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: 06-06 (100), 06-07 (100), 06-08 (100), 06-09 (100), 06-10 (100) — by astronomy; check the weather when the night is within four days.

2027-06-06astronomy score per night — click a bar for that night2027-07-05

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2027-06-06 Sun	100	—	unknown	23:05–03:40 (good, 4.58 h)	87.3° 05:20	4.64	6%	106.3°
2027-06-07 Mon	100	—	unknown	23:05–03:40 (good, 4.58 h)	87.3° 05:15	4.61	14%	113.5°
2027-06-08 Tue	100	—	unknown	23:05–03:40 (good, 4.58 h)	87.3° 05:10	4.59	23%	119.4°
2027-06-09 Wed	100	—	unknown	23:05–03:40 (good, 4.58 h)	87.3° 05:10	4.56	33%	123.4°
2027-06-10 Thu	100	—	unknown	23:05–03:40 (good, 4.58 h)	87.3° 05:05	4.54	44%	125.1°
2027-06-11 Fri	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.3° 05:00	4.52	55%	124.4°
2027-06-12 Sat	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.3° 04:55	4.5	66%	121.6°
2027-06-13 Sun	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.3° 04:50	4.48	76%	117.1°
2027-06-14 Mon	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.3° 04:50	4.47	84%	111.5°
2027-06-15 Tue	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.3° 04:45	4.45	91%	105.0°
2027-06-16 Wed	84	—	unknown	23:10–03:40 (good, 4.5 h)	87.3° 04:40	4.44	96%	98.2°
2027-06-17 Thu	79	—	unknown	23:10–03:40 (good, 4.5 h)	87.3° 04:35	4.44	99%	91.1°
2027-06-18 Fri	70	—	unknown	23:10–03:40 (good, 4.5 h)	87.3° 04:35	4.43	100%	84.1°
2027-06-19 Sat	63	—	unknown	23:10–03:40 (good, 4.5 h)	87.3° 04:30	4.42	99%	77.4°
2027-06-20 Sun	59	—	unknown	23:15–03:40 (good, 4.42 h)	87.3° 04:25	4.42	97%	71.1°
2027-06-21 Mon	59	—	unknown	23:15–03:40 (good, 4.42 h)	87.3° 04:20	4.42	92%	65.5°
2027-06-22 Tue	78	—	unknown	23:15–03:40 (good, 4.42 h)	87.3° 04:15	4.42	87%	60.8°
2027-06-23 Wed	85	—	unknown	23:15–03:40 (good, 4.42 h)	87.3° 04:15	4.43	80%	57.2°
2027-06-24 Thu	91	—	unknown	23:15–03:40 (good, 4.42 h)	87.3° 04:10	4.43	72%	55.2°
2027-06-25 Fri	94	—	unknown	23:15–03:40 (good, 4.42 h)	87.3° 04:05	4.44	62%	54.9°
2027-06-26 Sat	97	—	unknown	23:15–03:40 (good, 4.42 h)	87.3° 04:00	4.45	53%	56.3°
2027-06-27 Sun	100	—	unknown	23:15–03:40 (good, 4.42 h)	87.3° 03:55	4.46	43%	59.6°
2027-06-28 Mon	100	—	unknown	23:15–03:40 (good, 4.42 h)	87.3° 03:55	4.48	32%	64.4°
2027-06-29 Tue	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.3° 03:50	4.49	23%	70.6°
2027-06-30 Wed	100	—	unknown	23:10–03:45 (good, 4.58 h)	87.3° 03:45	4.51	14%	78.0°
2027-07-01 Thu	100	—	unknown	23:10–03:45 (good, 4.58 h)	87.3° 03:40	4.53	7%	86.0°
2027-07-02 Fri	100	—	unknown	23:10–03:45 (good, 4.58 h)	87.3° 03:40	4.55	2%	94.5°
2027-07-03 Sat	100	—	unknown	23:10–03:45 (good, 4.58 h)	87.3° 03:35	4.58	0%	103.0°
2027-07-04 Sun	100	—	unknown	23:10–03:45 (good, 4.58 h)	87.3° 03:30	4.6	1%	110.8°
2027-07-05 Mon	100	—	unknown	23:10–03:45 (good, 4.58 h)	87.3° 03:25	4.63	5%	117.5°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2027-06-06&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.