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.

2033-05-13astronomy score per night — click a bar for that night2033-06-11

night of	weather	overall	best window	highest	dark h	Moon	Moon sep.
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°
2033-06-03 Fri	—	unknown	—	42.9° 14:10	4.72	40%	69.8°
2033-06-04 Sat	—	unknown	—	42.9° 14:05	4.68	50%	80.7°
2033-06-05 Sun	—	unknown	—	42.9° 14:00	4.65	59%	91.5°
2033-06-06 Mon	—	unknown	—	42.9° 13:55	4.63	68%	102.3°
2033-06-07 Tue	—	unknown	—	42.9° 13:55	4.6	76%	113.1°
2033-06-08 Wed	—	unknown	—	42.9° 13:50	4.57	84%	123.7°
2033-06-09 Thu	—	unknown	—	42.9° 13:45	4.55	91%	134.1°
2033-06-10 Fri	—	unknown	—	42.9° 13:40	4.53	96%	143.8°
2033-06-11 Sat	—	unknown	—	42.9° 13:40	4.51	99%	151.7°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2033-05-13&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.