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: 08-17 (100), 08-18 (100), 08-19 (100), 08-20 (100), 08-21 (100) — by astronomy; check the weather when the night is within four days.

2047-08-17astronomy score per night — click a bar for that night2047-09-15

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2047-08-17 Sat	100	—	unknown	22:15–04:50 (good, 6.58 h)	89.7° 04:20	6.75	13%	76.8°
2047-08-18 Sun	100	—	unknown	22:15–04:50 (good, 6.58 h)	89.6° 04:15	6.81	7%	88.2°
2047-08-19 Mon	100	—	unknown	22:10–04:55 (good, 6.75 h)	89.6° 04:15	6.87	3%	99.9°
2047-08-20 Tue	100	—	unknown	22:05–04:55 (good, 6.83 h)	89.8° 04:10	6.93	0%	111.7°
2047-08-21 Wed	100	—	unknown	22:00–04:55 (good, 6.92 h)	89.8° 04:05	6.98	0%	123.5°
2047-08-22 Thu	100	—	unknown	21:55–05:00 (good, 7.08 h)	89.7° 04:00	7.04	3%	134.7°
2047-08-23 Fri	100	—	unknown	21:55–05:00 (good, 7.08 h)	89.5° 03:55	7.1	9%	144.4°
2047-08-24 Sat	100	—	unknown	21:50–05:00 (good, 7.17 h)	89.7° 03:55	7.15	16%	150.6°
2047-08-25 Sun	100	—	unknown	21:50–05:00 (good, 7.17 h)	89.8° 03:50	7.21	26%	151.0°
2047-08-26 Mon	100	—	unknown	21:50–05:05 (good, 7.25 h)	89.8° 03:45	7.27	36%	145.4°
2047-08-27 Tue	100	—	unknown	21:45–05:05 (good, 7.33 h)	89.6° 03:40	7.33	48%	136.2°
2047-08-28 Wed	100	—	unknown	21:45–05:05 (good, 7.33 h)	89.6° 03:40	7.38	59%	125.3°
2047-08-29 Thu	100	—	unknown	21:40–05:10 (good, 7.5 h)	89.7° 03:35	7.44	70%	113.8°
2047-08-30 Fri	100	—	unknown	21:45–05:10 (good, 7.42 h)	89.8° 03:30	7.49	80%	101.9°
2047-08-31 Sat	100	—	unknown	21:50–05:10 (good, 7.33 h)	89.8° 03:25	7.55	88%	90.1°
2047-09-01 Sun	100	—	unknown	23:10–05:10 (good, 6.0 h)	89.6° 03:20	7.61	94%	78.4°
2047-09-02 Mon	72	—	unknown	02:00–05:15 (good, 3.25 h)	89.6° 03:20	7.66	98%	67.1°
2047-09-03 Tue	61	—	unknown	05:00–05:15 (good, 0.25 h)	89.8° 03:15	7.72	100%	56.3°
2047-09-04 Wed	46	—	unknown	21:30–05:15 (marginal, 7.75 h)	89.8° 03:10	7.77	100%	46.3°
2047-09-05 Thu	34	—	unknown	21:30–05:15 (marginal, 7.75 h)	89.7° 03:05	7.83	97%	37.7°
2047-09-06 Fri	35	—	unknown	21:25–05:20 (marginal, 7.92 h)	89.5° 03:00	7.88	93%	31.3°
2047-09-07 Sat	42	—	unknown	21:25–05:20 (marginal, 7.92 h)	89.7° 03:00	7.94	88%	28.5°
2047-09-08 Sun	54	—	unknown	20:50–05:20 (marginal, 8.5 h)	89.8° 02:55	7.99	81%	30.1°
2047-09-09 Mon	83	—	unknown	21:20–00:20 (good, 3.0 h)	89.8° 02:50	8.05	73%	35.5°
2047-09-10 Tue	88	—	unknown	21:20–03:05 (good, 5.75 h)	89.6° 02:45	8.1	64%	43.2°
2047-09-11 Wed	93	—	unknown	21:15–05:25 (good, 8.17 h)	89.5° 02:45	8.16	55%	52.3°
2047-09-12 Thu	100	—	unknown	21:15–05:25 (good, 8.17 h)	89.7° 02:40	8.21	46%	62.2°
2047-09-13 Fri	100	—	unknown	21:10–05:30 (good, 8.33 h)	89.8° 02:35	8.26	36%	72.7°
2047-09-14 Sat	100	—	unknown	21:10–05:30 (good, 8.33 h)	89.8° 02:30	8.32	27%	83.7°
2047-09-15 Sun	100	—	unknown	21:10–05:30 (good, 8.33 h)	89.6° 02:25	8.37	18%	95.2°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2047-08-17&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.