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: 09-10 (100), 09-11 (100), 09-12 (100), 09-13 (100), 09-14 (100) — by astronomy; check the weather when the night is within four days.

2047-09-10astronomy score per night — click a bar for that night2047-10-09

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2047-09-10 Tue	100	—	unknown	21:20–02:55 (good, 5.58 h)	71.2° 22:05	8.1	64%	104.1°
2047-09-11 Wed	100	—	unknown	21:15–03:00 (good, 5.75 h)	71.2° 22:00	8.16	55%	112.8°
2047-09-12 Thu	100	—	unknown	21:15–03:00 (good, 5.75 h)	71.1° 21:55	8.21	46%	121.2°
2047-09-13 Fri	100	—	unknown	21:10–02:55 (good, 5.75 h)	71.1° 21:55	8.26	36%	128.8°
2047-09-14 Sat	100	—	unknown	21:10–02:55 (good, 5.75 h)	71.2° 21:50	8.32	27%	135.1°
2047-09-15 Sun	100	—	unknown	21:10–02:50 (good, 5.67 h)	71.2° 21:45	8.37	18%	139.2°
2047-09-16 Mon	100	—	unknown	21:05–02:50 (good, 5.75 h)	71.2° 21:40	8.42	10%	140.0°
2047-09-17 Tue	100	—	unknown	21:05–02:45 (good, 5.67 h)	71.1° 21:35	8.47	5%	137.0°
2047-09-18 Wed	100	—	unknown	21:00–02:40 (good, 5.67 h)	71.1° 21:35	8.52	1%	130.7°
2047-09-19 Thu	100	—	unknown	21:00–02:35 (good, 5.58 h)	71.2° 21:30	8.58	0%	121.9°
2047-09-20 Fri	100	—	unknown	21:00–02:30 (good, 5.5 h)	71.2° 21:25	8.63	2%	111.7°
2047-09-21 Sat	100	—	unknown	20:55–02:30 (good, 5.58 h)	71.1° 21:20	8.68	7%	100.6°
2047-09-22 Sun	100	—	unknown	20:55–02:25 (good, 5.5 h)	71.1° 21:20	8.73	14%	89.3°
2047-09-23 Mon	100	—	unknown	20:55–02:20 (good, 5.42 h)	71.2° 21:15	8.78	23%	78.1°
2047-09-24 Tue	100	—	unknown	20:50–02:15 (good, 5.42 h)	71.2° 21:10	8.83	34%	67.4°
2047-09-25 Wed	100	—	unknown	20:50–02:10 (good, 5.33 h)	71.2° 21:05	8.88	45%	57.7°
2047-09-26 Thu	91	—	unknown	20:45–02:10 (good, 5.42 h)	71.1° 21:00	8.93	56%	49.4°
2047-09-27 Fri	82	—	unknown	20:45–02:05 (good, 5.33 h)	71.1° 21:00	8.98	66%	43.3°
2047-09-28 Sat	51	—	unknown	20:45–02:30 (marginal, 5.75 h)	71.2° 20:55	9.03	76%	40.1°
2047-09-29 Sun	40	—	unknown	20:40–02:15 (marginal, 5.58 h)	71.2° 20:50	9.08	84%	40.4°
2047-09-30 Mon	34	—	unknown	20:40–02:00 (marginal, 5.33 h)	71.2° 20:45	9.13	91%	43.9°
2047-10-01 Tue	34	—	unknown	20:40–01:45 (marginal, 5.08 h)	71.1° 20:40	9.18	96%	49.8°
2047-10-02 Wed	38	—	unknown	20:35–01:40 (marginal, 5.08 h)	71.1° 20:40	9.22	99%	57.2°
2047-10-03 Thu	45	—	unknown	20:35–21:00 (good, 0.42 h)	71.2° 20:35	9.27	100%	65.5°
2047-10-04 Fri	54	—	unknown	20:35–22:35 (good, 2.0 h)	71.2° 20:30	9.32	99%	74.3°
2047-10-05 Sat	67	—	unknown	20:30–23:30 (good, 3.0 h)	71.1° 20:25	9.37	96%	83.4°
2047-10-06 Sun	80	—	unknown	20:30–00:30 (good, 4.0 h)	71.1° 20:25	9.41	92%	92.5°
2047-10-07 Mon	87	—	unknown	20:30–01:00 (good, 4.5 h)	71.2° 20:20	9.46	86%	101.6°
2047-10-08 Tue	100	—	unknown	20:25–01:05 (good, 4.67 h)	71.2° 20:15	9.5	79%	110.4°
2047-10-09 Wed	100	—	unknown	20:25–01:10 (good, 4.75 h)	71.2° 20:10	9.55	71%	118.8°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2047-09-10&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.