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.

2044-03-21astronomy score per night — click a bar for that night2044-04-19

night of	weather	overall	best window	highest	dark h	Moon	Moon sep.
2044-03-21 Mon	—	unknown	—	89.5° 13:10	8.64	48%	112.3°
2044-03-22 Tue	—	unknown	—	89.7° 13:05	8.58	38%	102.1°
2044-03-23 Wed	—	unknown	—	89.8° 13:00	8.53	29%	91.7°
2044-03-24 Thu	—	unknown	—	89.7° 12:55	8.48	21%	81.1°
2044-03-25 Fri	—	unknown	—	89.6° 12:50	8.43	13%	70.3°
2044-03-26 Sat	—	unknown	—	89.6° 12:50	8.37	7%	59.6°
2044-03-27 Sun	—	unknown	—	89.8° 13:45	8.32	3%	49.2°
2044-03-28 Mon	—	unknown	—	89.8° 13:40	8.27	0%	39.7°
2044-03-29 Tue	—	unknown	—	89.7° 13:35	8.21	0%	32.6°
2044-03-30 Wed	—	unknown	—	89.5° 13:30	8.16	3%	30.1°
2044-03-31 Thu	—	unknown	—	89.7° 13:30	8.1	8%	33.3°
2044-04-01 Fri	—	unknown	—	89.8° 13:25	8.05	16%	41.1°
2044-04-02 Sat	—	unknown	—	89.8° 13:20	7.99	25%	51.4°
2044-04-03 Sun	—	unknown	—	89.6° 13:15	7.94	36%	62.9°
2044-04-04 Mon	—	unknown	—	89.5° 13:15	7.88	47%	74.8°
2044-04-05 Tue	—	unknown	—	89.7° 13:10	7.83	59%	86.9°
2044-04-06 Wed	—	unknown	—	89.8° 13:05	7.77	70%	98.9°
2044-04-07 Thu	—	unknown	—	89.7° 13:00	7.71	79%	110.6°
2044-04-08 Fri	—	unknown	—	89.6° 12:55	7.66	87%	121.8°
2044-04-09 Sat	—	unknown	—	89.6° 12:55	7.6	94%	132.2°
2044-04-10 Sun	—	unknown	—	89.8° 12:50	7.54	98%	141.1°
2044-04-11 Mon	—	unknown	—	89.8° 12:45	7.49	100%	147.4°
2044-04-12 Tue	—	unknown	—	89.7° 12:40	7.43	100%	149.9°
2044-04-13 Wed	—	unknown	—	89.5° 12:35	7.37	98%	147.8°
2044-04-14 Thu	—	unknown	—	89.6° 12:35	7.31	94%	142.1°
2044-04-15 Fri	—	unknown	—	89.8° 12:30	7.26	88%	134.2°
2044-04-16 Sat	—	unknown	—	89.8° 12:25	7.2	81%	125.1°
2044-04-17 Sun	—	unknown	—	89.6° 12:20	7.14	73%	115.5°
2044-04-18 Mon	—	unknown	—	89.5° 12:20	7.08	65%	105.5°
2044-04-19 Tue	—	unknown	—	89.7° 12:15	7.02	55%	95.3°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2044-03-21&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.