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: 09-11 (100), 09-12 (100), 09-13 (100), 09-14 (100), 09-26 (100) — by astronomy; check the weather when the night is within four days.

2029-09-11astronomy score per night — click a bar for that night2029-10-10

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2029-09-11 Tue	100	—	unknown	21:15–03:05 (good, 5.83 h)	71.1° 22:00	8.17	17%	93.3°
2029-09-12 Wed	100	—	unknown	21:15–03:00 (good, 5.75 h)	71.1° 21:55	8.23	27%	82.0°
2029-09-13 Thu	100	—	unknown	21:10–02:55 (good, 5.75 h)	71.1° 21:50	8.28	37%	71.1°
2029-09-14 Fri	100	—	unknown	21:10–02:55 (good, 5.75 h)	71.1° 21:45	8.33	48%	61.0°
2029-09-15 Sat	94	—	unknown	21:05–02:50 (good, 5.75 h)	71.1° 21:45	8.39	60%	52.1°
2029-09-16 Sun	86	—	unknown	21:05–02:45 (good, 5.67 h)	71.1° 21:40	8.44	70%	45.0°
2029-09-17 Mon	58	—	unknown	02:35–02:40 (good, 0.08 h)	71.1° 21:35	8.49	79%	40.4°
2029-09-18 Tue	41	—	unknown	21:00–02:55 (marginal, 5.92 h)	71.1° 21:30	8.54	86%	39.0°
2029-09-19 Wed	35	—	unknown	21:00–02:40 (marginal, 5.67 h)	71.1° 21:25	8.59	93%	41.0°
2029-09-20 Thu	33	—	unknown	21:00–02:30 (marginal, 5.5 h)	71.1° 21:25	8.65	97%	45.9°
2029-09-21 Fri	37	—	unknown	20:55–02:20 (marginal, 5.42 h)	71.1° 21:20	8.7	99%	52.6°
2029-09-22 Sat	44	—	unknown	20:20–02:20 (marginal, 6.0 h)	71.1° 21:15	8.75	100%	60.6°
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°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2029-09-11&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.