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: 10-09 (100), 10-10 (100), 10-11 (100), 10-12 (100), 10-13 (100) — by astronomy; check the weather when the night is within four days.

2039-10-09astronomy score per night — click a bar for that night2039-11-07

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2039-10-09 Sun	100	—	unknown	20:25–01:10 (good, 4.75 h)	71.1° 20:10	9.55	54%	129.2°
2039-10-10 Mon	100	—	unknown	20:25–01:10 (good, 4.75 h)	71.1° 20:05	9.59	45%	132.6°
2039-10-11 Tue	100	—	unknown	20:20–01:10 (good, 4.83 h)	71.1° 20:05	9.64	35%	133.8°
2039-10-12 Wed	100	—	unknown	20:20–01:05 (good, 4.75 h)	71.1° 20:00	9.68	26%	132.5°
2039-10-13 Thu	100	—	unknown	20:20–01:00 (good, 4.67 h)	71.1° 19:55	9.73	18%	128.7°
2039-10-14 Fri	100	—	unknown	20:15–00:55 (good, 4.67 h)	71.1° 19:50	9.77	10%	122.8°
2039-10-15 Sat	100	—	unknown	20:15–00:55 (good, 4.67 h)	71.1° 19:45	9.81	5%	115.2°
2039-10-16 Sun	100	—	unknown	20:15–00:50 (good, 4.58 h)	71.1° 19:45	9.86	1%	106.4°
2039-10-17 Mon	100	—	unknown	20:10–00:45 (good, 4.58 h)	71.1° 19:40	9.9	0%	96.8°
2039-10-18 Tue	100	—	unknown	20:10–00:40 (good, 4.5 h)	71.1° 19:35	9.94	2%	86.7°
2039-10-19 Wed	100	—	unknown	20:10–00:40 (good, 4.5 h)	71.1° 19:30	9.99	6%	76.7°
2039-10-20 Thu	100	—	unknown	20:10–00:35 (good, 4.42 h)	71.1° 19:25	10.03	13%	67.2°
2039-10-21 Fri	100	—	unknown	20:05–00:30 (good, 4.42 h)	71.1° 19:25	10.07	22%	58.7°
2039-10-22 Sat	94	—	unknown	20:05–00:25 (good, 4.33 h)	71.1° 19:20	10.11	32%	52.0°
2039-10-23 Sun	83	—	unknown	20:05–00:20 (good, 4.25 h)	71.1° 19:15	10.15	44%	47.7°
2039-10-24 Mon	64	—	unknown	20:00–00:00 (good, 4.0 h)	71.1° 19:10	10.19	55%	46.4°
2039-10-25 Tue	52	—	unknown	20:00–23:10 (good, 3.17 h)	71.1° 19:10	10.23	66%	48.2°
2039-10-26 Wed	45	—	unknown	20:00–21:40 (good, 1.67 h)	71.1° 19:05	10.27	75%	52.6°
2039-10-27 Thu	42	—	unknown	20:00–21:05 (good, 1.08 h)	71.1° 19:00	10.31	84%	58.9°
2039-10-28 Fri	42	—	unknown	19:55–21:05 (good, 1.17 h)	71.1° 18:55	10.35	91%	66.3°
2039-10-29 Sat	44	—	unknown	19:55–21:25 (good, 1.5 h)	71.1° 18:50	10.38	96%	74.5°
2039-10-30 Sun	50	—	unknown	18:55–20:55 (good, 2.0 h)	71.1° 17:50	10.42	99%	83.0°
2039-10-31 Mon	57	—	unknown	18:55–21:30 (good, 2.58 h)	71.1° 17:45	10.46	100%	91.5°
2039-11-01 Tue	66	—	unknown	18:50–22:10 (good, 3.33 h)	71.1° 17:40	10.5	99%	99.9°
2039-11-02 Wed	74	—	unknown	18:50–22:25 (good, 3.58 h)	71.1° 17:35	10.53	96%	107.9°
2039-11-03 Thu	89	—	unknown	18:50–22:25 (good, 3.58 h)	71.1° 17:30	10.57	92%	115.4°
2039-11-04 Fri	92	—	unknown	18:50–22:25 (good, 3.58 h)	71.1° 17:30	10.6	86%	122.1°
2039-11-05 Sat	93	—	unknown	18:50–22:25 (good, 3.58 h)	71.1° 17:25	10.64	79%	127.6°
2039-11-06 Sun	95	—	unknown	18:45–22:20 (good, 3.58 h)	71.1° 17:20	10.67	71%	131.5°
2039-11-07 Mon	94	—	unknown	18:45–22:20 (good, 3.58 h)	71.1° 17:15	10.71	62%	133.4°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2039-10-09&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.