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.

2045-05-16astronomy score per night — click a bar for that night2045-06-14

night of	weather	overall	best window	highest	dark h	Moon	Moon sep.
2045-05-16 Tue	—	unknown	—	42.9° 15:20	5.5	0%	41.1°
2045-05-17 Wed	—	unknown	—	42.9° 15:15	5.45	2%	34.9°
2045-05-18 Thu	—	unknown	—	42.9° 15:10	5.4	6%	33.2°
2045-05-19 Fri	—	unknown	—	42.9° 15:10	5.35	13%	36.8°
2045-05-20 Sat	—	unknown	—	42.9° 15:05	5.3	22%	44.4°
2045-05-21 Sun	—	unknown	—	42.9° 15:00	5.25	32%	54.3°
2045-05-22 Mon	—	unknown	—	42.9° 14:55	5.2	43%	65.3°
2045-05-23 Tue	—	unknown	—	42.9° 14:55	5.16	55%	76.8°
2045-05-24 Wed	—	unknown	—	42.9° 14:50	5.11	66%	88.4°
2045-05-25 Thu	—	unknown	—	42.9° 14:45	5.06	76%	99.9°
2045-05-26 Fri	—	unknown	—	42.9° 14:40	5.02	84%	111.0°
2045-05-27 Sat	—	unknown	—	42.9° 14:35	4.98	91%	121.6°
2045-05-28 Sun	—	unknown	—	42.9° 14:35	4.93	96%	131.3°
2045-05-29 Mon	—	unknown	—	42.9° 14:30	4.89	99%	139.3°
2045-05-30 Tue	—	unknown	—	42.9° 14:25	4.86	100%	144.9°
2045-05-31 Wed	—	unknown	—	42.9° 14:20	4.82	98%	146.9°
2045-06-01 Thu	—	unknown	—	42.9° 14:15	4.78	95%	144.9°
2045-06-02 Fri	—	unknown	—	42.9° 14:15	4.75	90%	139.6°
2045-06-03 Sat	—	unknown	—	42.9° 14:10	4.71	84%	132.3°
2045-06-04 Sun	—	unknown	—	42.9° 14:05	4.68	76%	123.8°
2045-06-05 Mon	—	unknown	—	42.9° 14:00	4.65	68%	114.6°
2045-06-06 Tue	—	unknown	—	42.9° 13:55	4.62	59%	104.9°
2045-06-07 Wed	—	unknown	—	42.9° 13:55	4.6	49%	94.9°
2045-06-08 Thu	—	unknown	—	42.9° 13:50	4.57	40%	84.7°
2045-06-09 Fri	—	unknown	—	42.9° 13:45	4.55	30%	74.3°
2045-06-10 Sat	—	unknown	—	42.9° 13:40	4.53	21%	63.9°
2045-06-11 Sun	—	unknown	—	42.9° 13:40	4.51	13%	53.8°
2045-06-12 Mon	—	unknown	—	42.9° 13:35	4.49	7%	44.4°
2045-06-13 Tue	—	unknown	—	42.9° 13:30	4.47	2%	36.9°
2045-06-14 Wed	—	unknown	—	42.9° 13:25	4.46	0%	33.2°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2045-05-16&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.