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: 10-10 (100), 10-11 (100), 10-12 (100), 10-13 (100), 10-14 (100) — by astronomy; check the weather when the night is within four days.

2042-10-10astronomy score per night — click a bar for that night2042-11-08

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2042-10-10 Fri	100	—	unknown	20:25–01:10 (good, 4.75 h)	71.1° 20:05	9.61	9%	125.0°
2042-10-11 Sat	100	—	unknown	20:20–01:10 (good, 4.83 h)	71.1° 20:00	9.65	4%	119.0°
2042-10-12 Sun	100	—	unknown	20:20–01:05 (good, 4.75 h)	71.1° 20:00	9.69	1%	112.1°
2042-10-13 Mon	100	—	unknown	20:20–01:00 (good, 4.67 h)	71.1° 19:55	9.74	0%	104.6°
2042-10-14 Tue	100	—	unknown	20:15–00:55 (good, 4.67 h)	71.1° 19:50	9.78	1%	96.7°
2042-10-15 Wed	100	—	unknown	20:15–00:55 (good, 4.67 h)	71.1° 19:45	9.83	3%	88.7°
2042-10-16 Thu	100	—	unknown	20:15–00:50 (good, 4.58 h)	71.1° 19:40	9.87	7%	80.7°
2042-10-17 Fri	100	—	unknown	20:10–00:45 (good, 4.58 h)	71.1° 19:40	9.91	13%	72.8°
2042-10-18 Sat	100	—	unknown	20:10–00:40 (good, 4.5 h)	71.1° 19:35	9.95	20%	65.3°
2042-10-19 Sun	100	—	unknown	20:10–00:35 (good, 4.42 h)	71.1° 19:30	10.0	28%	58.5°
2042-10-20 Mon	93	—	unknown	20:05–00:35 (good, 4.5 h)	71.1° 19:25	10.04	38%	52.8°
2042-10-21 Tue	82	—	unknown	20:05–00:30 (good, 4.42 h)	71.1° 19:25	10.08	48%	48.8°
2042-10-22 Wed	61	—	unknown	20:05–00:05 (good, 4.0 h)	71.1° 19:20	10.12	58%	47.1°
2042-10-23 Thu	50	—	unknown	20:05–22:40 (good, 2.58 h)	71.1° 19:15	10.16	69%	48.3°
2042-10-24 Fri	43	—	unknown	20:00–21:15 (good, 1.25 h)	71.1° 19:10	10.2	79%	52.4°
2042-10-25 Sat	39	—	unknown	20:00–20:20 (good, 0.33 h)	71.1° 19:05	10.24	88%	59.1°
2042-10-26 Sun	40	—	unknown	19:00–19:50 (good, 0.83 h)	71.1° 18:05	10.28	94%	67.5°
2042-10-27 Mon	45	—	unknown	19:00–20:25 (good, 1.42 h)	71.1° 18:00	10.32	99%	77.2°
2042-10-28 Tue	54	—	unknown	18:55–21:15 (good, 2.33 h)	71.1° 17:55	10.36	100%	87.5°
2042-10-29 Wed	65	—	unknown	18:55–22:10 (good, 3.25 h)	71.1° 17:50	10.4	98%	97.8°
2042-10-30 Thu	76	—	unknown	18:55–22:35 (good, 3.67 h)	71.1° 17:45	10.43	93%	107.7°
2042-10-31 Fri	93	—	unknown	18:55–22:40 (good, 3.75 h)	71.1° 17:45	10.47	86%	116.6°
2042-11-01 Sat	98	—	unknown	18:50–22:40 (good, 3.83 h)	71.1° 17:40	10.51	78%	124.0°
2042-11-02 Sun	98	—	unknown	18:50–22:35 (good, 3.75 h)	71.1° 17:35	10.54	68%	129.5°
2042-11-03 Mon	98	—	unknown	18:50–22:35 (good, 3.75 h)	71.1° 17:30	10.58	58%	132.4°
2042-11-04 Tue	98	—	unknown	18:50–22:35 (good, 3.75 h)	71.1° 17:30	10.61	47%	132.8°
2042-11-05 Wed	96	—	unknown	18:50–22:30 (good, 3.67 h)	71.1° 17:25	10.65	38%	130.6°
2042-11-06 Thu	96	—	unknown	18:45–22:25 (good, 3.67 h)	71.1° 17:20	10.68	28%	126.4°
2042-11-07 Fri	95	—	unknown	18:45–22:20 (good, 3.58 h)	71.1° 17:15	10.71	20%	120.7°
2042-11-08 Sat	93	—	unknown	18:45–22:20 (good, 3.58 h)	71.1° 17:10	10.75	13%	114.0°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2042-10-10&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.