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.

2035-03-27astronomy score per night — click a bar for that night2035-04-25

night of	weather	overall	best window	highest	dark h	Moon	Moon sep.
2035-03-27 Tue	—	unknown	—	89.6° 13:45	8.36	85%	135.0°
2035-03-28 Wed	—	unknown	—	89.6° 13:45	8.31	77%	127.8°
2035-03-29 Thu	—	unknown	—	89.7° 13:40	8.26	69%	119.6°
2035-03-30 Fri	—	unknown	—	89.8° 13:35	8.2	60%	110.8°
2035-03-31 Sat	—	unknown	—	89.7° 13:30	8.15	50%	101.5°
2035-04-01 Sun	—	unknown	—	89.5° 13:25	8.09	41%	92.0°
2035-04-02 Mon	—	unknown	—	89.6° 13:25	8.04	31%	82.3°
2035-04-03 Tue	—	unknown	—	89.7° 13:20	7.98	22%	72.4°
2035-04-04 Wed	—	unknown	—	89.8° 13:15	7.93	14%	62.7°
2035-04-05 Thu	—	unknown	—	89.6° 13:10	7.87	8%	53.3°
2035-04-06 Fri	—	unknown	—	89.5° 13:10	7.82	3%	45.1°
2035-04-07 Sat	—	unknown	—	89.7° 13:05	7.76	0%	39.1°
2035-04-08 Sun	—	unknown	—	89.8° 13:00	7.7	0%	36.9°
2035-04-09 Mon	—	unknown	—	89.7° 12:55	7.65	3%	39.3°
2035-04-10 Tue	—	unknown	—	89.6° 12:50	7.59	8%	45.8°
2035-04-11 Wed	—	unknown	—	89.5° 12:50	7.53	16%	54.9°
2035-04-12 Thu	—	unknown	—	89.7° 12:45	7.48	26%	65.3°
2035-04-13 Fri	—	unknown	—	89.8° 12:40	7.42	37%	76.4°
2035-04-14 Sat	—	unknown	—	89.7° 12:35	7.36	48%	87.6°
2035-04-15 Sun	—	unknown	—	89.5° 12:30	7.3	59%	98.7°
2035-04-16 Mon	—	unknown	—	89.6° 12:30	7.25	70%	109.4°
2035-04-17 Tue	—	unknown	—	89.7° 12:25	7.19	79%	119.5°
2035-04-18 Wed	—	unknown	—	89.8° 12:20	7.13	87%	128.5°
2035-04-19 Thu	—	unknown	—	89.6° 12:15	7.07	93%	136.0°
2035-04-20 Fri	—	unknown	—	89.5° 12:15	7.01	97%	141.2°
2035-04-21 Sat	—	unknown	—	89.7° 12:10	6.96	100%	143.2°
2035-04-22 Sun	—	unknown	—	89.8° 12:05	6.9	100%	141.6°
2035-04-23 Mon	—	unknown	—	89.7° 12:00	6.84	98%	137.0°
2035-04-24 Tue	—	unknown	—	89.5° 11:55	6.78	94%	130.3°
2035-04-25 Wed	—	unknown	—	89.7° 11:50	6.72	90%	122.4°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2035-03-27&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.