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: 07-17 (100), 07-18 (100), 07-19 (100), 07-20 (100), 07-21 (100) — by astronomy; check the weather when the night is within four days.

2031-06-29astronomy score per night — click a bar for that night2031-07-28

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2031-06-29 Sun	58	—	unknown	01:35–03:40 (good, 2.08 h)	89.6° 07:35	4.5	70%	148.7°
2031-06-30 Mon	60	—	unknown	01:35–03:45 (good, 2.17 h)	89.7° 07:30	4.51	80%	143.8°
2031-07-01 Tue	60	—	unknown	01:30–03:45 (good, 2.25 h)	89.7° 07:25	4.53	88%	135.0°
2031-07-02 Wed	55	—	unknown	01:30–03:45 (good, 2.25 h)	89.6° 07:20	4.56	95%	124.0°
2031-07-03 Thu	50	—	unknown	01:30–03:45 (good, 2.25 h)	89.5° 07:20	4.58	99%	111.7°
2031-07-04 Fri	43	—	unknown	01:40–03:45 (good, 2.08 h)	89.6° 07:15	4.6	100%	98.7°
2031-07-05 Sat	35	—	unknown	02:30–03:45 (good, 1.25 h)	89.7° 07:10	4.63	98%	85.7°
2031-07-06 Sun	31	—	unknown	03:45–03:50 (good, 0.08 h)	89.7° 07:05	4.66	93%	72.8°
2031-07-07 Mon	28	—	unknown	00:35–03:50 (marginal, 3.25 h)	89.6° 07:00	4.69	86%	60.6°
2031-07-08 Tue	28	—	unknown	00:25–03:50 (marginal, 3.42 h)	89.5° 07:00	4.72	77%	49.4°
2031-07-09 Wed	31	—	unknown	00:20–03:50 (marginal, 3.5 h)	89.7° 06:55	4.76	66%	40.0°
2031-07-10 Thu	39	—	unknown	01:35–03:55 (good, 2.33 h)	89.7° 06:50	4.79	56%	33.3°
2031-07-11 Fri	49	—	unknown	01:05–03:55 (good, 2.83 h)	89.7° 06:45	4.83	45%	30.8°
2031-07-12 Sat	64	—	unknown	00:40–03:55 (good, 3.25 h)	89.5° 06:40	4.87	36%	32.9°
2031-07-13 Sun	74	—	unknown	00:35–03:55 (good, 3.33 h)	89.6° 06:40	4.91	26%	38.6°
2031-07-14 Mon	85	—	unknown	00:30–04:00 (good, 3.5 h)	89.7° 06:35	4.95	18%	46.4°
2031-07-15 Tue	93	—	unknown	00:25–04:00 (good, 3.58 h)	89.7° 06:30	4.99	12%	55.4°
2031-07-16 Wed	99	—	unknown	00:25–04:00 (good, 3.58 h)	89.6° 06:25	5.03	6%	65.0°
2031-07-17 Thu	100	—	unknown	00:20–04:00 (good, 3.67 h)	89.5° 06:25	5.08	2%	74.9°
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°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2031-06-29&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.