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: 10-04 (100), 10-05 (100), 10-06 (100), 10-07 (100), 10-08 (100) — by astronomy; check the weather when the night is within four days.

2031-09-29astronomy score per night — click a bar for that night2031-10-28

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
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°
2031-10-19 Sun	100	—	unknown	20:10–02:50 (good, 6.67 h)	87.3° 20:30	9.98	15%	87.1°
2031-10-20 Mon	100	—	unknown	20:10–02:45 (good, 6.58 h)	87.3° 20:25	10.02	24%	78.6°
2031-10-21 Tue	100	—	unknown	20:05–02:40 (good, 6.58 h)	87.3° 20:20	10.07	34%	70.6°
2031-10-22 Wed	94	—	unknown	20:05–02:35 (good, 6.5 h)	87.3° 20:15	10.11	46%	63.4°
2031-10-23 Thu	86	—	unknown	20:05–02:35 (good, 6.5 h)	87.3° 20:15	10.15	57%	57.7°
2031-10-24 Fri	70	—	unknown	20:00–02:00 (good, 6.0 h)	87.3° 20:10	10.19	68%	53.9°
2031-10-25 Sat	59	—	unknown	20:00–03:00 (marginal, 7.0 h)	87.3° 20:05	10.23	78%	52.5°
2031-10-26 Sun	50	—	unknown	19:00–01:45 (marginal, 6.75 h)	87.3° 19:00	10.27	87%	53.7°
2031-10-27 Mon	47	—	unknown	19:00–01:30 (marginal, 6.5 h)	87.3° 19:00	10.31	93%	57.2°
2031-10-28 Tue	50	—	unknown	18:55–01:20 (marginal, 6.42 h)	87.3° 18:55	10.34	98%	62.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2031-09-29&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.