{"assessment":{"best_window":{"end":"2026-09-01T18:45Z","end_local":"21:45","hours":0.17,"label":"good","mean_quality":0.86,"start":"2026-09-01T18:35Z","start_local":"21:35"},"cost":{"altitude":0.0,"clouds":0.54,"darkness":2.63,"moon":3.79},"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":3,"high":0,"iso":"2026-09-01T17:00Z","label":"unusable","low":2,"mid":1,"moon_alt":-16,"precip":0.0,"q":0.0,"rh":71,"sky":"civil twilight","temp":15.6,"time":"20:00","wind":3.6},{"alt":null,"cloud":13,"high":1,"iso":"2026-09-01T18:00Z","label":"marginal","low":8,"mid":9,"moon_alt":-7,"precip":0.0,"q":0.43,"rh":68,"sky":"astronomical twilight","temp":14.8,"time":"21:00","wind":3.2},{"alt":null,"cloud":13,"high":2,"iso":"2026-09-01T19:00Z","label":"marginal","low":6,"mid":11,"moon_alt":3,"precip":0.0,"q":0.58,"rh":65,"sky":"night","temp":14.9,"time":"22:00","wind":4.5},{"alt":null,"cloud":7,"high":0,"iso":"2026-09-01T20:00Z","label":"marginal","low":5,"mid":2,"moon_alt":13,"precip":0.0,"q":0.58,"rh":65,"sky":"night","temp":14.7,"time":"23:00","wind":4.5},{"alt":null,"cloud":3,"high":0,"iso":"2026-09-01T21:00Z","label":"marginal","low":2,"mid":1,"moon_alt":24,"precip":0.0,"q":0.55,"rh":66,"sky":"night","temp":14.4,"time":"00:00","wind":4.5},{"alt":null,"cloud":1,"high":0,"iso":"2026-09-01T22:00Z","label":"marginal","low":0,"mid":0,"moon_alt":35,"precip":0.0,"q":0.52,"rh":68,"sky":"night","temp":13.9,"time":"01:00","wind":4.1},{"alt":null,"cloud":2,"high":1,"iso":"2026-09-01T23:00Z","label":"marginal","low":1,"mid":1,"moon_alt":46,"precip":0.0,"q":0.47,"rh":69,"sky":"night","temp":13.4,"time":"02:00","wind":3.6},{"alt":null,"cloud":16,"high":14,"iso":"2026-09-02T00:00Z","label":"marginal","low":0,"mid":3,"moon_alt":56,"precip":0.0,"q":0.37,"rh":68,"sky":"night","temp":12.7,"time":"03:00","wind":3.3},{"alt":null,"cloud":33,"high":29,"iso":"2026-09-02T01:00Z","label":"poor","low":0,"mid":6,"moon_alt":64,"precip":0.0,"q":0.27,"rh":66,"sky":"night","temp":13.1,"time":"04:00","wind":3.7},{"alt":null,"cloud":16,"high":12,"iso":"2026-09-02T02:00Z","label":"marginal","low":0,"mid":5,"moon_alt":68,"precip":0.0,"q":0.34,"rh":63,"sky":"night","temp":13.6,"time":"05:00","wind":1.7},{"alt":null,"cloud":14,"high":9,"iso":"2026-09-02T03:00Z","label":"poor","low":0,"mid":5,"moon_alt":65,"precip":0.0,"q":0.05,"rh":62,"sky":"nautical twilight","temp":13.7,"time":"06:00","wind":1.8}],"peak_quality":0.86,"peak_sky":1.0,"quality_hours":4.04,"reasons":["moonlight cost 3.8 quality-hours","daylight and twilight cost 2.6 quality-hours","cloud cover cost 0.5 quality-hours"],"reference_hours":4.0,"score":88,"score_astronomy":100,"score_weather":88,"sky_hours":4.58,"verdict":"good","verdict_astronomy":"good","weather_known":true,"windows":[{"end":"2026-09-01T17:25Z","end_local":"20:25","hours":0.58,"label":"unusable","mean_quality":0.0,"start":"2026-09-01T16:50Z","start_local":"19:50"},{"end":"2026-09-01T18:00Z","end_local":"21:00","hours":0.58,"label":"poor","mean_quality":0.14,"start":"2026-09-01T17:25Z","start_local":"20:25"},{"end":"2026-09-01T18:35Z","end_local":"21:35","hours":0.58,"label":"marginal","mean_quality":0.43,"start":"2026-09-01T18:00Z","start_local":"21:00"},{"end":"2026-09-01T18:45Z","end_local":"21:45","hours":0.17,"label":"good","mean_quality":0.86,"start":"2026-09-01T18:35Z","start_local":"21:35"},{"end":"2026-09-02T01:00Z","end_local":"04:00","hours":6.25,"label":"marginal","mean_quality":0.5,"start":"2026-09-01T18:45Z","start_local":"21:45"},{"end":"2026-09-02T02:00Z","end_local":"05:00","hours":1.0,"label":"poor","mean_quality":0.27,"start":"2026-09-02T01:00Z","start_local":"04:00"},{"end":"2026-09-02T02:10Z","end_local":"05:10","hours":0.17,"label":"marginal","mean_quality":0.34,"start":"2026-09-02T02:00Z","start_local":"05:00"},{"end":"2026-09-02T03:20Z","end_local":"06:20","hours":1.17,"label":"poor","mean_quality":0.12,"start":"2026-09-02T02:10Z","start_local":"05:10"},{"end":"2026-09-02T03:50Z","end_local":"06:50","hours":0.5,"label":"unusable","mean_quality":0.0,"start":"2026-09-02T03:20Z","start_local":"06:20"}]},"calculation_version":"2026-10-10.1","forecast":[{"cloud":5,"dark":false,"high":0,"local":"19:00","low":3,"mid":2,"precip":0.0,"rh":58,"temp":18.5,"time":"2026-09-01T16:00Z","wind":6.4},{"cloud":3,"dark":false,"high":0,"local":"20:00","low":2,"mid":1,"precip":0.0,"rh":71,"temp":15.6,"time":"2026-09-01T17:00Z","wind":3.6},{"cloud":13,"dark":false,"high":1,"local":"21:00","low":8,"mid":9,"precip":0.0,"rh":68,"temp":14.8,"time":"2026-09-01T18:00Z","wind":3.2},{"cloud":13,"dark":true,"high":2,"local":"22:00","low":6,"mid":11,"precip":0.0,"rh":65,"temp":14.9,"time":"2026-09-01T19:00Z","wind":4.5},{"cloud":7,"dark":true,"high":0,"local":"23:00","low":5,"mid":2,"precip":0.0,"rh":65,"temp":14.7,"time":"2026-09-01T20:00Z","wind":4.5},{"cloud":3,"dark":true,"high":0,"local":"00:00","low":2,"mid":1,"precip":0.0,"rh":66,"temp":14.4,"time":"2026-09-01T21:00Z","wind":4.5},{"cloud":1,"dark":true,"high":0,"local":"01:00","low":0,"mid":0,"precip":0.0,"rh":68,"temp":13.9,"time":"2026-09-01T22:00Z","wind":4.1},{"cloud":2,"dark":true,"high":1,"local":"02:00","low":1,"mid":1,"precip":0.0,"rh":69,"temp":13.4,"time":"2026-09-01T23:00Z","wind":3.6},{"cloud":16,"dark":true,"high":14,"local":"03:00","low":0,"mid":3,"precip":0.0,"rh":68,"temp":12.7,"time":"2026-09-02T00:00Z","wind":3.3},{"cloud":33,"dark":true,"high":29,"local":"04:00","low":0,"mid":6,"precip":0.0,"rh":66,"temp":13.1,"time":"2026-09-02T01:00Z","wind":3.7},{"cloud":16,"dark":true,"high":12,"local":"05:00","low":0,"mid":5,"precip":0.0,"rh":63,"temp":13.6,"time":"2026-09-02T02:00Z","wind":1.7},{"cloud":14,"dark":false,"high":9,"local":"06:00","low":0,"mid":5,"precip":0.0,"rh":62,"temp":13.7,"time":"2026-09-02T03:00Z","wind":1.8},{"cloud":12,"dark":false,"high":6,"local":"07:00","low":0,"mid":5,"precip":0.0,"rh":62,"temp":13.7,"time":"2026-09-02T04:00Z","wind":1.5}],"forecast_source":"history","forecast_updated_at":"2026-10-10T17:41:44Z","limits":{"good_alt":30.0,"usable_alt":20.0},"night":{"dark_from":"2026-09-01T18:32:51Z","dark_hours":7.61,"dark_to":"2026-09-02T02:09:31Z","moon":{"illumination":0.759,"phase":"waning gibbous","waxing":false},"moon_free_dark_hours":0.18,"moonrise":"2026-09-01T18:44:23Z","moonset":null,"sunrise":"2026-09-02T03:47:48Z","sunset":"2026-09-01T16:54:38Z","twilight":{"astronomical":{"end":"2026-09-01T18:32:51Z","start":"2026-09-02T02:09:31Z"},"civil":{"end":"2026-09-01T17:23:09Z","start":"2026-09-02T03:19:16Z"},"nautical":{"end":"2026-09-01T17:57:12Z","start":"2026-09-02T02:45:11Z"}},"window_end":"2026-09-02T09:00:00Z","window_start":"2026-09-01T09:00:00Z"},"night_date":"2026-09-01","site":{"elev_m":1750,"lat":41.693,"lon":24.739,"name":"NAO Rozhen"},"warnings":[]}
