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: 09-03 (100), 09-04 (100), 09-05 (100), 09-06 (100), 09-07 (100) — by astronomy; check the weather when the night is within four days.

2042-09-01astronomy score per night — click a bar for that night2042-09-30

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2042-09-01 Mon	69	—	unknown	21:35–23:35 (good, 2.0 h)	87.2° 23:35	7.62	95%	62.2°
2042-09-02 Tue	75	—	unknown	21:35–01:15 (good, 3.67 h)	87.2° 23:35	7.67	88%	65.8°
2042-09-03 Wed	100	—	unknown	21:30–03:00 (good, 5.5 h)	87.3° 23:30	7.73	80%	70.9°
2042-09-04 Thu	100	—	unknown	21:30–04:10 (good, 6.67 h)	87.3° 23:25	7.78	70%	77.0°
2042-09-05 Fri	100	—	unknown	21:25–05:10 (good, 7.75 h)	87.3° 23:20	7.84	59%	83.6°
2042-09-06 Sat	100	—	unknown	21:25–05:20 (good, 7.92 h)	87.2° 23:15	7.89	48%	90.4°
2042-09-07 Sun	100	—	unknown	21:25–05:20 (good, 7.92 h)	87.2° 23:15	7.95	37%	97.0°
2042-09-08 Mon	100	—	unknown	21:20–05:20 (good, 8.0 h)	87.3° 23:10	8.0	27%	103.1°
2042-09-09 Tue	100	—	unknown	21:20–05:20 (good, 8.0 h)	87.3° 23:05	8.06	18%	108.6°
2042-09-10 Wed	100	—	unknown	21:15–05:20 (good, 8.08 h)	87.3° 23:00	8.11	11%	113.2°
2042-09-11 Thu	100	—	unknown	21:15–05:15 (good, 8.0 h)	87.2° 23:00	8.17	6%	116.6°
2042-09-12 Fri	100	—	unknown	21:15–05:15 (good, 8.0 h)	87.3° 22:55	8.22	2%	118.8°
2042-09-13 Sat	100	—	unknown	21:10–05:10 (good, 8.0 h)	87.3° 22:50	8.27	0%	119.5°
2042-09-14 Sun	100	—	unknown	21:10–05:05 (good, 7.92 h)	87.3° 22:45	8.33	0%	118.9°
2042-09-15 Mon	100	—	unknown	21:05–05:00 (good, 7.92 h)	87.2° 22:40	8.38	2%	116.9°
2042-09-16 Tue	100	—	unknown	21:05–05:00 (good, 7.92 h)	87.2° 22:40	8.43	6%	113.7°
2042-09-17 Wed	100	—	unknown	21:05–04:55 (good, 7.83 h)	87.3° 22:35	8.48	11%	109.6°
2042-09-18 Thu	100	—	unknown	21:00–04:50 (good, 7.83 h)	87.3° 22:30	8.54	18%	104.7°
2042-09-19 Fri	100	—	unknown	21:00–04:45 (good, 7.75 h)	87.3° 22:25	8.59	25%	99.2°
2042-09-20 Sat	100	—	unknown	21:00–04:40 (good, 7.67 h)	87.2° 22:20	8.64	34%	93.4°
2042-09-21 Sun	100	—	unknown	20:55–04:40 (good, 7.75 h)	87.2° 22:20	8.69	44%	87.4°
2042-09-22 Mon	100	—	unknown	20:55–04:35 (good, 7.67 h)	87.3° 22:15	8.74	54%	81.3°
2042-09-23 Tue	100	—	unknown	20:50–04:30 (good, 7.67 h)	87.3° 22:10	8.79	64%	75.4°
2042-09-24 Wed	94	—	unknown	20:50–04:25 (good, 7.58 h)	87.3° 22:05	8.84	74%	70.0°
2042-09-25 Thu	85	—	unknown	20:50–04:20 (good, 7.5 h)	87.2° 22:05	8.89	83%	65.3°
2042-09-26 Fri	64	—	unknown	20:45–01:45 (good, 5.0 h)	87.3° 22:00	8.94	91%	62.0°
2042-09-27 Sat	61	—	unknown	20:45–21:10 (good, 0.42 h)	87.3° 21:55	8.99	96%	60.5°
2042-09-28 Sun	62	—	unknown	20:45–21:05 (good, 0.33 h)	87.3° 21:50	9.04	100%	61.2°
2042-09-29 Mon	65	—	unknown	20:40–21:45 (good, 1.08 h)	87.2° 21:45	9.09	100%	64.0°
2042-09-30 Tue	70	—	unknown	20:40–23:00 (good, 2.33 h)	87.2° 21:45	9.14	97%	68.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2042-09-01&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.