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: 08-18 (100), 08-19 (100), 08-20 (100), 08-21 (100), 08-22 (100) — by astronomy; check the weather when the night is within four days.

2030-08-11astronomy score per night — click a bar for that night2030-09-09

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2030-08-11 Sun	43	—	unknown	22:15–04:40 (marginal, 6.42 h)	71.1° 00:00	6.41	97%	39.5°
2030-08-12 Mon	37	—	unknown	22:15–04:45 (marginal, 6.5 h)	71.1° 00:00	6.47	100%	38.1°
2030-08-13 Tue	39	—	unknown	22:15–04:45 (marginal, 6.5 h)	71.1° 23:55	6.53	100%	40.9°
2030-08-14 Wed	48	—	unknown	22:10–04:45 (marginal, 6.58 h)	71.1° 23:50	6.59	97%	47.1°
2030-08-15 Thu	62	—	unknown	22:10–23:20 (good, 1.17 h)	71.1° 23:45	6.64	92%	55.2°
2030-08-16 Fri	74	—	unknown	22:05–01:35 (good, 3.5 h)	71.1° 23:40	6.7	86%	64.2°
2030-08-17 Sat	81	—	unknown	22:05–02:50 (good, 4.75 h)	71.1° 23:40	6.76	78%	73.7°
2030-08-18 Sun	100	—	unknown	22:05–03:55 (good, 5.83 h)	71.1° 23:35	6.82	70%	83.3°
2030-08-19 Mon	100	—	unknown	22:00–04:15 (good, 6.25 h)	71.1° 23:30	6.87	61%	92.8°
2030-08-20 Tue	100	—	unknown	22:00–04:20 (good, 6.33 h)	71.1° 23:25	6.93	51%	102.2°
2030-08-21 Wed	100	—	unknown	21:55–04:20 (good, 6.42 h)	71.1° 23:20	6.99	42%	111.2°
2030-08-22 Thu	100	—	unknown	21:55–04:20 (good, 6.42 h)	71.1° 23:20	7.05	33%	119.9°
2030-08-23 Fri	100	—	unknown	21:55–04:20 (good, 6.42 h)	71.1° 23:15	7.1	24%	127.9°
2030-08-24 Sat	100	—	unknown	21:50–04:15 (good, 6.42 h)	71.1° 23:10	7.16	16%	134.8°
2030-08-25 Sun	100	—	unknown	21:50–04:10 (good, 6.33 h)	71.1° 23:05	7.22	10%	139.8°
2030-08-26 Mon	100	—	unknown	21:45–04:10 (good, 6.42 h)	71.1° 23:05	7.27	5%	142.0°
2030-08-27 Tue	100	—	unknown	21:45–04:05 (good, 6.33 h)	71.1° 23:00	7.33	1%	140.7°
2030-08-28 Wed	100	—	unknown	21:45–04:00 (good, 6.25 h)	71.1° 22:55	7.39	0%	135.9°
2030-08-29 Thu	100	—	unknown	21:40–03:55 (good, 6.25 h)	71.1° 22:50	7.44	1%	128.6°
2030-08-30 Fri	100	—	unknown	21:40–03:55 (good, 6.25 h)	71.1° 22:45	7.5	5%	119.5°
2030-08-31 Sat	100	—	unknown	21:35–03:50 (good, 6.25 h)	71.1° 22:45	7.56	11%	109.3°
2030-09-01 Sun	100	—	unknown	21:35–03:45 (good, 6.17 h)	71.1° 22:40	7.61	18%	98.4°
2030-09-02 Mon	100	—	unknown	21:35–03:40 (good, 6.08 h)	71.1° 22:35	7.67	28%	87.3°
2030-09-03 Tue	100	—	unknown	21:30–03:35 (good, 6.08 h)	71.1° 22:30	7.72	39%	76.2°
2030-09-04 Wed	100	—	unknown	21:30–03:35 (good, 6.08 h)	71.1° 22:25	7.78	50%	65.5°
2030-09-05 Thu	98	—	unknown	21:25–03:30 (good, 6.08 h)	71.1° 22:25	7.83	62%	55.5°
2030-09-06 Fri	89	—	unknown	21:25–03:25 (good, 6.0 h)	71.1° 22:20	7.89	72%	46.9°
2030-09-07 Sat	79	—	unknown	02:50–03:20 (good, 0.5 h)	71.1° 22:15	7.94	82%	40.7°
2030-09-08 Sun	40	—	unknown	21:20–03:35 (marginal, 6.25 h)	71.1° 22:10	8.0	90%	38.0°
2030-09-09 Mon	34	—	unknown	21:20–03:20 (marginal, 6.0 h)	71.1° 22:10	8.05	95%	39.4°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2030-08-11&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.