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.

2044-04-02astronomy score per night — click a bar for that night2044-05-01

night of	weather	overall	best window	highest	dark h	Moon	Moon sep.
2044-04-02 Sat	—	unknown	—	79.2° 14:10	7.99	25%	42.3°
2044-04-03 Sun	—	unknown	—	79.2° 14:10	7.94	36%	55.7°
2044-04-04 Mon	—	unknown	—	79.2° 14:05	7.88	47%	69.2°
2044-04-05 Tue	—	unknown	—	79.2° 14:00	7.83	59%	82.6°
2044-04-06 Wed	—	unknown	—	79.2° 13:55	7.77	70%	96.0°
2044-04-07 Thu	—	unknown	—	79.2° 13:50	7.71	79%	109.2°
2044-04-08 Fri	—	unknown	—	79.2° 13:50	7.66	87%	122.0°
2044-04-09 Sat	—	unknown	—	79.2° 13:45	7.6	94%	134.5°
2044-04-10 Sun	—	unknown	—	79.2° 13:40	7.54	98%	146.4°
2044-04-11 Mon	—	unknown	—	79.2° 13:35	7.49	100%	156.8°
2044-04-12 Tue	—	unknown	—	79.2° 13:30	7.43	100%	163.6°
2044-04-13 Wed	—	unknown	—	79.2° 13:30	7.37	98%	162.4°
2044-04-14 Thu	—	unknown	—	79.2° 13:25	7.31	94%	154.6°
2044-04-15 Fri	—	unknown	—	79.2° 13:20	7.26	88%	144.4°
2044-04-16 Sat	—	unknown	—	79.2° 13:15	7.2	81%	133.6°
2044-04-17 Sun	—	unknown	—	79.2° 13:15	7.14	73%	122.5°
2044-04-18 Mon	—	unknown	—	79.2° 13:10	7.08	65%	111.2°
2044-04-19 Tue	—	unknown	—	79.2° 13:05	7.02	55%	99.8°
2044-04-20 Wed	—	unknown	—	79.2° 13:00	6.97	46%	88.2°
2044-04-21 Thu	—	unknown	—	79.2° 12:55	6.91	36%	76.5°
2044-04-22 Fri	—	unknown	—	79.2° 12:55	6.85	27%	64.4°
2044-04-23 Sat	—	unknown	—	79.2° 12:50	6.79	18%	52.2°
2044-04-24 Sun	—	unknown	—	79.2° 12:45	6.73	11%	39.8°
2044-04-25 Mon	—	unknown	—	79.2° 12:40	6.67	5%	27.8°
2044-04-26 Tue	—	unknown	—	79.2° 12:35	6.62	1%	18.1°
2044-04-27 Wed	—	unknown	—	79.2° 12:35	6.56	0%	16.7°
2044-04-28 Thu	—	unknown	—	79.2° 12:30	6.5	2%	25.5°
2044-04-29 Fri	—	unknown	—	79.2° 12:25	6.44	6%	38.0°
2044-04-30 Sat	—	unknown	—	79.2° 12:20	6.38	14%	51.7°
2044-05-01 Sun	—	unknown	—	79.2° 12:20	6.33	23%	65.5°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2044-04-02&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.