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: 07-03 (100), 07-14 (100), 07-15 (100), 07-16 (100), 07-17 (100) — by astronomy; check the weather when the night is within four days.

2028-07-03astronomy score per night — click a bar for that night2028-08-01

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
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°
2028-07-15 Sat	100	—	unknown	23:00–04:00 (good, 5.0 h)	71.1° 01:45	5.02	40%	84.5°
2028-07-16 Sun	100	—	unknown	23:00–04:00 (good, 5.0 h)	71.1° 01:40	5.06	30%	94.0°
2028-07-17 Mon	100	—	unknown	22:55–04:05 (good, 5.17 h)	71.1° 01:40	5.11	21%	103.7°
2028-07-18 Tue	100	—	unknown	22:55–04:05 (good, 5.17 h)	71.1° 01:35	5.15	13%	113.4°
2028-07-19 Wed	100	—	unknown	22:55–04:05 (good, 5.17 h)	71.1° 01:30	5.2	6%	122.6°
2028-07-20 Thu	100	—	unknown	22:55–04:10 (good, 5.25 h)	71.1° 01:25	5.25	2%	130.8°
2028-07-21 Fri	100	—	unknown	22:50–04:10 (good, 5.33 h)	71.1° 01:20	5.3	0%	136.9°
2028-07-22 Sat	100	—	unknown	22:50–04:10 (good, 5.33 h)	71.1° 01:20	5.35	1%	139.4°
2028-07-23 Sun	100	—	unknown	22:50–04:10 (good, 5.33 h)	71.1° 01:15	5.4	5%	137.6°
2028-07-24 Mon	100	—	unknown	22:45–04:15 (good, 5.5 h)	71.1° 01:10	5.45	11%	131.9°
2028-07-25 Tue	100	—	unknown	22:45–04:15 (good, 5.5 h)	71.1° 01:05	5.5	20%	123.7°
2028-07-26 Wed	100	—	unknown	22:45–04:15 (good, 5.5 h)	71.1° 01:05	5.55	30%	114.0°
2028-07-27 Thu	100	—	unknown	22:40–04:20 (good, 5.67 h)	71.1° 01:00	5.6	41%	103.7°
2028-07-28 Fri	100	—	unknown	22:40–04:20 (good, 5.67 h)	71.1° 00:55	5.66	52%	93.3°
2028-07-29 Sat	100	—	unknown	22:40–04:20 (good, 5.67 h)	71.1° 00:50	5.71	63%	83.0°
2028-07-30 Sun	100	—	unknown	22:35–04:25 (good, 5.83 h)	71.1° 00:45	5.77	73%	73.1°
2028-07-31 Mon	100	—	unknown	22:35–04:25 (good, 5.83 h)	71.1° 00:45	5.82	82%	63.8°
2028-08-01 Tue	96	—	unknown	22:35–04:25 (good, 5.83 h)	71.1° 00:40	5.88	89%	55.5°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2028-07-03&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.