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: 01-13 (100), 01-14 (100), 01-15 (100), 01-16 (100), 01-17 (100) — by astronomy; check the weather when the night is within four days.

2047-01-13astronomy score per night — click a bar for that night2047-02-11

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2047-01-13 Sun	100	—	unknown	18:55–23:20 (good, 4.42 h)	72.6° 20:40	11.27	96%	78.1°
2047-01-14 Mon	100	—	unknown	18:55–00:55 (good, 6.0 h)	72.6° 20:35	11.25	90%	92.2°
2047-01-15 Tue	100	—	unknown	18:55–01:25 (good, 6.5 h)	72.6° 20:30	11.23	82%	106.4°
2047-01-16 Wed	100	—	unknown	18:55–01:30 (good, 6.58 h)	72.6° 20:25	11.21	72%	120.7°
2047-01-17 Thu	100	—	unknown	19:00–01:30 (good, 6.5 h)	72.6° 20:20	11.18	61%	134.9°
2047-01-18 Fri	100	—	unknown	19:00–01:25 (good, 6.42 h)	72.6° 20:20	11.16	50%	149.0°
2047-01-19 Sat	100	—	unknown	19:00–01:25 (good, 6.42 h)	72.6° 20:15	11.13	39%	163.1°
2047-01-20 Sun	100	—	unknown	19:00–01:20 (good, 6.33 h)	72.6° 20:10	11.11	28%	177.1°
2047-01-21 Mon	100	—	unknown	19:00–01:15 (good, 6.25 h)	72.6° 20:05	11.08	19%	169.1°
2047-01-22 Tue	100	—	unknown	19:05–01:15 (good, 6.17 h)	72.6° 20:00	11.06	11%	155.4°
2047-01-23 Wed	100	—	unknown	19:05–01:10 (good, 6.08 h)	72.6° 20:00	11.03	5%	141.8°
2047-01-24 Thu	100	—	unknown	19:05–01:05 (good, 6.0 h)	72.6° 19:55	11.0	1%	128.5°
2047-01-25 Fri	100	—	unknown	19:05–01:00 (good, 5.92 h)	72.6° 19:50	10.98	0%	115.4°
2047-01-26 Sat	100	—	unknown	19:10–00:55 (good, 5.75 h)	72.6° 19:45	10.95	1%	102.5°
2047-01-27 Sun	100	—	unknown	19:10–00:55 (good, 5.75 h)	72.6° 19:45	10.92	4%	89.9°
2047-01-28 Mon	100	—	unknown	19:10–00:50 (good, 5.67 h)	72.6° 19:40	10.89	8%	77.5°
2047-01-29 Tue	100	—	unknown	19:10–00:45 (good, 5.58 h)	72.6° 19:35	10.86	14%	65.3°
2047-01-30 Wed	95	—	unknown	19:10–00:40 (good, 5.5 h)	72.6° 19:30	10.82	22%	53.4°
2047-01-31 Thu	87	—	unknown	19:15–00:40 (good, 5.42 h)	72.6° 19:25	10.79	30%	41.5°
2047-02-01 Fri	77	—	unknown	19:15–00:35 (good, 5.33 h)	72.6° 19:25	10.76	39%	29.7°
2047-02-02 Sat	64	—	unknown	19:15–00:05 (good, 4.83 h)	72.6° 19:20	10.73	48%	17.8°
2047-02-03 Sun	48	—	unknown	19:15–00:50 (marginal, 5.58 h)	72.6° 19:15	10.69	58%	5.9°
2047-02-04 Mon	34	—	unknown	19:15–00:35 (marginal, 5.33 h)	72.6° 19:10	10.66	67%	6.3°
2047-02-05 Tue	23	—	unknown	19:20–00:20 (marginal, 5.0 h)	72.6° 19:05	10.62	76%	18.8°
2047-02-06 Wed	17	—	unknown	19:20–23:55 (marginal, 4.58 h)	72.6° 19:05	10.59	84%	31.7°
2047-02-07 Thu	22	—	unknown	19:20–23:50 (marginal, 4.5 h)	72.6° 19:00	10.55	91%	44.9°
2047-02-08 Fri	31	—	unknown	19:20–23:55 (marginal, 4.58 h)	72.6° 18:55	10.52	96%	58.6°
2047-02-09 Sat	44	—	unknown	19:25–20:25 (good, 1.0 h)	72.6° 18:50	10.48	99%	72.6°
2047-02-10 Sun	62	—	unknown	19:25–22:10 (good, 2.75 h)	72.6° 18:45	10.44	100%	87.0°
2047-02-11 Mon	80	—	unknown	19:25–23:30 (good, 4.08 h)	72.6° 18:45	10.41	98%	101.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2047-01-13&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.