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.

2039-06-11astronomy score per night — click a bar for that night2039-07-10

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2039-06-11 Sat	94	—	unknown	23:10–03:40 (good, 4.5 h)	87.3° 05:00	4.52	67%	62.8°
2039-06-12 Sun	97	—	unknown	23:10–03:40 (good, 4.5 h)	87.3° 04:55	4.5	57%	62.8°
2039-06-13 Mon	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.2° 04:50	4.48	47%	64.3°
2039-06-14 Tue	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.3° 04:50	4.47	37%	67.0°
2039-06-15 Wed	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.3° 04:45	4.45	28%	70.7°
2039-06-16 Thu	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.3° 04:40	4.44	19%	75.1°
2039-06-17 Fri	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.3° 04:35	4.44	12%	80.1°
2039-06-18 Sat	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.2° 04:35	4.43	7%	85.4°
2039-06-19 Sun	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.3° 04:30	4.42	3%	90.8°
2039-06-20 Mon	100	—	unknown	23:15–03:40 (good, 4.42 h)	87.3° 04:25	4.42	1%	96.2°
2039-06-21 Tue	100	—	unknown	23:15–03:40 (good, 4.42 h)	87.3° 04:20	4.42	0%	101.4°
2039-06-22 Wed	100	—	unknown	23:15–03:40 (good, 4.42 h)	87.3° 04:15	4.42	1%	106.3°
2039-06-23 Thu	100	—	unknown	23:15–03:40 (good, 4.42 h)	87.3° 04:15	4.43	4%	110.5°
2039-06-24 Fri	100	—	unknown	23:15–03:40 (good, 4.42 h)	87.3° 04:10	4.43	10%	114.0°
2039-06-25 Sat	100	—	unknown	23:15–03:40 (good, 4.42 h)	87.3° 04:05	4.44	16%	116.3°
2039-06-26 Sun	100	—	unknown	23:15–03:40 (good, 4.42 h)	87.3° 04:00	4.45	24%	117.4°
2039-06-27 Mon	100	—	unknown	23:15–03:40 (good, 4.42 h)	87.2° 03:55	4.47	34%	117.0°
2039-06-28 Tue	100	—	unknown	23:15–03:40 (good, 4.42 h)	87.3° 03:55	4.48	44%	115.1°
2039-06-29 Wed	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.3° 03:50	4.5	55%	111.7°
2039-06-30 Thu	100	—	unknown	23:10–03:45 (good, 4.58 h)	87.3° 03:45	4.51	66%	107.0°
2039-07-01 Fri	100	—	unknown	23:10–03:45 (good, 4.58 h)	87.3° 03:40	4.53	77%	101.3°
2039-07-02 Sat	100	—	unknown	23:10–03:45 (good, 4.58 h)	87.2° 03:40	4.56	86%	94.8°
2039-07-03 Sun	81	—	unknown	23:10–03:45 (good, 4.58 h)	87.3° 03:35	4.58	93%	88.0°
2039-07-04 Mon	75	—	unknown	23:10–03:45 (good, 4.58 h)	87.3° 03:30	4.61	98%	81.2°
2039-07-05 Tue	65	—	unknown	23:10–03:45 (good, 4.58 h)	87.3° 03:25	4.63	100%	74.9°
2039-07-06 Wed	60	—	unknown	23:10–03:50 (good, 4.67 h)	87.3° 03:20	4.66	99%	69.5°
2039-07-07 Thu	63	—	unknown	23:10–03:50 (good, 4.67 h)	87.3° 03:20	4.69	95%	65.5°
2039-07-08 Fri	91	—	unknown	23:05–03:50 (good, 4.75 h)	87.3° 03:15	4.73	89%	63.2°
2039-07-09 Sat	96	—	unknown	23:05–03:50 (good, 4.75 h)	87.3° 03:10	4.76	81%	62.5°
2039-07-10 Sun	99	—	unknown	23:05–03:55 (good, 4.83 h)	87.3° 03:05	4.79	72%	63.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2039-06-11&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.