{"assessment":{"best_window":null,"cost":{"altitude":0.0,"clouds":5.15,"darkness":3.36,"moon":0.48},"formula":"astronomy = 100 * min(1, sky_hours / reference_hours) * peak_sky; overall = astronomy * score_weather / 100 (null when the weather is unknown)","hard_limit":"Overcast (\u226580 % cloud) for 7.5 of 7.7 dark hours \u2014 the sky is closed whatever the geometry says.","headline":"Not tonight","hourly":[{"alt":null,"cloud":86,"high":72,"iso":"2026-06-08T18:00Z","label":"unusable","low":42,"mid":19,"moon_alt":-47,"precip":0.0,"q":0.0,"rh":94,"sky":"civil twilight","temp":10.2,"time":"21:00","wind":0.6},{"alt":null,"cloud":96,"high":95,"iso":"2026-06-08T19:00Z","label":"unusable","low":6,"mid":20,"moon_alt":-40,"precip":1.1,"q":0.0,"rh":99,"sky":"nautical twilight","temp":9.4,"time":"22:00","wind":3.8},{"alt":null,"cloud":99,"high":99,"iso":"2026-06-08T20:00Z","label":"unusable","low":5,"mid":10,"moon_alt":-31,"precip":0.1,"q":0.0,"rh":96,"sky":"astronomical twilight","temp":9.3,"time":"23:00","wind":1.3},{"alt":null,"cloud":98,"high":98,"iso":"2026-06-08T21:00Z","label":"unusable","low":5,"mid":4,"moon_alt":-21,"precip":0.0,"q":0.0,"rh":84,"sky":"night","temp":10.2,"time":"00:00","wind":1.4},{"alt":null,"cloud":95,"high":95,"iso":"2026-06-08T22:00Z","label":"unusable","low":2,"mid":7,"moon_alt":-10,"precip":0.0,"q":0.0,"rh":80,"sky":"night","temp":10.7,"time":"01:00","wind":1.9},{"alt":null,"cloud":98,"high":98,"iso":"2026-06-08T23:00Z","label":"unusable","low":0,"mid":3,"moon_alt":1,"precip":0.0,"q":0.0,"rh":80,"sky":"night","temp":10.3,"time":"02:00","wind":1.0},{"alt":null,"cloud":86,"high":84,"iso":"2026-06-09T00:00Z","label":"unusable","low":2,"mid":12,"moon_alt":12,"precip":0.0,"q":0.0,"rh":82,"sky":"night","temp":9.1,"time":"03:00","wind":0.2},{"alt":null,"cloud":88,"high":86,"iso":"2026-06-09T01:00Z","label":"unusable","low":3,"mid":9,"moon_alt":22,"precip":0.0,"q":0.0,"rh":84,"sky":"astronomical twilight","temp":8.6,"time":"04:00","wind":1.5},{"alt":null,"cloud":65,"high":62,"iso":"2026-06-09T02:00Z","label":"poor","low":2,"mid":7,"moon_alt":32,"precip":0.0,"q":0.03,"rh":85,"sky":"nautical twilight","temp":8.0,"time":"05:00","wind":2.3}],"peak_quality":0.03,"peak_sky":1.0,"quality_hours":0.01,"reasons":["cloud cover cost 5.2 quality-hours","daylight and twilight cost 3.4 quality-hours","moonlight cost 0.5 quality-hours"],"reference_hours":4.0,"score":0,"score_astronomy":100,"score_weather":0,"sky_hours":5.16,"verdict":"unusable","verdict_astronomy":"good","weather_known":true,"windows":[{"end":"2026-06-09T02:00Z","end_local":"05:00","hours":8.17,"label":"unusable","mean_quality":0.0,"start":"2026-06-08T17:50Z","start_local":"20:50"},{"end":"2026-06-09T02:15Z","end_local":"05:15","hours":0.25,"label":"poor","mean_quality":0.03,"start":"2026-06-09T02:00Z","start_local":"05:00"},{"end":"2026-06-09T02:50Z","end_local":"05:50","hours":0.58,"label":"unusable","mean_quality":0.0,"start":"2026-06-09T02:15Z","start_local":"05:15"}]},"calculation_version":"2026-10-10.1","forecast":[{"cloud":83,"dark":false,"high":79,"local":"20:00","low":13,"mid":9,"precip":0.1,"rh":88,"temp":12.4,"time":"2026-06-08T17:00Z","wind":3.4},{"cloud":86,"dark":false,"high":72,"local":"21:00","low":42,"mid":19,"precip":0.0,"rh":94,"temp":10.2,"time":"2026-06-08T18:00Z","wind":0.6},{"cloud":96,"dark":false,"high":95,"local":"22:00","low":6,"mid":20,"precip":1.1,"rh":99,"temp":9.4,"time":"2026-06-08T19:00Z","wind":3.8},{"cloud":99,"dark":false,"high":99,"local":"23:00","low":5,"mid":10,"precip":0.1,"rh":96,"temp":9.3,"time":"2026-06-08T20:00Z","wind":1.3},{"cloud":98,"dark":true,"high":98,"local":"00:00","low":5,"mid":4,"precip":0.0,"rh":84,"temp":10.2,"time":"2026-06-08T21:00Z","wind":1.4},{"cloud":95,"dark":true,"high":95,"local":"01:00","low":2,"mid":7,"precip":0.0,"rh":80,"temp":10.7,"time":"2026-06-08T22:00Z","wind":1.9},{"cloud":98,"dark":true,"high":98,"local":"02:00","low":0,"mid":3,"precip":0.0,"rh":80,"temp":10.3,"time":"2026-06-08T23:00Z","wind":1.0},{"cloud":86,"dark":true,"high":84,"local":"03:00","low":2,"mid":12,"precip":0.0,"rh":82,"temp":9.1,"time":"2026-06-09T00:00Z","wind":0.2},{"cloud":88,"dark":false,"high":86,"local":"04:00","low":3,"mid":9,"precip":0.0,"rh":84,"temp":8.6,"time":"2026-06-09T01:00Z","wind":1.5},{"cloud":65,"dark":false,"high":62,"local":"05:00","low":2,"mid":7,"precip":0.0,"rh":85,"temp":8.0,"time":"2026-06-09T02:00Z","wind":2.3},{"cloud":91,"dark":false,"high":91,"local":"06:00","low":1,"mid":6,"precip":0.0,"rh":87,"temp":7.5,"time":"2026-06-09T03:00Z","wind":1.7}],"forecast_source":"history","forecast_updated_at":"2026-10-12T16:38:15Z","limits":{"good_alt":30.0,"usable_alt":20.0},"night":{"dark_from":"2026-06-08T20:02:46Z","dark_hours":4.58,"dark_to":"2026-06-09T00:37:32Z","moon":{"illumination":0.446,"phase":"waning crescent","waxing":false},"moon_free_dark_hours":2.88,"moonrise":"2026-06-08T22:56:21Z","moonset":"2026-06-08T10:07:32Z","sunrise":"2026-06-09T02:46:29Z","sunset":"2026-06-08T17:53:49Z","twilight":{"astronomical":{"end":"2026-06-08T20:02:46Z","start":"2026-06-09T00:37:32Z"},"civil":{"end":"2026-06-08T18:27:42Z","start":"2026-06-09T02:12:35Z"},"nautical":{"end":"2026-06-08T19:11:05Z","start":"2026-06-09T01:29:12Z"}},"window_end":"2026-06-09T09:00:00Z","window_start":"2026-06-08T09:00:00Z"},"night_date":"2026-06-08","site":{"elev_m":1750,"lat":41.693,"lon":24.739,"name":"NAO Rozhen"},"warnings":[]}