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 Seven Sisters: 09-16 (100), 09-17 (100), 09-18 (100), 09-19 (100), 09-20 (100) — by astronomy; check the weather when the night is within four days.

2047-09-04astronomy score per night — click a bar for that night2047-10-03

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2047-09-04 Wed	40	—	unknown	04:20–05:15 (good, 0.92 h)	72.6° 06:15	7.77	100%	70.7°
2047-09-05 Thu	29	—	unknown	01:05–05:15 (marginal, 4.17 h)	72.6° 06:10	7.83	97%	58.3°
2047-09-06 Fri	21	—	unknown	01:10–05:20 (marginal, 4.17 h)	72.6° 06:05	7.88	93%	46.1°
2047-09-07 Sat	16	—	unknown	01:15–05:20 (marginal, 4.08 h)	72.6° 06:00	7.94	88%	34.0°
2047-09-08 Sun	18	—	unknown	00:55–05:20 (marginal, 4.42 h)	72.6° 06:00	7.99	81%	22.1°
2047-09-09 Mon	25	—	unknown	00:40–05:20 (marginal, 4.67 h)	72.6° 05:55	8.05	73%	10.3°
2047-09-10 Tue	35	—	unknown	00:25–05:25 (marginal, 5.0 h)	72.6° 05:50	8.1	64%	1.7°
2047-09-11 Wed	48	—	unknown	03:00–04:20 (good, 1.33 h)	72.6° 05:45	8.16	55%	13.5°
2047-09-12 Thu	64	—	unknown	01:00–05:25 (good, 4.42 h)	72.6° 05:40	8.21	46%	25.5°
2047-09-13 Fri	80	—	unknown	00:30–05:30 (good, 5.0 h)	72.6° 05:40	8.26	36%	37.8°
2047-09-14 Sat	89	—	unknown	00:30–05:30 (good, 5.0 h)	72.6° 05:35	8.32	27%	50.4°
2047-09-15 Sun	96	—	unknown	00:25–05:30 (good, 5.08 h)	72.6° 05:30	8.37	18%	63.4°
2047-09-16 Mon	100	—	unknown	00:20–05:30 (good, 5.17 h)	72.6° 05:25	8.42	10%	76.8°
2047-09-17 Tue	100	—	unknown	00:15–05:30 (good, 5.25 h)	72.6° 05:25	8.47	5%	90.7°
2047-09-18 Wed	100	—	unknown	00:15–05:35 (good, 5.33 h)	72.6° 05:20	8.52	1%	104.9°
2047-09-19 Thu	100	—	unknown	00:10–05:35 (good, 5.42 h)	72.6° 05:15	8.58	0%	119.5°
2047-09-20 Fri	100	—	unknown	00:05–05:35 (good, 5.5 h)	72.6° 05:10	8.63	2%	134.3°
2047-09-21 Sat	100	—	unknown	00:00–05:35 (good, 5.58 h)	72.6° 05:05	8.68	7%	149.1°
2047-09-22 Sun	100	—	unknown	23:55–05:40 (good, 5.75 h)	72.6° 05:05	8.73	14%	163.9°
2047-09-23 Mon	100	—	unknown	23:55–05:40 (good, 5.75 h)	72.6° 05:00	8.78	23%	178.4°
2047-09-24 Tue	100	—	unknown	23:50–05:40 (good, 5.83 h)	72.6° 04:55	8.83	34%	167.0°
2047-09-25 Wed	100	—	unknown	23:45–05:40 (good, 5.92 h)	72.6° 04:50	8.88	45%	152.9°
2047-09-26 Thu	100	—	unknown	23:45–05:45 (good, 6.0 h)	72.6° 04:45	8.93	56%	139.1°
2047-09-27 Fri	100	—	unknown	23:45–05:45 (good, 6.0 h)	72.6° 04:45	8.98	66%	125.6°
2047-09-28 Sat	100	—	unknown	23:45–05:45 (good, 6.0 h)	72.6° 04:40	9.03	76%	112.4°
2047-09-29 Sun	100	—	unknown	23:50–05:45 (good, 5.92 h)	72.6° 04:35	9.08	84%	99.5°
2047-09-30 Mon	100	—	unknown	00:25–05:50 (good, 5.42 h)	72.6° 04:30	9.13	91%	86.8°
2047-10-01 Tue	100	—	unknown	01:55–05:50 (good, 3.92 h)	72.6° 04:25	9.18	96%	74.2°
2047-10-02 Wed	63	—	unknown	04:25–05:50 (good, 1.42 h)	72.6° 04:25	9.22	99%	61.9°
2047-10-03 Thu	42	—	unknown	23:30–05:50 (marginal, 6.33 h)	72.6° 04:20	9.27	100%	49.7°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2047-09-04&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.