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: 07-18 (100), 07-19 (100), 07-20 (100), 07-21 (100), 07-22 (100) — by astronomy; check the weather when the night is within four days.

2031-07-18astronomy score per night — click a bar for that night2031-08-16

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2031-07-18 Fri	100	—	unknown	00:15–04:05 (good, 3.83 h)	89.6° 06:20	5.12	0%	85.0°
2031-07-19 Sat	100	—	unknown	00:10–04:05 (good, 3.92 h)	89.7° 06:15	5.17	0%	95.2°
2031-07-20 Sun	100	—	unknown	00:05–04:05 (good, 4.0 h)	89.7° 06:10	5.21	2%	105.3°
2031-07-21 Mon	100	—	unknown	00:05–04:10 (good, 4.08 h)	89.6° 06:05	5.26	5%	115.3°
2031-07-22 Tue	100	—	unknown	00:00–04:10 (good, 4.17 h)	89.5° 06:05	5.31	10%	125.0°
2031-07-23 Wed	100	—	unknown	23:55–04:10 (good, 4.25 h)	89.7° 06:00	5.36	17%	134.1°
2031-07-24 Thu	100	—	unknown	23:50–04:15 (good, 4.42 h)	89.7° 05:55	5.41	25%	142.0°
2031-07-25 Fri	100	—	unknown	23:45–04:15 (good, 4.5 h)	89.7° 05:50	5.46	34%	147.5°
2031-07-26 Sat	100	—	unknown	23:45–04:15 (good, 4.5 h)	89.5° 05:45	5.51	45%	149.0°
2031-07-27 Sun	100	—	unknown	23:45–04:15 (good, 4.5 h)	89.6° 05:45	5.57	55%	145.7°
2031-07-28 Mon	100	—	unknown	23:40–04:20 (good, 4.67 h)	89.7° 05:40	5.62	66%	138.3°
2031-07-29 Tue	100	—	unknown	23:40–04:20 (good, 4.67 h)	89.7° 05:35	5.67	77%	128.3°
2031-07-30 Wed	100	—	unknown	23:40–04:20 (good, 4.67 h)	89.6° 05:30	5.73	86%	116.8°
2031-07-31 Thu	100	—	unknown	23:45–04:25 (good, 4.67 h)	89.5° 05:25	5.78	93%	104.4°
2031-08-01 Fri	79	—	unknown	00:10–04:25 (good, 4.25 h)	89.6° 05:25	5.84	98%	91.5°
2031-08-02 Sat	63	—	unknown	01:40–04:25 (good, 2.75 h)	89.7° 05:20	5.89	100%	78.5°
2031-08-03 Sun	48	—	unknown	22:50–04:30 (marginal, 5.67 h)	89.7° 05:15	5.95	99%	65.8°
2031-08-04 Mon	37	—	unknown	22:50–04:30 (marginal, 5.67 h)	89.6° 05:10	6.0	95%	53.9°
2031-08-05 Tue	34	—	unknown	22:45–04:30 (marginal, 5.75 h)	89.5° 05:10	6.06	88%	43.5°
2031-08-06 Wed	38	—	unknown	22:35–04:35 (marginal, 6.0 h)	89.7° 05:05	6.12	80%	35.5°
2031-08-07 Thu	50	—	unknown	22:25–04:35 (marginal, 6.17 h)	89.7° 05:00	6.17	71%	31.3°
2031-08-08 Fri	79	—	unknown	22:50–03:20 (good, 4.5 h)	89.7° 04:55	6.23	61%	32.0°
2031-08-09 Sat	85	—	unknown	22:50–04:40 (good, 5.83 h)	89.5° 04:50	6.29	51%	36.9°
2031-08-10 Sun	90	—	unknown	22:45–04:40 (good, 5.92 h)	89.6° 04:50	6.34	41%	44.4°
2031-08-11 Mon	95	—	unknown	22:40–04:40 (good, 6.0 h)	89.7° 04:45	6.4	32%	53.1°
2031-08-12 Tue	100	—	unknown	22:35–04:45 (good, 6.17 h)	89.7° 04:40	6.46	23%	62.6°
2031-08-13 Wed	100	—	unknown	22:35–04:45 (good, 6.17 h)	89.6° 04:35	6.52	16%	72.4°
2031-08-14 Thu	100	—	unknown	22:30–04:45 (good, 6.25 h)	89.5° 04:30	6.57	10%	82.5°
2031-08-15 Fri	100	—	unknown	22:25–04:45 (good, 6.33 h)	89.6° 04:30	6.63	5%	92.6°
2031-08-16 Sat	100	—	unknown	22:20–04:50 (good, 6.5 h)	89.7° 04:25	6.69	2%	102.7°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2031-07-18&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.