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: 10-03 (100), 10-04 (100), 10-05 (100), 10-06 (100), 10-07 (100) — by astronomy; check the weather when the night is within four days.

2040-10-03astronomy score per night — click a bar for that night2040-11-01

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2040-10-03 Wed	100	—	unknown	20:35–01:40 (good, 5.08 h)	71.1° 20:30	9.3	6%	122.9°
2040-10-04 Thu	100	—	unknown	20:30–01:35 (good, 5.08 h)	71.1° 20:25	9.35	2%	116.2°
2040-10-05 Fri	100	—	unknown	20:30–01:30 (good, 5.0 h)	71.1° 20:25	9.4	0%	108.4°
2040-10-06 Sat	100	—	unknown	20:30–01:25 (good, 4.92 h)	71.1° 20:20	9.44	1%	99.9°
2040-10-07 Sun	100	—	unknown	20:25–01:20 (good, 4.92 h)	71.1° 20:15	9.49	3%	91.0°
2040-10-08 Mon	100	—	unknown	20:25–01:20 (good, 4.92 h)	71.1° 20:10	9.54	8%	81.9°
2040-10-09 Tue	100	—	unknown	20:25–01:15 (good, 4.83 h)	71.1° 20:10	9.58	15%	72.9°
2040-10-10 Wed	100	—	unknown	20:20–01:10 (good, 4.83 h)	71.1° 20:05	9.63	24%	64.4°
2040-10-11 Thu	99	—	unknown	20:20–01:05 (good, 4.75 h)	71.1° 20:00	9.67	34%	57.0°
2040-10-12 Fri	92	—	unknown	20:20–01:00 (good, 4.67 h)	71.1° 19:55	9.72	45%	51.1°
2040-10-13 Sat	80	—	unknown	20:15–01:00 (good, 4.75 h)	71.1° 19:50	9.76	56%	47.7°
2040-10-14 Sun	57	—	unknown	20:15–00:10 (good, 3.92 h)	71.1° 19:50	9.8	68%	47.4°
2040-10-15 Mon	48	—	unknown	20:15–22:05 (good, 1.83 h)	71.1° 19:45	9.85	78%	50.2°
2040-10-16 Tue	44	—	unknown	20:10–20:50 (good, 0.67 h)	71.1° 19:40	9.89	87%	55.7°
2040-10-17 Wed	43	—	unknown	20:10–21:00 (good, 0.83 h)	71.1° 19:35	9.93	93%	63.1°
2040-10-18 Thu	47	—	unknown	20:10–21:40 (good, 1.5 h)	71.1° 19:30	9.98	98%	71.6°
2040-10-19 Fri	53	—	unknown	20:10–22:20 (good, 2.17 h)	71.1° 19:30	10.02	100%	80.7°
2040-10-20 Sat	64	—	unknown	20:05–23:05 (good, 3.0 h)	71.1° 19:25	10.06	99%	89.9°
2040-10-21 Sun	74	—	unknown	20:05–23:50 (good, 3.75 h)	71.1° 19:20	10.1	97%	98.8°
2040-10-22 Mon	84	—	unknown	20:05–00:05 (good, 4.0 h)	71.1° 19:15	10.14	92%	107.4°
2040-10-23 Tue	100	—	unknown	20:05–00:05 (good, 4.0 h)	71.1° 19:15	10.18	86%	115.1°
2040-10-24 Wed	100	—	unknown	20:00–00:05 (good, 4.08 h)	71.1° 19:10	10.22	78%	121.9°
2040-10-25 Thu	100	—	unknown	20:00–00:05 (good, 4.08 h)	71.1° 19:05	10.26	69%	127.3°
2040-10-26 Fri	100	—	unknown	20:00–00:00 (good, 4.0 h)	71.1° 19:00	10.3	60%	131.0°
2040-10-27 Sat	100	—	unknown	19:55–00:00 (good, 4.08 h)	71.1° 18:55	10.34	51%	132.7°
2040-10-28 Sun	100	—	unknown	18:55–23:00 (good, 4.08 h)	71.1° 17:55	10.38	42%	132.2°
2040-10-29 Mon	100	—	unknown	18:55–22:55 (good, 4.0 h)	71.1° 17:50	10.41	32%	129.5°
2040-10-30 Tue	100	—	unknown	18:55–22:50 (good, 3.92 h)	71.1° 17:45	10.45	24%	124.9°
2040-10-31 Wed	100	—	unknown	18:55–22:50 (good, 3.92 h)	71.1° 17:40	10.49	16%	118.7°
2040-11-01 Thu	100	—	unknown	18:50–22:45 (good, 3.92 h)	71.1° 17:35	10.52	9%	111.3°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2040-10-03&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.