{"assessment":{"best_window":{"end":"2025-12-31T04:10Z","end_local":"06:10","hours":1.17,"label":"good","mean_quality":0.94,"start":"2025-12-31T03:00Z","start_local":"05:00"},"cost":{"altitude":0.0,"clouds":4.62,"darkness":2.7,"moon":5.54},"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":22,"high":22,"iso":"2025-12-30T15:00Z","label":"unusable","low":0,"mid":0,"moon_alt":40,"precip":0.0,"q":0.0,"rh":67,"sky":"civil twilight","temp":-5.7,"time":"17:00","wind":10.2},{"alt":null,"cloud":2,"high":2,"iso":"2025-12-30T16:00Z","label":"poor","low":0,"mid":0,"moon_alt":51,"precip":0.0,"q":0.06,"rh":74,"sky":"nautical twilight","temp":-7.3,"time":"18:00","wind":12.5},{"alt":null,"cloud":10,"high":0,"iso":"2025-12-30T17:00Z","label":"marginal","low":10,"mid":0,"moon_alt":61,"precip":0.0,"q":0.34,"rh":83,"sky":"night","temp":-8.7,"time":"19:00","wind":11.9},{"alt":null,"cloud":80,"high":0,"iso":"2025-12-30T18:00Z","label":"unusable","low":80,"mid":0,"moon_alt":68,"precip":0.0,"q":0.0,"rh":89,"sky":"night","temp":-8.1,"time":"20:00","wind":15.7},{"alt":null,"cloud":100,"high":0,"iso":"2025-12-30T19:00Z","label":"unusable","low":100,"mid":2,"moon_alt":70,"precip":0.0,"q":0.0,"rh":90,"sky":"night","temp":-8.0,"time":"21:00","wind":15.0},{"alt":null,"cloud":100,"high":3,"iso":"2025-12-30T20:00Z","label":"unusable","low":100,"mid":16,"moon_alt":64,"precip":0.0,"q":0.0,"rh":91,"sky":"night","temp":-8.9,"time":"22:00","wind":16.2},{"alt":null,"cloud":100,"high":0,"iso":"2025-12-30T21:00Z","label":"unusable","low":100,"mid":2,"moon_alt":56,"precip":0.0,"q":0.0,"rh":92,"sky":"night","temp":-9.2,"time":"23:00","wind":15.9},{"alt":null,"cloud":100,"high":0,"iso":"2025-12-30T22:00Z","label":"unusable","low":100,"mid":2,"moon_alt":45,"precip":0.0,"q":0.0,"rh":91,"sky":"night","temp":-9.8,"time":"00:00","wind":17.5},{"alt":null,"cloud":100,"high":0,"iso":"2025-12-30T23:00Z","label":"unusable","low":100,"mid":0,"moon_alt":35,"precip":0.0,"q":0.0,"rh":91,"sky":"night","temp":-10.4,"time":"01:00","wind":16.8},{"alt":null,"cloud":85,"high":0,"iso":"2025-12-31T00:00Z","label":"unusable","low":84,"mid":8,"moon_alt":24,"precip":0.0,"q":0.0,"rh":86,"sky":"night","temp":-11.3,"time":"02:00","wind":18.8},{"alt":null,"cloud":95,"high":0,"iso":"2025-12-31T01:00Z","label":"unusable","low":70,"mid":82,"moon_alt":14,"precip":0.0,"q":0.0,"rh":86,"sky":"night","temp":-12.4,"time":"03:00","wind":18.1},{"alt":null,"cloud":81,"high":0,"iso":"2025-12-31T02:00Z","label":"unusable","low":13,"mid":80,"moon_alt":4,"precip":0.0,"q":0.0,"rh":81,"sky":"night","temp":-12.8,"time":"04:00","wind":20.2},{"alt":null,"cloud":6,"high":0,"iso":"2025-12-31T03:00Z","label":"good","low":4,"mid":5,"moon_alt":-5,"precip":0.0,"q":0.93,"rh":72,"sky":"night","temp":-13.9,"time":"05:00","wind":18.7},{"alt":null,"cloud":0,"high":0,"iso":"2025-12-31T04:00Z","label":"good","low":0,"mid":0,"moon_alt":-13,"precip":0.0,"q":1.0,"rh":69,"sky":"night","temp":-14.9,"time":"06:00","wind":16.9},{"alt":null,"cloud":0,"high":0,"iso":"2025-12-31T05:00Z","label":"poor","low":0,"mid":0,"moon_alt":-19,"precip":0.0,"q":0.15,"rh":72,"sky":"nautical twilight","temp":-15.5,"time":"07:00","wind":15.3}],"peak_quality":1.0,"peak_sky":1.0,"quality_hours":2.06,"reasons":["moonlight cost 5.5 quality-hours","cloud cover cost 4.6 quality-hours","daylight and twilight cost 2.7 quality-hours"],"reference_hours":4.0,"score":31,"score_astronomy":100,"score_weather":31,"sky_hours":6.68,"verdict":"poor","verdict_astronomy":"good","weather_known":true,"windows":[{"end":"2025-12-30T15:35Z","end_local":"17:35","hours":0.67,"label":"unusable","mean_quality":0.0,"start":"2025-12-30T14:55Z","start_local":"16:55"},{"end":"2025-12-30T16:40Z","end_local":"18:40","hours":1.08,"label":"poor","mean_quality":0.12,"start":"2025-12-30T15:35Z","start_local":"17:35"},{"end":"2025-12-30T18:00Z","end_local":"20:00","hours":1.33,"label":"marginal","mean_quality":0.34,"start":"2025-12-30T16:40Z","start_local":"18:40"},{"end":"2025-12-31T03:00Z","end_local":"05:00","hours":9.0,"label":"unusable","mean_quality":0.0,"start":"2025-12-30T18:00Z","start_local":"20:00"},{"end":"2025-12-31T04:10Z","end_local":"06:10","hours":1.17,"label":"good","mean_quality":0.94,"start":"2025-12-31T03:00Z","start_local":"05:00"},{"end":"2025-12-31T04:45Z","end_local":"06:45","hours":0.58,"label":"marginal","mean_quality":0.5,"start":"2025-12-31T04:10Z","start_local":"06:10"},{"end":"2025-12-31T05:20Z","end_local":"07:20","hours":0.58,"label":"poor","mean_quality":0.15,"start":"2025-12-31T04:45Z","start_local":"06:45"},{"end":"2025-12-31T05:50Z","end_local":"07:50","hours":0.5,"label":"unusable","mean_quality":0.0,"start":"2025-12-31T05:20Z","start_local":"07:20"}]},"calculation_version":"2026-10-10.1","forecast":[{"cloud":1,"dark":false,"high":1,"local":"16:00","low":0,"mid":0,"precip":0.0,"rh":61,"temp":-3.4,"time":"2025-12-30T14:00Z","wind":9.4},{"cloud":22,"dark":false,"high":22,"local":"17:00","low":0,"mid":0,"precip":0.0,"rh":67,"temp":-5.7,"time":"2025-12-30T15:00Z","wind":10.2},{"cloud":2,"dark":false,"high":2,"local":"18:00","low":0,"mid":0,"precip":0.0,"rh":74,"temp":-7.3,"time":"2025-12-30T16:00Z","wind":12.5},{"cloud":10,"dark":true,"high":0,"local":"19:00","low":10,"mid":0,"precip":0.0,"rh":83,"temp":-8.7,"time":"2025-12-30T17:00Z","wind":11.9},{"cloud":80,"dark":true,"high":0,"local":"20:00","low":80,"mid":0,"precip":0.0,"rh":89,"temp":-8.1,"time":"2025-12-30T18:00Z","wind":15.7},{"cloud":100,"dark":true,"high":0,"local":"21:00","low":100,"mid":2,"precip":0.0,"rh":90,"temp":-8.0,"time":"2025-12-30T19:00Z","wind":15.0},{"cloud":100,"dark":true,"high":3,"local":"22:00","low":100,"mid":16,"precip":0.0,"rh":91,"temp":-8.9,"time":"2025-12-30T20:00Z","wind":16.2},{"cloud":100,"dark":true,"high":0,"local":"23:00","low":100,"mid":2,"precip":0.0,"rh":92,"temp":-9.2,"time":"2025-12-30T21:00Z","wind":15.9},{"cloud":100,"dark":true,"high":0,"local":"00:00","low":100,"mid":2,"precip":0.0,"rh":91,"temp":-9.8,"time":"2025-12-30T22:00Z","wind":17.5},{"cloud":100,"dark":true,"high":0,"local":"01:00","low":100,"mid":0,"precip":0.0,"rh":91,"temp":-10.4,"time":"2025-12-30T23:00Z","wind":16.8},{"cloud":85,"dark":true,"high":0,"local":"02:00","low":84,"mid":8,"precip":0.0,"rh":86,"temp":-11.3,"time":"2025-12-31T00:00Z","wind":18.8},{"cloud":95,"dark":true,"high":0,"local":"03:00","low":70,"mid":82,"precip":0.0,"rh":86,"temp":-12.4,"time":"2025-12-31T01:00Z","wind":18.1},{"cloud":81,"dark":true,"high":0,"local":"04:00","low":13,"mid":80,"precip":0.0,"rh":81,"temp":-12.8,"time":"2025-12-31T02:00Z","wind":20.2},{"cloud":6,"dark":true,"high":0,"local":"05:00","low":4,"mid":5,"precip":0.0,"rh":72,"temp":-13.9,"time":"2025-12-31T03:00Z","wind":18.7},{"cloud":0,"dark":true,"high":0,"local":"06:00","low":0,"mid":0,"precip":0.0,"rh":69,"temp":-14.9,"time":"2025-12-31T04:00Z","wind":16.9},{"cloud":0,"dark":false,"high":0,"local":"07:00","low":0,"mid":0,"precip":0.0,"rh":72,"temp":-15.5,"time":"2025-12-31T05:00Z","wind":15.3},{"cloud":0,"dark":false,"high":0,"local":"08:00","low":0,"mid":0,"precip":0.0,"rh":78,"temp":-15.2,"time":"2025-12-31T06:00Z","wind":17.0}],"forecast_source":"history","forecast_updated_at":"2026-10-18T11:26:17Z","limits":{"good_alt":30.0,"usable_alt":20.0},"night":{"dark_from":"2025-12-30T16:39:45Z","dark_hours":11.47,"dark_to":"2025-12-31T04:07:52Z","moon":{"illumination":0.829,"phase":"waxing gibbous","waxing":true},"moon_free_dark_hours":1.72,"moonrise":"2025-12-30T11:14:11Z","moonset":"2025-12-31T02:23:38Z","sunrise":"2025-12-31T05:48:01Z","sunset":"2025-12-30T14:59:32Z","twilight":{"astronomical":{"end":"2025-12-30T16:39:45Z","start":"2025-12-31T04:07:52Z"},"civil":{"end":"2025-12-30T15:31:00Z","start":"2025-12-31T05:16:35Z"},"nautical":{"end":"2025-12-30T16:05:57Z","start":"2025-12-31T04:41:38Z"}},"window_end":"2025-12-31T10:00:00Z","window_start":"2025-12-30T10:00:00Z"},"night_date":"2025-12-30","site":{"elev_m":1750,"lat":41.693,"lon":24.739,"name":"NAO Rozhen"},"warnings":[]}
