{"assessment":{"best_window":{"end":"2026-06-18T00:40Z","end_local":"03:40","hours":0.67,"label":"good","mean_quality":0.9,"start":"2026-06-18T00:00Z","start_local":"03:00"},"cost":{"altitude":0.0,"clouds":3.74,"darkness":3.36,"moon":0.04},"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":98,"high":98,"iso":"2026-06-17T18:00Z","label":"unusable","low":2,"mid":8,"moon_alt":25,"precip":0.0,"q":0.0,"rh":89,"sky":"civil twilight","temp":9.9,"time":"21:00","wind":2.2},{"alt":null,"cloud":99,"high":99,"iso":"2026-06-17T19:00Z","label":"unusable","low":0,"mid":35,"moon_alt":14,"precip":0.0,"q":0.0,"rh":93,"sky":"nautical twilight","temp":9.0,"time":"22:00","wind":3.5},{"alt":null,"cloud":98,"high":98,"iso":"2026-06-17T20:00Z","label":"unusable","low":1,"mid":5,"moon_alt":4,"precip":0.0,"q":0.0,"rh":93,"sky":"astronomical twilight","temp":8.5,"time":"23:00","wind":4.2},{"alt":null,"cloud":88,"high":88,"iso":"2026-06-17T21:00Z","label":"unusable","low":1,"mid":1,"moon_alt":-6,"precip":0.0,"q":0.0,"rh":91,"sky":"night","temp":8.0,"time":"00:00","wind":4.4},{"alt":null,"cloud":60,"high":59,"iso":"2026-06-17T22:00Z","label":"marginal","low":0,"mid":0,"moon_alt":-14,"precip":0.0,"q":0.33,"rh":89,"sky":"night","temp":7.3,"time":"01:00","wind":4.3},{"alt":null,"cloud":60,"high":59,"iso":"2026-06-17T23:00Z","label":"marginal","low":1,"mid":1,"moon_alt":-21,"precip":0.0,"q":0.33,"rh":87,"sky":"night","temp":7.3,"time":"02:00","wind":4.3},{"alt":null,"cloud":9,"high":4,"iso":"2026-06-18T00:00Z","label":"good","low":5,"mid":4,"moon_alt":-26,"precip":0.0,"q":0.9,"rh":89,"sky":"night","temp":7.2,"time":"03:00","wind":5.0},{"alt":null,"cloud":1,"high":0,"iso":"2026-06-18T01:00Z","label":"marginal","low":1,"mid":0,"moon_alt":-29,"precip":0.0,"q":0.49,"rh":89,"sky":"astronomical twilight","temp":6.9,"time":"04:00","wind":7.4},{"alt":null,"cloud":0,"high":0,"iso":"2026-06-18T02:00Z","label":"poor","low":0,"mid":0,"moon_alt":-28,"precip":0.0,"q":0.15,"rh":87,"sky":"nautical twilight","temp":6.9,"time":"05:00","wind":7.1}],"peak_quality":0.9,"peak_sky":1.0,"quality_hours":1.78,"reasons":["cloud cover cost 3.7 quality-hours","daylight and twilight cost 3.4 quality-hours"],"reference_hours":4.0,"score":32,"score_astronomy":100,"score_weather":32,"sky_hours":5.52,"verdict":"poor","verdict_astronomy":"good","weather_known":true,"windows":[{"end":"2026-06-17T22:00Z","end_local":"01:00","hours":4.08,"label":"unusable","mean_quality":0.0,"start":"2026-06-17T17:55Z","start_local":"20:55"},{"end":"2026-06-18T00:00Z","end_local":"03:00","hours":2.0,"label":"marginal","mean_quality":0.33,"start":"2026-06-17T22:00Z","start_local":"01:00"},{"end":"2026-06-18T00:40Z","end_local":"03:40","hours":0.67,"label":"good","mean_quality":0.9,"start":"2026-06-18T00:00Z","start_local":"03:00"},{"end":"2026-06-18T01:30Z","end_local":"04:30","hours":0.83,"label":"marginal","mean_quality":0.48,"start":"2026-06-18T00:40Z","start_local":"03:40"},{"end":"2026-06-18T02:15Z","end_local":"05:15","hours":0.75,"label":"poor","mean_quality":0.15,"start":"2026-06-18T01:30Z","start_local":"04:30"},{"end":"2026-06-18T02:50Z","end_local":"05:50","hours":0.58,"label":"unusable","mean_quality":0.0,"start":"2026-06-18T02:15Z","start_local":"05:15"}]},"calculation_version":"2026-10-10.1","forecast":[{"cloud":77,"dark":false,"high":76,"local":"20:00","low":2,"mid":4,"precip":0.0,"rh":84,"temp":11.8,"time":"2026-06-17T17:00Z","wind":2.8},{"cloud":98,"dark":false,"high":98,"local":"21:00","low":2,"mid":8,"precip":0.0,"rh":89,"temp":9.9,"time":"2026-06-17T18:00Z","wind":2.2},{"cloud":99,"dark":false,"high":99,"local":"22:00","low":0,"mid":35,"precip":0.0,"rh":93,"temp":9.0,"time":"2026-06-17T19:00Z","wind":3.5},{"cloud":98,"dark":false,"high":98,"local":"23:00","low":1,"mid":5,"precip":0.0,"rh":93,"temp":8.5,"time":"2026-06-17T20:00Z","wind":4.2},{"cloud":88,"dark":true,"high":88,"local":"00:00","low":1,"mid":1,"precip":0.0,"rh":91,"temp":8.0,"time":"2026-06-17T21:00Z","wind":4.4},{"cloud":60,"dark":true,"high":59,"local":"01:00","low":0,"mid":0,"precip":0.0,"rh":89,"temp":7.3,"time":"2026-06-17T22:00Z","wind":4.3},{"cloud":60,"dark":true,"high":59,"local":"02:00","low":1,"mid":1,"precip":0.0,"rh":87,"temp":7.3,"time":"2026-06-17T23:00Z","wind":4.3},{"cloud":9,"dark":true,"high":4,"local":"03:00","low":5,"mid":4,"precip":0.0,"rh":89,"temp":7.2,"time":"2026-06-18T00:00Z","wind":5.0},{"cloud":1,"dark":false,"high":0,"local":"04:00","low":1,"mid":0,"precip":0.0,"rh":89,"temp":6.9,"time":"2026-06-18T01:00Z","wind":7.4},{"cloud":0,"dark":false,"high":0,"local":"05:00","low":0,"mid":0,"precip":0.0,"rh":87,"temp":6.9,"time":"2026-06-18T02:00Z","wind":7.1},{"cloud":0,"dark":false,"high":0,"local":"06:00","low":0,"mid":0,"precip":0.0,"rh":85,"temp":6.9,"time":"2026-06-18T03:00Z","wind":6.1}],"forecast_source":"history","forecast_updated_at":"2026-10-12T07:05:15Z","limits":{"good_alt":30.0,"usable_alt":20.0},"night":{"dark_from":"2026-06-17T20:09:04Z","dark_hours":4.43,"dark_to":"2026-06-18T00:35:04Z","moon":{"illumination":0.115,"phase":"waxing crescent","waxing":true},"moon_free_dark_hours":4.18,"moonrise":"2026-06-18T06:25:31Z","moonset":"2026-06-17T20:23:02Z","sunrise":"2026-06-18T02:46:08Z","sunset":"2026-06-17T17:58:01Z","twilight":{"astronomical":{"end":"2026-06-17T20:09:04Z","start":"2026-06-18T00:35:04Z"},"civil":{"end":"2026-06-17T18:32:13Z","start":"2026-06-18T02:11:56Z"},"nautical":{"end":"2026-06-17T19:16:11Z","start":"2026-06-18T01:27:58Z"}},"window_end":"2026-06-18T09:00:00Z","window_start":"2026-06-17T09:00:00Z"},"night_date":"2026-06-17","site":{"elev_m":1750,"lat":41.693,"lon":24.739,"name":"NAO Rozhen"},"warnings":[]}