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: 08-13 (100), 08-14 (100), 08-15 (100), 08-16 (100), 08-17 (100) — by astronomy; check the weather when the night is within four days.

2044-08-10astronomy score per night — click a bar for that night2044-09-08

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2044-08-10 Wed	59	—	unknown	22:15–23:00 (good, 0.75 h)	71.1° 00:05	6.39	96%	51.7°
2044-08-11 Thu	70	—	unknown	22:15–00:20 (good, 2.08 h)	71.1° 00:00	6.45	91%	58.0°
2044-08-12 Fri	76	—	unknown	22:15–02:10 (good, 3.92 h)	71.1° 23:55	6.51	84%	65.7°
2044-08-13 Sat	100	—	unknown	22:10–03:20 (good, 5.17 h)	71.1° 23:50	6.56	76%	74.3°
2044-08-14 Sun	100	—	unknown	22:10–04:20 (good, 6.17 h)	71.1° 23:50	6.62	66%	83.6°
2044-08-15 Mon	100	—	unknown	22:10–04:35 (good, 6.42 h)	71.1° 23:45	6.68	55%	93.2°
2044-08-16 Tue	100	—	unknown	22:05–04:35 (good, 6.5 h)	71.1° 23:40	6.74	44%	102.9°
2044-08-17 Wed	100	—	unknown	22:05–04:40 (good, 6.58 h)	71.1° 23:35	6.79	33%	112.4°
2044-08-18 Thu	100	—	unknown	22:00–04:35 (good, 6.58 h)	71.1° 23:30	6.85	22%	121.2°
2044-08-19 Fri	100	—	unknown	22:00–04:35 (good, 6.58 h)	71.1° 23:30	6.91	13%	128.6°
2044-08-20 Sat	100	—	unknown	22:00–04:30 (good, 6.5 h)	71.1° 23:25	6.97	6%	133.6°
2044-08-21 Sun	100	—	unknown	21:55–04:25 (good, 6.5 h)	71.1° 23:20	7.02	2%	135.1°
2044-08-22 Mon	100	—	unknown	21:55–04:25 (good, 6.5 h)	71.1° 23:15	7.08	0%	133.0°
2044-08-23 Tue	100	—	unknown	21:50–04:20 (good, 6.5 h)	71.1° 23:15	7.14	1%	127.8°
2044-08-24 Wed	100	—	unknown	21:50–04:15 (good, 6.42 h)	71.1° 23:10	7.2	5%	120.4°
2044-08-25 Thu	100	—	unknown	21:50–04:10 (good, 6.33 h)	71.1° 23:05	7.25	10%	112.0°
2044-08-26 Fri	100	—	unknown	21:45–04:05 (good, 6.33 h)	71.1° 23:00	7.31	18%	103.1°
2044-08-27 Sat	100	—	unknown	21:45–04:05 (good, 6.33 h)	71.1° 22:55	7.37	27%	94.0°
2044-08-28 Sun	100	—	unknown	21:40–04:00 (good, 6.33 h)	71.1° 22:55	7.42	36%	85.2°
2044-08-29 Mon	100	—	unknown	21:40–03:55 (good, 6.25 h)	71.1° 22:50	7.48	46%	76.6°
2044-08-30 Tue	100	—	unknown	21:40–03:50 (good, 6.17 h)	71.1° 22:45	7.54	55%	68.5°
2044-08-31 Wed	100	—	unknown	21:35–03:50 (good, 6.25 h)	71.1° 22:40	7.59	64%	61.1°
2044-09-01 Thu	95	—	unknown	21:35–03:45 (good, 6.17 h)	71.1° 22:35	7.65	73%	54.6°
2044-09-02 Fri	87	—	unknown	21:30–03:40 (good, 6.17 h)	71.1° 22:35	7.7	81%	49.4°
2044-09-03 Sat	70	—	unknown	03:20–03:35 (good, 0.25 h)	71.1° 22:30	7.76	88%	46.0°
2044-09-04 Sun	47	—	unknown	21:30–03:50 (marginal, 6.33 h)	71.1° 22:25	7.81	94%	44.8°
2044-09-05 Mon	43	—	unknown	21:25–03:35 (marginal, 6.17 h)	71.1° 22:20	7.87	98%	46.3°
2044-09-06 Tue	43	—	unknown	21:25–03:25 (marginal, 6.0 h)	71.1° 22:20	7.92	100%	50.2°
2044-09-07 Wed	48	—	unknown	21:20–21:30 (good, 0.17 h)	71.1° 22:15	7.98	100%	56.2°
2044-09-08 Thu	58	—	unknown	21:20–22:40 (good, 1.33 h)	71.1° 22:10	8.03	98%	63.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2044-08-10&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.