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: 10-04 (100), 10-05 (100), 10-06 (100), 10-07 (100), 10-08 (100) — by astronomy; check the weather when the night is within four days.

2031-10-04astronomy score per night — click a bar for that night2031-11-02

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2031-10-04 Sat	100	—	unknown	20:35–01:20 (good, 4.75 h)	71.1° 20:30	9.31	82%	108.0°
2031-10-05 Sun	100	—	unknown	20:30–01:25 (good, 4.92 h)	71.1° 20:25	9.36	73%	117.4°
2031-10-06 Mon	100	—	unknown	20:30–01:20 (good, 4.83 h)	71.1° 20:20	9.41	64%	125.9°
2031-10-07 Tue	100	—	unknown	20:30–01:20 (good, 4.83 h)	71.1° 20:20	9.45	55%	133.3°
2031-10-08 Wed	100	—	unknown	20:25–01:15 (good, 4.83 h)	71.1° 20:15	9.5	46%	139.0°
2031-10-09 Thu	100	—	unknown	20:25–01:15 (good, 4.83 h)	71.1° 20:10	9.54	36%	142.4°
2031-10-10 Fri	100	—	unknown	20:25–01:15 (good, 4.83 h)	71.1° 20:05	9.59	27%	142.7°
2031-10-11 Sat	100	—	unknown	20:20–01:10 (good, 4.83 h)	71.1° 20:05	9.64	19%	139.8°
2031-10-12 Sun	100	—	unknown	20:20–01:05 (good, 4.75 h)	71.1° 20:00	9.68	12%	134.2°
2031-10-13 Mon	100	—	unknown	20:20–01:00 (good, 4.67 h)	71.1° 19:55	9.72	6%	126.6°
2031-10-14 Tue	100	—	unknown	20:15–00:55 (good, 4.67 h)	71.1° 19:50	9.77	2%	117.7°
2031-10-15 Wed	100	—	unknown	20:15–00:55 (good, 4.67 h)	71.1° 19:45	9.81	0%	107.8°
2031-10-16 Thu	100	—	unknown	20:15–00:50 (good, 4.58 h)	71.1° 19:45	9.86	0%	97.3°
2031-10-17 Fri	100	—	unknown	20:10–00:45 (good, 4.58 h)	71.1° 19:40	9.9	3%	86.4°
2031-10-18 Sat	100	—	unknown	20:10–00:40 (good, 4.5 h)	71.1° 19:35	9.94	8%	75.5°
2031-10-19 Sun	100	—	unknown	20:10–00:40 (good, 4.5 h)	71.1° 19:30	9.98	15%	64.7°
2031-10-20 Mon	98	—	unknown	20:10–00:35 (good, 4.42 h)	71.1° 19:25	10.02	24%	54.7°
2031-10-21 Tue	90	—	unknown	20:05–00:30 (good, 4.42 h)	71.1° 19:25	10.07	34%	46.0°
2031-10-22 Wed	75	—	unknown	20:05–00:25 (good, 4.33 h)	71.1° 19:20	10.11	46%	39.6°
2031-10-23 Thu	53	—	unknown	20:05–23:50 (good, 3.75 h)	71.1° 19:15	10.15	57%	37.0°
2031-10-24 Fri	41	—	unknown	20:00–00:40 (marginal, 4.67 h)	71.1° 19:10	10.19	68%	38.9°
2031-10-25 Sat	34	—	unknown	20:00–00:30 (marginal, 4.5 h)	71.1° 19:10	10.23	78%	44.6°
2031-10-26 Sun	32	—	unknown	19:00–23:15 (marginal, 4.25 h)	71.1° 18:05	10.27	87%	52.9°
2031-10-27 Mon	34	—	unknown	19:00–23:10 (marginal, 4.17 h)	71.1° 18:00	10.31	93%	62.6°
2031-10-28 Tue	41	—	unknown	18:55–20:00 (good, 1.08 h)	71.1° 17:55	10.34	98%	72.9°
2031-10-29 Wed	49	—	unknown	18:55–20:50 (good, 1.92 h)	71.1° 17:50	10.38	100%	83.5°
2031-10-30 Thu	59	—	unknown	18:55–21:45 (good, 2.83 h)	71.1° 17:50	10.42	100%	94.0°
2031-10-31 Fri	71	—	unknown	18:55–22:25 (good, 3.5 h)	71.1° 17:45	10.46	97%	104.3°
2031-11-01 Sat	81	—	unknown	18:55–22:30 (good, 3.58 h)	71.1° 17:40	10.49	93%	114.0°
2031-11-02 Sun	95	—	unknown	18:50–22:35 (good, 3.75 h)	71.1° 17:35	10.53	87%	123.0°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2031-10-04&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.