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.

2033-05-10astronomy score per night — click a bar for that night2033-06-08

night of	weather	overall	best window	highest	dark h	Moon	Moon sep.
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°
2033-05-21 Sat	—	unknown	—	72.6° 13:10	5.26	48%	86.3°
2033-05-22 Sun	—	unknown	—	72.6° 13:10	5.21	37%	72.3°
2033-05-23 Mon	—	unknown	—	72.6° 13:05	5.16	26%	58.1°
2033-05-24 Tue	—	unknown	—	72.6° 13:00	5.11	16%	43.8°
2033-05-25 Wed	—	unknown	—	72.6° 12:55	5.07	9%	29.6°
2033-05-26 Thu	—	unknown	—	72.6° 12:55	5.02	3%	16.0°
2033-05-27 Fri	—	unknown	—	72.6° 12:50	4.98	0%	7.4°
2033-05-28 Sat	—	unknown	—	72.6° 12:45	4.94	0%	16.2°
2033-05-29 Sun	—	unknown	—	72.6° 12:40	4.9	3%	29.2°
2033-05-30 Mon	—	unknown	—	72.6° 12:35	4.86	8%	42.4°
2033-05-31 Tue	—	unknown	—	72.6° 12:35	4.82	14%	55.4°
2033-06-01 Wed	—	unknown	—	72.6° 12:30	4.79	22%	68.0°
2033-06-02 Thu	—	unknown	—	72.6° 12:25	4.75	31%	80.4°
2033-06-03 Fri	—	unknown	—	72.6° 12:20	4.72	40%	92.4°
2033-06-04 Sat	—	unknown	—	72.6° 12:15	4.68	50%	104.3°
2033-06-05 Sun	—	unknown	—	72.6° 12:15	4.65	59%	116.1°
2033-06-06 Mon	—	unknown	—	72.6° 12:10	4.63	68%	127.8°
2033-06-07 Tue	—	unknown	—	72.6° 12:05	4.6	76%	139.5°
2033-06-08 Wed	—	unknown	—	72.6° 12:00	4.57	84%	151.2°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2033-05-10&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.