{"assessment":{"best_window":{"end":"2026-03-28T01:00Z","end_local":"03:00","hours":1.0,"label":"marginal","mean_quality":0.36,"start":"2026-03-28T00:00Z","start_local":"02:00"},"cost":{"altitude":0.0,"clouds":4.87,"darkness":2.5,"moon":3.73},"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 8.6 of 10.6 dark hours \u2014 the sky is closed whatever the geometry says.","headline":"Barely","hourly":[{"alt":null,"cloud":100,"high":100,"iso":"2026-03-27T17:00Z","label":"unusable","low":63,"mid":100,"moon_alt":65,"precip":1.5,"q":0.0,"rh":96,"sky":"civil twilight","temp":-1.8,"time":"19:00","wind":8.9},{"alt":null,"cloud":100,"high":100,"iso":"2026-03-27T18:00Z","label":"unusable","low":76,"mid":100,"moon_alt":70,"precip":4.0,"q":0.0,"rh":96,"sky":"astronomical twilight","temp":-2.3,"time":"20:00","wind":7.4},{"alt":null,"cloud":100,"high":98,"iso":"2026-03-27T19:00Z","label":"unusable","low":100,"mid":100,"moon_alt":69,"precip":1.2,"q":0.0,"rh":99,"sky":"night","temp":-2.5,"time":"21:00","wind":2.3},{"alt":null,"cloud":100,"high":38,"iso":"2026-03-27T20:00Z","label":"unusable","low":100,"mid":100,"moon_alt":62,"precip":1.2,"q":0.0,"rh":99,"sky":"night","temp":-2.2,"time":"22:00","wind":0.0},{"alt":null,"cloud":99,"high":2,"iso":"2026-03-27T21:00Z","label":"unusable","low":97,"mid":83,"moon_alt":52,"precip":0.6,"q":0.0,"rh":99,"sky":"night","temp":-2.1,"time":"23:00","wind":4.7},{"alt":null,"cloud":91,"high":1,"iso":"2026-03-27T22:00Z","label":"unusable","low":82,"mid":63,"moon_alt":41,"precip":0.3,"q":0.0,"rh":99,"sky":"night","temp":-3.0,"time":"00:00","wind":3.4},{"alt":null,"cloud":72,"high":0,"iso":"2026-03-27T23:00Z","label":"poor","low":57,"mid":34,"moon_alt":30,"precip":0.3,"q":0.11,"rh":97,"sky":"night","temp":-3.5,"time":"01:00","wind":3.2},{"alt":null,"cloud":39,"high":0,"iso":"2026-03-28T00:00Z","label":"marginal","low":32,"mid":11,"moon_alt":19,"precip":0.0,"q":0.35,"rh":99,"sky":"night","temp":-4.2,"time":"02:00","wind":5.1},{"alt":null,"cloud":96,"high":0,"iso":"2026-03-28T01:00Z","label":"unusable","low":96,"mid":0,"moon_alt":9,"precip":0.0,"q":0.0,"rh":100,"sky":"night","temp":-6.0,"time":"03:00","wind":4.2},{"alt":null,"cloud":100,"high":0,"iso":"2026-03-28T02:00Z","label":"unusable","low":100,"mid":2,"moon_alt":-1,"precip":0.0,"q":0.0,"rh":99,"sky":"night","temp":-6.3,"time":"04:00","wind":2.3},{"alt":null,"cloud":100,"high":22,"iso":"2026-03-28T03:00Z","label":"unusable","low":100,"mid":8,"moon_alt":-10,"precip":0.0,"q":0.0,"rh":98,"sky":"astronomical twilight","temp":-5.7,"time":"05:00","wind":1.9},{"alt":null,"cloud":100,"high":29,"iso":"2026-03-28T04:00Z","label":"unusable","low":100,"mid":13,"moon_alt":-18,"precip":0.0,"q":0.0,"rh":97,"sky":"civil twilight","temp":-5.0,"time":"06:00","wind":2.4}],"peak_quality":0.37,"peak_sky":1.0,"quality_hours":0.48,"reasons":["cloud cover cost 4.9 quality-hours","moonlight cost 3.7 quality-hours","daylight and twilight cost 2.5 quality-hours"],"reference_hours":4.0,"score":9,"score_astronomy":100,"score_weather":9,"sky_hours":5.35,"verdict":"poor","verdict_astronomy":"good","weather_known":true,"windows":[{"end":"2026-03-27T23:00Z","end_local":"01:00","hours":6.33,"label":"unusable","mean_quality":0.0,"start":"2026-03-27T16:40Z","start_local":"18:40"},{"end":"2026-03-28T00:00Z","end_local":"02:00","hours":1.0,"label":"poor","mean_quality":0.12,"start":"2026-03-27T23:00Z","start_local":"01:00"},{"end":"2026-03-28T01:00Z","end_local":"03:00","hours":1.0,"label":"marginal","mean_quality":0.36,"start":"2026-03-28T00:00Z","start_local":"02:00"},{"end":"2026-03-28T04:15Z","end_local":"06:15","hours":3.25,"label":"unusable","mean_quality":0.0,"start":"2026-03-28T01:00Z","start_local":"03:00"}]},"calculation_version":"2026-10-10.1","forecast":[{"cloud":100,"dark":false,"high":99,"local":"18:00","low":9,"mid":100,"precip":0.2,"rh":92,"temp":-0.4,"time":"2026-03-27T16:00Z","wind":7.2},{"cloud":100,"dark":false,"high":100,"local":"19:00","low":63,"mid":100,"precip":1.5,"rh":96,"temp":-1.8,"time":"2026-03-27T17:00Z","wind":8.9},{"cloud":100,"dark":false,"high":100,"local":"20:00","low":76,"mid":100,"precip":4.0,"rh":96,"temp":-2.3,"time":"2026-03-27T18:00Z","wind":7.4},{"cloud":100,"dark":true,"high":98,"local":"21:00","low":100,"mid":100,"precip":1.2,"rh":99,"temp":-2.5,"time":"2026-03-27T19:00Z","wind":2.3},{"cloud":100,"dark":true,"high":38,"local":"22:00","low":100,"mid":100,"precip":1.2,"rh":99,"temp":-2.2,"time":"2026-03-27T20:00Z","wind":0.0},{"cloud":99,"dark":true,"high":2,"local":"23:00","low":97,"mid":83,"precip":0.6,"rh":99,"temp":-2.1,"time":"2026-03-27T21:00Z","wind":4.7},{"cloud":91,"dark":true,"high":1,"local":"00:00","low":82,"mid":63,"precip":0.3,"rh":99,"temp":-3.0,"time":"2026-03-27T22:00Z","wind":3.4},{"cloud":72,"dark":true,"high":0,"local":"01:00","low":57,"mid":34,"precip":0.3,"rh":97,"temp":-3.5,"time":"2026-03-27T23:00Z","wind":3.2},{"cloud":39,"dark":true,"high":0,"local":"02:00","low":32,"mid":11,"precip":0.0,"rh":99,"temp":-4.2,"time":"2026-03-28T00:00Z","wind":5.1},{"cloud":96,"dark":true,"high":0,"local":"03:00","low":96,"mid":0,"precip":0.0,"rh":100,"temp":-6.0,"time":"2026-03-28T01:00Z","wind":4.2},{"cloud":100,"dark":true,"high":0,"local":"04:00","low":100,"mid":2,"precip":0.0,"rh":99,"temp":-6.3,"time":"2026-03-28T02:00Z","wind":2.3},{"cloud":100,"dark":false,"high":22,"local":"05:00","low":100,"mid":8,"precip":0.0,"rh":98,"temp":-5.7,"time":"2026-03-28T03:00Z","wind":1.9},{"cloud":100,"dark":false,"high":29,"local":"06:00","low":100,"mid":13,"precip":0.0,"rh":97,"temp":-5.0,"time":"2026-03-28T04:00Z","wind":2.4},{"cloud":100,"dark":false,"high":16,"local":"07:00","low":100,"mid":7,"precip":0.0,"rh":96,"temp":-3.8,"time":"2026-03-28T05:00Z","wind":2.6}],"forecast_source":"history","forecast_updated_at":"2026-10-14T22:38:39Z","limits":{"good_alt":30.0,"usable_alt":20.0},"night":{"dark_from":"2026-03-27T18:15:23Z","dark_hours":8.35,"dark_to":"2026-03-28T02:36:35Z","moon":{"illumination":0.73,"phase":"waxing gibbous","waxing":true},"moon_free_dark_hours":0.72,"moonrise":"2026-03-27T10:38:25Z","moonset":"2026-03-28T01:52:54Z","sunrise":"2026-03-28T04:11:06Z","sunset":"2026-03-27T16:40:46Z","twilight":{"astronomical":{"end":"2026-03-27T18:15:23Z","start":"2026-03-28T02:36:35Z"},"civil":{"end":"2026-03-27T17:08:40Z","start":"2026-03-28T03:43:14Z"},"nautical":{"end":"2026-03-27T17:41:34Z","start":"2026-03-28T03:10:23Z"}},"window_end":"2026-03-28T10:00:00Z","window_start":"2026-03-27T10:00:00Z"},"night_date":"2026-03-27","site":{"elev_m":1750,"lat":41.693,"lon":24.739,"name":"NAO Rozhen"},"warnings":[]}
