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: 06-16 (100), 06-17 (100), 06-18 (100), 06-19 (100), 06-20 (100) — by astronomy; check the weather when the night is within four days.

2028-06-15astronomy score per night — click a bar for that night2028-07-14

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2028-06-15 Thu	98	—	unknown	23:10–03:40 (good, 4.5 h)	71.1° 03:45	4.45	43%	61.1°
2028-06-16 Fri	100	—	unknown	23:10–03:40 (good, 4.5 h)	71.1° 03:40	4.44	34%	69.5°
2028-06-17 Sat	100	—	unknown	23:10–03:40 (good, 4.5 h)	71.1° 03:35	4.43	25%	78.5°
2028-06-18 Sun	100	—	unknown	23:10–03:40 (good, 4.5 h)	71.1° 03:30	4.43	16%	87.9°
2028-06-19 Mon	100	—	unknown	23:10–03:40 (good, 4.5 h)	71.1° 03:30	4.42	10%	97.7°
2028-06-20 Tue	100	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 03:25	4.42	4%	107.5°
2028-06-21 Wed	100	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 03:20	4.42	1%	117.2°
2028-06-22 Thu	100	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 03:15	4.43	0%	126.1°
2028-06-23 Fri	100	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 03:10	4.43	2%	133.6°
2028-06-24 Sat	100	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 03:10	4.44	6%	138.3°
2028-06-25 Sun	100	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 03:05	4.45	13%	139.3°
2028-06-26 Mon	100	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 03:00	4.46	22%	136.1°
2028-06-27 Tue	100	—	unknown	23:15–03:40 (good, 4.42 h)	71.1° 02:55	4.47	32%	129.7°
2028-06-28 Wed	100	—	unknown	23:10–03:40 (good, 4.5 h)	71.1° 02:55	4.49	43%	121.2°
2028-06-29 Thu	100	—	unknown	23:10–03:45 (good, 4.58 h)	71.1° 02:50	4.51	55%	111.5°
2028-06-30 Fri	100	—	unknown	23:10–03:45 (good, 4.58 h)	71.1° 02:45	4.53	66%	101.3°
2028-07-01 Sat	100	—	unknown	23:10–03:45 (good, 4.58 h)	71.1° 02:40	4.55	76%	90.9°
2028-07-02 Sun	100	—	unknown	23:10–03:45 (good, 4.58 h)	71.1° 02:35	4.57	85%	80.7°
2028-07-03 Mon	100	—	unknown	23:10–03:45 (good, 4.58 h)	71.1° 02:35	4.6	92%	70.9°
2028-07-04 Tue	65	—	unknown	00:10–03:45 (good, 3.58 h)	71.1° 02:30	4.62	96%	61.7°
2028-07-05 Wed	51	—	unknown	03:00–03:50 (good, 0.83 h)	71.1° 02:25	4.65	99%	53.5°
2028-07-06 Thu	42	—	unknown	23:10–03:50 (marginal, 4.67 h)	71.1° 02:20	4.68	100%	46.8°
2028-07-07 Fri	38	—	unknown	23:05–03:50 (marginal, 4.75 h)	71.1° 02:15	4.71	99%	42.3°
2028-07-08 Sat	40	—	unknown	23:05–03:50 (marginal, 4.75 h)	71.1° 02:15	4.75	95%	40.6°
2028-07-09 Sun	47	—	unknown	23:05–03:55 (marginal, 4.83 h)	71.1° 02:10	4.78	90%	41.8°
2028-07-10 Mon	57	—	unknown	23:05–01:05 (good, 2.0 h)	71.1° 02:05	4.82	84%	45.6°
2028-07-11 Tue	92	—	unknown	23:05–03:00 (good, 3.92 h)	71.1° 02:00	4.86	77%	51.4°
2028-07-12 Wed	96	—	unknown	23:05–03:55 (good, 4.83 h)	71.1° 02:00	4.9	68%	58.5°
2028-07-13 Thu	99	—	unknown	23:00–04:00 (good, 5.0 h)	71.1° 01:55	4.94	59%	66.6°
2028-07-14 Fri	100	—	unknown	23:00–04:00 (good, 5.0 h)	71.1° 01:50	4.98	49%	75.3°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2028-06-15&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.