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: 09-27 (100), 09-28 (100), 09-29 (100), 09-30 (100), 10-01 (100) — by astronomy; check the weather when the night is within four days.

2046-09-27astronomy score per night — click a bar for that night2046-10-26

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2046-09-27 Thu	100	—	unknown	20:45–02:05 (good, 5.33 h)	71.1° 20:55	8.99	7%	134.4°
2046-09-28 Fri	100	—	unknown	20:45–02:00 (good, 5.25 h)	71.1° 20:55	9.04	2%	127.3°
2046-09-29 Sat	100	—	unknown	20:40–01:55 (good, 5.25 h)	71.1° 20:50	9.09	0%	118.0°
2046-09-30 Sun	100	—	unknown	20:40–01:50 (good, 5.17 h)	71.1° 20:45	9.14	1%	107.4°
2046-10-01 Mon	100	—	unknown	20:40–01:50 (good, 5.17 h)	71.1° 20:40	9.19	5%	96.3°
2046-10-02 Tue	100	—	unknown	20:35–01:45 (good, 5.17 h)	71.1° 20:35	9.24	12%	85.2°
2046-10-03 Wed	100	—	unknown	20:35–01:40 (good, 5.08 h)	71.1° 20:35	9.28	20%	74.5°
2046-10-04 Thu	100	—	unknown	20:30–01:35 (good, 5.08 h)	71.1° 20:30	9.33	30%	64.6°
2046-10-05 Fri	98	—	unknown	20:30–01:30 (good, 5.0 h)	71.1° 20:25	9.38	40%	55.9°
2046-10-06 Sat	90	—	unknown	20:30–01:30 (good, 5.0 h)	71.1° 20:20	9.42	51%	48.8°
2046-10-07 Sun	79	—	unknown	20:25–01:25 (good, 5.0 h)	71.1° 20:20	9.47	61%	43.8°
2046-10-08 Mon	52	—	unknown	20:25–23:25 (good, 3.0 h)	71.1° 20:15	9.52	70%	41.5°
2046-10-09 Tue	42	—	unknown	20:25–01:35 (marginal, 5.17 h)	71.1° 20:10	9.56	78%	42.0°
2046-10-10 Wed	36	—	unknown	20:20–01:25 (marginal, 5.08 h)	71.1° 20:05	9.61	86%	45.3°
2046-10-11 Thu	34	—	unknown	20:20–01:10 (marginal, 4.83 h)	71.1° 20:00	9.65	92%	50.6°
2046-10-12 Fri	35	—	unknown	20:20–01:05 (marginal, 4.75 h)	71.1° 20:00	9.7	96%	57.4°
2046-10-13 Sat	40	—	unknown	20:20–20:25 (good, 0.08 h)	71.1° 19:55	9.74	99%	65.2°
2046-10-14 Sun	47	—	unknown	20:15–21:45 (good, 1.5 h)	71.1° 19:50	9.78	100%	73.6°
2046-10-15 Mon	57	—	unknown	20:15–22:35 (good, 2.33 h)	71.1° 19:45	9.83	99%	82.4°
2046-10-16 Tue	68	—	unknown	20:15–23:30 (good, 3.25 h)	71.1° 19:40	9.87	96%	91.4°
2046-10-17 Wed	81	—	unknown	20:10–00:20 (good, 4.17 h)	71.1° 19:40	9.91	92%	100.4°
2046-10-18 Thu	100	—	unknown	20:10–00:25 (good, 4.25 h)	71.1° 19:35	9.96	86%	109.4°
2046-10-19 Fri	100	—	unknown	20:10–00:25 (good, 4.25 h)	71.1° 19:30	10.0	78%	118.0°
2046-10-20 Sat	100	—	unknown	20:05–00:25 (good, 4.33 h)	71.1° 19:25	10.04	70%	126.0°
2046-10-21 Sun	100	—	unknown	20:05–00:25 (good, 4.33 h)	71.1° 19:25	10.08	60%	132.7°
2046-10-22 Mon	100	—	unknown	20:05–00:20 (good, 4.25 h)	71.1° 19:20	10.12	49%	137.3°
2046-10-23 Tue	100	—	unknown	20:05–00:20 (good, 4.25 h)	71.1° 19:15	10.16	38%	138.8°
2046-10-24 Wed	100	—	unknown	20:00–00:15 (good, 4.25 h)	71.1° 19:10	10.2	28%	136.6°
2046-10-25 Thu	100	—	unknown	20:00–00:15 (good, 4.25 h)	71.1° 19:05	10.24	18%	130.8°
2046-10-26 Fri	100	—	unknown	20:00–00:10 (good, 4.17 h)	71.1° 19:05	10.28	10%	122.4°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2046-09-27&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.