{"assessment":{"best_window":null,"cost":{"altitude":0.0,"clouds":8.05,"darkness":2.55,"moon":0.32},"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 9.9 of 9.9 dark hours \u2014 the sky is closed whatever the geometry says.","headline":"Not tonight","hourly":[{"alt":null,"cloud":100,"high":9,"iso":"2026-04-10T17:00Z","label":"unusable","low":14,"mid":100,"moon_alt":-73,"precip":0.0,"q":0.0,"rh":61,"sky":"civil twilight","temp":-2.1,"time":"20:00","wind":2.5},{"alt":null,"cloud":100,"high":100,"iso":"2026-04-10T18:00Z","label":"unusable","low":15,"mid":99,"moon_alt":-69,"precip":0.0,"q":0.0,"rh":68,"sky":"astronomical twilight","temp":-3.3,"time":"21:00","wind":0.4},{"alt":null,"cloud":100,"high":100,"iso":"2026-04-10T19:00Z","label":"unusable","low":31,"mid":100,"moon_alt":-61,"precip":0.0,"q":0.0,"rh":67,"sky":"night","temp":-4.0,"time":"22:00","wind":3.2},{"alt":null,"cloud":100,"high":100,"iso":"2026-04-10T20:00Z","label":"unusable","low":12,"mid":45,"moon_alt":-51,"precip":0.0,"q":0.0,"rh":68,"sky":"night","temp":-3.9,"time":"23:00","wind":4.1},{"alt":null,"cloud":100,"high":100,"iso":"2026-04-10T21:00Z","label":"unusable","low":6,"mid":76,"moon_alt":-40,"precip":0.0,"q":0.0,"rh":77,"sky":"night","temp":-5.2,"time":"00:00","wind":3.6},{"alt":null,"cloud":100,"high":100,"iso":"2026-04-10T22:00Z","label":"unusable","low":6,"mid":100,"moon_alt":-29,"precip":0.0,"q":0.0,"rh":77,"sky":"night","temp":-5.2,"time":"01:00","wind":3.6},{"alt":null,"cloud":100,"high":100,"iso":"2026-04-10T23:00Z","label":"unusable","low":2,"mid":100,"moon_alt":-19,"precip":0.0,"q":0.0,"rh":70,"sky":"night","temp":-4.5,"time":"02:00","wind":4.3},{"alt":null,"cloud":100,"high":100,"iso":"2026-04-11T00:00Z","label":"unusable","low":3,"mid":100,"moon_alt":-9,"precip":0.1,"q":0.0,"rh":70,"sky":"night","temp":-4.0,"time":"03:00","wind":4.7},{"alt":null,"cloud":100,"high":100,"iso":"2026-04-11T01:00Z","label":"unusable","low":53,"mid":100,"moon_alt":1,"precip":0.1,"q":0.0,"rh":73,"sky":"night","temp":-4.1,"time":"04:00","wind":4.7},{"alt":null,"cloud":100,"high":0,"iso":"2026-04-11T02:00Z","label":"unusable","low":100,"mid":100,"moon_alt":10,"precip":0.2,"q":0.0,"rh":77,"sky":"night","temp":-3.7,"time":"05:00","wind":4.1},{"alt":null,"cloud":100,"high":0,"iso":"2026-04-11T03:00Z","label":"unusable","low":100,"mid":100,"moon_alt":17,"precip":0.2,"q":0.0,"rh":84,"sky":"nautical twilight","temp":-3.5,"time":"06:00","wind":4.2}],"peak_quality":0.0,"peak_sky":1.0,"quality_hours":0.0,"reasons":["cloud cover cost 8.0 quality-hours","daylight and twilight cost 2.5 quality-hours","moonlight cost 0.3 quality-hours"],"reference_hours":4.0,"score":0,"score_astronomy":100,"score_weather":0,"sky_hours":8.05,"verdict":"unusable","verdict_astronomy":"good","weather_known":true,"windows":[{"end":"2026-04-11T03:50Z","end_local":"06:50","hours":10.92,"label":"unusable","mean_quality":0.0,"start":"2026-04-10T16:55Z","start_local":"19:55"}]},"calculation_version":"2026-10-10.1","forecast":[{"cloud":100,"dark":false,"high":81,"local":"19:00","low":41,"mid":100,"precip":0.0,"rh":43,"temp":-0.2,"time":"2026-04-10T16:00Z","wind":9.9},{"cloud":100,"dark":false,"high":9,"local":"20:00","low":14,"mid":100,"precip":0.0,"rh":61,"temp":-2.1,"time":"2026-04-10T17:00Z","wind":2.5},{"cloud":100,"dark":false,"high":100,"local":"21:00","low":15,"mid":99,"precip":0.0,"rh":68,"temp":-3.3,"time":"2026-04-10T18:00Z","wind":0.4},{"cloud":100,"dark":true,"high":100,"local":"22:00","low":31,"mid":100,"precip":0.0,"rh":67,"temp":-4.0,"time":"2026-04-10T19:00Z","wind":3.2},{"cloud":100,"dark":true,"high":100,"local":"23:00","low":12,"mid":45,"precip":0.0,"rh":68,"temp":-3.9,"time":"2026-04-10T20:00Z","wind":4.1},{"cloud":100,"dark":true,"high":100,"local":"00:00","low":6,"mid":76,"precip":0.0,"rh":77,"temp":-5.2,"time":"2026-04-10T21:00Z","wind":3.6},{"cloud":100,"dark":true,"high":100,"local":"01:00","low":6,"mid":100,"precip":0.0,"rh":77,"temp":-5.2,"time":"2026-04-10T22:00Z","wind":3.6},{"cloud":100,"dark":true,"high":100,"local":"02:00","low":2,"mid":100,"precip":0.0,"rh":70,"temp":-4.5,"time":"2026-04-10T23:00Z","wind":4.3},{"cloud":100,"dark":true,"high":100,"local":"03:00","low":3,"mid":100,"precip":0.1,"rh":70,"temp":-4.0,"time":"2026-04-11T00:00Z","wind":4.7},{"cloud":100,"dark":true,"high":100,"local":"04:00","low":53,"mid":100,"precip":0.1,"rh":73,"temp":-4.1,"time":"2026-04-11T01:00Z","wind":4.7},{"cloud":100,"dark":true,"high":0,"local":"05:00","low":100,"mid":100,"precip":0.2,"rh":77,"temp":-3.7,"time":"2026-04-11T02:00Z","wind":4.1},{"cloud":100,"dark":false,"high":0,"local":"06:00","low":100,"mid":100,"precip":0.2,"rh":84,"temp":-3.5,"time":"2026-04-11T03:00Z","wind":4.2},{"cloud":100,"dark":false,"high":69,"local":"07:00","low":100,"mid":100,"precip":0.2,"rh":89,"temp":-3.4,"time":"2026-04-11T04:00Z","wind":4.5}],"forecast_source":"history","forecast_updated_at":"2026-10-14T22:38:44Z","limits":{"good_alt":30.0,"usable_alt":20.0},"night":{"dark_from":"2026-04-10T18:34:35Z","dark_hours":7.58,"dark_to":"2026-04-11T02:09:20Z","moon":{"illumination":0.429,"phase":"waning crescent","waxing":false},"moon_free_dark_hours":6.32,"moonrise":"2026-04-11T00:54:01Z","moonset":null,"sunrise":"2026-04-11T03:47:45Z","sunset":"2026-04-10T16:56:06Z","twilight":{"astronomical":{"end":"2026-04-10T18:34:35Z","start":"2026-04-11T02:09:20Z"},"civil":{"end":"2026-04-10T17:24:40Z","start":"2026-04-11T03:19:13Z"},"nautical":{"end":"2026-04-10T17:58:49Z","start":"2026-04-11T02:45:06Z"}},"window_end":"2026-04-11T09:00:00Z","window_start":"2026-04-10T09:00:00Z"},"night_date":"2026-04-10","site":{"elev_m":1750,"lat":41.693,"lon":24.739,"name":"NAO Rozhen"},"warnings":[]}
