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.

2034-03-25astronomy score per night — click a bar for that night2034-04-23

night of	weather	overall	best window	highest	dark h	Moon	Moon sep.
2034-03-25 Sat	—	unknown	—	89.7° 12:55	8.46	38%	63.3°
2034-03-26 Sun	—	unknown	—	89.8° 13:50	8.4	49%	74.0°
2034-03-27 Mon	—	unknown	—	89.7° 13:45	8.35	60%	84.9°
2034-03-28 Tue	—	unknown	—	89.6° 13:40	8.3	70%	95.6°
2034-03-29 Wed	—	unknown	—	89.6° 13:40	8.24	79%	106.0°
2034-03-30 Thu	—	unknown	—	89.7° 13:35	8.19	86%	115.9°
2034-03-31 Fri	—	unknown	—	89.8° 13:30	8.13	92%	125.0°
2034-04-01 Sat	—	unknown	—	89.7° 13:25	8.08	97%	133.1°
2034-04-02 Sun	—	unknown	—	89.5° 13:20	8.02	99%	139.6°
2034-04-03 Mon	—	unknown	—	89.6° 13:20	7.97	100%	143.6°
2034-04-04 Tue	—	unknown	—	89.7° 13:15	7.91	99%	144.5°
2034-04-05 Wed	—	unknown	—	89.7° 13:10	7.86	96%	141.9°
2034-04-06 Thu	—	unknown	—	89.6° 13:05	7.8	91%	136.7°
2034-04-07 Fri	—	unknown	—	89.5° 13:05	7.75	85%	129.5°
2034-04-08 Sat	—	unknown	—	89.7° 13:00	7.69	78%	121.2°
2034-04-09 Sun	—	unknown	—	89.8° 12:55	7.63	70%	112.1°
2034-04-10 Mon	—	unknown	—	89.7° 12:50	7.58	60%	102.3°
2034-04-11 Tue	—	unknown	—	89.6° 12:45	7.52	50%	92.2°
2034-04-12 Wed	—	unknown	—	89.6° 12:45	7.46	40%	81.8°
2034-04-13 Thu	—	unknown	—	89.7° 12:40	7.4	30%	71.1°
2034-04-14 Fri	—	unknown	—	89.8° 12:35	7.35	20%	60.5°
2034-04-15 Sat	—	unknown	—	89.7° 12:30	7.29	12%	50.5°
2034-04-16 Sun	—	unknown	—	89.5° 12:25	7.23	5%	41.9°
2034-04-17 Mon	—	unknown	—	89.6° 12:25	7.17	1%	36.4°
2034-04-18 Tue	—	unknown	—	89.7° 12:20	7.12	0%	35.9°
2034-04-19 Wed	—	unknown	—	89.7° 12:15	7.06	2%	40.7°
2034-04-20 Thu	—	unknown	—	89.6° 12:10	7.0	7%	49.1°
2034-04-21 Fri	—	unknown	—	89.5° 12:10	6.94	14%	59.4°
2034-04-22 Sat	—	unknown	—	89.8° 12:00	6.88	23%	70.5°
2034-04-23 Sun	—	unknown	—	89.8° 12:00	6.83	33%	81.7°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2034-03-25&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.