{"assessment":{"best_window":{"end":"2026-07-31T01:20Z","end_local":"04:20","hours":5.67,"label":"marginal","mean_quality":0.43,"start":"2026-07-30T19:40Z","start_local":"22:40"},"cost":{"altitude":0.0,"clouds":0.0,"darkness":2.97,"moon":3.72},"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":0,"high":0,"iso":"2026-07-30T18:00Z","label":"unusable","low":0,"mid":0,"moon_alt":-4,"precip":0.0,"q":0.0,"rh":70,"sky":"civil twilight","temp":11.6,"time":"21:00","wind":4.2},{"alt":null,"cloud":0,"high":0,"iso":"2026-07-30T19:00Z","label":"poor","low":0,"mid":0,"moon_alt":6,"precip":0.0,"q":0.28,"rh":68,"sky":"astronomical twilight","temp":11.1,"time":"22:00","wind":4.2},{"alt":null,"cloud":0,"high":0,"iso":"2026-07-30T20:00Z","label":"marginal","low":0,"mid":0,"moon_alt":15,"precip":0.0,"q":0.5,"rh":69,"sky":"night","temp":10.8,"time":"23:00","wind":4.5},{"alt":null,"cloud":0,"high":0,"iso":"2026-07-30T21:00Z","label":"marginal","low":0,"mid":0,"moon_alt":23,"precip":0.0,"q":0.45,"rh":72,"sky":"night","temp":10.5,"time":"00:00","wind":4.5},{"alt":null,"cloud":0,"high":0,"iso":"2026-07-30T22:00Z","label":"marginal","low":0,"mid":0,"moon_alt":29,"precip":0.0,"q":0.41,"rh":76,"sky":"night","temp":10.2,"time":"01:00","wind":4.5},{"alt":null,"cloud":0,"high":0,"iso":"2026-07-30T23:00Z","label":"marginal","low":0,"mid":0,"moon_alt":33,"precip":0.0,"q":0.39,"rh":79,"sky":"night","temp":9.6,"time":"02:00","wind":5.8},{"alt":null,"cloud":0,"high":0,"iso":"2026-07-31T00:00Z","label":"marginal","low":0,"mid":0,"moon_alt":33,"precip":0.0,"q":0.39,"rh":81,"sky":"night","temp":9.0,"time":"03:00","wind":5.5},{"alt":null,"cloud":0,"high":0,"iso":"2026-07-31T01:00Z","label":"marginal","low":0,"mid":0,"moon_alt":30,"precip":0.0,"q":0.41,"rh":83,"sky":"night","temp":9.1,"time":"04:00","wind":7.1},{"alt":null,"cloud":0,"high":0,"iso":"2026-07-31T02:00Z","label":"poor","low":0,"mid":0,"moon_alt":24,"precip":0.0,"q":0.22,"rh":86,"sky":"astronomical twilight","temp":8.9,"time":"05:00","wind":8.1},{"alt":null,"cloud":0,"high":0,"iso":"2026-07-31T03:00Z","label":"unusable","low":0,"mid":0,"moon_alt":17,"precip":0.0,"q":0.0,"rh":88,"sky":"civil twilight","temp":8.7,"time":"06:00","wind":8.5}],"peak_quality":0.52,"peak_sky":0.52,"quality_hours":2.9,"reasons":["moonlight cost 3.7 quality-hours","daylight and twilight cost 3.0 quality-hours"],"reference_hours":4.0,"score":38,"score_astronomy":38,"score_weather":100,"sky_hours":2.9,"verdict":"poor","verdict_astronomy":"poor","weather_known":true,"windows":[{"end":"2026-07-30T18:15Z","end_local":"21:15","hours":0.58,"label":"unusable","mean_quality":0.0,"start":"2026-07-30T17:40Z","start_local":"20:40"},{"end":"2026-07-30T19:40Z","end_local":"22:40","hours":1.42,"label":"poor","mean_quality":0.19,"start":"2026-07-30T18:15Z","start_local":"21:15"},{"end":"2026-07-31T01:20Z","end_local":"04:20","hours":5.67,"label":"marginal","mean_quality":0.43,"start":"2026-07-30T19:40Z","start_local":"22:40"},{"end":"2026-07-31T02:45Z","end_local":"05:45","hours":1.42,"label":"poor","mean_quality":0.15,"start":"2026-07-31T01:20Z","start_local":"04:20"},{"end":"2026-07-31T03:15Z","end_local":"06:15","hours":0.5,"label":"unusable","mean_quality":0.0,"start":"2026-07-31T02:45Z","start_local":"05:45"}]},"calculation_version":"2026-10-10.1","forecast":[{"cloud":0,"dark":false,"high":0,"local":"20:00","low":0,"mid":0,"precip":0.0,"rh":70,"temp":14.2,"time":"2026-07-30T17:00Z","wind":3.7},{"cloud":0,"dark":false,"high":0,"local":"21:00","low":0,"mid":0,"precip":0.0,"rh":70,"temp":11.6,"time":"2026-07-30T18:00Z","wind":4.2},{"cloud":0,"dark":false,"high":0,"local":"22:00","low":0,"mid":0,"precip":0.0,"rh":68,"temp":11.1,"time":"2026-07-30T19:00Z","wind":4.2},{"cloud":0,"dark":true,"high":0,"local":"23:00","low":0,"mid":0,"precip":0.0,"rh":69,"temp":10.8,"time":"2026-07-30T20:00Z","wind":4.5},{"cloud":0,"dark":true,"high":0,"local":"00:00","low":0,"mid":0,"precip":0.0,"rh":72,"temp":10.5,"time":"2026-07-30T21:00Z","wind":4.5},{"cloud":0,"dark":true,"high":0,"local":"01:00","low":0,"mid":0,"precip":0.0,"rh":76,"temp":10.2,"time":"2026-07-30T22:00Z","wind":4.5},{"cloud":0,"dark":true,"high":0,"local":"02:00","low":0,"mid":0,"precip":0.0,"rh":79,"temp":9.6,"time":"2026-07-30T23:00Z","wind":5.8},{"cloud":0,"dark":true,"high":0,"local":"03:00","low":0,"mid":0,"precip":0.0,"rh":81,"temp":9.0,"time":"2026-07-31T00:00Z","wind":5.5},{"cloud":0,"dark":true,"high":0,"local":"04:00","low":0,"mid":0,"precip":0.0,"rh":83,"temp":9.1,"time":"2026-07-31T01:00Z","wind":7.1},{"cloud":0,"dark":false,"high":0,"local":"05:00","low":0,"mid":0,"precip":0.0,"rh":86,"temp":8.9,"time":"2026-07-31T02:00Z","wind":8.1},{"cloud":0,"dark":false,"high":0,"local":"06:00","low":0,"mid":0,"precip":0.0,"rh":88,"temp":8.7,"time":"2026-07-31T03:00Z","wind":8.5},{"cloud":0,"dark":false,"high":0,"local":"07:00","low":0,"mid":0,"precip":0.0,"rh":86,"temp":9.8,"time":"2026-07-31T04:00Z","wind":9.2}],"forecast_source":"history","forecast_updated_at":"2026-10-11T09:19:38Z","limits":{"good_alt":30.0,"usable_alt":20.0},"night":{"dark_from":"2026-07-30T19:35:34Z","dark_hours":5.74,"dark_to":"2026-07-31T01:19:49Z","moon":{"illumination":0.983,"phase":"full moon","waxing":false},"moon_free_dark_hours":0.0,"moonrise":"2026-07-30T18:23:48Z","moonset":"2026-07-31T04:45:24Z","sunrise":"2026-07-31T03:14:07Z","sunset":"2026-07-30T17:41:17Z","twilight":{"astronomical":{"end":"2026-07-30T19:35:34Z","start":"2026-07-31T01:19:49Z"},"civil":{"end":"2026-07-30T18:12:45Z","start":"2026-07-31T02:42:38Z"},"nautical":{"end":"2026-07-30T18:51:51Z","start":"2026-07-31T02:03:32Z"}},"window_end":"2026-07-31T09:00:00Z","window_start":"2026-07-30T09:00:00Z"},"night_date":"2026-07-30","site":{"elev_m":1750,"lat":41.693,"lon":24.739,"name":"NAO Rozhen"},"warnings":[]}