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: 03-11 (4), 03-12 (4), 03-13 (4), 03-14 (4), 03-15 (3) — by astronomy; check the weather when the night is within four days.

2033-03-11astronomy score per night — click a bar for that night2033-04-09

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2033-03-11 Fri	4	—	unknown	20:00–20:30 (marginal, 0.5 h)	89.5° 13:50	9.16	85%	100.0°
2033-03-12 Sat	4	—	unknown	20:00–20:25 (marginal, 0.42 h)	89.7° 13:45	9.11	91%	109.8°
2033-03-13 Sun	4	—	unknown	20:00–20:20 (marginal, 0.33 h)	89.8° 13:40	9.06	96%	119.3°
2033-03-14 Mon	4	—	unknown	20:00–20:20 (marginal, 0.33 h)	89.7° 13:35	9.01	99%	128.1°
2033-03-15 Tue	3	—	unknown	20:05–20:15 (marginal, 0.17 h)	89.5° 13:30	8.96	100%	135.9°
2033-03-16 Wed	2	—	unknown	20:05–20:10 (marginal, 0.08 h)	89.6° 13:30	8.91	99%	142.0°
2033-03-17 Thu	1	—	unknown	—	89.7° 13:25	8.86	97%	145.7°
2033-03-18 Fri	1	—	unknown	—	89.8° 13:20	8.81	93%	145.8°
2033-03-19 Sat	1	—	unknown	—	89.7° 13:15	8.76	87%	142.4°
2033-03-20 Sun	1	—	unknown	—	89.5° 13:10	8.71	80%	136.2°
2033-03-21 Mon	1	—	unknown	—	89.6° 13:10	8.65	71%	128.1°
2033-03-22 Tue	0	—	unknown	—	89.7° 13:05	8.6	62%	118.8°
2033-03-23 Wed	0	—	unknown	—	89.7° 13:00	8.55	52%	108.5°
2033-03-24 Thu	0	—	unknown	—	89.6° 12:55	8.5	41%	97.6°
2033-03-25 Fri	0	—	unknown	—	89.5° 12:55	8.44	30%	86.1°
2033-03-26 Sat	0	—	unknown	—	89.7° 12:50	8.39	20%	74.4°
2033-03-27 Sun	0	—	unknown	—	89.8° 13:45	8.34	12%	62.7°
2033-03-28 Mon	0	—	unknown	—	89.7° 13:40	8.28	5%	51.6°
2033-03-29 Tue	0	—	unknown	—	89.6° 13:35	8.23	1%	41.9°
2033-03-30 Wed	0	—	unknown	—	89.6° 13:35	8.18	0%	35.4°
2033-03-31 Thu	0	—	unknown	—	89.7° 13:30	8.12	2%	34.0°
2033-04-01 Fri	0	—	unknown	—	89.8° 13:25	8.07	7%	38.2°
2033-04-02 Sat	0	—	unknown	—	89.7° 13:20	8.01	14%	46.0°
2033-04-03 Sun	0	—	unknown	—	89.5° 13:15	7.96	23%	55.7°
2033-04-04 Mon	0	—	unknown	—	89.6° 13:15	7.9	33%	66.1°
2033-04-05 Tue	0	—	unknown	—	89.7° 13:10	7.84	43%	76.7°
2033-04-06 Wed	0	—	unknown	—	89.7° 13:05	7.79	53%	87.1°
2033-04-07 Thu	0	—	unknown	—	89.6° 13:00	7.73	63%	97.4°
2033-04-08 Fri	0	—	unknown	—	89.5° 13:00	7.68	72%	107.3°
2033-04-09 Sat	0	—	unknown	—	89.7° 12:55	7.62	80%	116.9°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2033-03-11&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.