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: 07-19 (100), 07-20 (100), 07-21 (100), 07-22 (100), 07-23 (100) — by astronomy; check the weather when the night is within four days.

2031-07-19astronomy score per night — click a bar for that night2031-08-17

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2031-07-19 Sat	100	—	unknown	22:55–04:05 (good, 5.17 h)	87.3° 02:30	5.17	0%	119.2°
2031-07-20 Sun	100	—	unknown	22:55–04:05 (good, 5.17 h)	87.3° 02:25	5.21	2%	123.5°
2031-07-21 Mon	100	—	unknown	22:50–04:10 (good, 5.33 h)	87.3° 02:25	5.26	5%	126.4°
2031-07-22 Tue	100	—	unknown	22:50–04:10 (good, 5.33 h)	87.3° 02:20	5.31	10%	127.5°
2031-07-23 Wed	100	—	unknown	22:50–04:10 (good, 5.33 h)	87.3° 02:15	5.36	17%	126.6°
2031-07-24 Thu	100	—	unknown	22:50–04:15 (good, 5.42 h)	87.3° 02:10	5.41	25%	123.8°
2031-07-25 Fri	100	—	unknown	22:45–04:15 (good, 5.5 h)	87.3° 02:05	5.46	34%	119.2°
2031-07-26 Sat	100	—	unknown	22:45–04:15 (good, 5.5 h)	87.3° 02:05	5.51	45%	113.2°
2031-07-27 Sun	100	—	unknown	22:45–04:15 (good, 5.5 h)	87.3° 02:00	5.57	55%	106.0°
2031-07-28 Mon	100	—	unknown	22:40–04:20 (good, 5.67 h)	87.3° 01:55	5.62	66%	98.0°
2031-07-29 Tue	100	—	unknown	22:40–04:20 (good, 5.67 h)	87.3° 01:50	5.67	77%	89.4°
2031-07-30 Wed	100	—	unknown	22:40–04:20 (good, 5.67 h)	87.3° 01:50	5.73	86%	80.6°
2031-07-31 Thu	100	—	unknown	22:35–04:25 (good, 5.83 h)	87.3° 01:45	5.78	93%	72.0°
2031-08-01 Fri	68	—	unknown	01:35–04:25 (good, 2.83 h)	87.3° 01:40	5.84	98%	64.2°
2031-08-02 Sat	56	—	unknown	22:35–04:25 (marginal, 5.83 h)	87.3° 01:35	5.89	100%	57.9°
2031-08-03 Sun	52	—	unknown	22:30–04:30 (marginal, 6.0 h)	87.3° 01:30	5.95	99%	53.9°
2031-08-04 Mon	56	—	unknown	22:30–23:05 (good, 0.58 h)	87.3° 01:30	6.0	95%	52.6°
2031-08-05 Tue	67	—	unknown	22:30–00:15 (good, 1.75 h)	87.3° 01:25	6.06	88%	54.1°
2031-08-06 Wed	75	—	unknown	22:25–02:15 (good, 3.83 h)	87.3° 01:20	6.12	80%	57.9°
2031-08-07 Thu	100	—	unknown	22:25–04:35 (good, 6.17 h)	87.3° 01:15	6.17	71%	63.5°
2031-08-08 Fri	100	—	unknown	22:25–04:35 (good, 6.17 h)	87.3° 01:10	6.23	61%	70.0°
2031-08-09 Sat	100	—	unknown	22:20–04:40 (good, 6.33 h)	87.3° 01:10	6.29	51%	77.1°
2031-08-10 Sun	100	—	unknown	22:20–04:40 (good, 6.33 h)	87.3° 01:05	6.34	41%	84.5°
2031-08-11 Mon	100	—	unknown	22:15–04:40 (good, 6.42 h)	87.3° 01:00	6.4	32%	91.8°
2031-08-12 Tue	100	—	unknown	22:15–04:45 (good, 6.5 h)	87.3° 00:55	6.46	23%	99.0°
2031-08-13 Wed	100	—	unknown	22:15–04:45 (good, 6.5 h)	87.3° 00:55	6.52	16%	105.9°
2031-08-14 Thu	100	—	unknown	22:10–04:45 (good, 6.58 h)	87.3° 00:50	6.57	10%	112.3°
2031-08-15 Fri	100	—	unknown	22:10–04:45 (good, 6.58 h)	87.3° 00:45	6.63	5%	117.9°
2031-08-16 Sat	100	—	unknown	22:05–04:50 (good, 6.75 h)	87.3° 00:40	6.69	2%	122.6°
2031-08-17 Sun	100	—	unknown	22:05–04:50 (good, 6.75 h)	87.3° 00:35	6.75	0%	125.8°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2031-07-19&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.