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: 08-18 (100), 08-19 (100), 08-20 (100), 08-21 (100), 08-22 (100) — by astronomy; check the weather when the night is within four days.

2042-08-18astronomy score per night — click a bar for that night2042-09-16

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2042-08-18 Mon	100	—	unknown	22:10–04:50 (good, 6.67 h)	89.7° 04:15	6.82	9%	137.4°
2042-08-19 Tue	100	—	unknown	22:10–04:55 (good, 6.75 h)	89.6° 04:10	6.88	16%	143.6°
2042-08-20 Wed	100	—	unknown	22:05–04:55 (good, 6.83 h)	89.6° 04:10	6.94	23%	147.2°
2042-08-21 Thu	100	—	unknown	22:05–04:55 (good, 6.83 h)	89.8° 04:05	6.99	32%	147.1°
2042-08-22 Fri	100	—	unknown	22:00–05:00 (good, 7.0 h)	89.8° 04:00	7.05	41%	143.4°
2042-08-23 Sat	100	—	unknown	21:55–05:00 (good, 7.08 h)	89.7° 03:55	7.11	50%	136.9°
2042-08-24 Sun	100	—	unknown	21:55–05:00 (good, 7.08 h)	89.5° 03:50	7.17	60%	128.5°
2042-08-25 Mon	100	—	unknown	21:50–05:00 (good, 7.17 h)	89.7° 03:50	7.22	70%	118.9°
2042-08-26 Tue	100	—	unknown	21:55–05:05 (good, 7.17 h)	89.8° 03:45	7.28	79%	108.4°
2042-08-27 Wed	100	—	unknown	22:00–05:05 (good, 7.08 h)	89.8° 03:40	7.34	87%	97.2°
2042-08-28 Thu	100	—	unknown	22:10–05:05 (good, 6.92 h)	89.6° 03:35	7.39	94%	85.5°
2042-08-29 Fri	75	—	unknown	23:55–05:10 (good, 5.25 h)	89.5° 03:35	7.45	98%	73.5°
2042-08-30 Sat	63	—	unknown	04:15–05:10 (good, 0.92 h)	89.7° 03:30	7.51	100%	61.6°
2042-08-31 Sun	51	—	unknown	21:35–05:10 (marginal, 7.58 h)	89.8° 03:25	7.56	99%	50.3°
2042-09-01 Mon	43	—	unknown	21:35–05:10 (marginal, 7.58 h)	89.7° 03:20	7.62	95%	40.6°
2042-09-02 Tue	46	—	unknown	21:35–05:15 (marginal, 7.67 h)	89.6° 03:15	7.67	88%	34.0°
2042-09-03 Wed	80	—	unknown	21:30–21:45 (good, 0.25 h)	89.6° 03:15	7.73	80%	32.6°
2042-09-04 Thu	84	—	unknown	21:30–01:15 (good, 3.75 h)	89.8° 03:10	7.78	70%	36.6°
2042-09-05 Fri	88	—	unknown	21:25–05:20 (good, 7.92 h)	89.8° 03:05	7.84	59%	44.5°
2042-09-06 Sat	94	—	unknown	21:25–05:20 (good, 7.92 h)	89.7° 03:00	7.89	48%	54.2°
2042-09-07 Sun	100	—	unknown	21:25–05:20 (good, 7.92 h)	89.5° 02:55	7.95	37%	64.7°
2042-09-08 Mon	100	—	unknown	21:20–05:20 (good, 8.0 h)	89.6° 02:55	8.0	27%	75.5°
2042-09-09 Tue	100	—	unknown	21:20–05:25 (good, 8.08 h)	89.8° 02:50	8.06	18%	86.3°
2042-09-10 Wed	100	—	unknown	21:15–05:25 (good, 8.17 h)	89.8° 02:45	8.11	11%	97.0°
2042-09-11 Thu	100	—	unknown	21:15–05:25 (good, 8.17 h)	89.6° 02:40	8.17	6%	107.4°
2042-09-12 Fri	100	—	unknown	21:15–05:25 (good, 8.17 h)	89.5° 02:40	8.22	2%	117.4°
2042-09-13 Sat	100	—	unknown	21:10–05:30 (good, 8.33 h)	89.7° 02:35	8.27	0%	126.8°
2042-09-14 Sun	100	—	unknown	21:10–05:30 (good, 8.33 h)	89.8° 02:30	8.33	0%	135.2°
2042-09-15 Mon	100	—	unknown	21:05–05:30 (good, 8.42 h)	89.7° 02:25	8.38	2%	142.1°
2042-09-16 Tue	100	—	unknown	21:05–05:30 (good, 8.42 h)	89.6° 02:20	8.43	6%	146.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2042-08-18&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.