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: 06-19 (100), 06-20 (100), 06-21 (100), 06-22 (100), 06-23 (100) — by astronomy; check the weather when the night is within four days.

2044-06-12astronomy score per night — click a bar for that night2044-07-11

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2044-06-12 Sun	44	—	unknown	23:10–03:40 (marginal, 4.5 h)	71.1° 03:55	4.48	95%	50.2°
2044-06-13 Mon	67	—	unknown	23:10–23:40 (good, 0.5 h)	71.1° 03:50	4.47	90%	46.5°
2044-06-14 Tue	75	—	unknown	23:10–02:50 (good, 3.67 h)	71.1° 03:50	4.46	84%	45.0°
2044-06-15 Wed	85	—	unknown	23:10–03:40 (good, 4.5 h)	71.1° 03:45	4.45	76%	46.0°
2044-06-16 Thu	93	—	unknown	23:10–03:40 (good, 4.5 h)	71.1° 03:40	4.44	68%	49.4°
2044-06-17 Fri	96	—	unknown	23:10–03:40 (good, 4.5 h)	71.1° 03:35	4.43	58%	54.8°
2044-06-18 Sat	99	—	unknown	23:10–03:40 (good, 4.5 h)	71.1° 03:30	4.42	48%	61.9°
2044-06-19 Sun	100	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 03:30	4.42	37%	70.3°
2044-06-20 Mon	100	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 03:25	4.42	27%	79.6°
2044-06-21 Tue	100	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 03:20	4.42	17%	89.5°
2044-06-22 Wed	100	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 03:15	4.43	9%	99.8°
2044-06-23 Thu	100	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 03:10	4.43	4%	110.0°
2044-06-24 Fri	100	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 03:10	4.44	1%	119.5°
2044-06-25 Sat	100	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 03:05	4.45	0%	127.5°
2044-06-26 Sun	100	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 03:00	4.46	4%	133.0°
2044-06-27 Mon	100	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 02:55	4.48	9%	135.1°
2044-06-28 Tue	100	—	unknown	23:10–03:40 (good, 4.5 h)	71.1° 02:55	4.49	17%	133.4°
2044-06-29 Wed	100	—	unknown	23:10–03:45 (good, 4.58 h)	71.1° 02:50	4.51	26%	128.7°
2044-06-30 Thu	100	—	unknown	23:10–03:45 (good, 4.58 h)	71.1° 02:45	4.53	37%	122.0°
2044-07-01 Fri	100	—	unknown	23:10–03:45 (good, 4.58 h)	71.1° 02:40	4.55	47%	114.1°
2044-07-02 Sat	100	—	unknown	23:10–03:45 (good, 4.58 h)	71.1° 02:35	4.58	57%	105.7°
2044-07-03 Sun	100	—	unknown	23:10–03:45 (good, 4.58 h)	71.1° 02:35	4.6	67%	97.0°
2044-07-04 Mon	100	—	unknown	23:10–03:45 (good, 4.58 h)	71.1° 02:30	4.63	76%	88.4°
2044-07-05 Tue	100	—	unknown	23:10–03:50 (good, 4.67 h)	71.1° 02:25	4.66	84%	79.9°
2044-07-06 Wed	100	—	unknown	23:10–03:50 (good, 4.67 h)	71.1° 02:20	4.69	90%	71.7°
2044-07-07 Thu	100	—	unknown	23:25–03:50 (good, 4.42 h)	71.1° 02:15	4.72	95%	64.1°
2044-07-08 Fri	60	—	unknown	00:20–03:50 (good, 3.5 h)	71.1° 02:15	4.75	98%	57.1°
2044-07-09 Sat	51	—	unknown	03:35–03:55 (good, 0.33 h)	71.1° 02:10	4.79	100%	51.3°
2044-07-10 Sun	44	—	unknown	23:05–03:55 (marginal, 4.83 h)	71.1° 02:05	4.82	100%	47.1°
2044-07-11 Mon	45	—	unknown	23:05–03:55 (marginal, 4.83 h)	71.1° 02:00	4.86	97%	45.0°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2044-06-12&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.