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: 09-30 (100), 10-01 (100), 10-02 (100), 10-03 (100), 10-04 (100) — by astronomy; check the weather when the night is within four days.

2034-09-23astronomy score per night — click a bar for that night2034-10-22

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2034-09-23 Sat	46	—	unknown	20:50–02:40 (marginal, 5.83 h)	71.1° 21:15	8.79	79%	38.3°
2034-09-24 Sun	38	—	unknown	20:50–02:30 (marginal, 5.67 h)	71.1° 21:10	8.84	87%	40.6°
2034-09-25 Mon	36	—	unknown	20:50–02:15 (marginal, 5.42 h)	71.1° 21:05	8.89	94%	46.2°
2034-09-26 Tue	40	—	unknown	20:45–02:10 (marginal, 5.42 h)	71.1° 21:00	8.94	98%	54.4°
2034-09-27 Wed	48	—	unknown	20:45–21:30 (good, 0.75 h)	71.1° 20:55	8.99	100%	64.3°
2034-09-28 Thu	61	—	unknown	20:45–23:15 (good, 2.5 h)	71.1° 20:55	9.04	99%	75.3°
2034-09-29 Fri	78	—	unknown	20:40–00:25 (good, 3.75 h)	71.1° 20:50	9.09	95%	86.8°
2034-09-30 Sat	100	—	unknown	20:40–01:25 (good, 4.75 h)	71.1° 20:45	9.13	89%	98.4°
2034-10-01 Sun	100	—	unknown	20:40–01:30 (good, 4.83 h)	71.1° 20:40	9.18	80%	109.7°
2034-10-02 Mon	100	—	unknown	20:35–01:35 (good, 5.0 h)	71.1° 20:35	9.23	70%	120.3°
2034-10-03 Tue	100	—	unknown	20:35–01:35 (good, 5.0 h)	71.1° 20:35	9.28	59%	129.5°
2034-10-04 Wed	100	—	unknown	20:35–01:30 (good, 4.92 h)	71.1° 20:30	9.33	48%	136.7°
2034-10-05 Thu	100	—	unknown	20:30–01:30 (good, 5.0 h)	71.1° 20:25	9.37	37%	140.9°
2034-10-06 Fri	100	—	unknown	20:30–01:30 (good, 5.0 h)	71.1° 20:20	9.42	27%	141.4°
2034-10-07 Sat	100	—	unknown	20:30–01:25 (good, 4.92 h)	71.1° 20:20	9.47	18%	138.1°
2034-10-08 Sun	100	—	unknown	20:25–01:20 (good, 4.92 h)	71.1° 20:15	9.51	11%	132.1°
2034-10-09 Mon	100	—	unknown	20:25–01:15 (good, 4.83 h)	71.1° 20:10	9.56	6%	124.4°
2034-10-10 Tue	100	—	unknown	20:25–01:10 (good, 4.75 h)	71.1° 20:05	9.6	2%	115.8°
2034-10-11 Wed	100	—	unknown	20:20–01:10 (good, 4.83 h)	71.1° 20:00	9.65	0%	106.6°
2034-10-12 Thu	100	—	unknown	20:20–01:05 (good, 4.75 h)	71.1° 20:00	9.69	0%	97.2°
2034-10-13 Fri	100	—	unknown	20:20–01:00 (good, 4.67 h)	71.1° 19:55	9.74	2%	87.8°
2034-10-14 Sat	100	—	unknown	20:15–00:55 (good, 4.67 h)	71.1° 19:50	9.78	6%	78.5°
2034-10-15 Sun	100	—	unknown	20:15–00:50 (good, 4.58 h)	71.1° 19:45	9.82	12%	69.5°
2034-10-16 Mon	100	—	unknown	20:15–00:50 (good, 4.58 h)	71.1° 19:40	9.87	18%	60.9°
2034-10-17 Tue	97	—	unknown	20:10–00:45 (good, 4.58 h)	71.1° 19:40	9.91	26%	53.0°
2034-10-18 Wed	90	—	unknown	20:10–00:40 (good, 4.5 h)	71.1° 19:35	9.95	35%	46.2°
2034-10-19 Thu	81	—	unknown	20:10–00:35 (good, 4.42 h)	71.1° 19:30	9.99	44%	41.1°
2034-10-20 Fri	61	—	unknown	20:05–00:10 (good, 4.08 h)	71.1° 19:25	10.04	54%	38.5°
2034-10-21 Sat	48	—	unknown	20:05–22:35 (good, 2.5 h)	71.1° 19:25	10.08	64%	39.3°
2034-10-22 Sun	40	—	unknown	20:05–00:45 (marginal, 4.67 h)	71.1° 19:20	10.12	74%	43.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2034-09-23&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.