{"assessment":{"best_window":{"end":"2026-05-31T00:45Z","end_local":"03:45","hours":1.75,"label":"marginal","mean_quality":0.42,"start":"2026-05-30T23:00Z","start_local":"02:00"},"cost":{"altitude":0.0,"clouds":0.94,"darkness":3.2,"moon":3.03},"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":4,"high":4,"iso":"2026-05-30T18:00Z","label":"unusable","low":0,"mid":0,"moon_alt":4,"precip":0.0,"q":0.0,"rh":66,"sky":"civil twilight","temp":8.2,"time":"21:00","wind":7.0},{"alt":null,"cloud":9,"high":8,"iso":"2026-05-30T19:00Z","label":"poor","low":0,"mid":1,"moon_alt":11,"precip":0.0,"q":0.07,"rh":70,"sky":"nautical twilight","temp":7.4,"time":"22:00","wind":6.4},{"alt":null,"cloud":36,"high":35,"iso":"2026-05-30T20:00Z","label":"poor","low":0,"mid":1,"moon_alt":17,"precip":0.0,"q":0.29,"rh":74,"sky":"night","temp":6.6,"time":"23:00","wind":4.6},{"alt":null,"cloud":51,"high":49,"iso":"2026-05-30T21:00Z","label":"poor","low":0,"mid":15,"moon_alt":20,"precip":0.0,"q":0.2,"rh":74,"sky":"night","temp":6.3,"time":"00:00","wind":5.5},{"alt":null,"cloud":45,"high":42,"iso":"2026-05-30T22:00Z","label":"poor","low":0,"mid":13,"moon_alt":21,"precip":0.0,"q":0.23,"rh":72,"sky":"night","temp":6.5,"time":"01:00","wind":5.9},{"alt":null,"cloud":12,"high":0,"iso":"2026-05-30T23:00Z","label":"marginal","low":1,"mid":12,"moon_alt":20,"precip":0.0,"q":0.4,"rh":74,"sky":"night","temp":6.1,"time":"02:00","wind":6.0},{"alt":null,"cloud":16,"high":0,"iso":"2026-05-31T00:00Z","label":"marginal","low":2,"mid":15,"moon_alt":16,"precip":0.0,"q":0.41,"rh":76,"sky":"night","temp":5.7,"time":"03:00","wind":7.6},{"alt":null,"cloud":32,"high":0,"iso":"2026-05-31T01:00Z","label":"poor","low":2,"mid":31,"moon_alt":9,"precip":0.0,"q":0.17,"rh":77,"sky":"astronomical twilight","temp":5.4,"time":"04:00","wind":6.0},{"alt":null,"cloud":41,"high":0,"iso":"2026-05-31T02:00Z","label":"poor","low":3,"mid":39,"moon_alt":2,"precip":0.0,"q":0.05,"rh":78,"sky":"nautical twilight","temp":5.1,"time":"05:00","wind":5.7}],"peak_quality":0.44,"peak_sky":0.52,"quality_hours":1.92,"reasons":["daylight and twilight cost 3.2 quality-hours","moonlight cost 3.0 quality-hours","cloud cover cost 0.9 quality-hours"],"reference_hours":4.0,"score":25,"score_astronomy":37,"score_weather":67,"sky_hours":2.85,"verdict":"poor","verdict_astronomy":"poor","weather_known":true,"windows":[{"end":"2026-05-30T18:25Z","end_local":"21:25","hours":0.67,"label":"unusable","mean_quality":0.0,"start":"2026-05-30T17:45Z","start_local":"20:45"},{"end":"2026-05-30T19:55Z","end_local":"22:55","hours":1.5,"label":"poor","mean_quality":0.16,"start":"2026-05-30T18:25Z","start_local":"21:25"},{"end":"2026-05-30T20:00Z","end_local":"23:00","hours":0.08,"label":"marginal","mean_quality":0.44,"start":"2026-05-30T19:55Z","start_local":"22:55"},{"end":"2026-05-30T23:00Z","end_local":"02:00","hours":3.0,"label":"poor","mean_quality":0.24,"start":"2026-05-30T20:00Z","start_local":"23:00"},{"end":"2026-05-31T00:45Z","end_local":"03:45","hours":1.75,"label":"marginal","mean_quality":0.42,"start":"2026-05-30T23:00Z","start_local":"02:00"},{"end":"2026-05-31T02:20Z","end_local":"05:20","hours":1.58,"label":"poor","mean_quality":0.13,"start":"2026-05-31T00:45Z","start_local":"03:45"},{"end":"2026-05-31T02:50Z","end_local":"05:50","hours":0.5,"label":"unusable","mean_quality":0.0,"start":"2026-05-31T02:20Z","start_local":"05:20"}]},"calculation_version":"2026-10-10.1","forecast":[{"cloud":2,"dark":false,"high":2,"local":"20:00","low":0,"mid":0,"precip":0.0,"rh":56,"temp":11.0,"time":"2026-05-30T17:00Z","wind":9.2},{"cloud":4,"dark":false,"high":4,"local":"21:00","low":0,"mid":0,"precip":0.0,"rh":66,"temp":8.2,"time":"2026-05-30T18:00Z","wind":7.0},{"cloud":9,"dark":false,"high":8,"local":"22:00","low":0,"mid":1,"precip":0.0,"rh":70,"temp":7.4,"time":"2026-05-30T19:00Z","wind":6.4},{"cloud":36,"dark":true,"high":35,"local":"23:00","low":0,"mid":1,"precip":0.0,"rh":74,"temp":6.6,"time":"2026-05-30T20:00Z","wind":4.6},{"cloud":51,"dark":true,"high":49,"local":"00:00","low":0,"mid":15,"precip":0.0,"rh":74,"temp":6.3,"time":"2026-05-30T21:00Z","wind":5.5},{"cloud":45,"dark":true,"high":42,"local":"01:00","low":0,"mid":13,"precip":0.0,"rh":72,"temp":6.5,"time":"2026-05-30T22:00Z","wind":5.9},{"cloud":12,"dark":true,"high":0,"local":"02:00","low":1,"mid":12,"precip":0.0,"rh":74,"temp":6.1,"time":"2026-05-30T23:00Z","wind":6.0},{"cloud":16,"dark":true,"high":0,"local":"03:00","low":2,"mid":15,"precip":0.0,"rh":76,"temp":5.7,"time":"2026-05-31T00:00Z","wind":7.6},{"cloud":32,"dark":false,"high":0,"local":"04:00","low":2,"mid":31,"precip":0.0,"rh":77,"temp":5.4,"time":"2026-05-31T01:00Z","wind":6.0},{"cloud":41,"dark":false,"high":0,"local":"05:00","low":3,"mid":39,"precip":0.0,"rh":78,"temp":5.1,"time":"2026-05-31T02:00Z","wind":5.7},{"cloud":16,"dark":false,"high":0,"local":"06:00","low":2,"mid":13,"precip":0.0,"rh":79,"temp":5.2,"time":"2026-05-31T03:00Z","wind":5.2}],"forecast_source":"history","forecast_updated_at":"2026-10-13T18:22:05Z","limits":{"good_alt":30.0,"usable_alt":20.0},"night":{"dark_from":"2026-05-30T19:52:27Z","dark_hours":4.87,"dark_to":"2026-05-31T00:44:40Z","moon":{"illumination":0.996,"phase":"full moon","waxing":true},"moon_free_dark_hours":0.0,"moonrise":"2026-05-30T17:32:45Z","moonset":"2026-05-31T02:10:18Z","sunrise":"2026-05-31T02:49:35Z","sunset":"2026-05-30T17:47:31Z","twilight":{"astronomical":{"end":"2026-05-30T19:52:27Z","start":"2026-05-31T00:44:40Z"},"civil":{"end":"2026-05-30T18:20:47Z","start":"2026-05-31T02:16:19Z"},"nautical":{"end":"2026-05-30T19:03:02Z","start":"2026-05-31T01:34:04Z"}},"window_end":"2026-05-31T09:00:00Z","window_start":"2026-05-30T09:00:00Z"},"night_date":"2026-05-30","site":{"elev_m":1750,"lat":41.693,"lon":24.739,"name":"NAO Rozhen"},"warnings":[]}