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.

2033-04-21astronomy score per night — click a bar for that night2033-05-20

night of	weather	overall	best window	highest	dark h	Moon	Moon sep.
2033-04-21 Thu	—	unknown	—	72.6° 15:10	6.93	56%	124.0°
2033-04-22 Fri	—	unknown	—	72.6° 15:05	6.87	45%	110.6°
2033-04-23 Sat	—	unknown	—	72.6° 15:00	6.81	34%	96.7°
2033-04-24 Sun	—	unknown	—	72.6° 15:00	6.75	24%	82.5°
2033-04-25 Mon	—	unknown	—	72.6° 14:55	6.69	14%	68.0°
2033-04-26 Tue	—	unknown	—	72.6° 14:50	6.64	7%	53.3°
2033-04-27 Wed	—	unknown	—	72.6° 14:45	6.58	2%	38.5°
2033-04-28 Thu	—	unknown	—	72.6° 14:45	6.52	0%	24.1°
2033-04-29 Fri	—	unknown	—	72.6° 14:40	6.46	1%	11.1°
2033-04-30 Sat	—	unknown	—	72.6° 14:35	6.4	5%	9.7°
2033-05-01 Sun	—	unknown	—	72.6° 14:30	6.35	11%	21.6°
2033-05-02 Mon	—	unknown	—	72.6° 14:25	6.29	18%	34.6°
2033-05-03 Tue	—	unknown	—	72.6° 14:25	6.23	27%	47.5°
2033-05-04 Wed	—	unknown	—	72.6° 14:20	6.17	37%	60.1°
2033-05-05 Thu	—	unknown	—	72.6° 14:15	6.12	46%	72.4°
2033-05-06 Fri	—	unknown	—	72.6° 14:10	6.06	56%	84.4°
2033-05-07 Sat	—	unknown	—	72.6° 14:05	6.0	66%	96.3°
2033-05-08 Sun	—	unknown	—	72.6° 14:05	5.95	74%	108.1°
2033-05-09 Mon	—	unknown	—	72.6° 14:00	5.89	82%	119.8°
2033-05-10 Tue	—	unknown	—	72.6° 13:55	5.83	89%	131.5°
2033-05-11 Wed	—	unknown	—	72.6° 13:50	5.78	94%	143.2°
2033-05-12 Thu	—	unknown	—	72.6° 13:50	5.72	98%	154.9°
2033-05-13 Fri	—	unknown	—	72.6° 13:45	5.67	100%	166.1°
2033-05-14 Sat	—	unknown	—	72.6° 13:40	5.62	100%	172.5°
2033-05-15 Sun	—	unknown	—	72.6° 13:35	5.56	98%	164.8°
2033-05-16 Mon	—	unknown	—	72.6° 13:30	5.51	94%	152.9°
2033-05-17 Tue	—	unknown	—	72.6° 13:30	5.46	87%	140.2°
2033-05-18 Wed	—	unknown	—	72.6° 13:25	5.41	80%	127.1°
2033-05-19 Thu	—	unknown	—	72.6° 13:20	5.35	70%	113.7°
2033-05-20 Fri	—	unknown	—	72.6° 13:15	5.3	60%	100.2°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2033-04-21&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.