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.

2033-05-04astronomy score per night — click a bar for that night2033-06-02

night of	weather	overall	best window	highest	dark h	Moon	Moon sep.
2033-05-04 Wed	—	unknown	—	42.9° 16:05	6.17	37%	41.6°
2033-05-05 Thu	—	unknown	—	42.9° 16:05	6.12	46%	51.9°
2033-05-06 Fri	—	unknown	—	42.9° 16:00	6.06	56%	62.5°
2033-05-07 Sat	—	unknown	—	42.9° 15:55	6.0	66%	73.2°
2033-05-08 Sun	—	unknown	—	42.9° 15:50	5.95	74%	84.0°
2033-05-09 Mon	—	unknown	—	42.9° 15:45	5.89	82%	94.8°
2033-05-10 Tue	—	unknown	—	42.9° 15:45	5.83	89%	105.6°
2033-05-11 Wed	—	unknown	—	42.9° 15:40	5.78	94%	116.4°
2033-05-12 Thu	—	unknown	—	42.9° 15:35	5.72	98%	127.0°
2033-05-13 Fri	—	unknown	—	42.9° 15:30	5.67	100%	137.2°
2033-05-14 Sat	—	unknown	—	42.9° 15:30	5.62	100%	146.5°
2033-05-15 Sun	—	unknown	—	42.9° 15:25	5.56	98%	153.5°
2033-05-16 Mon	—	unknown	—	42.9° 15:20	5.51	94%	155.9°
2033-05-17 Tue	—	unknown	—	42.9° 15:15	5.46	87%	152.1°
2033-05-18 Wed	—	unknown	—	42.9° 15:10	5.41	80%	143.9°
2033-05-19 Thu	—	unknown	—	42.9° 15:10	5.35	70%	133.3°
2033-05-20 Fri	—	unknown	—	42.9° 15:05	5.3	60%	121.6°
2033-05-21 Sat	—	unknown	—	42.9° 15:00	5.26	48%	109.2°
2033-05-22 Sun	—	unknown	—	42.9° 14:55	5.21	37%	96.3°
2033-05-23 Mon	—	unknown	—	42.9° 14:50	5.16	26%	83.2°
2033-05-24 Tue	—	unknown	—	42.9° 14:50	5.11	16%	70.0°
2033-05-25 Wed	—	unknown	—	42.9° 14:45	5.07	9%	57.1°
2033-05-26 Thu	—	unknown	—	42.9° 14:40	5.02	3%	44.7°
2033-05-27 Fri	—	unknown	—	42.9° 14:35	4.98	0%	33.8°
2033-05-28 Sat	—	unknown	—	42.9° 14:35	4.94	0%	26.1°
2033-05-29 Sun	—	unknown	—	42.9° 14:30	4.9	3%	24.3°
2033-05-30 Mon	—	unknown	—	42.9° 14:25	4.86	8%	29.3°
2033-05-31 Tue	—	unknown	—	42.9° 14:20	4.82	14%	38.0°
2033-06-01 Wed	—	unknown	—	42.9° 14:15	4.79	22%	48.2°
2033-06-02 Thu	—	unknown	—	42.9° 14:15	4.75	31%	58.9°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2033-05-04&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.