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: 06-17 (100), 06-18 (100), 06-19 (100), 06-20 (100), 06-21 (100) — by astronomy; check the weather when the night is within four days.

2045-06-17astronomy score per night — click a bar for that night2045-07-16

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2045-06-17 Sat	100	—	unknown	23:10–03:40 (good, 4.5 h)	71.1° 03:35	4.43	11%	136.1°
2045-06-18 Sun	100	—	unknown	23:10–03:40 (good, 4.5 h)	71.1° 03:35	4.43	20%	136.2°
2045-06-19 Mon	100	—	unknown	23:10–03:40 (good, 4.5 h)	71.1° 03:30	4.42	30%	132.5°
2045-06-20 Tue	100	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 03:25	4.42	41%	126.1°
2045-06-21 Wed	100	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 03:20	4.42	52%	118.0°
2045-06-22 Thu	100	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 03:15	4.43	63%	109.0°
2045-06-23 Fri	100	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 03:15	4.43	73%	99.6°
2045-06-24 Sat	100	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 03:10	4.44	82%	90.1°
2045-06-25 Sun	100	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 03:05	4.45	89%	80.8°
2045-06-26 Mon	74	—	unknown	23:35–03:40 (good, 4.08 h)	71.1° 03:00	4.46	94%	71.9°
2045-06-27 Tue	61	—	unknown	00:25–03:40 (good, 3.25 h)	71.1° 03:00	4.47	98%	63.5°
2045-06-28 Wed	51	—	unknown	02:30–03:40 (good, 1.17 h)	71.1° 02:55	4.49	100%	56.1°
2045-06-29 Thu	44	—	unknown	23:10–03:45 (marginal, 4.58 h)	71.1° 02:50	4.51	100%	50.0°
2045-06-30 Fri	42	—	unknown	23:10–03:45 (marginal, 4.58 h)	71.1° 02:45	4.53	98%	45.6°
2045-07-01 Sat	45	—	unknown	23:10–03:45 (marginal, 4.58 h)	71.1° 02:40	4.55	94%	43.4°
2045-07-02 Sun	51	—	unknown	23:10–00:55 (good, 1.75 h)	71.1° 02:40	4.57	88%	43.8°
2045-07-03 Mon	83	—	unknown	23:10–02:10 (good, 3.0 h)	71.1° 02:35	4.59	82%	46.7°
2045-07-04 Tue	94	—	unknown	23:10–03:45 (good, 4.58 h)	71.1° 02:30	4.62	74%	51.6°
2045-07-05 Wed	97	—	unknown	23:10–03:50 (good, 4.67 h)	71.1° 02:25	4.65	65%	58.1°
2045-07-06 Thu	99	—	unknown	23:10–03:50 (good, 4.67 h)	71.1° 02:20	4.68	55%	65.8°
2045-07-07 Fri	100	—	unknown	23:05–03:50 (good, 4.75 h)	71.1° 02:20	4.71	45%	74.3°
2045-07-08 Sat	100	—	unknown	23:05–03:50 (good, 4.75 h)	71.1° 02:15	4.74	35%	83.4°
2045-07-09 Sun	100	—	unknown	23:05–03:50 (good, 4.75 h)	71.1° 02:10	4.78	26%	93.0°
2045-07-10 Mon	100	—	unknown	23:05–03:55 (good, 4.83 h)	71.1° 02:05	4.81	17%	102.8°
2045-07-11 Tue	100	—	unknown	23:05–03:55 (good, 4.83 h)	71.1° 02:05	4.85	9%	112.6°
2045-07-12 Wed	100	—	unknown	23:05–03:55 (good, 4.83 h)	71.1° 02:00	4.89	3%	121.8°
2045-07-13 Thu	100	—	unknown	23:00–04:00 (good, 5.0 h)	71.1° 01:55	4.93	0%	129.7°
2045-07-14 Fri	100	—	unknown	23:00–04:00 (good, 5.0 h)	71.1° 01:50	4.97	0%	135.1°
2045-07-15 Sat	100	—	unknown	23:00–04:00 (good, 5.0 h)	71.1° 01:45	5.02	3%	136.7°
2045-07-16 Sun	100	—	unknown	23:00–04:00 (good, 5.0 h)	71.1° 01:45	5.06	9%	134.3°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2045-06-17&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.