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.

2047-04-26astronomy score per night — click a bar for that night2047-05-25

night of	weather	overall	best window	highest	dark h	Moon	Moon sep.
2047-04-26 Fri	—	unknown	—	72.6° 14:55	6.66	3%	4.2°
2047-04-27 Sat	—	unknown	—	72.6° 14:50	6.6	7%	7.8°
2047-04-28 Sun	—	unknown	—	72.6° 14:45	6.54	12%	19.8°
2047-04-29 Mon	—	unknown	—	72.6° 14:40	6.48	19%	32.1°
2047-04-30 Tue	—	unknown	—	72.6° 14:35	6.43	28%	44.5°
2047-05-01 Wed	—	unknown	—	72.6° 14:35	6.37	37%	57.2°
2047-05-02 Thu	—	unknown	—	72.6° 14:30	6.31	48%	70.3°
2047-05-03 Fri	—	unknown	—	72.6° 14:25	6.25	58%	83.7°
2047-05-04 Sat	—	unknown	—	72.6° 14:20	6.19	69%	97.5°
2047-05-05 Sun	—	unknown	—	72.6° 14:15	6.14	79%	111.8°
2047-05-06 Mon	—	unknown	—	72.6° 14:15	6.08	88%	126.4°
2047-05-07 Tue	—	unknown	—	72.6° 14:10	6.02	95%	141.4°
2047-05-08 Wed	—	unknown	—	72.6° 14:05	5.97	99%	156.6°
2047-05-09 Thu	—	unknown	—	72.6° 14:00	5.91	100%	171.8°
2047-05-10 Fri	—	unknown	—	72.6° 14:00	5.85	98%	173.1°
2047-05-11 Sat	—	unknown	—	72.6° 13:55	5.8	93%	158.3°
2047-05-12 Sun	—	unknown	—	72.6° 13:50	5.74	86%	143.9°
2047-05-13 Mon	—	unknown	—	72.6° 13:45	5.69	78%	130.0°
2047-05-14 Tue	—	unknown	—	72.6° 13:40	5.64	68%	116.5°
2047-05-15 Wed	—	unknown	—	72.6° 13:40	5.58	58%	103.5°
2047-05-16 Thu	—	unknown	—	72.6° 13:35	5.53	48%	90.9°
2047-05-17 Fri	—	unknown	—	72.6° 13:30	5.48	38%	78.6°
2047-05-18 Sat	—	unknown	—	72.6° 13:25	5.42	29%	66.5°
2047-05-19 Sun	—	unknown	—	72.6° 13:20	5.37	21%	54.6°
2047-05-20 Mon	—	unknown	—	72.6° 13:20	5.32	14%	42.7°
2047-05-21 Tue	—	unknown	—	72.6° 13:15	5.27	8%	30.9°
2047-05-22 Wed	—	unknown	—	72.6° 13:10	5.23	4%	19.1°
2047-05-23 Thu	—	unknown	—	72.6° 13:05	5.18	1%	7.2°
2047-05-24 Fri	—	unknown	—	72.6° 13:05	5.13	0%	4.8°
2047-05-25 Sat	—	unknown	—	72.6° 13:00	5.09	1%	16.9°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2047-04-26&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.