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: 12-20 (100), 12-21 (100), 12-22 (100), 12-23 (100), 12-24 (100) — by astronomy; check the weather when the night is within four days.

2044-12-20astronomy score per night — click a bar for that night2045-01-18

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2044-12-20 Tue	100	—	unknown	18:35–03:20 (good, 8.75 h)	72.6° 22:10	11.51	2%	133.2°
2044-12-21 Wed	100	—	unknown	18:35–03:15 (good, 8.67 h)	72.6° 22:05	11.51	6%	121.4°
2044-12-22 Thu	100	—	unknown	18:35–03:15 (good, 8.67 h)	72.6° 22:00	11.51	11%	109.6°
2044-12-23 Fri	100	—	unknown	18:40–03:10 (good, 8.5 h)	72.6° 22:00	11.5	17%	97.7°
2044-12-24 Sat	100	—	unknown	18:40–03:05 (good, 8.42 h)	72.6° 21:55	11.5	25%	85.8°
2044-12-25 Sun	100	—	unknown	18:40–03:00 (good, 8.33 h)	72.6° 21:50	11.5	34%	73.7°
2044-12-26 Mon	99	—	unknown	18:40–02:55 (good, 8.25 h)	72.6° 21:45	11.49	44%	61.4°
2044-12-27 Tue	92	—	unknown	18:40–02:55 (good, 8.25 h)	72.6° 21:40	11.49	54%	48.8°
2044-12-28 Wed	82	—	unknown	22:10–02:50 (good, 4.67 h)	72.6° 21:40	11.48	64%	35.8°
2044-12-29 Thu	53	—	unknown	18:40–03:15 (marginal, 8.58 h)	72.6° 21:35	11.47	74%	22.4°
2044-12-30 Fri	36	—	unknown	18:45–02:55 (marginal, 8.17 h)	72.6° 21:30	11.47	83%	8.5°
2044-12-31 Sat	23	—	unknown	23:00–02:25 (marginal, 3.42 h)	72.6° 21:25	11.46	91%	6.1°
2045-01-01 Sun	20	—	unknown	18:45–20:05 (marginal, 1.33 h)	72.6° 21:25	11.45	96%	20.9°
2045-01-02 Mon	26	—	unknown	18:45–21:35 (marginal, 2.83 h)	72.6° 21:20	11.43	100%	36.0°
2045-01-03 Tue	49	—	unknown	18:45–02:00 (marginal, 7.25 h)	72.6° 21:15	11.42	100%	51.3°
2045-01-04 Wed	70	—	unknown	18:45–21:35 (good, 2.83 h)	72.6° 21:10	11.41	96%	66.5°
2045-01-05 Thu	100	—	unknown	18:45–00:25 (good, 5.67 h)	72.6° 21:05	11.4	91%	81.6°
2045-01-06 Fri	100	—	unknown	18:50–01:50 (good, 7.0 h)	72.6° 21:05	11.38	83%	96.3°
2045-01-07 Sat	100	—	unknown	18:50–02:00 (good, 7.17 h)	72.6° 21:00	11.37	73%	110.6°
2045-01-08 Sun	100	—	unknown	18:50–02:00 (good, 7.17 h)	72.6° 20:55	11.35	63%	124.5°
2045-01-09 Mon	100	—	unknown	18:50–02:00 (good, 7.17 h)	72.6° 20:50	11.33	52%	137.9°
2045-01-10 Tue	100	—	unknown	18:50–01:55 (good, 7.08 h)	72.6° 20:45	11.32	42%	150.8°
2045-01-11 Wed	100	—	unknown	18:55–01:55 (good, 7.0 h)	72.6° 20:45	11.3	32%	163.5°
2045-01-12 Thu	100	—	unknown	18:55–01:50 (good, 6.92 h)	72.6° 20:40	11.28	23%	175.8°
2045-01-13 Fri	100	—	unknown	18:55–01:45 (good, 6.83 h)	72.6° 20:35	11.26	16%	171.9°
2045-01-14 Sat	100	—	unknown	18:55–01:45 (good, 6.83 h)	72.6° 20:30	11.24	9%	159.9°
2045-01-15 Sun	100	—	unknown	18:55–01:40 (good, 6.75 h)	72.6° 20:30	11.22	5%	148.0°
2045-01-16 Mon	100	—	unknown	19:00–01:35 (good, 6.58 h)	72.6° 20:25	11.19	2%	136.1°
2045-01-17 Tue	100	—	unknown	19:00–01:30 (good, 6.5 h)	72.6° 20:20	11.17	0%	124.3°
2045-01-18 Wed	100	—	unknown	19:00–01:25 (good, 6.42 h)	72.6° 20:15	11.15	0%	112.5°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2044-12-20&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.