{"assessment":{"best_window":{"end":"2026-05-11T21:00Z","end_local":"00:00","hours":1.58,"label":"good","mean_quality":0.89,"start":"2026-05-11T19:25Z","start_local":"22:25"},"cost":{"altitude":0.0,"clouds":4.25,"darkness":2.97,"moon":0.15},"formula":"astronomy = 100 * min(1, sky_hours / reference_hours) * peak_sky; overall = astronomy * score_weather / 100 (null when the weather is unknown)","hard_limit":null,"headline":"Barely","hourly":[{"alt":null,"cloud":26,"high":13,"iso":"2026-05-11T18:00Z","label":"unusable","low":15,"mid":0,"moon_alt":-55,"precip":0.0,"q":0.0,"rh":95,"sky":"civil twilight","temp":8.4,"time":"21:00","wind":9.1},{"alt":null,"cloud":5,"high":0,"iso":"2026-05-11T19:00Z","label":"marginal","low":4,"mid":0,"moon_alt":-52,"precip":0.0,"q":0.47,"rh":95,"sky":"astronomical twilight","temp":8.0,"time":"22:00","wind":7.7},{"alt":null,"cloud":13,"high":0,"iso":"2026-05-11T20:00Z","label":"good","low":12,"mid":2,"moon_alt":-46,"precip":0.0,"q":0.86,"rh":96,"sky":"night","temp":7.4,"time":"23:00","wind":6.2},{"alt":null,"cloud":41,"high":0,"iso":"2026-05-11T21:00Z","label":"marginal","low":39,"mid":5,"moon_alt":-38,"precip":0.0,"q":0.54,"rh":98,"sky":"night","temp":6.8,"time":"00:00","wind":5.5},{"alt":null,"cloud":98,"high":0,"iso":"2026-05-11T22:00Z","label":"unusable","low":98,"mid":12,"moon_alt":-28,"precip":0.0,"q":0.0,"rh":99,"sky":"night","temp":6.0,"time":"01:00","wind":6.7},{"alt":null,"cloud":98,"high":0,"iso":"2026-05-11T23:00Z","label":"unusable","low":98,"mid":16,"moon_alt":-17,"precip":0.0,"q":0.0,"rh":99,"sky":"night","temp":5.8,"time":"02:00","wind":6.7},{"alt":null,"cloud":98,"high":0,"iso":"2026-05-12T00:00Z","label":"unusable","low":98,"mid":17,"moon_alt":-6,"precip":0.0,"q":0.0,"rh":99,"sky":"night","temp":5.5,"time":"03:00","wind":6.6},{"alt":null,"cloud":98,"high":0,"iso":"2026-05-12T01:00Z","label":"unusable","low":98,"mid":9,"moon_alt":5,"precip":0.0,"q":0.0,"rh":99,"sky":"night","temp":5.7,"time":"04:00","wind":7.4},{"alt":null,"cloud":97,"high":0,"iso":"2026-05-12T02:00Z","label":"unusable","low":97,"mid":1,"moon_alt":16,"precip":0.0,"q":0.0,"rh":99,"sky":"nautical twilight","temp":5.2,"time":"05:00","wind":6.4},{"alt":null,"cloud":97,"high":0,"iso":"2026-05-12T03:00Z","label":"unusable","low":97,"mid":0,"moon_alt":26,"precip":0.0,"q":0.0,"rh":99,"sky":"civil twilight","temp":4.2,"time":"06:00","wind":5.1}],"peak_quality":0.94,"peak_sky":1.0,"quality_hours":2.31,"reasons":["cloud cover cost 4.2 quality-hours","daylight and twilight cost 3.0 quality-hours"],"reference_hours":4.0,"score":35,"score_astronomy":100,"score_weather":35,"sky_hours":6.55,"verdict":"poor","verdict_astronomy":"good","weather_known":true,"windows":[{"end":"2026-05-11T18:05Z","end_local":"21:05","hours":0.67,"label":"unusable","mean_quality":0.0,"start":"2026-05-11T17:25Z","start_local":"20:25"},{"end":"2026-05-11T18:45Z","end_local":"21:45","hours":0.67,"label":"poor","mean_quality":0.11,"start":"2026-05-11T18:05Z","start_local":"21:05"},{"end":"2026-05-11T19:25Z","end_local":"22:25","hours":0.67,"label":"marginal","mean_quality":0.43,"start":"2026-05-11T18:45Z","start_local":"21:45"},{"end":"2026-05-11T21:00Z","end_local":"00:00","hours":1.58,"label":"good","mean_quality":0.89,"start":"2026-05-11T19:25Z","start_local":"22:25"},{"end":"2026-05-11T22:00Z","end_local":"01:00","hours":1.0,"label":"marginal","mean_quality":0.54,"start":"2026-05-11T21:00Z","start_local":"00:00"},{"end":"2026-05-12T03:05Z","end_local":"06:05","hours":5.08,"label":"unusable","mean_quality":0.0,"start":"2026-05-11T22:00Z","start_local":"01:00"}]},"calculation_version":"2026-10-10.1","forecast":[{"cloud":16,"dark":false,"high":10,"local":"20:00","low":7,"mid":1,"precip":0.0,"rh":81,"temp":10.4,"time":"2026-05-11T17:00Z","wind":7.3},{"cloud":26,"dark":false,"high":13,"local":"21:00","low":15,"mid":0,"precip":0.0,"rh":95,"temp":8.4,"time":"2026-05-11T18:00Z","wind":9.1},{"cloud":5,"dark":false,"high":0,"local":"22:00","low":4,"mid":0,"precip":0.0,"rh":95,"temp":8.0,"time":"2026-05-11T19:00Z","wind":7.7},{"cloud":13,"dark":true,"high":0,"local":"23:00","low":12,"mid":2,"precip":0.0,"rh":96,"temp":7.4,"time":"2026-05-11T20:00Z","wind":6.2},{"cloud":41,"dark":true,"high":0,"local":"00:00","low":39,"mid":5,"precip":0.0,"rh":98,"temp":6.8,"time":"2026-05-11T21:00Z","wind":5.5},{"cloud":98,"dark":true,"high":0,"local":"01:00","low":98,"mid":12,"precip":0.0,"rh":99,"temp":6.0,"time":"2026-05-11T22:00Z","wind":6.7},{"cloud":98,"dark":true,"high":0,"local":"02:00","low":98,"mid":16,"precip":0.0,"rh":99,"temp":5.8,"time":"2026-05-11T23:00Z","wind":6.7},{"cloud":98,"dark":true,"high":0,"local":"03:00","low":98,"mid":17,"precip":0.0,"rh":99,"temp":5.5,"time":"2026-05-12T00:00Z","wind":6.6},{"cloud":98,"dark":true,"high":0,"local":"04:00","low":98,"mid":9,"precip":0.0,"rh":99,"temp":5.7,"time":"2026-05-12T01:00Z","wind":7.4},{"cloud":97,"dark":false,"high":0,"local":"05:00","low":97,"mid":1,"precip":0.0,"rh":99,"temp":5.2,"time":"2026-05-12T02:00Z","wind":6.4},{"cloud":97,"dark":false,"high":0,"local":"06:00","low":97,"mid":0,"precip":0.0,"rh":99,"temp":4.2,"time":"2026-05-12T03:00Z","wind":5.1},{"cloud":98,"dark":false,"high":0,"local":"07:00","low":98,"mid":0,"precip":0.0,"rh":99,"temp":4.6,"time":"2026-05-12T04:00Z","wind":6.5}],"forecast_source":"history","forecast_updated_at":"2026-10-14T07:29:51Z","limits":{"good_alt":30.0,"usable_alt":20.0},"night":{"dark_from":"2026-05-11T19:23:24Z","dark_hours":5.79,"dark_to":"2026-05-12T01:11:03Z","moon":{"illumination":0.295,"phase":"waning crescent","waxing":false},"moon_free_dark_hours":5.13,"moonrise":"2026-05-12T00:32:53Z","moonset":"2026-05-11T11:13:44Z","sunrise":"2026-05-12T03:04:43Z","sunset":"2026-05-11T17:29:42Z","twilight":{"astronomical":{"end":"2026-05-11T19:23:24Z","start":"2026-05-12T01:11:03Z"},"civil":{"end":"2026-05-11T18:01:05Z","start":"2026-05-12T02:33:21Z"},"nautical":{"end":"2026-05-11T18:40:00Z","start":"2026-05-12T01:54:26Z"}},"window_end":"2026-05-12T09:00:00Z","window_start":"2026-05-11T09:00:00Z"},"night_date":"2026-05-11","site":{"elev_m":1750,"lat":41.693,"lon":24.739,"name":"NAO Rozhen"},"warnings":[]}
