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: 07-22 (100), 07-23 (100), 07-24 (100), 07-25 (100), 07-26 (100) — by astronomy; check the weather when the night is within four days.

2044-07-22astronomy score per night — click a bar for that night2044-08-20

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2044-07-22 Fri	100	—	unknown	22:50–04:10 (good, 5.33 h)	71.1° 01:20	5.35	5%	124.2°
2044-07-23 Sat	100	—	unknown	22:50–04:10 (good, 5.33 h)	71.1° 01:15	5.4	1%	131.0°
2044-07-24 Sun	100	—	unknown	22:45–04:15 (good, 5.5 h)	71.1° 01:10	5.45	0%	134.7°
2044-07-25 Mon	100	—	unknown	22:45–04:15 (good, 5.5 h)	71.1° 01:05	5.51	2%	134.7°
2044-07-26 Tue	100	—	unknown	22:45–04:15 (good, 5.5 h)	71.1° 01:05	5.56	7%	131.0°
2044-07-27 Wed	100	—	unknown	22:40–04:20 (good, 5.67 h)	71.1° 01:00	5.61	14%	124.8°
2044-07-28 Thu	100	—	unknown	22:40–04:20 (good, 5.67 h)	71.1° 00:55	5.67	22%	117.1°
2044-07-29 Fri	100	—	unknown	22:40–04:20 (good, 5.67 h)	71.1° 00:50	5.72	32%	108.5°
2044-07-30 Sat	100	—	unknown	22:35–04:25 (good, 5.83 h)	71.1° 00:45	5.77	42%	99.7°
2044-07-31 Sun	100	—	unknown	22:35–04:25 (good, 5.83 h)	71.1° 00:45	5.83	52%	90.9°
2044-08-01 Mon	100	—	unknown	22:35–04:25 (good, 5.83 h)	71.1° 00:40	5.88	62%	82.3°
2044-08-02 Tue	100	—	unknown	22:30–04:30 (good, 6.0 h)	71.1° 00:35	5.94	71%	74.0°
2044-08-03 Wed	100	—	unknown	22:30–04:30 (good, 6.0 h)	71.1° 00:30	5.99	79%	66.1°
2044-08-04 Thu	99	—	unknown	22:30–04:30 (good, 6.0 h)	71.1° 00:25	6.05	86%	59.0°
2044-08-05 Fri	92	—	unknown	22:25–04:35 (good, 6.17 h)	71.1° 00:25	6.11	92%	52.8°
2044-08-06 Sat	84	—	unknown	04:25–04:35 (good, 0.17 h)	71.1° 00:20	6.16	96%	48.1°
2044-08-07 Sun	50	—	unknown	22:25–04:35 (marginal, 6.17 h)	71.1° 00:15	6.22	99%	45.3°
2044-08-08 Mon	49	—	unknown	22:20–04:40 (marginal, 6.33 h)	71.1° 00:10	6.28	100%	45.0°
2044-08-09 Tue	51	—	unknown	22:20–04:40 (marginal, 6.33 h)	71.1° 00:10	6.33	99%	47.2°
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°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2044-07-22&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.