{"assessment":{"best_window":{"end":"2026-02-03T17:00Z","end_local":"19:00","hours":0.25,"label":"marginal","mean_quality":0.37,"start":"2026-02-03T16:45Z","start_local":"18:45"},"cost":{"altitude":0.0,"clouds":4.73,"darkness":2.58,"moon":6.4},"formula":"astronomy = 100 * min(1, sky_hours / reference_hours) * peak_sky; overall = astronomy * score_weather / 100 (null when the weather is unknown)","hard_limit":"Overcast (\u226580 % cloud) for 11.1 of 12.9 dark hours \u2014 the sky is closed whatever the geometry says.","headline":"Barely","hourly":[{"alt":null,"cloud":23,"high":2,"iso":"2026-02-03T16:00Z","label":"unusable","low":17,"mid":7,"moon_alt":-16,"precip":0.0,"q":0.0,"rh":96,"sky":"civil twilight","temp":-4.2,"time":"18:00","wind":7.6},{"alt":null,"cloud":73,"high":17,"iso":"2026-02-03T17:00Z","label":"poor","low":60,"mid":19,"moon_alt":-7,"precip":0.0,"q":0.09,"rh":96,"sky":"astronomical twilight","temp":-5.8,"time":"19:00","wind":7.0},{"alt":null,"cloud":100,"high":43,"iso":"2026-02-03T18:00Z","label":"unusable","low":100,"mid":2,"moon_alt":4,"precip":0.0,"q":0.0,"rh":98,"sky":"night","temp":-5.4,"time":"20:00","wind":8.9},{"alt":null,"cloud":100,"high":15,"iso":"2026-02-03T19:00Z","label":"unusable","low":100,"mid":4,"moon_alt":14,"precip":0.0,"q":0.0,"rh":97,"sky":"night","temp":-6.2,"time":"21:00","wind":7.8},{"alt":null,"cloud":100,"high":42,"iso":"2026-02-03T20:00Z","label":"unusable","low":100,"mid":12,"moon_alt":25,"precip":0.0,"q":0.0,"rh":97,"sky":"night","temp":-6.0,"time":"22:00","wind":7.6},{"alt":null,"cloud":100,"high":85,"iso":"2026-02-03T21:00Z","label":"unusable","low":99,"mid":3,"moon_alt":35,"precip":0.0,"q":0.0,"rh":97,"sky":"night","temp":-6.0,"time":"23:00","wind":7.5},{"alt":null,"cloud":100,"high":99,"iso":"2026-02-03T22:00Z","label":"unusable","low":99,"mid":1,"moon_alt":44,"precip":0.0,"q":0.0,"rh":97,"sky":"night","temp":-5.9,"time":"00:00","wind":7.8},{"alt":null,"cloud":100,"high":98,"iso":"2026-02-03T23:00Z","label":"unusable","low":98,"mid":33,"moon_alt":51,"precip":0.0,"q":0.0,"rh":97,"sky":"night","temp":-5.5,"time":"01:00","wind":8.3},{"alt":null,"cloud":100,"high":100,"iso":"2026-02-04T00:00Z","label":"unusable","low":87,"mid":8,"moon_alt":55,"precip":0.0,"q":0.0,"rh":96,"sky":"night","temp":-4.5,"time":"02:00","wind":8.8},{"alt":null,"cloud":100,"high":100,"iso":"2026-02-04T01:00Z","label":"unusable","low":92,"mid":5,"moon_alt":53,"precip":0.0,"q":0.0,"rh":97,"sky":"night","temp":-4.3,"time":"03:00","wind":8.1},{"alt":null,"cloud":100,"high":100,"iso":"2026-02-04T02:00Z","label":"unusable","low":95,"mid":2,"moon_alt":48,"precip":0.0,"q":0.0,"rh":97,"sky":"night","temp":-3.9,"time":"04:00","wind":8.7},{"alt":null,"cloud":100,"high":100,"iso":"2026-02-04T03:00Z","label":"unusable","low":88,"mid":2,"moon_alt":39,"precip":0.0,"q":0.0,"rh":98,"sky":"night","temp":-3.6,"time":"05:00","wind":8.3},{"alt":null,"cloud":100,"high":100,"iso":"2026-02-04T04:00Z","label":"unusable","low":98,"mid":2,"moon_alt":29,"precip":0.0,"q":0.0,"rh":99,"sky":"astronomical twilight","temp":-3.4,"time":"06:00","wind":7.9},{"alt":null,"cloud":100,"high":100,"iso":"2026-02-04T05:00Z","label":"unusable","low":97,"mid":5,"moon_alt":19,"precip":0.0,"q":0.0,"rh":99,"sky":"nautical twilight","temp":-3.4,"time":"07:00","wind":7.8}],"peak_quality":0.37,"peak_sky":1.0,"quality_hours":0.3,"reasons":["moonlight cost 6.4 quality-hours","cloud cover cost 4.7 quality-hours","daylight and twilight cost 2.6 quality-hours"],"reference_hours":4.0,"score":6,"score_astronomy":100,"score_weather":6,"sky_hours":5.03,"verdict":"poor","verdict_astronomy":"good","weather_known":true,"windows":[{"end":"2026-02-03T16:10Z","end_local":"18:10","hours":0.58,"label":"unusable","mean_quality":0.0,"start":"2026-02-03T15:35Z","start_local":"17:35"},{"end":"2026-02-03T16:45Z","end_local":"18:45","hours":0.58,"label":"poor","mean_quality":0.11,"start":"2026-02-03T16:10Z","start_local":"18:10"},{"end":"2026-02-03T17:00Z","end_local":"19:00","hours":0.25,"label":"marginal","mean_quality":0.37,"start":"2026-02-03T16:45Z","start_local":"18:45"},{"end":"2026-02-03T18:00Z","end_local":"20:00","hours":1.0,"label":"poor","mean_quality":0.14,"start":"2026-02-03T17:00Z","start_local":"19:00"},{"end":"2026-02-04T05:35Z","end_local":"07:35","hours":11.58,"label":"unusable","mean_quality":0.0,"start":"2026-02-03T18:00Z","start_local":"20:00"}]},"calculation_version":"2026-10-10.1","forecast":[{"cloud":27,"dark":false,"high":13,"local":"17:00","low":13,"mid":2,"precip":0.0,"rh":80,"temp":-1.8,"time":"2026-02-03T15:00Z","wind":5.8},{"cloud":23,"dark":false,"high":2,"local":"18:00","low":17,"mid":7,"precip":0.0,"rh":96,"temp":-4.2,"time":"2026-02-03T16:00Z","wind":7.6},{"cloud":73,"dark":false,"high":17,"local":"19:00","low":60,"mid":19,"precip":0.0,"rh":96,"temp":-5.8,"time":"2026-02-03T17:00Z","wind":7.0},{"cloud":100,"dark":true,"high":43,"local":"20:00","low":100,"mid":2,"precip":0.0,"rh":98,"temp":-5.4,"time":"2026-02-03T18:00Z","wind":8.9},{"cloud":100,"dark":true,"high":15,"local":"21:00","low":100,"mid":4,"precip":0.0,"rh":97,"temp":-6.2,"time":"2026-02-03T19:00Z","wind":7.8},{"cloud":100,"dark":true,"high":42,"local":"22:00","low":100,"mid":12,"precip":0.0,"rh":97,"temp":-6.0,"time":"2026-02-03T20:00Z","wind":7.6},{"cloud":100,"dark":true,"high":85,"local":"23:00","low":99,"mid":3,"precip":0.0,"rh":97,"temp":-6.0,"time":"2026-02-03T21:00Z","wind":7.5},{"cloud":100,"dark":true,"high":99,"local":"00:00","low":99,"mid":1,"precip":0.0,"rh":97,"temp":-5.9,"time":"2026-02-03T22:00Z","wind":7.8},{"cloud":100,"dark":true,"high":98,"local":"01:00","low":98,"mid":33,"precip":0.0,"rh":97,"temp":-5.5,"time":"2026-02-03T23:00Z","wind":8.3},{"cloud":100,"dark":true,"high":100,"local":"02:00","low":87,"mid":8,"precip":0.0,"rh":96,"temp":-4.5,"time":"2026-02-04T00:00Z","wind":8.8},{"cloud":100,"dark":true,"high":100,"local":"03:00","low":92,"mid":5,"precip":0.0,"rh":97,"temp":-4.3,"time":"2026-02-04T01:00Z","wind":8.1},{"cloud":100,"dark":true,"high":100,"local":"04:00","low":95,"mid":2,"precip":0.0,"rh":97,"temp":-3.9,"time":"2026-02-04T02:00Z","wind":8.7},{"cloud":100,"dark":true,"high":100,"local":"05:00","low":88,"mid":2,"precip":0.0,"rh":98,"temp":-3.6,"time":"2026-02-04T03:00Z","wind":8.3},{"cloud":100,"dark":false,"high":100,"local":"06:00","low":98,"mid":2,"precip":0.0,"rh":99,"temp":-3.4,"time":"2026-02-04T04:00Z","wind":7.9},{"cloud":100,"dark":false,"high":100,"local":"07:00","low":97,"mid":5,"precip":0.0,"rh":99,"temp":-3.4,"time":"2026-02-04T05:00Z","wind":7.8},{"cloud":100,"dark":false,"high":100,"local":"08:00","low":100,"mid":34,"precip":0.0,"rh":99,"temp":-3.2,"time":"2026-02-04T06:00Z","wind":8.2}],"forecast_source":"history","forecast_updated_at":"2026-10-17T11:02:47Z","limits":{"good_alt":30.0,"usable_alt":20.0},"night":{"dark_from":"2026-02-03T17:13:56Z","dark_hours":10.69,"dark_to":"2026-02-04T03:55:22Z","moon":{"illumination":0.95,"phase":"waning gibbous","waxing":false},"moon_free_dark_hours":0.42,"moonrise":"2026-02-03T17:39:23Z","moonset":"2026-02-04T06:41:22Z","sunrise":"2026-02-04T05:30:10Z","sunset":"2026-02-03T15:38:55Z","twilight":{"astronomical":{"end":"2026-02-03T17:13:56Z","start":"2026-02-04T03:55:22Z"},"civil":{"end":"2026-02-03T16:08:13Z","start":"2026-02-04T05:00:57Z"},"nautical":{"end":"2026-02-03T16:41:23Z","start":"2026-02-04T04:27:52Z"}},"window_end":"2026-02-04T10:00:00Z","window_start":"2026-02-03T10:00:00Z"},"night_date":"2026-02-03","site":{"elev_m":1750,"lat":41.693,"lon":24.739,"name":"NAO Rozhen"},"warnings":[]}
