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: 12-19 (100), 12-20 (100), 12-21 (100), 12-22 (100), 12-23 (100) — by astronomy; check the weather when the night is within four days.

2043-12-16astronomy score per night — click a bar for that night2044-01-14

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2043-12-16 Wed	31	—	unknown	18:35–22:15 (marginal, 3.67 h)	72.6° 22:30	11.5	99%	33.4°
2043-12-17 Thu	56	—	unknown	18:35–03:10 (marginal, 8.58 h)	72.6° 22:25	11.5	96%	48.5°
2043-12-18 Fri	92	—	unknown	18:35–22:50 (good, 4.25 h)	72.6° 22:20	11.5	90%	63.3°
2043-12-19 Sat	100	—	unknown	18:35–01:35 (good, 7.0 h)	72.6° 22:15	11.51	82%	77.7°
2043-12-20 Sun	100	—	unknown	18:35–03:00 (good, 8.42 h)	72.5° 22:15	11.51	73%	91.6°
2043-12-21 Mon	100	—	unknown	18:35–03:05 (good, 8.5 h)	72.6° 22:10	11.51	63%	105.0°
2043-12-22 Tue	100	—	unknown	18:35–03:10 (good, 8.58 h)	72.6° 22:05	11.51	53%	117.9°
2043-12-23 Wed	100	—	unknown	18:40–03:10 (good, 8.5 h)	72.6° 22:00	11.51	43%	130.4°
2043-12-24 Thu	100	—	unknown	18:40–03:05 (good, 8.42 h)	72.5° 21:55	11.5	33%	142.7°
2043-12-25 Fri	100	—	unknown	18:40–03:05 (good, 8.42 h)	72.6° 21:55	11.5	25%	154.7°
2043-12-26 Sat	100	—	unknown	18:40–03:00 (good, 8.33 h)	72.6° 21:50	11.5	17%	166.6°
2043-12-27 Sun	100	—	unknown	18:40–02:55 (good, 8.25 h)	72.6° 21:45	11.49	11%	178.4°
2043-12-28 Mon	100	—	unknown	18:40–02:50 (good, 8.17 h)	72.6° 21:40	11.49	6%	169.7°
2043-12-29 Tue	100	—	unknown	18:40–02:50 (good, 8.17 h)	72.5° 21:35	11.48	2%	157.9°
2043-12-30 Wed	100	—	unknown	18:40–02:45 (good, 8.08 h)	72.6° 21:35	11.47	0%	146.0°
2043-12-31 Thu	100	—	unknown	18:45–02:40 (good, 7.92 h)	72.6° 21:30	11.46	0%	134.0°
2044-01-01 Fri	100	—	unknown	18:45–02:35 (good, 7.83 h)	72.6° 21:25	11.45	2%	121.9°
2044-01-02 Sat	100	—	unknown	18:45–02:35 (good, 7.83 h)	72.6° 21:20	11.44	6%	109.7°
2044-01-03 Sun	100	—	unknown	18:45–02:30 (good, 7.75 h)	72.5° 21:20	11.43	11%	97.3°
2044-01-04 Mon	100	—	unknown	18:45–02:25 (good, 7.67 h)	72.6° 21:15	11.42	18%	84.7°
2044-01-05 Tue	100	—	unknown	18:45–02:20 (good, 7.58 h)	72.6° 21:10	11.41	27%	71.9°
2044-01-06 Wed	99	—	unknown	18:45–02:15 (good, 7.5 h)	72.6° 21:05	11.39	37%	58.8°
2044-01-07 Thu	90	—	unknown	18:50–02:15 (good, 7.42 h)	72.5° 21:00	11.38	47%	45.4°
2044-01-08 Fri	80	—	unknown	21:00–02:10 (good, 5.17 h)	72.6° 21:00	11.36	58%	31.7°
2044-01-09 Sat	54	—	unknown	18:50–02:30 (marginal, 7.67 h)	72.6° 20:55	11.35	69%	17.6°
2044-01-10 Sun	34	—	unknown	18:50–02:10 (marginal, 7.33 h)	72.6° 20:50	11.33	80%	3.2°
2044-01-11 Mon	22	—	unknown	18:50–01:45 (marginal, 6.92 h)	72.6° 20:45	11.31	88%	11.6°
2044-01-12 Tue	18	—	unknown	18:55–20:05 (marginal, 1.17 h)	72.5° 20:40	11.29	95%	26.6°
2044-01-13 Wed	28	—	unknown	18:55–22:55 (marginal, 4.0 h)	72.6° 20:40	11.27	99%	41.6°
2044-01-14 Thu	49	—	unknown	18:55–01:25 (marginal, 6.5 h)	72.6° 20:35	11.25	100%	56.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2043-12-16&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.