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.

2044-08-13astronomy score per night — click a bar for that night2044-09-11

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2044-08-13 Sat	48	—	unknown	22:10–04:45 (marginal, 6.58 h)	89.7° 04:35	6.56	76%	30.8°
2044-08-14 Sun	74	—	unknown	22:25–22:50 (good, 0.42 h)	89.8° 04:30	6.62	66%	29.7°
2044-08-15 Mon	83	—	unknown	22:20–04:50 (good, 6.5 h)	89.8° 04:25	6.68	55%	33.9°
2044-08-16 Tue	87	—	unknown	22:20–04:50 (good, 6.5 h)	89.6° 04:20	6.74	44%	42.0°
2044-08-17 Wed	93	—	unknown	22:15–04:50 (good, 6.58 h)	89.6° 04:20	6.79	33%	52.4°
2044-08-18 Thu	100	—	unknown	22:10–04:55 (good, 6.75 h)	89.7° 04:15	6.85	22%	64.2°
2044-08-19 Fri	100	—	unknown	22:05–04:55 (good, 6.83 h)	89.8° 04:10	6.91	13%	76.6°
2044-08-20 Sat	100	—	unknown	22:00–04:55 (good, 6.92 h)	89.7° 04:05	6.97	6%	89.5°
2044-08-21 Sun	100	—	unknown	22:00–04:55 (good, 6.92 h)	89.5° 04:00	7.02	2%	102.3°
2044-08-22 Mon	100	—	unknown	21:55–05:00 (good, 7.08 h)	89.6° 04:00	7.08	0%	114.8°
2044-08-23 Tue	100	—	unknown	21:50–05:00 (good, 7.17 h)	89.8° 03:55	7.14	1%	126.7°
2044-08-24 Wed	100	—	unknown	21:50–05:00 (good, 7.17 h)	89.8° 03:50	7.2	5%	137.2°
2044-08-25 Thu	100	—	unknown	21:50–05:05 (good, 7.25 h)	89.7° 03:45	7.25	10%	145.5°
2044-08-26 Fri	100	—	unknown	21:45–05:05 (good, 7.33 h)	89.5° 03:45	7.31	18%	150.1°
2044-08-27 Sat	100	—	unknown	21:45–05:05 (good, 7.33 h)	89.7° 03:40	7.37	27%	149.7°
2044-08-28 Sun	100	—	unknown	21:40–05:05 (good, 7.42 h)	89.8° 03:35	7.42	36%	145.0°
2044-08-29 Mon	100	—	unknown	21:40–05:10 (good, 7.5 h)	89.8° 03:30	7.48	46%	137.5°
2044-08-30 Tue	100	—	unknown	21:40–05:10 (good, 7.5 h)	89.6° 03:25	7.54	55%	128.7°
2044-08-31 Wed	100	—	unknown	21:35–05:10 (good, 7.58 h)	89.6° 03:25	7.59	64%	119.1°
2044-09-01 Thu	100	—	unknown	21:35–05:15 (good, 7.67 h)	89.7° 03:20	7.65	73%	109.2°
2044-09-02 Fri	100	—	unknown	21:30–05:15 (good, 7.75 h)	89.8° 03:15	7.7	81%	98.9°
2044-09-03 Sat	100	—	unknown	21:35–05:15 (good, 7.67 h)	89.7° 03:10	7.76	88%	88.5°
2044-09-04 Sun	100	—	unknown	22:40–05:15 (good, 6.58 h)	89.5° 03:05	7.81	94%	78.0°
2044-09-05 Mon	73	—	unknown	01:00–05:20 (good, 4.33 h)	89.6° 03:05	7.87	98%	67.5°
2044-09-06 Tue	63	—	unknown	04:45–05:20 (good, 0.58 h)	89.8° 03:00	7.92	100%	57.1°
2044-09-07 Wed	51	—	unknown	21:20–05:20 (marginal, 8.0 h)	89.8° 02:55	7.98	100%	47.2°
2044-09-08 Thu	38	—	unknown	21:20–05:20 (marginal, 8.0 h)	89.7° 02:50	8.03	98%	38.3°
2044-09-09 Fri	38	—	unknown	21:20–05:25 (marginal, 8.08 h)	89.5° 02:50	8.09	94%	31.8°
2044-09-10 Sat	46	—	unknown	21:15–05:25 (marginal, 8.17 h)	89.7° 02:45	8.14	87%	29.5°
2044-09-11 Sun	81	—	unknown	21:15–21:20 (good, 0.08 h)	89.8° 02:40	8.19	79%	32.5°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2044-08-13&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.