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: 09-26 (100), 09-27 (100), 09-28 (100), 09-29 (100), 09-30 (100) — by astronomy; check the weather when the night is within four days.

2029-09-23astronomy score per night — click a bar for that night2029-10-22

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2029-09-23 Sun	55	—	unknown	20:50–22:30 (good, 1.67 h)	71.1° 21:10	8.8	98%	69.2°
2029-09-24 Mon	67	—	unknown	20:50–23:45 (good, 2.92 h)	71.1° 21:10	8.85	95%	78.2°
2029-09-25 Tue	80	—	unknown	20:50–00:45 (good, 3.92 h)	71.1° 21:05	8.9	91%	87.3°
2029-09-26 Wed	100	—	unknown	20:45–01:40 (good, 4.92 h)	71.1° 21:00	8.95	84%	96.5°
2029-09-27 Thu	100	—	unknown	20:45–01:45 (good, 5.0 h)	71.1° 20:55	9.0	77%	105.6°
2029-09-28 Fri	100	—	unknown	20:45–01:50 (good, 5.08 h)	71.1° 20:50	9.05	69%	114.5°
2029-09-29 Sat	100	—	unknown	20:40–01:50 (good, 5.17 h)	71.1° 20:50	9.1	59%	122.9°
2029-09-30 Sun	100	—	unknown	20:40–01:45 (good, 5.08 h)	71.1° 20:45	9.14	50%	130.6°
2029-10-01 Mon	100	—	unknown	20:35–01:45 (good, 5.17 h)	71.1° 20:40	9.19	39%	136.8°
2029-10-02 Tue	100	—	unknown	20:35–01:40 (good, 5.08 h)	71.1° 20:35	9.24	29%	140.5°
2029-10-03 Wed	100	—	unknown	20:35–01:40 (good, 5.08 h)	71.1° 20:30	9.29	20%	140.8°
2029-10-04 Thu	100	—	unknown	20:30–01:35 (good, 5.08 h)	71.1° 20:30	9.34	12%	137.0°
2029-10-05 Fri	100	—	unknown	20:30–01:30 (good, 5.0 h)	71.1° 20:25	9.38	5%	129.9°
2029-10-06 Sat	100	—	unknown	20:30–01:25 (good, 4.92 h)	71.1° 20:20	9.43	1%	120.4°
2029-10-07 Sun	100	—	unknown	20:25–01:25 (good, 5.0 h)	71.1° 20:15	9.48	0%	109.5°
2029-10-08 Mon	100	—	unknown	20:25–01:20 (good, 4.92 h)	71.1° 20:15	9.52	2%	97.9°
2029-10-09 Tue	100	—	unknown	20:25–01:15 (good, 4.83 h)	71.1° 20:10	9.57	7%	86.1°
2029-10-10 Wed	100	—	unknown	20:20–01:10 (good, 4.83 h)	71.1° 20:05	9.61	14%	74.6°
2029-10-11 Thu	100	—	unknown	20:20–01:05 (good, 4.75 h)	71.1° 20:00	9.66	23%	63.8°
2029-10-12 Fri	97	—	unknown	20:20–01:05 (good, 4.75 h)	71.1° 19:55	9.7	33%	54.2°
2029-10-13 Sat	89	—	unknown	20:20–01:00 (good, 4.67 h)	71.1° 19:55	9.75	44%	46.3°
2029-10-14 Sun	71	—	unknown	20:15–00:55 (good, 4.67 h)	71.1° 19:50	9.79	55%	40.9°
2029-10-15 Mon	51	—	unknown	20:15–23:10 (good, 2.92 h)	71.1° 19:45	9.83	65%	38.8°
2029-10-16 Tue	40	—	unknown	20:15–01:05 (marginal, 4.83 h)	71.1° 19:40	9.88	74%	40.1°
2029-10-17 Wed	34	—	unknown	20:10–00:55 (marginal, 4.75 h)	71.1° 19:35	9.92	82%	44.3°
2029-10-18 Thu	32	—	unknown	20:10–00:45 (marginal, 4.58 h)	71.1° 19:35	9.96	89%	50.7°
2029-10-19 Fri	34	—	unknown	20:10–00:35 (marginal, 4.42 h)	71.1° 19:30	10.0	94%	58.4°
2029-10-20 Sat	38	—	unknown	20:05–20:15 (good, 0.17 h)	71.1° 19:25	10.05	98%	66.9°
2029-10-21 Sun	45	—	unknown	20:05–21:30 (good, 1.42 h)	71.1° 19:20	10.09	100%	75.8°
2029-10-22 Mon	55	—	unknown	20:05–22:20 (good, 2.25 h)	71.1° 19:20	10.13	100%	84.9°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2029-09-23&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.