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: 10-23 (100), 10-24 (100), 10-25 (100), 10-26 (100), 10-27 (100) — by astronomy; check the weather when the night is within four days.

2043-10-23astronomy score per night — click a bar for that night2043-11-21

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2043-10-23 Fri	100	—	unknown	20:05–00:15 (good, 4.17 h)	71.1° 19:15	10.15	63%	128.2°
2043-10-24 Sat	100	—	unknown	20:00–00:15 (good, 4.25 h)	71.1° 19:10	10.19	52%	132.5°
2043-10-25 Sun	100	—	unknown	19:00–23:15 (good, 4.25 h)	71.1° 18:10	10.23	41%	133.9°
2043-10-26 Mon	100	—	unknown	19:00–23:10 (good, 4.17 h)	71.1° 18:05	10.27	31%	132.4°
2043-10-27 Tue	100	—	unknown	19:00–23:05 (good, 4.08 h)	71.1° 18:00	10.31	22%	128.3°
2043-10-28 Wed	100	—	unknown	18:55–23:00 (good, 4.08 h)	71.1° 17:55	10.35	14%	122.4°
2043-10-29 Thu	100	—	unknown	18:55–23:00 (good, 4.08 h)	71.1° 17:50	10.39	8%	115.4°
2043-10-30 Fri	100	—	unknown	18:55–22:55 (good, 4.0 h)	71.1° 17:50	10.42	3%	107.6°
2043-10-31 Sat	100	—	unknown	18:55–22:50 (good, 3.92 h)	71.1° 17:45	10.46	1%	99.4°
2043-11-01 Sun	100	—	unknown	18:50–22:45 (good, 3.92 h)	71.1° 17:40	10.5	0%	91.1°
2043-11-02 Mon	100	—	unknown	18:50–22:45 (good, 3.92 h)	71.1° 17:35	10.53	1%	82.8°
2043-11-03 Tue	99	—	unknown	18:50–22:40 (good, 3.83 h)	71.1° 17:30	10.57	4%	74.8°
2043-11-04 Wed	98	—	unknown	18:50–22:35 (good, 3.75 h)	71.1° 17:30	10.6	8%	67.1°
2043-11-05 Thu	96	—	unknown	18:50–22:30 (good, 3.67 h)	71.1° 17:25	10.64	14%	60.1°
2043-11-06 Fri	89	—	unknown	18:45–22:25 (good, 3.67 h)	71.1° 17:20	10.67	22%	54.1°
2043-11-07 Sat	77	—	unknown	18:45–22:25 (good, 3.67 h)	71.1° 17:15	10.71	30%	49.4°
2043-11-08 Sun	65	—	unknown	18:45–22:20 (good, 3.58 h)	71.1° 17:15	10.74	39%	46.5°
2043-11-09 Mon	54	—	unknown	18:45–21:55 (good, 3.17 h)	71.1° 17:10	10.77	49%	46.1°
2043-11-10 Tue	45	—	unknown	18:45–21:15 (good, 2.5 h)	71.1° 17:05	10.8	59%	48.3°
2043-11-11 Wed	38	—	unknown	18:45–19:55 (good, 1.17 h)	71.1° 17:00	10.84	69%	53.0°
2043-11-12 Thu	34	—	unknown	18:40–19:15 (good, 0.58 h)	71.1° 16:55	10.87	79%	59.8°
2043-11-13 Fri	33	—	unknown	18:40–19:10 (good, 0.5 h)	71.1° 16:55	10.9	87%	68.3°
2043-11-14 Sat	36	—	unknown	18:40–19:30 (good, 0.83 h)	71.1° 16:50	10.93	94%	77.9°
2043-11-15 Sun	41	—	unknown	18:40–20:10 (good, 1.5 h)	71.1° 16:45	10.96	98%	88.2°
2043-11-16 Mon	48	—	unknown	18:40–21:00 (good, 2.33 h)	71.1° 16:40	10.98	100%	98.7°
2043-11-17 Tue	57	—	unknown	18:40–21:25 (good, 2.75 h)	71.1° 16:35	11.01	98%	109.0°
2043-11-18 Wed	64	—	unknown	18:40–21:30 (good, 2.83 h)	71.1° 16:35	11.04	94%	118.4°
2043-11-19 Thu	74	—	unknown	18:35–21:30 (good, 2.92 h)	71.1° 16:30	11.07	87%	126.1°
2043-11-20 Fri	75	—	unknown	18:35–21:25 (good, 2.83 h)	71.1° 16:25	11.09	78%	131.6°
2043-11-21 Sat	74	—	unknown	18:35–21:30 (good, 2.92 h)	71.1° 16:20	11.12	68%	134.0°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2043-10-23&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.