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: 05-31 (100), 06-01 (100), 06-02 (100), 06-03 (100), 06-16 (100) — by astronomy; check the weather when the night is within four days.

2028-05-31astronomy score per night — click a bar for that night2028-06-29

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2028-05-31 Wed	100	—	unknown	23:35–03:45 (good, 4.17 h)	87.3° 05:40	4.81	57%	126.3°
2028-06-01 Thu	100	—	unknown	23:30–03:45 (good, 4.25 h)	87.3° 05:35	4.78	68%	124.2°
2028-06-02 Fri	100	—	unknown	23:30–03:45 (good, 4.25 h)	87.3° 05:35	4.74	78%	119.8°
2028-06-03 Sat	100	—	unknown	23:30–03:45 (good, 4.25 h)	87.3° 05:30	4.71	87%	113.8°
2028-06-04 Sun	88	—	unknown	23:30–03:40 (good, 4.17 h)	87.3° 05:25	4.68	93%	106.7°
2028-06-05 Mon	80	—	unknown	23:35–03:40 (good, 4.08 h)	87.3° 05:20	4.65	98%	99.0°
2028-06-06 Tue	71	—	unknown	23:35–03:40 (good, 4.08 h)	87.3° 05:15	4.62	100%	91.1°
2028-06-07 Wed	64	—	unknown	23:45–03:40 (good, 3.92 h)	87.3° 05:15	4.59	99%	83.3°
2028-06-08 Thu	59	—	unknown	23:55–03:40 (good, 3.75 h)	87.3° 05:10	4.57	97%	75.8°
2028-06-09 Fri	61	—	unknown	23:30–03:40 (good, 4.17 h)	87.3° 05:05	4.54	92%	69.1°
2028-06-10 Sat	74	—	unknown	23:05–03:40 (good, 4.58 h)	87.3° 05:00	4.52	86%	63.2°
2028-06-11 Sun	80	—	unknown	23:10–03:40 (good, 4.5 h)	87.3° 04:55	4.5	79%	58.5°
2028-06-12 Mon	88	—	unknown	23:10–03:40 (good, 4.5 h)	87.3° 04:55	4.49	71%	55.2°
2028-06-13 Tue	91	—	unknown	23:10–03:40 (good, 4.5 h)	87.3° 04:50	4.47	62%	53.7°
2028-06-14 Wed	94	—	unknown	23:10–03:40 (good, 4.5 h)	87.3° 04:45	4.46	52%	53.9°
2028-06-15 Thu	97	—	unknown	23:10–03:40 (good, 4.5 h)	87.3° 04:40	4.45	43%	55.8°
2028-06-16 Fri	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.3° 04:40	4.44	34%	59.4°
2028-06-17 Sat	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.3° 04:35	4.43	25%	64.4°
2028-06-18 Sun	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.3° 04:30	4.43	16%	70.6°
2028-06-19 Mon	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.3° 04:25	4.42	10%	77.6°
2028-06-20 Tue	100	—	unknown	23:15–03:40 (good, 4.42 h)	87.3° 04:20	4.42	4%	85.3°
2028-06-21 Wed	100	—	unknown	23:15–03:40 (good, 4.42 h)	87.3° 04:20	4.42	1%	93.4°
2028-06-22 Thu	100	—	unknown	23:15–03:40 (good, 4.42 h)	87.3° 04:15	4.43	0%	101.5°
2028-06-23 Fri	100	—	unknown	23:15–03:40 (good, 4.42 h)	87.3° 04:10	4.43	2%	109.3°
2028-06-24 Sat	100	—	unknown	23:15–03:40 (good, 4.42 h)	87.3° 04:05	4.44	6%	116.3°
2028-06-25 Sun	100	—	unknown	23:15–03:40 (good, 4.42 h)	87.3° 04:00	4.45	13%	121.9°
2028-06-26 Mon	100	—	unknown	23:15–03:40 (good, 4.42 h)	87.3° 04:00	4.46	22%	125.5°
2028-06-27 Tue	100	—	unknown	23:15–03:40 (good, 4.42 h)	87.3° 03:55	4.47	32%	126.5°
2028-06-28 Wed	100	—	unknown	23:10–03:40 (good, 4.5 h)	87.3° 03:50	4.49	43%	125.0°
2028-06-29 Thu	100	—	unknown	23:10–03:45 (good, 4.58 h)	87.3° 03:45	4.51	55%	121.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2028-05-31&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.