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.

2029-03-27astronomy score per night — click a bar for that night2029-04-25

night of	weather	overall	best window	highest	dark h	Moon	Moon sep.
2029-03-27 Tue	—	unknown	—	89.7° 13:45	8.34	93%	124.3°
2029-03-28 Wed	—	unknown	—	89.7° 13:40	8.28	98%	136.0°
2029-03-29 Thu	—	unknown	—	89.6° 13:35	8.23	100%	145.7°
2029-03-30 Fri	—	unknown	—	89.5° 13:35	8.18	99%	151.1°
2029-03-31 Sat	—	unknown	—	89.7° 13:30	8.12	95%	149.6°
2029-04-01 Sun	—	unknown	—	89.7° 13:25	8.07	88%	142.4°
2029-04-02 Mon	—	unknown	—	89.7° 13:20	8.01	80%	132.2°
2029-04-03 Tue	—	unknown	—	89.5° 13:15	7.96	70%	121.0°
2029-04-04 Wed	—	unknown	—	89.6° 13:15	7.9	59%	109.5°
2029-04-05 Thu	—	unknown	—	89.7° 13:10	7.85	49%	98.1°
2029-04-06 Fri	—	unknown	—	89.7° 13:05	7.79	39%	86.9°
2029-04-07 Sat	—	unknown	—	89.6° 13:00	7.73	29%	76.0°
2029-04-08 Sun	—	unknown	—	89.5° 13:00	7.68	21%	65.5°
2029-04-09 Mon	—	unknown	—	89.6° 12:55	7.62	14%	55.5°
2029-04-10 Tue	—	unknown	—	89.7° 12:50	7.56	8%	46.1°
2029-04-11 Wed	—	unknown	—	89.7° 12:45	7.51	4%	37.9°
2029-04-12 Thu	—	unknown	—	89.6° 12:40	7.45	1%	31.7°
2029-04-13 Fri	—	unknown	—	89.5° 12:40	7.39	0%	28.7°
2029-04-14 Sat	—	unknown	—	89.7° 12:35	7.33	1%	30.0°
2029-04-15 Sun	—	unknown	—	89.7° 12:30	7.28	4%	35.2°
2029-04-16 Mon	—	unknown	—	89.7° 12:25	7.22	8%	43.0°
2029-04-17 Tue	—	unknown	—	89.5° 12:20	7.16	14%	52.2°
2029-04-18 Wed	—	unknown	—	89.6° 12:20	7.1	22%	62.3°
2029-04-19 Thu	—	unknown	—	89.7° 12:15	7.05	31%	73.0°
2029-04-20 Fri	—	unknown	—	89.7° 12:10	6.99	40%	84.2°
2029-04-21 Sat	—	unknown	—	89.6° 12:05	6.93	51%	95.8°
2029-04-22 Sun	—	unknown	—	89.6° 12:00	6.87	62%	107.7°
2029-04-23 Mon	—	unknown	—	89.7° 11:55	6.81	73%	119.6°
2029-04-24 Tue	—	unknown	—	89.7° 11:50	6.75	82%	131.3°
2029-04-25 Wed	—	unknown	—	89.6° 11:45	6.7	90%	141.8°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2029-03-27&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.