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: 08-19 (100), 08-20 (100), 08-21 (100), 08-29 (100), 08-30 (100) — by astronomy; check the weather when the night is within four days.

2037-08-19astronomy score per night — click a bar for that night2037-09-17

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2037-08-19 Wed	100	—	unknown	22:00–04:55 (good, 6.92 h)	87.3° 00:25	6.89	70%	81.3°
2037-08-20 Thu	100	—	unknown	22:00–04:55 (good, 6.92 h)	87.3° 00:25	6.95	79%	75.4°
2037-08-21 Fri	100	—	unknown	21:55–04:55 (good, 7.0 h)	87.3° 00:20	7.01	86%	70.3°
2037-08-22 Sat	93	—	unknown	21:55–05:00 (good, 7.08 h)	87.3° 00:15	7.06	92%	66.0°
2037-08-23 Sun	64	—	unknown	01:05–05:00 (good, 3.92 h)	87.3° 00:10	7.12	97%	62.9°
2037-08-24 Mon	62	—	unknown	21:50–22:30 (good, 0.67 h)	87.3° 00:05	7.18	99%	61.0°
2037-08-25 Tue	63	—	unknown	21:50–22:40 (good, 0.83 h)	87.3° 00:05	7.24	100%	60.6°
2037-08-26 Wed	67	—	unknown	21:45–23:15 (good, 1.5 h)	87.3° 00:00	7.29	99%	61.5°
2037-08-27 Thu	71	—	unknown	21:45–00:15 (good, 2.5 h)	87.3° 23:55	7.35	96%	63.8°
2037-08-28 Fri	75	—	unknown	21:45–01:40 (good, 3.92 h)	87.3° 23:50	7.41	91%	67.1°
2037-08-29 Sat	100	—	unknown	21:40–03:10 (good, 5.5 h)	87.3° 23:50	7.46	85%	71.4°
2037-08-30 Sun	100	—	unknown	21:40–04:00 (good, 6.33 h)	87.3° 23:45	7.52	78%	76.4°
2037-08-31 Mon	100	—	unknown	21:35–05:00 (good, 7.42 h)	87.3° 23:40	7.57	69%	81.9°
2037-09-01 Tue	100	—	unknown	21:35–05:10 (good, 7.58 h)	87.3° 23:35	7.63	60%	87.9°
2037-09-02 Wed	100	—	unknown	21:35–05:15 (good, 7.67 h)	87.3° 23:30	7.69	50%	94.0°
2037-09-03 Thu	100	—	unknown	21:30–05:15 (good, 7.75 h)	87.3° 23:30	7.74	40%	100.2°
2037-09-04 Fri	100	—	unknown	21:30–05:15 (good, 7.75 h)	87.3° 23:25	7.8	29%	106.1°
2037-09-05 Sat	100	—	unknown	21:25–05:20 (good, 7.92 h)	87.3° 23:20	7.85	20%	111.5°
2037-09-06 Sun	100	—	unknown	21:25–05:20 (good, 7.92 h)	87.3° 23:15	7.91	12%	115.8°
2037-09-07 Mon	100	—	unknown	21:25–05:20 (good, 7.92 h)	87.3° 23:10	7.96	5%	118.6°
2037-09-08 Tue	100	—	unknown	21:20–05:20 (good, 8.0 h)	87.3° 23:10	8.02	1%	119.4°
2037-09-09 Wed	100	—	unknown	21:20–05:25 (good, 8.08 h)	87.3° 23:05	8.07	0%	118.0°
2037-09-10 Thu	100	—	unknown	21:15–05:20 (good, 8.08 h)	87.3° 23:00	8.12	2%	114.5°
2037-09-11 Fri	100	—	unknown	21:15–05:15 (good, 8.0 h)	87.3° 22:55	8.18	7%	109.3°
2037-09-12 Sat	100	—	unknown	21:15–05:15 (good, 8.0 h)	87.3° 22:55	8.23	15%	103.2°
2037-09-13 Sun	100	—	unknown	21:10–05:10 (good, 8.0 h)	87.3° 22:50	8.28	24%	96.4°
2037-09-14 Mon	100	—	unknown	21:10–05:05 (good, 7.92 h)	87.3° 22:45	8.34	34%	89.6°
2037-09-15 Tue	100	—	unknown	21:05–05:00 (good, 7.92 h)	87.3° 22:40	8.39	45%	83.1°
2037-09-16 Wed	100	—	unknown	21:05–04:55 (good, 7.83 h)	87.3° 22:35	8.44	55%	77.0°
2037-09-17 Thu	100	—	unknown	21:05–04:55 (good, 7.83 h)	87.3° 22:35	8.49	65%	71.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2037-08-19&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.