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: 07-20 (100), 07-21 (100), 07-22 (100), 07-23 (100), 07-24 (100) — by astronomy; check the weather when the night is within four days.

2033-07-20astronomy score per night — click a bar for that night2033-08-18

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2033-07-20 Wed	100	—	unknown	22:55–04:05 (good, 5.17 h)	71.1° 01:25	5.24	31%	101.4°
2033-07-21 Thu	100	—	unknown	22:50–04:10 (good, 5.33 h)	71.1° 01:25	5.29	21%	112.0°
2033-07-22 Fri	100	—	unknown	22:50–04:10 (good, 5.33 h)	71.1° 01:20	5.34	13%	121.9°
2033-07-23 Sat	100	—	unknown	22:50–04:10 (good, 5.33 h)	71.1° 01:15	5.39	6%	130.6°
2033-07-24 Sun	100	—	unknown	22:45–04:15 (good, 5.5 h)	71.1° 01:10	5.44	2%	137.5°
2033-07-25 Mon	100	—	unknown	22:45–04:15 (good, 5.5 h)	71.1° 01:10	5.49	0%	141.6°
2033-07-26 Tue	100	—	unknown	22:45–04:15 (good, 5.5 h)	71.1° 01:05	5.54	0%	142.3°
2033-07-27 Wed	100	—	unknown	22:40–04:20 (good, 5.67 h)	71.1° 01:00	5.59	3%	139.5°
2033-07-28 Thu	100	—	unknown	22:40–04:20 (good, 5.67 h)	71.1° 00:55	5.65	7%	134.0°
2033-07-29 Fri	100	—	unknown	22:40–04:20 (good, 5.67 h)	71.1° 00:50	5.7	12%	126.8°
2033-07-30 Sat	100	—	unknown	22:40–04:25 (good, 5.75 h)	71.1° 00:50	5.76	19%	118.6°
2033-07-31 Sun	100	—	unknown	22:35–04:25 (good, 5.83 h)	71.1° 00:45	5.81	27%	109.8°
2033-08-01 Mon	100	—	unknown	22:35–04:25 (good, 5.83 h)	71.1° 00:40	5.86	36%	100.6°
2033-08-02 Tue	100	—	unknown	22:30–04:30 (good, 6.0 h)	71.1° 00:35	5.92	45%	91.2°
2033-08-03 Wed	100	—	unknown	22:30–04:30 (good, 6.0 h)	71.1° 00:30	5.98	55%	81.7°
2033-08-04 Thu	100	—	unknown	22:30–04:30 (good, 6.0 h)	71.1° 00:30	6.03	64%	72.1°
2033-08-05 Fri	100	—	unknown	22:25–04:30 (good, 6.08 h)	71.1° 00:25	6.09	74%	62.7°
2033-08-06 Sat	96	—	unknown	22:25–04:35 (good, 6.17 h)	71.1° 00:20	6.14	82%	53.7°
2033-08-07 Sun	89	—	unknown	01:45–04:35 (good, 2.83 h)	71.1° 00:15	6.2	90%	45.8°
2033-08-08 Mon	47	—	unknown	22:20–04:35 (marginal, 6.25 h)	71.1° 00:10	6.26	95%	39.9°
2033-08-09 Tue	37	—	unknown	22:20–04:40 (marginal, 6.33 h)	71.1° 00:10	6.32	99%	37.5°
2033-08-10 Wed	38	—	unknown	22:20–04:40 (marginal, 6.33 h)	71.1° 00:05	6.37	100%	39.7°
2033-08-11 Thu	47	—	unknown	22:15–04:40 (marginal, 6.42 h)	71.1° 00:00	6.43	98%	45.9°
2033-08-12 Fri	63	—	unknown	22:15–23:30 (good, 1.25 h)	71.1° 23:55	6.49	93%	54.8°
2033-08-13 Sat	75	—	unknown	22:10–02:00 (good, 3.83 h)	71.1° 23:55	6.54	86%	65.3°
2033-08-14 Sun	100	—	unknown	22:10–03:25 (good, 5.25 h)	71.1° 23:50	6.6	77%	76.5°
2033-08-15 Mon	100	—	unknown	22:10–04:25 (good, 6.25 h)	71.1° 23:45	6.66	66%	87.8°
2033-08-16 Tue	100	—	unknown	22:05–04:35 (good, 6.5 h)	71.1° 23:40	6.72	55%	99.0°
2033-08-17 Wed	100	—	unknown	22:05–04:35 (good, 6.5 h)	71.1° 23:35	6.78	44%	109.8°
2033-08-18 Thu	100	—	unknown	22:05–04:35 (good, 6.5 h)	71.1° 23:35	6.83	34%	119.8°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2033-07-20&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.