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: 06-13 (100), 06-14 (100), 06-15 (100), 06-16 (100), 06-17 (100) — by astronomy; check the weather when the night is within four days.

2039-06-12astronomy score per night — click a bar for that night2039-07-11

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2039-06-12 Sun	98	—	unknown	23:10–03:40 (good, 4.5 h)	71.1° 04:00	4.5	57%	57.2°
2039-06-13 Mon	100	—	unknown	23:10–03:40 (good, 4.5 h)	71.1° 03:55	4.48	47%	64.4°
2039-06-14 Tue	100	—	unknown	23:10–03:40 (good, 4.5 h)	71.1° 03:50	4.47	37%	72.3°
2039-06-15 Wed	100	—	unknown	23:10–03:40 (good, 4.5 h)	71.1° 03:45	4.45	28%	80.5°
2039-06-16 Thu	100	—	unknown	23:10–03:40 (good, 4.5 h)	71.1° 03:45	4.44	19%	88.8°
2039-06-17 Fri	100	—	unknown	23:10–03:40 (good, 4.5 h)	71.1° 03:40	4.44	12%	97.1°
2039-06-18 Sat	100	—	unknown	23:10–03:40 (good, 4.5 h)	71.1° 03:35	4.43	7%	105.2°
2039-06-19 Sun	100	—	unknown	23:10–03:40 (good, 4.5 h)	71.1° 03:30	4.42	3%	112.8°
2039-06-20 Mon	100	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 03:25	4.42	1%	119.9°
2039-06-21 Tue	100	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 03:25	4.42	0%	126.0°
2039-06-22 Wed	100	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 03:20	4.42	1%	130.7°
2039-06-23 Thu	100	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 03:15	4.43	4%	133.5°
2039-06-24 Fri	100	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 03:10	4.43	10%	134.0°
2039-06-25 Sat	100	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 03:10	4.44	16%	131.9°
2039-06-26 Sun	100	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 03:05	4.45	24%	127.5°
2039-06-27 Mon	100	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 03:00	4.47	34%	121.1°
2039-06-28 Tue	100	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 02:55	4.48	44%	113.4°
2039-06-29 Wed	100	—	unknown	23:10–03:40 (good, 4.5 h)	71.1° 02:50	4.5	55%	104.6°
2039-06-30 Thu	100	—	unknown	23:10–03:45 (good, 4.58 h)	71.1° 02:50	4.51	66%	95.1°
2039-07-01 Fri	100	—	unknown	23:10–03:45 (good, 4.58 h)	71.1° 02:45	4.53	77%	85.2°
2039-07-02 Sat	100	—	unknown	23:10–03:45 (good, 4.58 h)	71.1° 02:40	4.56	86%	75.2°
2039-07-03 Sun	70	—	unknown	00:00–03:45 (good, 3.75 h)	71.1° 02:35	4.58	93%	65.5°
2039-07-04 Mon	55	—	unknown	01:55–03:45 (good, 1.83 h)	71.1° 02:30	4.61	98%	57.0°
2039-07-05 Tue	46	—	unknown	23:10–03:45 (marginal, 4.58 h)	71.1° 02:30	4.63	100%	50.3°
2039-07-06 Wed	42	—	unknown	23:10–03:50 (marginal, 4.67 h)	71.1° 02:25	4.66	99%	46.5°
2039-07-07 Thu	48	—	unknown	23:10–03:50 (marginal, 4.67 h)	71.1° 02:20	4.69	95%	46.2°
2039-07-08 Fri	85	—	unknown	23:05–01:45 (good, 2.67 h)	71.1° 02:15	4.73	89%	49.2°
2039-07-09 Sat	97	—	unknown	23:05–03:50 (good, 4.75 h)	71.1° 02:10	4.76	81%	54.8°
2039-07-10 Sun	100	—	unknown	23:05–03:55 (good, 4.83 h)	71.1° 02:10	4.79	72%	61.8°
2039-07-11 Mon	100	—	unknown	23:05–03:55 (good, 4.83 h)	71.1° 02:05	4.83	62%	69.7°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2039-06-12&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.