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 HD 189733: 08-07 (100), 08-08 (100), 08-09 (100), 08-10 (100), 08-11 (100) — by astronomy; check the weather when the night is within four days.

2031-08-05astronomy score per night — click a bar for that night2031-09-03

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2031-08-05 Tue	66	—	unknown	22:30–00:20 (good, 1.83 h)	71.1° 00:25	6.06	88%	54.5°
2031-08-06 Wed	77	—	unknown	22:25–02:45 (good, 4.33 h)	71.1° 00:20	6.12	80%	64.4°
2031-08-07 Thu	100	—	unknown	22:25–04:05 (good, 5.67 h)	71.1° 00:20	6.17	71%	74.7°
2031-08-08 Fri	100	—	unknown	22:25–04:35 (good, 6.17 h)	71.1° 00:15	6.23	61%	85.0°
2031-08-09 Sat	100	—	unknown	22:20–04:40 (good, 6.33 h)	71.1° 00:10	6.29	51%	95.0°
2031-08-10 Sun	100	—	unknown	22:20–04:40 (good, 6.33 h)	71.1° 00:05	6.34	41%	104.8°
2031-08-11 Mon	100	—	unknown	22:15–04:40 (good, 6.42 h)	71.1° 00:05	6.4	32%	114.0°
2031-08-12 Tue	100	—	unknown	22:15–04:45 (good, 6.5 h)	71.1° 00:00	6.46	23%	122.7°
2031-08-13 Wed	100	—	unknown	22:15–04:45 (good, 6.5 h)	71.1° 23:55	6.52	16%	130.4°
2031-08-14 Thu	100	—	unknown	22:10–04:45 (good, 6.58 h)	71.1° 23:50	6.57	10%	136.8°
2031-08-15 Fri	100	—	unknown	22:10–04:45 (good, 6.58 h)	71.1° 23:45	6.63	5%	141.1°
2031-08-16 Sat	100	—	unknown	22:05–04:50 (good, 6.75 h)	71.1° 23:45	6.69	2%	142.7°
2031-08-17 Sun	100	—	unknown	22:05–04:45 (good, 6.67 h)	71.1° 23:40	6.75	0%	141.0°
2031-08-18 Mon	100	—	unknown	22:05–04:40 (good, 6.58 h)	71.1° 23:35	6.8	1%	136.4°
2031-08-19 Tue	100	—	unknown	22:00–04:35 (good, 6.58 h)	71.1° 23:30	6.86	3%	129.6°
2031-08-20 Wed	100	—	unknown	22:00–04:35 (good, 6.58 h)	71.1° 23:25	6.92	7%	121.4°
2031-08-21 Thu	100	—	unknown	22:00–04:30 (good, 6.5 h)	71.1° 23:25	6.98	14%	112.1°
2031-08-22 Fri	100	—	unknown	21:55–04:25 (good, 6.5 h)	71.1° 23:20	7.03	21%	102.1°
2031-08-23 Sat	100	—	unknown	21:55–04:20 (good, 6.42 h)	71.1° 23:15	7.09	30%	91.8°
2031-08-24 Sun	100	—	unknown	21:50–04:20 (good, 6.5 h)	71.1° 23:10	7.15	41%	81.1°
2031-08-25 Mon	100	—	unknown	21:50–04:15 (good, 6.42 h)	71.1° 23:10	7.2	52%	70.4°
2031-08-26 Tue	100	—	unknown	21:50–04:10 (good, 6.33 h)	71.1° 23:05	7.26	63%	60.0°
2031-08-27 Wed	93	—	unknown	21:45–04:05 (good, 6.33 h)	71.1° 23:00	7.32	74%	50.4°
2031-08-28 Thu	84	—	unknown	00:30–02:25 (good, 1.92 h)	71.1° 22:55	7.37	83%	42.6°
2031-08-29 Fri	44	—	unknown	21:40–04:25 (marginal, 6.75 h)	71.1° 22:50	7.43	91%	37.9°
2031-08-30 Sat	35	—	unknown	21:40–04:00 (marginal, 6.33 h)	71.1° 22:50	7.49	97%	37.9°
2031-08-31 Sun	35	—	unknown	21:40–03:45 (marginal, 6.08 h)	71.1° 22:45	7.54	100%	42.6°
2031-09-01 Mon	43	—	unknown	21:35–03:40 (marginal, 6.08 h)	71.1° 22:40	7.6	99%	50.5°
2031-09-02 Tue	56	—	unknown	21:35–22:35 (good, 1.0 h)	71.1° 22:35	7.66	97%	60.2°
2031-09-03 Wed	74	—	unknown	21:30–00:45 (good, 3.25 h)	71.1° 22:30	7.71	92%	70.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2031-08-05&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.