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.

2036-03-23astronomy score per night — click a bar for that night2036-04-21

night of	weather	overall	best window	highest	dark h	Moon	Moon sep.
2036-03-23 Sun	—	unknown	—	89.8° 13:00	8.54	14%	72.1°
2036-03-24 Mon	—	unknown	—	89.7° 12:55	8.48	8%	63.1°
2036-03-25 Tue	—	unknown	—	89.6° 12:50	8.43	4%	54.5°
2036-03-26 Wed	—	unknown	—	89.5° 12:50	8.38	1%	47.0°
2036-03-27 Thu	—	unknown	—	89.7° 12:45	8.32	0%	41.1°
2036-03-28 Fri	—	unknown	—	89.8° 12:40	8.27	1%	38.1°
2036-03-29 Sat	—	unknown	—	89.7° 12:35	8.21	5%	38.7°
2036-03-30 Sun	—	unknown	—	89.5° 13:30	8.16	10%	43.1°
2036-03-31 Mon	—	unknown	—	89.6° 13:30	8.11	18%	50.2°
2036-04-01 Tue	—	unknown	—	89.7° 13:25	8.05	27%	59.2°
2036-04-02 Wed	—	unknown	—	89.8° 13:20	8.0	38%	69.4°
2036-04-03 Thu	—	unknown	—	89.6° 13:15	7.94	49%	80.2°
2036-04-04 Fri	—	unknown	—	89.5° 13:15	7.88	61%	91.4°
2036-04-05 Sat	—	unknown	—	89.7° 13:10	7.83	72%	102.6°
2036-04-06 Sun	—	unknown	—	89.8° 13:05	7.77	81%	113.4°
2036-04-07 Mon	—	unknown	—	89.7° 13:00	7.72	89%	123.6°
2036-04-08 Tue	—	unknown	—	89.6° 12:55	7.66	95%	132.4°
2036-04-09 Wed	—	unknown	—	89.5° 12:55	7.6	99%	138.9°
2036-04-10 Thu	—	unknown	—	89.7° 12:50	7.55	100%	142.0°
2036-04-11 Fri	—	unknown	—	89.8° 12:45	7.49	98%	141.0°
2036-04-12 Sat	—	unknown	—	89.7° 12:40	7.43	95%	136.4°
2036-04-13 Sun	—	unknown	—	89.5° 12:35	7.38	89%	129.5°
2036-04-14 Mon	—	unknown	—	89.6° 12:35	7.32	82%	121.3°
2036-04-15 Tue	—	unknown	—	89.7° 12:30	7.26	74%	112.4°
2036-04-16 Wed	—	unknown	—	89.8° 12:25	7.2	66%	103.2°
2036-04-17 Thu	—	unknown	—	89.7° 12:20	7.14	56%	93.9°
2036-04-18 Fri	—	unknown	—	89.5° 12:15	7.09	47%	84.6°
2036-04-19 Sat	—	unknown	—	89.6° 12:15	7.03	37%	75.3°
2036-04-20 Sun	—	unknown	—	89.8° 12:10	6.97	28%	66.2°
2036-04-21 Mon	—	unknown	—	89.7° 12:05	6.91	20%	57.5°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2036-03-23&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.