{"assessment":{"best_window":{"end":"2026-01-20T04:10Z","end_local":"06:10","hours":11.17,"label":"good","mean_quality":0.95,"start":"2026-01-19T17:00Z","start_local":"19:00"},"cost":{"altitude":0.0,"clouds":0.54,"darkness":2.55,"moon":0.0},"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":"Worth it","hourly":[{"alt":null,"cloud":0,"high":0,"iso":"2026-01-19T16:00Z","label":"poor","low":0,"mid":0,"moon_alt":-1,"precip":0.0,"q":0.15,"rh":79,"sky":"nautical twilight","temp":-10.9,"time":"18:00","wind":7.8},{"alt":null,"cloud":0,"high":0,"iso":"2026-01-19T17:00Z","label":"good","low":0,"mid":0,"moon_alt":-11,"precip":0.0,"q":1.0,"rh":86,"sky":"night","temp":-11.8,"time":"19:00","wind":7.3},{"alt":null,"cloud":27,"high":0,"iso":"2026-01-19T18:00Z","label":"good","low":27,"mid":0,"moon_alt":-22,"precip":0.0,"q":0.7,"rh":88,"sky":"night","temp":-11.8,"time":"20:00","wind":7.6},{"alt":null,"cloud":9,"high":0,"iso":"2026-01-19T19:00Z","label":"good","low":9,"mid":0,"moon_alt":-32,"precip":0.0,"q":0.9,"rh":85,"sky":"night","temp":-11.9,"time":"21:00","wind":6.2},{"alt":null,"cloud":0,"high":0,"iso":"2026-01-19T20:00Z","label":"good","low":0,"mid":0,"moon_alt":-43,"precip":0.0,"q":1.0,"rh":84,"sky":"night","temp":-11.9,"time":"22:00","wind":4.6},{"alt":null,"cloud":0,"high":0,"iso":"2026-01-19T21:00Z","label":"good","low":0,"mid":0,"moon_alt":-53,"precip":0.0,"q":1.0,"rh":82,"sky":"night","temp":-11.7,"time":"23:00","wind":3.6},{"alt":null,"cloud":3,"high":0,"iso":"2026-01-19T22:00Z","label":"good","low":3,"mid":0,"moon_alt":-62,"precip":0.0,"q":0.97,"rh":79,"sky":"night","temp":-11.5,"time":"00:00","wind":1.5},{"alt":null,"cloud":10,"high":0,"iso":"2026-01-19T23:00Z","label":"good","low":10,"mid":0,"moon_alt":-67,"precip":0.0,"q":0.89,"rh":79,"sky":"night","temp":-11.4,"time":"01:00","wind":1.0},{"alt":null,"cloud":0,"high":0,"iso":"2026-01-20T00:00Z","label":"good","low":0,"mid":0,"moon_alt":-67,"precip":0.0,"q":1.0,"rh":82,"sky":"night","temp":-11.7,"time":"02:00","wind":2.5},{"alt":null,"cloud":0,"high":0,"iso":"2026-01-20T01:00Z","label":"good","low":0,"mid":0,"moon_alt":-61,"precip":0.0,"q":1.0,"rh":83,"sky":"night","temp":-11.5,"time":"03:00","wind":2.9},{"alt":null,"cloud":0,"high":0,"iso":"2026-01-20T02:00Z","label":"good","low":0,"mid":0,"moon_alt":-52,"precip":0.0,"q":1.0,"rh":81,"sky":"night","temp":-11.1,"time":"04:00","wind":3.1},{"alt":null,"cloud":0,"high":0,"iso":"2026-01-20T03:00Z","label":"good","low":0,"mid":0,"moon_alt":-42,"precip":0.0,"q":1.0,"rh":77,"sky":"night","temp":-10.9,"time":"05:00","wind":2.3},{"alt":null,"cloud":0,"high":0,"iso":"2026-01-20T04:00Z","label":"good","low":0,"mid":0,"moon_alt":-31,"precip":0.0,"q":1.0,"rh":74,"sky":"night","temp":-10.9,"time":"06:00","wind":3.3},{"alt":null,"cloud":0,"high":0,"iso":"2026-01-20T05:00Z","label":"poor","low":0,"mid":0,"moon_alt":-20,"precip":0.0,"q":0.15,"rh":72,"sky":"nautical twilight","temp":-10.9,"time":"07:00","wind":3.2}],"peak_quality":1.0,"peak_sky":1.0,"quality_hours":11.33,"reasons":["daylight and twilight cost 2.5 quality-hours","cloud cover cost 0.5 quality-hours"],"reference_hours":4.0,"score":95,"score_astronomy":100,"score_weather":95,"sky_hours":11.87,"verdict":"good","verdict_astronomy":"good","weather_known":true,"windows":[{"end":"2026-01-19T15:55Z","end_local":"17:55","hours":0.58,"label":"unusable","mean_quality":0.0,"start":"2026-01-19T15:20Z","start_local":"17:20"},{"end":"2026-01-19T16:25Z","end_local":"18:25","hours":0.5,"label":"poor","mean_quality":0.15,"start":"2026-01-19T15:55Z","start_local":"17:55"},{"end":"2026-01-19T17:00Z","end_local":"19:00","hours":0.58,"label":"marginal","mean_quality":0.5,"start":"2026-01-19T16:25Z","start_local":"18:25"},{"end":"2026-01-20T04:10Z","end_local":"06:10","hours":11.17,"label":"good","mean_quality":0.95,"start":"2026-01-19T17:00Z","start_local":"19:00"},{"end":"2026-01-20T04:40Z","end_local":"06:40","hours":0.5,"label":"marginal","mean_quality":0.5,"start":"2026-01-20T04:10Z","start_local":"06:10"},{"end":"2026-01-20T05:15Z","end_local":"07:15","hours":0.58,"label":"poor","mean_quality":0.15,"start":"2026-01-20T04:40Z","start_local":"06:40"},{"end":"2026-01-20T05:45Z","end_local":"07:45","hours":0.5,"label":"unusable","mean_quality":0.0,"start":"2026-01-20T05:15Z","start_local":"07:15"}]},"calculation_version":"2026-10-10.1","forecast":[{"cloud":0,"dark":false,"high":0,"local":"17:00","low":0,"mid":0,"precip":0.0,"rh":66,"temp":-9.0,"time":"2026-01-19T15:00Z","wind":7.2},{"cloud":0,"dark":false,"high":0,"local":"18:00","low":0,"mid":0,"precip":0.0,"rh":79,"temp":-10.9,"time":"2026-01-19T16:00Z","wind":7.8},{"cloud":0,"dark":true,"high":0,"local":"19:00","low":0,"mid":0,"precip":0.0,"rh":86,"temp":-11.8,"time":"2026-01-19T17:00Z","wind":7.3},{"cloud":27,"dark":true,"high":0,"local":"20:00","low":27,"mid":0,"precip":0.0,"rh":88,"temp":-11.8,"time":"2026-01-19T18:00Z","wind":7.6},{"cloud":9,"dark":true,"high":0,"local":"21:00","low":9,"mid":0,"precip":0.0,"rh":85,"temp":-11.9,"time":"2026-01-19T19:00Z","wind":6.2},{"cloud":0,"dark":true,"high":0,"local":"22:00","low":0,"mid":0,"precip":0.0,"rh":84,"temp":-11.9,"time":"2026-01-19T20:00Z","wind":4.6},{"cloud":0,"dark":true,"high":0,"local":"23:00","low":0,"mid":0,"precip":0.0,"rh":82,"temp":-11.7,"time":"2026-01-19T21:00Z","wind":3.6},{"cloud":3,"dark":true,"high":0,"local":"00:00","low":3,"mid":0,"precip":0.0,"rh":79,"temp":-11.5,"time":"2026-01-19T22:00Z","wind":1.5},{"cloud":10,"dark":true,"high":0,"local":"01:00","low":10,"mid":0,"precip":0.0,"rh":79,"temp":-11.4,"time":"2026-01-19T23:00Z","wind":1.0},{"cloud":0,"dark":true,"high":0,"local":"02:00","low":0,"mid":0,"precip":0.0,"rh":82,"temp":-11.7,"time":"2026-01-20T00:00Z","wind":2.5},{"cloud":0,"dark":true,"high":0,"local":"03:00","low":0,"mid":0,"precip":0.0,"rh":83,"temp":-11.5,"time":"2026-01-20T01:00Z","wind":2.9},{"cloud":0,"dark":true,"high":0,"local":"04:00","low":0,"mid":0,"precip":0.0,"rh":81,"temp":-11.1,"time":"2026-01-20T02:00Z","wind":3.1},{"cloud":0,"dark":true,"high":0,"local":"05:00","low":0,"mid":0,"precip":0.0,"rh":77,"temp":-10.9,"time":"2026-01-20T03:00Z","wind":2.3},{"cloud":0,"dark":true,"high":0,"local":"06:00","low":0,"mid":0,"precip":0.0,"rh":74,"temp":-10.9,"time":"2026-01-20T04:00Z","wind":3.3},{"cloud":0,"dark":false,"high":0,"local":"07:00","low":0,"mid":0,"precip":0.0,"rh":72,"temp":-10.9,"time":"2026-01-20T05:00Z","wind":3.2},{"cloud":0,"dark":false,"high":0,"local":"08:00","low":0,"mid":0,"precip":0.0,"rh":72,"temp":-10.9,"time":"2026-01-20T06:00Z","wind":3.1}],"forecast_source":"history","forecast_updated_at":"2026-10-17T10:38:15Z","limits":{"good_alt":30.0,"usable_alt":20.0},"night":{"dark_from":"2026-01-19T16:57:44Z","dark_hours":11.13,"dark_to":"2026-01-20T04:05:42Z","moon":{"illumination":0.013,"phase":"new moon","waxing":true},"moon_free_dark_hours":11.12,"moonrise":"2026-01-20T06:55:07Z","moonset":"2026-01-19T15:50:04Z","sunrise":"2026-01-20T05:43:07Z","sunset":"2026-01-19T15:20:07Z","twilight":{"astronomical":{"end":"2026-01-19T16:57:44Z","start":"2026-01-20T04:05:42Z"},"civil":{"end":"2026-01-19T15:50:31Z","start":"2026-01-20T05:12:48Z"},"nautical":{"end":"2026-01-19T16:24:35Z","start":"2026-01-20T04:38:48Z"}},"window_end":"2026-01-20T10:00:00Z","window_start":"2026-01-19T10:00:00Z"},"night_date":"2026-01-19","site":{"elev_m":1750,"lat":41.693,"lon":24.739,"name":"NAO Rozhen"},"warnings":[]}