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.

2038-03-23astronomy score per night — click a bar for that night2038-04-21

night of	weather	overall	best window	highest	dark h	Moon	Moon sep.
2038-03-23 Tue	—	unknown	—	89.6° 13:00	8.56	88%	139.3°
2038-03-24 Wed	—	unknown	—	89.5° 13:00	8.51	79%	133.0°
2038-03-25 Thu	—	unknown	—	89.7° 12:55	8.46	69%	124.4°
2038-03-26 Fri	—	unknown	—	89.8° 12:50	8.4	59%	114.8°
2038-03-27 Sat	—	unknown	—	89.7° 12:45	8.35	48%	104.7°
2038-03-28 Sun	—	unknown	—	89.6° 13:40	8.3	38%	94.6°
2038-03-29 Mon	—	unknown	—	89.6° 13:40	8.24	28%	84.7°
2038-03-30 Tue	—	unknown	—	89.7° 13:35	8.19	20%	75.0°
2038-03-31 Wed	—	unknown	—	89.8° 13:30	8.13	12%	65.8°
2038-04-01 Thu	—	unknown	—	89.7° 13:25	8.08	7%	57.3°
2038-04-02 Fri	—	unknown	—	89.5° 13:20	8.02	3%	49.7°
2038-04-03 Sat	—	unknown	—	89.6° 13:20	7.97	1%	43.5°
2038-04-04 Sun	—	unknown	—	89.8° 13:15	7.91	0%	39.5°
2038-04-05 Mon	—	unknown	—	89.8° 13:10	7.86	2%	38.2°
2038-04-06 Tue	—	unknown	—	89.6° 13:05	7.8	5%	40.0°
2038-04-07 Wed	—	unknown	—	89.5° 13:05	7.74	9%	44.4°
2038-04-08 Thu	—	unknown	—	89.7° 13:00	7.69	16%	50.9°
2038-04-09 Fri	—	unknown	—	89.8° 12:55	7.63	23%	58.8°
2038-04-10 Sat	—	unknown	—	89.7° 12:50	7.57	32%	67.6°
2038-04-11 Sun	—	unknown	—	89.6° 12:45	7.52	42%	77.2°
2038-04-12 Mon	—	unknown	—	89.6° 12:45	7.46	52%	87.3°
2038-04-13 Tue	—	unknown	—	89.7° 12:40	7.4	62%	97.7°
2038-04-14 Wed	—	unknown	—	89.8° 12:35	7.35	73%	108.4°
2038-04-15 Thu	—	unknown	—	89.7° 12:30	7.29	82%	118.9°
2038-04-16 Fri	—	unknown	—	89.5° 12:25	7.23	90%	128.6°
2038-04-17 Sat	—	unknown	—	89.6° 12:25	7.17	96%	136.6°
2038-04-18 Sun	—	unknown	—	89.8° 12:20	7.11	99%	141.2°
2038-04-19 Mon	—	unknown	—	89.8° 12:15	7.06	100%	141.1°
2038-04-20 Tue	—	unknown	—	89.6° 12:10	7.0	96%	136.2°
2038-04-21 Wed	—	unknown	—	89.5° 12:10	6.94	91%	128.2°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2038-03-23&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.