19:55–20:40 (marginal, 0.75 h)	89.8° 14:00	9.3	43%	50.6°
2041-03-09 Sat	5	—	unknown	19:55–20:35 (marginal, 0.67 h)	89.7° 13:55	9.25	53%	59.5°
2041-03-10 Sun	4	—	unknown	19:55–20:25 (marginal, 0.5 h)	89.6° 13:50	9.21	62%	69.0°
2041-03-11 Mon	3	—	unknown	20:00–20:25 (marginal, 0.42 h)	89.6° 13:50	9.16	71%	78.6°
2041-03-12 Tue	3	—	unknown	20:00–20:20 (marginal, 0.33 h)	89.7° 13:45	9.11	80%	88.3°
2041-03-13 Wed	3	—	unknown	20:00–20:20 (marginal, 0.33 h)	89.8° 13:40	9.06	86%	98.0°
2041-03-14 Thu	3	—	unknown	20:00–20:20 (marginal, 0.33 h)	89.7° 13:35	9.01	92%	107.5°
2041-03-15 Fri	2	—	unknown	20:05–20:15 (marginal, 0.17 h)	89.5° 13:30	8.96	96%	116.8°
2041-03-16 Sat	2	—	unknown	20:05–20:10 (marginal, 0.08 h)	89.6° 13:30	8.91	99%	125.7°
2041-03-17 Sun	1	—	unknown	—	89.8° 13:25	8.86	100%	133.8°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2041-02-16&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.