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: 09-07 (100), 09-08 (100), 09-09 (100), 09-10 (100), 09-11 (100) — by astronomy; check the weather when the night is within four days.

2042-08-31astronomy score per night — click a bar for that night2042-09-29

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
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°
2042-09-17 Wed	100	—	unknown	21:05–05:35 (good, 8.5 h)	89.6° 02:20	8.48	11%	147.6°
2042-09-18 Thu	100	—	unknown	21:00–05:35 (good, 8.58 h)	89.7° 02:15	8.54	18%	144.9°
2042-09-19 Fri	100	—	unknown	21:00–05:35 (good, 8.58 h)	89.8° 02:10	8.59	25%	139.2°
2042-09-20 Sat	100	—	unknown	21:00–05:35 (good, 8.58 h)	89.7° 02:05	8.64	34%	131.4°
2042-09-21 Sun	100	—	unknown	20:55–05:35 (good, 8.67 h)	89.5° 02:00	8.69	44%	122.4°
2042-09-22 Mon	100	—	unknown	20:55–05:40 (good, 8.75 h)	89.6° 02:00	8.74	54%	112.4°
2042-09-23 Tue	100	—	unknown	20:50–05:40 (good, 8.83 h)	89.8° 01:55	8.79	64%	101.7°
2042-09-24 Wed	100	—	unknown	20:50–05:40 (good, 8.83 h)	89.8° 01:50	8.84	74%	90.4°
2042-09-25 Thu	100	—	unknown	20:50–05:40 (good, 8.83 h)	89.6° 01:45	8.89	83%	78.8°
2042-09-26 Fri	100	—	unknown	22:20–05:45 (good, 7.42 h)	89.5° 01:45	8.94	91%	67.0°
2042-09-27 Sat	91	—	unknown	03:35–05:45 (good, 2.17 h)	89.7° 01:40	8.99	96%	55.4°
2042-09-28 Sun	52	—	unknown	20:45–05:45 (marginal, 9.0 h)	89.8° 01:35	9.04	100%	44.7°
2042-09-29 Mon	41	—	unknown	20:40–05:45 (marginal, 9.08 h)	89.8° 01:30	9.09	100%	36.3°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2042-08-31&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.