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: 09-05 (100), 09-06 (100), 09-07 (100), 09-08 (100), 09-09 (100) — by astronomy; check the weather when the night is within four days.

2031-09-03astronomy score per night — click a bar for that night2031-10-02

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2031-09-03 Wed	70	—	unknown	21:30–23:40 (good, 2.17 h)	87.3° 23:30	7.71	92%	61.2°
2031-09-04 Thu	77	—	unknown	21:30–02:15 (good, 4.75 h)	87.3° 23:25	7.77	84%	67.6°
2031-09-05 Fri	100	—	unknown	21:30–03:30 (good, 6.0 h)	87.3° 23:20	7.82	76%	74.8°
2031-09-06 Sat	100	—	unknown	21:25–04:45 (good, 7.33 h)	87.3° 23:20	7.88	67%	82.2°
2031-09-07 Sun	100	—	unknown	21:25–05:10 (good, 7.75 h)	87.3° 23:15	7.93	57%	89.7°
2031-09-08 Mon	100	—	unknown	21:20–05:15 (good, 7.92 h)	87.3° 23:10	7.99	48%	97.1°
2031-09-09 Tue	100	—	unknown	21:20–05:15 (good, 7.92 h)	87.3° 23:05	8.04	38%	104.1°
2031-09-10 Wed	100	—	unknown	21:20–05:15 (good, 7.92 h)	87.3° 23:00	8.09	29%	110.6°
2031-09-11 Thu	100	—	unknown	21:15–05:15 (good, 8.0 h)	87.3° 23:00	8.15	21%	116.5°
2031-09-12 Fri	100	—	unknown	21:15–05:15 (good, 8.0 h)	87.3° 22:55	8.2	14%	121.5°
2031-09-13 Sat	100	—	unknown	21:10–05:10 (good, 8.0 h)	87.3° 22:50	8.26	8%	125.1°
2031-09-14 Sun	100	—	unknown	21:10–05:05 (good, 7.92 h)	87.3° 22:45	8.31	4%	127.1°
2031-09-15 Mon	100	—	unknown	21:10–05:05 (good, 7.92 h)	87.3° 22:45	8.36	1%	127.2°
2031-09-16 Tue	100	—	unknown	21:05–05:00 (good, 7.92 h)	87.3° 22:40	8.41	0%	125.2°
2031-09-17 Wed	100	—	unknown	21:05–04:55 (good, 7.83 h)	87.3° 22:35	8.47	2%	121.4°
2031-09-18 Thu	100	—	unknown	21:00–04:50 (good, 7.83 h)	87.3° 22:30	8.52	5%	115.9°
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°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2031-09-03&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.