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: 10-28 (100), 10-29 (100), 10-30 (100), 10-31 (100), 11-01 (100) — by astronomy; check the weather when the night is within four days.

2037-10-23astronomy score per night — click a bar for that night2037-11-21

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2037-10-23 Fri	56	—	unknown	20:05–22:30 (good, 2.42 h)	71.1° 19:15	10.17	100%	85.3°
2037-10-24 Sat	66	—	unknown	20:00–23:15 (good, 3.25 h)	71.1° 19:10	10.21	99%	94.1°
2037-10-25 Sun	75	—	unknown	19:00–22:50 (good, 3.83 h)	71.1° 18:05	10.25	97%	102.9°
2037-10-26 Mon	95	—	unknown	19:00–22:50 (good, 3.83 h)	71.1° 18:00	10.29	93%	111.4°
2037-10-27 Tue	99	—	unknown	19:00–22:55 (good, 3.92 h)	71.1° 18:00	10.33	87%	119.6°
2037-10-28 Wed	100	—	unknown	18:55–22:50 (good, 3.92 h)	71.1° 17:55	10.37	79%	126.8°
2037-10-29 Thu	100	—	unknown	18:55–22:50 (good, 3.92 h)	71.1° 17:50	10.4	70%	132.5°
2037-10-30 Fri	100	—	unknown	18:55–22:50 (good, 3.92 h)	71.1° 17:45	10.44	60%	136.0°
2037-10-31 Sat	100	—	unknown	18:55–22:50 (good, 3.92 h)	71.1° 17:40	10.48	50%	136.4°
2037-11-01 Sun	100	—	unknown	18:50–22:45 (good, 3.92 h)	71.1° 17:40	10.51	38%	133.4°
2037-11-02 Mon	100	—	unknown	18:50–22:40 (good, 3.83 h)	71.1° 17:35	10.55	28%	127.4°
2037-11-03 Tue	99	—	unknown	18:50–22:35 (good, 3.75 h)	71.1° 17:30	10.58	18%	119.2°
2037-11-04 Wed	98	—	unknown	18:50–22:35 (good, 3.75 h)	71.1° 17:25	10.62	10%	109.6°
2037-11-05 Thu	96	—	unknown	18:50–22:30 (good, 3.67 h)	71.1° 17:25	10.65	4%	99.0°
2037-11-06 Fri	95	—	unknown	18:45–22:25 (good, 3.67 h)	71.1° 17:20	10.69	1%	88.2°
2037-11-07 Sat	94	—	unknown	18:45–22:20 (good, 3.58 h)	71.1° 17:15	10.72	0%	77.6°
2037-11-08 Sun	93	—	unknown	18:45–22:15 (good, 3.5 h)	71.1° 17:10	10.75	3%	67.5°
2037-11-09 Mon	91	—	unknown	18:45–22:15 (good, 3.5 h)	71.1° 17:05	10.79	8%	58.5°
2037-11-10 Tue	84	—	unknown	18:45–22:10 (good, 3.42 h)	71.1° 17:05	10.82	15%	51.2°
2037-11-11 Wed	77	—	unknown	18:40–22:05 (good, 3.42 h)	71.1° 17:00	10.85	23%	46.0°
2037-11-12 Thu	66	—	unknown	18:40–22:00 (good, 3.33 h)	71.1° 16:55	10.88	32%	43.6°
2037-11-13 Fri	55	—	unknown	18:40–21:40 (good, 3.0 h)	71.1° 16:50	10.91	42%	44.2°
2037-11-14 Sat	47	—	unknown	18:40–21:30 (good, 2.83 h)	71.1° 16:45	10.94	52%	47.3°
2037-11-15 Sun	41	—	unknown	18:40–20:40 (good, 2.0 h)	71.1° 16:45	10.97	61%	52.4°
2037-11-16 Mon	37	—	unknown	18:40–19:55 (good, 1.25 h)	71.1° 16:40	11.0	70%	58.9°
2037-11-17 Tue	35	—	unknown	18:40–19:35 (good, 0.92 h)	71.1° 16:35	11.02	78%	66.3°
2037-11-18 Wed	35	—	unknown	18:35–19:40 (good, 1.08 h)	71.1° 16:30	11.05	86%	74.4°
2037-11-19 Thu	37	—	unknown	18:35–19:55 (good, 1.33 h)	71.1° 16:30	11.08	92%	82.9°
2037-11-20 Fri	40	—	unknown	18:35–20:20 (good, 1.75 h)	71.1° 16:25	11.1	96%	91.6°
2037-11-21 Sat	45	—	unknown	18:35–20:55 (good, 2.33 h)	71.1° 16:20	11.13	99%	100.4°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2037-10-23&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.