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: 09-17 (100), 09-18 (100), 09-19 (100), 09-20 (100), 09-21 (100) — by astronomy; check the weather when the night is within four days.

2047-09-17astronomy score per night — click a bar for that night2047-10-16

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2047-09-17 Tue	100	—	unknown	21:05–02:15 (good, 5.17 h)	87.1° 20:15	8.47	5%	113.0°
2047-09-18 Wed	100	—	unknown	21:00–02:10 (good, 5.17 h)	87.1° 20:10	8.52	1%	108.1°
2047-09-19 Thu	100	—	unknown	21:00–02:05 (good, 5.08 h)	87.1° 20:05	8.58	0%	101.9°
2047-09-20 Fri	100	—	unknown	21:00–02:00 (good, 5.0 h)	87.1° 20:00	8.63	2%	95.1°
2047-09-21 Sat	100	—	unknown	20:55–01:55 (good, 5.0 h)	87.1° 20:00	8.68	7%	87.9°
2047-09-22 Sun	100	—	unknown	20:55–01:55 (good, 5.0 h)	87.1° 19:55	8.73	14%	80.9°
2047-09-23 Mon	100	—	unknown	20:55–01:50 (good, 4.92 h)	87.1° 19:50	8.78	23%	74.4°
2047-09-24 Tue	100	—	unknown	20:50–01:45 (good, 4.92 h)	87.1° 19:45	8.83	34%	68.9°
2047-09-25 Wed	95	—	unknown	20:50–01:40 (good, 4.83 h)	87.1° 19:40	8.88	45%	64.7°
2047-09-26 Thu	86	—	unknown	20:45–01:35 (good, 4.83 h)	87.1° 19:40	8.93	56%	62.0°
2047-09-27 Fri	70	—	unknown	20:45–01:10 (good, 4.42 h)	87.1° 19:35	8.98	66%	61.1°
2047-09-28 Sat	58	—	unknown	20:45–00:25 (good, 3.67 h)	87.1° 19:30	9.03	76%	61.8°
2047-09-29 Sun	51	—	unknown	20:40–22:50 (good, 2.17 h)	87.1° 19:25	9.08	84%	64.1°
2047-09-30 Mon	48	—	unknown	20:40–22:10 (good, 1.5 h)	87.1° 19:20	9.13	91%	67.7°
2047-10-01 Tue	47	—	unknown	20:40–22:05 (good, 1.42 h)	87.1° 19:20	9.18	96%	72.2°
2047-10-02 Wed	50	—	unknown	20:35–22:20 (good, 1.75 h)	87.1° 19:15	9.22	99%	77.4°
2047-10-03 Thu	55	—	unknown	20:35–22:45 (good, 2.17 h)	87.1° 19:10	9.27	100%	83.0°
2047-10-04 Fri	61	—	unknown	20:35–23:15 (good, 2.67 h)	87.1° 19:05	9.32	99%	88.8°
2047-10-05 Sat	70	—	unknown	20:30–23:55 (good, 3.42 h)	87.1° 19:05	9.37	96%	94.6°
2047-10-06 Sun	79	—	unknown	20:30–00:30 (good, 4.0 h)	87.1° 19:00	9.41	92%	100.2°
2047-10-07 Mon	86	—	unknown	20:30–00:30 (good, 4.0 h)	87.1° 18:55	9.46	86%	105.4°
2047-10-08 Tue	100	—	unknown	20:25–00:35 (good, 4.17 h)	87.1° 18:50	9.5	79%	110.1°
2047-10-09 Wed	100	—	unknown	20:25–00:35 (good, 4.17 h)	87.1° 18:45	9.55	71%	114.0°
2047-10-10 Thu	100	—	unknown	20:25–00:35 (good, 4.17 h)	87.1° 18:45	9.6	62%	117.0°
2047-10-11 Fri	100	—	unknown	20:20–00:35 (good, 4.25 h)	87.1° 18:40	9.64	53%	118.7°
2047-10-12 Sat	100	—	unknown	20:20–00:35 (good, 4.25 h)	87.1° 18:35	9.69	43%	119.0°
2047-10-13 Sun	100	—	unknown	20:20–00:30 (good, 4.17 h)	87.1° 18:30	9.73	33%	117.8°
2047-10-14 Mon	100	—	unknown	20:15–00:25 (good, 4.17 h)	87.1° 18:25	9.77	23%	114.9°
2047-10-15 Tue	100	—	unknown	20:15–00:25 (good, 4.17 h)	87.1° 18:25	9.82	14%	110.6°
2047-10-16 Wed	100	—	unknown	20:15–00:20 (good, 4.08 h)	87.1° 18:20	9.86	7%	104.9°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2047-09-17&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.