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: 10-19 (100), 10-20 (100), 10-21 (100), 10-22 (100), 10-23 (100) — by astronomy; check the weather when the night is within four days.

2041-10-19astronomy score per night — click a bar for that night2041-11-17

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2041-10-19 Sat	100	—	unknown	20:10–00:35 (good, 4.42 h)	71.1° 19:30	10.01	22%	129.0°
2041-10-20 Sun	100	—	unknown	20:05–00:30 (good, 4.42 h)	71.1° 19:25	10.05	15%	124.5°
2041-10-21 Mon	100	—	unknown	20:05–00:30 (good, 4.42 h)	71.1° 19:20	10.09	9%	118.6°
2041-10-22 Tue	100	—	unknown	20:05–00:25 (good, 4.33 h)	71.1° 19:20	10.13	4%	111.6°
2041-10-23 Wed	100	—	unknown	20:05–00:20 (good, 4.25 h)	71.1° 19:15	10.17	1%	104.0°
2041-10-24 Thu	100	—	unknown	20:00–00:15 (good, 4.25 h)	71.1° 19:10	10.21	0%	95.9°
2041-10-25 Fri	100	—	unknown	20:00–00:10 (good, 4.17 h)	71.1° 19:05	10.25	1%	87.5°
2041-10-26 Sat	100	—	unknown	20:00–00:10 (good, 4.17 h)	71.1° 19:00	10.29	3%	79.1°
2041-10-27 Sun	100	—	unknown	19:00–23:05 (good, 4.08 h)	71.1° 18:00	10.33	8%	70.8°
2041-10-28 Mon	100	—	unknown	18:55–23:00 (good, 4.08 h)	71.1° 17:55	10.37	15%	63.1°
2041-10-29 Tue	98	—	unknown	18:55–22:55 (good, 4.0 h)	71.1° 17:50	10.4	23%	56.2°
2041-10-30 Wed	87	—	unknown	18:55–22:55 (good, 4.0 h)	71.1° 17:45	10.44	33%	51.0°
2041-10-31 Thu	70	—	unknown	18:55–22:50 (good, 3.92 h)	71.1° 17:40	10.48	44%	47.9°
2041-11-01 Fri	57	—	unknown	18:50–22:25 (good, 3.58 h)	71.1° 17:40	10.51	55%	47.8°
2041-11-02 Sat	47	—	unknown	18:50–21:15 (good, 2.42 h)	71.1° 17:35	10.55	66%	50.7°
2041-11-03 Sun	41	—	unknown	18:50–20:05 (good, 1.25 h)	71.1° 17:30	10.59	76%	56.3°
2041-11-04 Mon	38	—	unknown	18:50–19:40 (good, 0.83 h)	71.1° 17:25	10.62	86%	63.9°
2041-11-05 Tue	39	—	unknown	18:50–19:50 (good, 1.0 h)	71.1° 17:25	10.66	93%	72.8°
2041-11-06 Wed	44	—	unknown	18:45–20:20 (good, 1.58 h)	71.1° 17:20	10.69	98%	82.4°
2041-11-07 Thu	51	—	unknown	18:45–21:00 (good, 2.25 h)	71.1° 17:15	10.72	100%	92.2°
2041-11-08 Fri	60	—	unknown	18:45–21:50 (good, 3.08 h)	71.1° 17:10	10.76	99%	101.7°
2041-11-09 Sat	68	—	unknown	18:45–21:55 (good, 3.17 h)	71.1° 17:05	10.79	96%	110.7°
2041-11-10 Sun	75	—	unknown	18:45–22:00 (good, 3.25 h)	71.1° 17:05	10.82	91%	118.6°
2041-11-11 Mon	85	—	unknown	18:40–21:55 (good, 3.25 h)	71.1° 17:00	10.85	84%	125.1°
2041-11-12 Tue	86	—	unknown	18:40–21:55 (good, 3.25 h)	71.1° 16:55	10.88	76%	129.8°
2041-11-13 Wed	86	—	unknown	18:40–21:55 (good, 3.25 h)	71.1° 16:50	10.91	67%	132.2°
2041-11-14 Thu	85	—	unknown	18:40–21:55 (good, 3.25 h)	71.1° 16:45	10.94	57%	132.3°
2041-11-15 Fri	83	—	unknown	18:40–21:50 (good, 3.17 h)	71.1° 16:45	10.97	48%	130.2°
2041-11-16 Sat	82	—	unknown	18:40–21:45 (good, 3.08 h)	71.1° 16:40	11.0	38%	126.1°
2041-11-17 Sun	80	—	unknown	18:40–21:40 (good, 3.0 h)	71.1° 16:35	11.03	29%	120.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2041-10-19&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.