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: 08-22 (100), 08-23 (100), 08-24 (100), 08-25 (100), 08-26 (100) — by astronomy; check the weather when the night is within four days.

2035-08-19astronomy score per night — click a bar for that night2035-09-17

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2035-08-19 Sun	51	—	unknown	22:00–04:40 (marginal, 6.67 h)	71.1° 23:30	6.86	99%	49.4°
2035-08-20 Mon	63	—	unknown	22:00–23:15 (good, 1.25 h)	71.1° 23:25	6.92	96%	57.1°
2035-08-21 Tue	73	—	unknown	22:00–01:20 (good, 3.33 h)	71.1° 23:25	6.98	91%	66.0°
2035-08-22 Wed	100	—	unknown	21:55–02:30 (good, 4.58 h)	71.1° 23:20	7.03	85%	75.6°
2035-08-23 Thu	100	—	unknown	21:55–03:40 (good, 5.75 h)	71.1° 23:15	7.09	76%	85.8°
2035-08-24 Fri	100	—	unknown	21:50–04:00 (good, 6.17 h)	71.1° 23:10	7.15	66%	96.3°
2035-08-25 Sat	100	—	unknown	21:50–04:05 (good, 6.25 h)	71.1° 23:10	7.21	55%	106.8°
2035-08-26 Sun	100	—	unknown	21:50–04:05 (good, 6.25 h)	71.1° 23:05	7.26	44%	117.0°
2035-08-27 Mon	100	—	unknown	21:45–04:05 (good, 6.33 h)	71.1° 23:00	7.32	32%	126.3°
2035-08-28 Tue	100	—	unknown	21:45–04:00 (good, 6.25 h)	71.1° 22:55	7.38	22%	134.1°
2035-08-29 Wed	100	—	unknown	21:40–03:55 (good, 6.25 h)	71.1° 22:50	7.43	13%	139.2°
2035-08-30 Thu	100	—	unknown	21:40–03:55 (good, 6.25 h)	71.1° 22:50	7.49	6%	140.2°
2035-08-31 Fri	100	—	unknown	21:40–03:50 (good, 6.17 h)	71.1° 22:45	7.55	2%	137.0°
2035-09-01 Sat	100	—	unknown	21:35–03:45 (good, 6.17 h)	71.1° 22:40	7.6	0%	130.5°
2035-09-02 Sun	100	—	unknown	21:35–03:40 (good, 6.08 h)	71.1° 22:35	7.66	1%	121.9°
2035-09-03 Mon	100	—	unknown	21:30–03:40 (good, 6.17 h)	71.1° 22:30	7.71	4%	112.4°
2035-09-04 Tue	100	—	unknown	21:30–03:35 (good, 6.08 h)	71.1° 22:30	7.77	10%	102.4°
2035-09-05 Wed	100	—	unknown	21:30–03:30 (good, 6.0 h)	71.1° 22:25	7.82	17%	92.5°
2035-09-06 Thu	100	—	unknown	21:25–03:25 (good, 6.0 h)	71.1° 22:20	7.88	25%	82.8°
2035-09-07 Fri	100	—	unknown	21:25–03:25 (good, 6.0 h)	71.1° 22:15	7.93	34%	73.5°
2035-09-08 Sat	100	—	unknown	21:20–03:20 (good, 6.0 h)	71.1° 22:15	7.99	43%	64.7°
2035-09-09 Sun	98	—	unknown	21:20–03:15 (good, 5.92 h)	71.1° 22:10	8.04	53%	56.6°
2035-09-10 Mon	93	—	unknown	21:20–03:10 (good, 5.83 h)	71.1° 22:05	8.1	62%	49.5°
2035-09-11 Tue	87	—	unknown	21:15–03:05 (good, 5.83 h)	71.1° 22:00	8.15	71%	43.9°
2035-09-12 Wed	72	—	unknown	02:40–03:05 (good, 0.42 h)	71.1° 21:55	8.2	80%	40.4°
2035-09-13 Thu	44	—	unknown	21:10–03:20 (marginal, 6.17 h)	71.1° 21:55	8.26	87%	39.8°
2035-09-14 Fri	39	—	unknown	21:10–03:10 (marginal, 6.0 h)	71.1° 21:50	8.31	93%	42.2°
2035-09-15 Sat	39	—	unknown	21:10–02:55 (marginal, 5.75 h)	71.1° 21:45	8.36	97%	47.3°
2035-09-16 Sun	44	—	unknown	21:05–02:50 (marginal, 5.75 h)	71.1° 21:40	8.42	100%	54.5°
2035-09-17 Mon	53	—	unknown	21:05–22:05 (good, 1.0 h)	71.1° 21:35	8.47	100%	63.2°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2035-08-19&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.