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.

2036-07-13astronomy score per night — click a bar for that night2036-08-11

night of	weather	overall	best window	highest	dark h	Moon	Moon sep.
2036-07-13 Sun	—	unknown	—	42.9° 11:25	4.94	75%	89.8°
2036-07-14 Mon	—	unknown	—	42.9° 11:25	4.98	66%	78.7°
2036-07-15 Tue	—	unknown	—	42.9° 11:20	5.02	57%	67.6°
2036-07-16 Wed	—	unknown	—	42.9° 11:15	5.07	47%	56.4°
2036-07-17 Thu	—	unknown	—	42.9° 11:10	5.11	36%	45.4°
2036-07-18 Fri	—	unknown	—	42.9° 11:05	5.16	26%	35.1°
2036-07-19 Sat	—	unknown	—	42.9° 11:05	5.2	17%	27.0°
2036-07-20 Sun	—	unknown	—	42.9° 11:00	5.25	9%	24.4°
2036-07-21 Mon	—	unknown	—	42.9° 10:55	5.3	3%	29.4°
2036-07-22 Tue	—	unknown	—	42.9° 10:50	5.35	0%	39.5°
2036-07-23 Wed	—	unknown	—	42.9° 10:50	5.4	0%	51.9°
2036-07-24 Thu	—	unknown	—	42.9° 10:45	5.45	3%	65.1°
2036-07-25 Fri	—	unknown	—	42.9° 10:40	5.5	9%	78.7°
2036-07-26 Sat	—	unknown	—	42.9° 10:35	5.56	17%	92.0°
2036-07-27 Sun	—	unknown	—	42.9° 10:30	5.61	27%	105.0°
2036-07-28 Mon	—	unknown	—	42.9° 10:30	5.66	37%	117.4°
2036-07-29 Tue	—	unknown	—	42.9° 10:25	5.72	48%	129.0°
2036-07-30 Wed	—	unknown	—	42.9° 10:20	5.77	58%	139.6°
2036-07-31 Thu	—	unknown	—	42.9° 10:15	5.82	68%	148.5°
2036-08-01 Fri	—	unknown	—	42.9° 10:10	5.88	77%	154.4°
2036-08-02 Sat	—	unknown	—	42.9° 10:10	5.94	85%	155.4°
2036-08-03 Sun	—	unknown	—	42.9° 10:05	5.99	91%	151.2°
2036-08-04 Mon	—	unknown	—	42.9° 10:00	6.05	96%	143.7°
2036-08-05 Tue	—	unknown	—	42.9° 09:55	6.1	99%	134.5°
2036-08-06 Wed	—	unknown	—	42.9° 09:55	6.16	100%	124.5°
2036-08-07 Thu	—	unknown	—	42.9° 09:50	6.22	99%	114.1°
2036-08-08 Fri	—	unknown	—	42.9° 09:45	6.27	97%	103.4°
2036-08-09 Sat	—	unknown	—	42.9° 09:40	6.33	93%	92.5°
2036-08-10 Sun	—	unknown	—	42.9° 09:35	6.39	87%	81.5°
2036-08-11 Mon	—	unknown	—	42.9° 09:35	6.45	80%	70.5°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2036-07-13&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.