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.

2047-04-25astronomy score per night — click a bar for that night2047-05-24

night of	weather	overall	best window	highest	dark h	Moon	Moon sep.
2047-04-25 Thu	—	unknown	—	79.2° 12:45	6.72	1%	18.0°
2047-04-26 Fri	—	unknown	—	79.2° 12:40	6.66	3%	26.6°
2047-04-27 Sat	—	unknown	—	79.2° 12:35	6.6	7%	37.1°
2047-04-28 Sun	—	unknown	—	79.2° 12:30	6.54	12%	48.3°
2047-04-29 Mon	—	unknown	—	79.2° 12:30	6.48	19%	60.0°
2047-04-30 Tue	—	unknown	—	79.2° 12:25	6.43	28%	71.9°
2047-05-01 Wed	—	unknown	—	79.2° 12:20	6.37	37%	84.2°
2047-05-02 Thu	—	unknown	—	79.2° 12:15	6.31	48%	96.8°
2047-05-03 Fri	—	unknown	—	79.2° 12:15	6.25	58%	109.8°
2047-05-04 Sat	—	unknown	—	79.2° 12:10	6.19	69%	123.1°
2047-05-05 Sun	—	unknown	—	79.2° 12:05	6.14	79%	136.5°
2047-05-06 Mon	—	unknown	—	79.2° 12:00	6.08	88%	149.8°
2047-05-07 Tue	—	unknown	—	79.2° 11:55	6.02	95%	161.4°
2047-05-08 Wed	—	unknown	—	79.2° 11:50	5.97	99%	165.1°
2047-05-09 Thu	—	unknown	—	79.2° 11:45	5.91	100%	156.6°
2047-05-10 Fri	—	unknown	—	79.2° 11:40	5.85	98%	143.7°
2047-05-11 Sat	—	unknown	—	79.2° 11:35	5.8	93%	129.9°
2047-05-12 Sun	—	unknown	—	79.2° 11:35	5.74	86%	116.2°
2047-05-13 Mon	—	unknown	—	79.2° 11:30	5.69	78%	102.8°
2047-05-14 Tue	—	unknown	—	79.2° 11:25	5.64	68%	89.7°
2047-05-15 Wed	—	unknown	—	79.2° 11:20	5.58	58%	77.1°
2047-05-16 Thu	—	unknown	—	79.2° 11:20	5.53	48%	65.0°
2047-05-17 Fri	—	unknown	—	79.2° 11:15	5.48	38%	53.2°
2047-05-18 Sat	—	unknown	—	79.2° 11:10	5.42	29%	41.8°
2047-05-19 Sun	—	unknown	—	79.2° 11:05	5.37	21%	31.0°
2047-05-20 Mon	—	unknown	—	79.2° 11:00	5.32	14%	21.4°
2047-05-21 Tue	—	unknown	—	79.2° 11:00	5.27	8%	15.0°
2047-05-22 Wed	—	unknown	—	79.2° 10:55	5.23	4%	16.3°
2047-05-23 Thu	—	unknown	—	79.2° 10:50	5.18	1%	24.2°
2047-05-24 Fri	—	unknown	—	79.2° 10:45	5.13	0%	34.4°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2047-04-25&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.