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 V1057 Cyg: 06-13 (100), 06-14 (100), 06-15 (100), 06-16 (100), 06-17 (100) — by astronomy; check the weather when the night is within four days.

2031-06-02astronomy score per night — click a bar for that night2031-07-01

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2031-06-02 Mon	89	—	unknown	23:40–03:45 (good, 4.08 h)	87.3° 05:35	4.77	91%	108.4°
2031-06-03 Tue	80	—	unknown	23:45–03:45 (good, 4.0 h)	87.3° 05:30	4.73	96%	100.1°
2031-06-04 Wed	69	—	unknown	00:00–03:45 (good, 3.75 h)	87.3° 05:30	4.7	100%	91.1°
2031-06-05 Thu	59	—	unknown	00:40–03:40 (good, 3.0 h)	87.3° 05:25	4.67	100%	82.0°
2031-06-06 Fri	53	—	unknown	01:10–03:40 (good, 2.5 h)	87.3° 05:20	4.64	97%	73.1°
2031-06-07 Sat	51	—	unknown	01:05–03:40 (good, 2.58 h)	87.3° 05:15	4.61	91%	65.1°
2031-06-08 Sun	70	—	unknown	23:05–03:40 (good, 4.58 h)	87.3° 05:10	4.59	83%	58.7°
2031-06-09 Mon	80	—	unknown	23:05–03:40 (good, 4.58 h)	87.3° 05:10	4.56	74%	54.2°
2031-06-10 Tue	89	—	unknown	23:05–03:40 (good, 4.58 h)	87.3° 05:05	4.54	63%	52.3°
2031-06-11 Wed	93	—	unknown	23:10–03:40 (good, 4.5 h)	87.3° 05:00	4.52	52%	53.0°
2031-06-12 Thu	97	—	unknown	23:10–03:40 (good, 4.5 h)	87.3° 04:55	4.5	41%	56.0°
2031-06-13 Fri	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.3° 04:50	4.48	31%	60.7°
2031-06-14 Sat	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.3° 04:50	4.47	22%	66.7°
2031-06-15 Sun	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.3° 04:45	4.46	14%	73.4°
2031-06-16 Mon	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.3° 04:40	4.44	8%	80.6°
2031-06-17 Tue	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.3° 04:35	4.44	4%	87.9°
2031-06-18 Wed	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.3° 04:35	4.43	1%	95.2°
2031-06-19 Thu	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.3° 04:30	4.43	0%	102.4°
2031-06-20 Fri	100	—	unknown	23:15–03:40 (good, 4.42 h)	87.3° 04:25	4.42	1%	109.1°
2031-06-21 Sat	100	—	unknown	23:15–03:40 (good, 4.42 h)	87.3° 04:20	4.42	4%	115.2°
2031-06-22 Sun	100	—	unknown	23:15–03:40 (good, 4.42 h)	87.3° 04:15	4.42	8%	120.5°
2031-06-23 Mon	100	—	unknown	23:15–03:40 (good, 4.42 h)	87.3° 04:15	4.43	14%	124.5°
2031-06-24 Tue	100	—	unknown	23:15–03:40 (good, 4.42 h)	87.3° 04:10	4.43	21%	127.0°
2031-06-25 Wed	100	—	unknown	23:15–03:40 (good, 4.42 h)	87.3° 04:05	4.44	30%	127.6°
2031-06-26 Thu	100	—	unknown	23:15–03:40 (good, 4.42 h)	87.3° 04:00	4.45	39%	126.3°
2031-06-27 Fri	100	—	unknown	23:15–03:40 (good, 4.42 h)	87.3° 03:55	4.46	49%	123.0°
2031-06-28 Sat	100	—	unknown	23:15–03:40 (good, 4.42 h)	87.3° 03:55	4.48	60%	117.9°
2031-06-29 Sun	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.3° 03:50	4.5	70%	111.3°
2031-06-30 Mon	100	—	unknown	23:10–03:45 (good, 4.58 h)	87.3° 03:45	4.51	80%	103.6°
2031-07-01 Tue	100	—	unknown	23:10–03:45 (good, 4.58 h)	87.3° 03:40	4.53	88%	95.0°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2031-06-02&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.