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 Vega: 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.

2031-09-05astronomy score per night — click a bar for that night2031-10-04

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2031-09-05 Fri	100	—	unknown	21:30–02:35 (good, 5.08 h)	87.1° 21:00	7.82	76%	101.4°
2031-09-06 Sat	100	—	unknown	21:25–02:40 (good, 5.25 h)	87.1° 20:55	7.88	67%	107.6°
2031-09-07 Sun	100	—	unknown	21:25–02:40 (good, 5.25 h)	87.1° 20:55	7.93	57%	113.0°
2031-09-08 Mon	100	—	unknown	21:20–02:40 (good, 5.33 h)	87.1° 20:50	7.99	48%	117.4°
2031-09-09 Tue	100	—	unknown	21:20–02:40 (good, 5.33 h)	87.1° 20:45	8.04	38%	120.5°
2031-09-10 Wed	100	—	unknown	21:20–02:40 (good, 5.33 h)	87.1° 20:40	8.09	29%	122.2°
2031-09-11 Thu	100	—	unknown	21:15–02:35 (good, 5.33 h)	87.1° 20:35	8.15	21%	122.4°
2031-09-12 Fri	100	—	unknown	21:15–02:30 (good, 5.25 h)	87.1° 20:35	8.2	14%	121.0°
2031-09-13 Sat	100	—	unknown	21:10–02:30 (good, 5.33 h)	87.1° 20:30	8.26	8%	118.2°
2031-09-14 Sun	100	—	unknown	21:10–02:25 (good, 5.25 h)	87.1° 20:25	8.31	4%	114.1°
2031-09-15 Mon	100	—	unknown	21:10–02:20 (good, 5.17 h)	87.1° 20:20	8.36	1%	108.9°
2031-09-16 Tue	100	—	unknown	21:05–02:15 (good, 5.17 h)	87.1° 20:15	8.41	0%	102.9°
2031-09-17 Wed	100	—	unknown	21:05–02:15 (good, 5.17 h)	87.1° 20:15	8.47	2%	96.3°
2031-09-18 Thu	100	—	unknown	21:00–02:10 (good, 5.17 h)	87.1° 20:10	8.52	5%	89.3°
2031-09-19 Fri	100	—	unknown	21:00–02:05 (good, 5.08 h)	87.1° 20:05	8.57	10%	82.3°
2031-09-20 Sat	100	—	unknown	21:00–02:00 (good, 5.0 h)	87.1° 20:00	8.62	18%	75.4°
2031-09-21 Sun	100	—	unknown	20:55–01:55 (good, 5.0 h)	87.1° 20:00	8.67	27%	69.1°
2031-09-22 Mon	98	—	unknown	20:55–01:55 (good, 5.0 h)	87.1° 19:55	8.72	37%	63.7°
2031-09-23 Tue	91	—	unknown	20:55–01:50 (good, 4.92 h)	87.1° 19:50	8.77	48%	59.8°
2031-09-24 Wed	82	—	unknown	20:50–01:45 (good, 4.92 h)	87.1° 19:45	8.82	60%	57.6°
2031-09-25 Thu	62	—	unknown	20:50–01:10 (good, 4.33 h)	87.1° 19:40	8.87	71%	57.7°
2031-09-26 Fri	52	—	unknown	20:45–23:05 (good, 2.33 h)	87.1° 19:40	8.92	81%	60.0°
2031-09-27 Sat	47	—	unknown	20:45–21:50 (good, 1.08 h)	87.1° 19:35	8.97	89%	64.3°
2031-09-28 Sun	46	—	unknown	20:45–21:55 (good, 1.17 h)	87.1° 19:30	9.02	95%	70.1°
2031-09-29 Mon	51	—	unknown	20:40–22:25 (good, 1.75 h)	87.1° 19:25	9.07	99%	76.9°
2031-09-30 Tue	58	—	unknown	20:40–23:05 (good, 2.42 h)	87.1° 19:20	9.12	100%	84.2°
2031-10-01 Wed	67	—	unknown	20:40–23:50 (good, 3.17 h)	87.1° 19:20	9.17	98%	91.6°
2031-10-02 Thu	79	—	unknown	20:35–00:35 (good, 4.0 h)	87.1° 19:15	9.22	95%	98.8°
2031-10-03 Fri	88	—	unknown	20:35–00:45 (good, 4.17 h)	87.1° 19:10	9.27	89%	105.4°
2031-10-04 Sat	100	—	unknown	20:35–00:50 (good, 4.25 h)	87.1° 19:05	9.31	82%	111.3°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2031-09-05&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.