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: 10-08 (100), 10-09 (100), 10-10 (100), 10-11 (100), 10-12 (100) — by astronomy; check the weather when the night is within four days.

2047-09-27astronomy score per night — click a bar for that night2047-10-26

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2047-09-27 Fri	82	—	unknown	20:45–02:05 (good, 5.33 h)	71.1° 21:00	8.98	66%	43.3°
2047-09-28 Sat	51	—	unknown	20:45–02:30 (marginal, 5.75 h)	71.2° 20:55	9.03	76%	40.1°
2047-09-29 Sun	40	—	unknown	20:40–02:15 (marginal, 5.58 h)	71.2° 20:50	9.08	84%	40.4°
2047-09-30 Mon	34	—	unknown	20:40–02:00 (marginal, 5.33 h)	71.2° 20:45	9.13	91%	43.9°
2047-10-01 Tue	34	—	unknown	20:40–01:45 (marginal, 5.08 h)	71.1° 20:40	9.18	96%	49.8°
2047-10-02 Wed	38	—	unknown	20:35–01:40 (marginal, 5.08 h)	71.1° 20:40	9.22	99%	57.2°
2047-10-03 Thu	45	—	unknown	20:35–21:00 (good, 0.42 h)	71.2° 20:35	9.27	100%	65.5°
2047-10-04 Fri	54	—	unknown	20:35–22:35 (good, 2.0 h)	71.2° 20:30	9.32	99%	74.3°
2047-10-05 Sat	67	—	unknown	20:30–23:30 (good, 3.0 h)	71.1° 20:25	9.37	96%	83.4°
2047-10-06 Sun	80	—	unknown	20:30–00:30 (good, 4.0 h)	71.1° 20:25	9.41	92%	92.5°
2047-10-07 Mon	87	—	unknown	20:30–01:00 (good, 4.5 h)	71.2° 20:20	9.46	86%	101.6°
2047-10-08 Tue	100	—	unknown	20:25–01:05 (good, 4.67 h)	71.2° 20:15	9.5	79%	110.4°
2047-10-09 Wed	100	—	unknown	20:25–01:10 (good, 4.75 h)	71.2° 20:10	9.55	71%	118.8°
2047-10-10 Thu	100	—	unknown	20:25–01:05 (good, 4.67 h)	71.1° 20:05	9.6	62%	126.6°
2047-10-11 Fri	100	—	unknown	20:20–01:05 (good, 4.75 h)	71.1° 20:05	9.64	53%	133.3°
2047-10-12 Sat	100	—	unknown	20:20–01:00 (good, 4.67 h)	71.2° 20:00	9.69	43%	138.2°
2047-10-13 Sun	100	—	unknown	20:20–01:00 (good, 4.67 h)	71.2° 19:55	9.73	33%	140.3°
2047-10-14 Mon	100	—	unknown	20:15–01:00 (good, 4.75 h)	71.2° 19:50	9.77	23%	138.9°
2047-10-15 Tue	100	—	unknown	20:15–00:55 (good, 4.67 h)	71.1° 19:45	9.82	14%	134.0°
2047-10-16 Wed	100	—	unknown	20:15–00:50 (good, 4.58 h)	71.1° 19:45	9.86	7%	126.2°
2047-10-17 Thu	100	—	unknown	20:10–00:45 (good, 4.58 h)	71.2° 19:40	9.9	2%	116.4°
2047-10-18 Fri	100	—	unknown	20:10–00:40 (good, 4.5 h)	71.2° 19:35	9.95	0%	105.5°
2047-10-19 Sat	100	—	unknown	20:10–00:40 (good, 4.5 h)	71.1° 19:30	9.99	1%	93.9°
2047-10-20 Sun	100	—	unknown	20:10–00:35 (good, 4.42 h)	71.1° 19:30	10.03	5%	82.3°
2047-10-21 Mon	100	—	unknown	20:05–00:30 (good, 4.42 h)	71.2° 19:25	10.07	11%	70.9°
2047-10-22 Tue	100	—	unknown	20:05–00:25 (good, 4.33 h)	71.2° 19:20	10.11	20%	60.4°
2047-10-23 Wed	95	—	unknown	20:05–00:20 (good, 4.25 h)	71.2° 19:15	10.15	30%	51.3°
2047-10-24 Thu	82	—	unknown	20:00–00:20 (good, 4.33 h)	71.1° 19:10	10.19	40%	44.3°
2047-10-25 Fri	61	—	unknown	20:00–23:55 (good, 3.92 h)	71.1° 19:10	10.23	51%	40.3°
2047-10-26 Sat	48	—	unknown	20:00–22:35 (good, 2.58 h)	71.2° 19:05	10.27	62%	39.7°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2047-09-27&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.