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: 10-18 (100), 10-19 (100), 10-20 (100), 10-21 (100), 10-22 (100) — by astronomy; check the weather when the night is within four days.

2046-10-18astronomy score per night — click a bar for that night2046-11-16

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
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°
2046-10-27 Sat	100	—	unknown	20:00–00:05 (good, 4.08 h)	71.1° 19:00	10.32	4%	112.4°
2046-10-28 Sun	100	—	unknown	18:55–23:00 (good, 4.08 h)	71.1° 17:55	10.36	1%	101.4°
2046-10-29 Mon	100	—	unknown	18:55–23:00 (good, 4.08 h)	71.1° 17:50	10.4	0%	90.2°
2046-10-30 Tue	100	—	unknown	18:55–22:55 (good, 4.0 h)	71.1° 17:45	10.43	3%	79.0°
2046-10-31 Wed	100	—	unknown	18:55–22:50 (good, 3.92 h)	71.1° 17:45	10.47	8%	68.5°
2046-11-01 Thu	100	—	unknown	18:50–22:45 (good, 3.92 h)	71.1° 17:40	10.51	16%	58.9°
2046-11-02 Fri	90	—	unknown	18:50–22:40 (good, 3.83 h)	71.1° 17:35	10.54	25%	50.9°
2046-11-03 Sat	75	—	unknown	18:50–22:40 (good, 3.83 h)	71.1° 17:30	10.58	34%	44.9°
2046-11-04 Sun	61	—	unknown	18:50–22:20 (good, 3.5 h)	71.1° 17:30	10.61	44%	41.6°
2046-11-05 Mon	49	—	unknown	18:50–22:05 (good, 3.25 h)	71.1° 17:25	10.65	54%	41.3°
2046-11-06 Tue	41	—	unknown	18:45–20:15 (good, 1.5 h)	71.1° 17:20	10.68	63%	43.9°
2046-11-07 Wed	35	—	unknown	18:45–19:05 (good, 0.33 h)	71.1° 17:15	10.72	72%	48.8°
2046-11-08 Thu	31	—	unknown	18:45–22:30 (marginal, 3.75 h)	71.1° 17:10	10.75	80%	55.3°
2046-11-09 Fri	31	—	unknown	18:45–22:25 (marginal, 3.67 h)	71.1° 17:10	10.78	87%	62.9°
2046-11-10 Sat	33	—	unknown	18:45–19:10 (good, 0.42 h)	71.1° 17:05	10.81	93%	71.2°
2046-11-11 Sun	37	—	unknown	18:45–19:40 (good, 0.92 h)	71.1° 17:00	10.84	97%	79.9°
2046-11-12 Mon	44	—	unknown	18:40–20:25 (good, 1.75 h)	71.1° 16:55	10.87	99%	89.0°
2046-11-13 Tue	51	—	unknown	18:40–21:10 (good, 2.5 h)	71.1° 16:50	10.91	100%	98.2°
2046-11-14 Wed	59	—	unknown	18:40–21:35 (good, 2.92 h)	71.1° 16:50	10.93	98%	107.3°
2046-11-15 Thu	67	—	unknown	18:40–21:35 (good, 2.92 h)	71.1° 16:45	10.96	95%	116.2°
2046-11-16 Fri	76	—	unknown	18:40–21:35 (good, 2.92 h)	71.1° 16:40	10.99	90%	124.4°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2046-10-18&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.