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: 08-27 (100), 08-28 (100), 08-29 (100), 08-30 (100), 08-31 (100) — by astronomy; check the weather when the night is within four days.

2035-08-23astronomy score per night — click a bar for that night2035-09-21

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2035-08-23 Thu	82	—	unknown	21:55–22:45 (good, 0.83 h)	89.5° 03:55	7.09	76%	37.6°
2035-08-24 Fri	86	—	unknown	21:50–03:20 (good, 5.5 h)	89.6° 03:55	7.15	66%	40.8°
2035-08-25 Sat	91	—	unknown	21:50–05:00 (good, 7.17 h)	89.7° 03:50	7.21	55%	47.3°
2035-08-26 Sun	97	—	unknown	21:50–05:05 (good, 7.25 h)	89.8° 03:45	7.26	44%	56.1°
2035-08-27 Mon	100	—	unknown	21:45–05:05 (good, 7.33 h)	89.6° 03:40	7.32	32%	66.3°
2035-08-28 Tue	100	—	unknown	21:45–05:05 (good, 7.33 h)	89.5° 03:35	7.38	22%	77.3°
2035-08-29 Wed	100	—	unknown	21:40–05:10 (good, 7.5 h)	89.6° 03:35	7.43	13%	88.8°
2035-08-30 Thu	100	—	unknown	21:40–05:10 (good, 7.5 h)	89.8° 03:30	7.49	6%	100.3°
2035-08-31 Fri	100	—	unknown	21:40–05:10 (good, 7.5 h)	89.7° 03:25	7.55	2%	111.5°
2035-09-01 Sat	100	—	unknown	21:35–05:10 (good, 7.58 h)	89.6° 03:20	7.6	0%	122.0°
2035-09-02 Sun	100	—	unknown	21:35–05:15 (good, 7.67 h)	89.5° 03:20	7.66	1%	131.1°
2035-09-03 Mon	100	—	unknown	21:30–05:15 (good, 7.75 h)	89.7° 03:15	7.71	4%	138.1°
2035-09-04 Tue	100	—	unknown	21:30–05:15 (good, 7.75 h)	89.8° 03:10	7.77	10%	142.0°
2035-09-05 Wed	100	—	unknown	21:30–05:15 (good, 7.75 h)	89.7° 03:05	7.82	17%	142.1°
2035-09-06 Thu	100	—	unknown	21:25–05:20 (good, 7.92 h)	89.5° 03:00	7.88	25%	138.8°
2035-09-07 Fri	100	—	unknown	21:25–05:20 (good, 7.92 h)	89.6° 03:00	7.93	34%	132.9°
2035-09-08 Sat	100	—	unknown	21:20–05:20 (good, 8.0 h)	89.7° 02:55	7.99	43%	125.5°
2035-09-09 Sun	100	—	unknown	21:20–05:20 (good, 8.0 h)	89.8° 02:50	8.04	53%	117.1°
2035-09-10 Mon	100	—	unknown	21:20–05:25 (good, 8.08 h)	89.7° 02:45	8.1	62%	108.3°
2035-09-11 Tue	100	—	unknown	21:15–05:25 (good, 8.17 h)	89.5° 02:40	8.15	71%	99.0°
2035-09-12 Wed	100	—	unknown	21:15–05:25 (good, 8.17 h)	89.6° 02:40	8.2	80%	89.6°
2035-09-13 Thu	100	—	unknown	21:45–05:25 (good, 7.67 h)	89.8° 02:35	8.26	87%	80.0°
2035-09-14 Fri	100	—	unknown	23:10–05:30 (good, 6.33 h)	89.7° 02:30	8.31	93%	70.4°
2035-09-15 Sat	70	—	unknown	02:50–05:30 (good, 2.67 h)	89.6° 02:25	8.36	97%	61.1°
2035-09-16 Sun	60	—	unknown	05:20–05:30 (good, 0.17 h)	89.5° 02:25	8.42	100%	52.3°
2035-09-17 Mon	50	—	unknown	21:05–05:30 (marginal, 8.42 h)	89.7° 02:20	8.47	100%	44.8°
2035-09-18 Tue	46	—	unknown	21:00–05:35 (marginal, 8.58 h)	89.8° 02:15	8.52	98%	39.4°
2035-09-19 Wed	52	—	unknown	21:00–05:35 (marginal, 8.58 h)	89.7° 02:10	8.57	94%	37.4°
2035-09-20 Thu	85	—	unknown	21:00–21:20 (good, 0.33 h)	89.6° 02:05	8.62	87%	39.6°
2035-09-21 Fri	90	—	unknown	20:55–00:35 (good, 3.67 h)	89.6° 02:05	8.67	79%	45.5°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2035-08-23&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.