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: 09-19 (100), 09-20 (100), 09-21 (100), 09-22 (100), 09-23 (100) — by astronomy; check the weather when the night is within four days.

2031-09-19astronomy score per night — click a bar for that night2031-10-18

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2031-09-19 Fri	100	—	unknown	21:00–04:45 (good, 7.75 h)	87.3° 22:25	8.57	10%	109.2°
2031-09-20 Sat	100	—	unknown	21:00–04:45 (good, 7.75 h)	87.3° 22:25	8.62	18%	101.6°
2031-09-21 Sun	100	—	unknown	20:55–04:40 (good, 7.75 h)	87.3° 22:20	8.67	27%	93.5°
2031-09-22 Mon	100	—	unknown	20:55–04:35 (good, 7.67 h)	87.3° 22:15	8.72	37%	85.1°
2031-09-23 Tue	100	—	unknown	20:55–04:30 (good, 7.58 h)	87.3° 22:10	8.77	48%	76.8°
2031-09-24 Wed	100	—	unknown	20:50–04:25 (good, 7.58 h)	87.3° 22:05	8.82	60%	69.0°
2031-09-25 Thu	92	—	unknown	20:50–04:25 (good, 7.58 h)	87.3° 22:05	8.87	71%	62.0°
2031-09-26 Fri	84	—	unknown	20:45–04:20 (good, 7.58 h)	87.3° 22:00	8.92	81%	56.6°
2031-09-27 Sat	57	—	unknown	20:45–04:50 (marginal, 8.08 h)	87.3° 21:55	8.97	89%	53.3°
2031-09-28 Sun	54	—	unknown	20:45–04:35 (marginal, 7.83 h)	87.3° 21:50	9.02	95%	52.6°
2031-09-29 Mon	52	—	unknown	20:40–04:20 (marginal, 7.67 h)	87.3° 21:50	9.07	99%	54.7°
2031-09-30 Tue	57	—	unknown	20:10–04:05 (marginal, 7.92 h)	87.3° 21:45	9.12	100%	59.0°
2031-10-01 Wed	66	—	unknown	20:40–21:55 (good, 1.25 h)	87.3° 21:40	9.17	98%	64.9°
2031-10-02 Thu	73	—	unknown	20:35–23:55 (good, 3.33 h)	87.3° 21:35	9.22	95%	71.9°
2031-10-03 Fri	80	—	unknown	20:35–01:20 (good, 4.75 h)	87.3° 21:30	9.27	89%	79.4°
2031-10-04 Sat	100	—	unknown	20:35–02:30 (good, 5.92 h)	87.3° 21:30	9.31	82%	87.1°
2031-10-05 Sun	100	—	unknown	20:30–03:15 (good, 6.75 h)	87.3° 21:25	9.36	73%	94.6°
2031-10-06 Mon	100	—	unknown	20:30–03:20 (good, 6.83 h)	87.3° 21:20	9.41	64%	101.9°
2031-10-07 Tue	100	—	unknown	20:30–03:25 (good, 6.92 h)	87.3° 21:15	9.45	55%	108.7°
2031-10-08 Wed	100	—	unknown	20:25–03:25 (good, 7.0 h)	87.3° 21:10	9.5	46%	114.8°
2031-10-09 Thu	100	—	unknown	20:25–03:25 (good, 7.0 h)	87.3° 21:10	9.54	36%	120.1°
2031-10-10 Fri	100	—	unknown	20:25–03:20 (good, 6.92 h)	87.3° 21:05	9.59	27%	124.2°
2031-10-11 Sat	100	—	unknown	20:20–03:20 (good, 7.0 h)	87.3° 21:00	9.64	19%	126.8°
2031-10-12 Sun	100	—	unknown	20:20–03:15 (good, 6.92 h)	87.3° 20:55	9.68	12%	127.5°
2031-10-13 Mon	100	—	unknown	20:20–03:10 (good, 6.83 h)	87.3° 20:55	9.72	6%	126.2°
2031-10-14 Tue	100	—	unknown	20:15–03:10 (good, 6.92 h)	87.3° 20:50	9.77	2%	122.9°
2031-10-15 Wed	100	—	unknown	20:15–03:05 (good, 6.83 h)	87.3° 20:45	9.81	0%	117.8°
2031-10-16 Thu	100	—	unknown	20:15–03:00 (good, 6.75 h)	87.3° 20:40	9.86	0%	111.3°
2031-10-17 Fri	100	—	unknown	20:10–02:55 (good, 6.75 h)	87.3° 20:35	9.9	3%	103.8°
2031-10-18 Sat	100	—	unknown	20:10–02:55 (good, 6.75 h)	87.3° 20:35	9.94	8%	95.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2031-09-19&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.