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.

2028-07-09astronomy score per night — click a bar for that night2028-08-07

night of	weather	overall	best window	highest	dark h	Moon	Moon sep.
2028-07-09 Sun	—	unknown	—	42.9° 11:45	4.78	90%	116.5°
2028-07-10 Mon	—	unknown	—	42.9° 11:40	4.82	84%	106.6°
2028-07-11 Tue	—	unknown	—	42.9° 11:35	4.86	77%	96.6°
2028-07-12 Wed	—	unknown	—	42.9° 11:30	4.9	68%	86.5°
2028-07-13 Thu	—	unknown	—	42.9° 11:25	4.94	59%	76.4°
2028-07-14 Fri	—	unknown	—	42.9° 11:25	4.98	49%	66.3°
2028-07-15 Sat	—	unknown	—	42.9° 11:20	5.02	40%	56.5°
2028-07-16 Sun	—	unknown	—	42.9° 11:15	5.06	30%	47.1°
2028-07-17 Mon	—	unknown	—	42.9° 11:10	5.11	21%	38.8°
2028-07-18 Tue	—	unknown	—	42.9° 11:05	5.15	13%	32.9°
2028-07-19 Wed	—	unknown	—	42.9° 11:05	5.2	6%	31.4°
2028-07-20 Thu	—	unknown	—	42.9° 11:00	5.25	2%	35.1°
2028-07-21 Fri	—	unknown	—	42.9° 10:55	5.3	0%	43.1°
2028-07-22 Sat	—	unknown	—	42.9° 10:50	5.35	1%	53.7°
2028-07-23 Sun	—	unknown	—	42.9° 10:45	5.4	5%	65.6°
2028-07-24 Mon	—	unknown	—	42.9° 10:45	5.45	11%	78.0°
2028-07-25 Tue	—	unknown	—	42.9° 10:40	5.5	20%	90.5°
2028-07-26 Wed	—	unknown	—	42.9° 10:35	5.55	30%	102.9°
2028-07-27 Thu	—	unknown	—	42.9° 10:30	5.6	41%	114.8°
2028-07-28 Fri	—	unknown	—	42.9° 10:30	5.66	52%	125.8°
2028-07-29 Sat	—	unknown	—	42.9° 10:25	5.71	63%	135.7°
2028-07-30 Sun	—	unknown	—	42.9° 10:20	5.77	73%	143.5°
2028-07-31 Mon	—	unknown	—	42.9° 10:15	5.82	82%	148.1°
2028-08-01 Tue	—	unknown	—	42.9° 10:10	5.88	89%	148.3°
2028-08-02 Wed	—	unknown	—	42.9° 10:10	5.93	94%	144.2°
2028-08-03 Thu	—	unknown	—	42.9° 10:05	5.99	98%	137.3°
2028-08-04 Fri	—	unknown	—	42.9° 10:00	6.04	100%	128.7°
2028-08-05 Sat	—	unknown	—	42.9° 09:55	6.1	100%	119.3°
2028-08-06 Sun	—	unknown	—	42.9° 09:50	6.16	98%	109.5°
2028-08-07 Mon	—	unknown	—	42.9° 09:50	6.21	94%	99.5°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2028-07-09&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.