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.

2046-03-29astronomy score per night — click a bar for that night2046-04-27

night of	weather	overall	best window	highest	dark h	Moon	Moon sep.
2046-03-29 Thu	—	unknown	—	89.6° 13:40	8.24	44%	100.5°
2046-03-30 Fri	—	unknown	—	89.8° 13:35	8.18	34%	89.7°
2046-03-31 Sat	—	unknown	—	89.8° 13:30	8.13	25%	79.2°
2046-04-01 Sun	—	unknown	—	89.7° 13:25	8.07	18%	68.9°
2046-04-02 Mon	—	unknown	—	89.5° 13:25	8.02	11%	58.8°
2046-04-03 Tue	—	unknown	—	89.7° 13:20	7.96	6%	49.3°
2046-04-04 Wed	—	unknown	—	89.8° 13:15	7.91	2%	40.6°
2046-04-05 Thu	—	unknown	—	89.8° 13:10	7.85	0%	33.4°
2046-04-06 Fri	—	unknown	—	89.6° 13:05	7.8	0%	29.1°
2046-04-07 Sat	—	unknown	—	89.6° 13:05	7.74	2%	29.0°
2046-04-08 Sun	—	unknown	—	89.7° 13:00	7.68	6%	33.3°
2046-04-09 Mon	—	unknown	—	89.8° 12:55	7.63	11%	40.8°
2046-04-10 Tue	—	unknown	—	89.7° 12:50	7.57	18%	50.2°
2046-04-11 Wed	—	unknown	—	89.6° 12:45	7.51	27%	60.8°
2046-04-12 Thu	—	unknown	—	89.6° 12:45	7.46	37%	72.0°
2046-04-13 Fri	—	unknown	—	89.8° 12:40	7.4	48%	83.8°
2046-04-14 Sat	—	unknown	—	89.8° 12:35	7.34	59%	95.9°
2046-04-15 Sun	—	unknown	—	89.7° 12:30	7.28	70%	108.3°
2046-04-16 Mon	—	unknown	—	89.5° 12:30	7.23	80%	120.6°
2046-04-17 Tue	—	unknown	—	89.7° 12:25	7.17	88%	132.5°
2046-04-18 Wed	—	unknown	—	89.8° 12:20	7.11	95%	142.9°
2046-04-19 Thu	—	unknown	—	89.8° 12:15	7.05	99%	150.0°
2046-04-20 Fri	—	unknown	—	89.6° 12:10	6.99	100%	151.2°
2046-04-21 Sat	—	unknown	—	89.6° 12:10	6.94	98%	146.0°
2046-04-22 Sun	—	unknown	—	89.8° 12:00	6.88	94%	137.0°
2046-04-23 Mon	—	unknown	—	89.8° 12:00	6.82	87%	126.4°
2046-04-24 Tue	—	unknown	—	89.6° 11:50	6.76	79%	115.2°
2046-04-25 Wed	—	unknown	—	89.6° 11:50	6.7	70%	104.1°
2046-04-26 Thu	—	unknown	—	89.8° 11:45	6.64	60%	93.0°
2046-04-27 Fri	—	unknown	—	89.8° 11:40	6.59	50%	82.3°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2046-03-29&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.