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: 06-23 (100), 06-24 (100), 06-25 (100), 06-26 (100), 06-27 (100) — by astronomy; check the weather when the night is within four days.

2028-06-23astronomy score per night — click a bar for that night2028-07-22

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
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°
2028-06-30 Fri	100	—	unknown	23:10–03:45 (good, 4.58 h)	87.3° 03:45	4.53	66%	115.5°
2028-07-01 Sat	100	—	unknown	23:10–03:45 (good, 4.58 h)	87.3° 03:40	4.55	76%	108.7°
2028-07-02 Sun	100	—	unknown	23:10–03:45 (good, 4.58 h)	87.3° 03:35	4.57	85%	101.2°
2028-07-03 Mon	100	—	unknown	23:10–03:45 (good, 4.58 h)	87.3° 03:30	4.6	92%	93.4°
2028-07-04 Tue	79	—	unknown	23:10–03:45 (good, 4.58 h)	87.3° 03:25	4.62	96%	85.6°
2028-07-05 Wed	71	—	unknown	23:10–03:50 (good, 4.67 h)	87.3° 03:25	4.65	99%	78.1°
2028-07-06 Thu	61	—	unknown	23:10–03:50 (good, 4.67 h)	87.3° 03:20	4.68	100%	71.1°
2028-07-07 Fri	55	—	unknown	23:05–03:50 (good, 4.75 h)	87.3° 03:15	4.71	99%	64.9°
2028-07-08 Sat	53	—	unknown	23:05–01:05 (good, 2.0 h)	87.3° 03:10	4.75	95%	59.8°
2028-07-09 Sun	56	—	unknown	23:05–01:20 (good, 2.25 h)	87.3° 03:05	4.78	90%	56.1°
2028-07-10 Mon	62	—	unknown	23:05–02:00 (good, 2.92 h)	87.3° 03:05	4.82	84%	53.9°
2028-07-11 Tue	92	—	unknown	23:05–03:25 (good, 4.33 h)	87.3° 03:00	4.86	77%	53.5°
2028-07-12 Wed	95	—	unknown	23:05–03:55 (good, 4.83 h)	87.3° 02:55	4.9	68%	54.9°
2028-07-13 Thu	99	—	unknown	23:00–04:00 (good, 5.0 h)	87.3° 02:50	4.94	59%	58.0°
2028-07-14 Fri	100	—	unknown	23:00–04:00 (good, 5.0 h)	87.3° 02:50	4.98	49%	62.5°
2028-07-15 Sat	100	—	unknown	23:00–04:00 (good, 5.0 h)	87.3° 02:45	5.02	40%	68.2°
2028-07-16 Sun	100	—	unknown	23:00–04:00 (good, 5.0 h)	87.3° 02:40	5.06	30%	74.8°
2028-07-17 Mon	100	—	unknown	22:55–04:05 (good, 5.17 h)	87.3° 02:35	5.11	21%	82.2°
2028-07-18 Tue	100	—	unknown	22:55–04:05 (good, 5.17 h)	87.3° 02:30	5.15	13%	90.1°
2028-07-19 Wed	100	—	unknown	22:55–04:05 (good, 5.17 h)	87.3° 02:30	5.2	6%	98.2°
2028-07-20 Thu	100	—	unknown	22:55–04:10 (good, 5.25 h)	87.3° 02:25	5.25	2%	106.3°
2028-07-21 Fri	100	—	unknown	22:50–04:10 (good, 5.33 h)	87.3° 02:20	5.3	0%	113.8°
2028-07-22 Sat	100	—	unknown	22:50–04:10 (good, 5.33 h)	87.3° 02:15	5.35	1%	120.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2028-06-23&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.