{"assessment":{"best_window":null,"cost":{"altitude":0.0,"clouds":3.71,"darkness":2.55,"moon":7.75},"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 12.9 of 12.9 dark hours \u2014 the sky is closed whatever the geometry says.","headline":"Not tonight","hourly":[{"alt":null,"cloud":100,"high":48,"iso":"2026-02-01T16:00Z","label":"unusable","low":100,"mid":99,"moon_alt":8,"precip":1.6,"q":0.0,"rh":91,"sky":"civil twilight","temp":-8.5,"time":"18:00","wind":6.3},{"alt":null,"cloud":100,"high":96,"iso":"2026-02-01T17:00Z","label":"unusable","low":100,"mid":99,"moon_alt":19,"precip":1.6,"q":0.0,"rh":92,"sky":"astronomical twilight","temp":-8.9,"time":"19:00","wind":7.5},{"alt":null,"cloud":100,"high":99,"iso":"2026-02-01T18:00Z","label":"unusable","low":100,"mid":96,"moon_alt":29,"precip":1.3,"q":0.0,"rh":92,"sky":"night","temp":-9.1,"time":"20:00","wind":8.4},{"alt":null,"cloud":100,"high":100,"iso":"2026-02-01T19:00Z","label":"unusable","low":100,"mid":100,"moon_alt":40,"precip":1.2,"q":0.0,"rh":91,"sky":"night","temp":-9.8,"time":"21:00","wind":8.6},{"alt":null,"cloud":100,"high":36,"iso":"2026-02-01T20:00Z","label":"unusable","low":100,"mid":100,"moon_alt":50,"precip":1.1,"q":0.0,"rh":91,"sky":"night","temp":-10.3,"time":"22:00","wind":8.3},{"alt":null,"cloud":100,"high":58,"iso":"2026-02-01T21:00Z","label":"unusable","low":100,"mid":100,"moon_alt":59,"precip":1.1,"q":0.0,"rh":89,"sky":"night","temp":-10.5,"time":"23:00","wind":8.3},{"alt":null,"cloud":100,"high":0,"iso":"2026-02-01T22:00Z","label":"unusable","low":100,"mid":100,"moon_alt":66,"precip":0.7,"q":0.0,"rh":90,"sky":"night","temp":-10.6,"time":"00:00","wind":7.4},{"alt":null,"cloud":100,"high":0,"iso":"2026-02-01T23:00Z","label":"unusable","low":100,"mid":98,"moon_alt":66,"precip":0.7,"q":0.0,"rh":91,"sky":"night","temp":-10.7,"time":"01:00","wind":6.8},{"alt":null,"cloud":100,"high":100,"iso":"2026-02-02T00:00Z","label":"unusable","low":100,"mid":82,"moon_alt":61,"precip":0.4,"q":0.0,"rh":92,"sky":"night","temp":-11.0,"time":"02:00","wind":7.2},{"alt":null,"cloud":100,"high":100,"iso":"2026-02-02T01:00Z","label":"unusable","low":100,"mid":91,"moon_alt":52,"precip":0.2,"q":0.0,"rh":92,"sky":"night","temp":-10.9,"time":"03:00","wind":4.9},{"alt":null,"cloud":100,"high":99,"iso":"2026-02-02T02:00Z","label":"unusable","low":100,"mid":100,"moon_alt":42,"precip":0.1,"q":0.0,"rh":92,"sky":"night","temp":-10.4,"time":"04:00","wind":5.5},{"alt":null,"cloud":100,"high":98,"iso":"2026-02-02T03:00Z","label":"unusable","low":100,"mid":99,"moon_alt":31,"precip":0.2,"q":0.0,"rh":91,"sky":"night","temp":-10.0,"time":"05:00","wind":6.6},{"alt":null,"cloud":100,"high":100,"iso":"2026-02-02T04:00Z","label":"unusable","low":100,"mid":88,"moon_alt":20,"precip":0.2,"q":0.0,"rh":92,"sky":"astronomical twilight","temp":-10.0,"time":"06:00","wind":6.9},{"alt":null,"cloud":100,"high":88,"iso":"2026-02-02T05:00Z","label":"unusable","low":100,"mid":68,"moon_alt":9,"precip":0.1,"q":0.0,"rh":91,"sky":"nautical twilight","temp":-9.9,"time":"07:00","wind":6.3}],"peak_quality":0.0,"peak_sky":0.46,"quality_hours":0.0,"reasons":["moonlight cost 7.7 quality-hours","cloud cover cost 3.7 quality-hours","daylight and twilight cost 2.5 quality-hours"],"reference_hours":4.0,"score":0,"score_astronomy":42,"score_weather":0,"sky_hours":3.71,"verdict":"unusable","verdict_astronomy":"marginal","weather_known":true,"windows":[{"end":"2026-02-02T05:35Z","end_local":"07:35","hours":14.0,"label":"unusable","mean_quality":0.0,"start":"2026-02-01T15:35Z","start_local":"17:35"}]},"calculation_version":"2026-10-10.1","forecast":[{"cloud":100,"dark":false,"high":84,"local":"17:00","low":100,"mid":100,"precip":1.9,"rh":91,"temp":-8.1,"time":"2026-02-01T15:00Z","wind":6.7},{"cloud":100,"dark":false,"high":48,"local":"18:00","low":100,"mid":99,"precip":1.6,"rh":91,"temp":-8.5,"time":"2026-02-01T16:00Z","wind":6.3},{"cloud":100,"dark":false,"high":96,"local":"19:00","low":100,"mid":99,"precip":1.6,"rh":92,"temp":-8.9,"time":"2026-02-01T17:00Z","wind":7.5},{"cloud":100,"dark":true,"high":99,"local":"20:00","low":100,"mid":96,"precip":1.3,"rh":92,"temp":-9.1,"time":"2026-02-01T18:00Z","wind":8.4},{"cloud":100,"dark":true,"high":100,"local":"21:00","low":100,"mid":100,"precip":1.2,"rh":91,"temp":-9.8,"time":"2026-02-01T19:00Z","wind":8.6},{"cloud":100,"dark":true,"high":36,"local":"22:00","low":100,"mid":100,"precip":1.1,"rh":91,"temp":-10.3,"time":"2026-02-01T20:00Z","wind":8.3},{"cloud":100,"dark":true,"high":58,"local":"23:00","low":100,"mid":100,"precip":1.1,"rh":89,"temp":-10.5,"time":"2026-02-01T21:00Z","wind":8.3},{"cloud":100,"dark":true,"high":0,"local":"00:00","low":100,"mid":100,"precip":0.7,"rh":90,"temp":-10.6,"time":"2026-02-01T22:00Z","wind":7.4},{"cloud":100,"dark":true,"high":0,"local":"01:00","low":100,"mid":98,"precip":0.7,"rh":91,"temp":-10.7,"time":"2026-02-01T23:00Z","wind":6.8},{"cloud":100,"dark":true,"high":100,"local":"02:00","low":100,"mid":82,"precip":0.4,"rh":92,"temp":-11.0,"time":"2026-02-02T00:00Z","wind":7.2},{"cloud":100,"dark":true,"high":100,"local":"03:00","low":100,"mid":91,"precip":0.2,"rh":92,"temp":-10.9,"time":"2026-02-02T01:00Z","wind":4.9},{"cloud":100,"dark":true,"high":99,"local":"04:00","low":100,"mid":100,"precip":0.1,"rh":92,"temp":-10.4,"time":"2026-02-02T02:00Z","wind":5.5},{"cloud":100,"dark":true,"high":98,"local":"05:00","low":100,"mid":99,"precip":0.2,"rh":91,"temp":-10.0,"time":"2026-02-02T03:00Z","wind":6.6},{"cloud":100,"dark":false,"high":100,"local":"06:00","low":100,"mid":88,"precip":0.2,"rh":92,"temp":-10.0,"time":"2026-02-02T04:00Z","wind":6.9},{"cloud":100,"dark":false,"high":88,"local":"07:00","low":100,"mid":68,"precip":0.1,"rh":91,"temp":-9.9,"time":"2026-02-02T05:00Z","wind":6.3},{"cloud":100,"dark":false,"high":43,"local":"08:00","low":100,"mid":98,"precip":0.1,"rh":91,"temp":-9.2,"time":"2026-02-02T06:00Z","wind":6.1}],"forecast_source":"history","forecast_updated_at":"2026-10-17T12:13:04Z","limits":{"good_alt":30.0,"usable_alt":20.0},"night":{"dark_from":"2026-02-01T17:11:43Z","dark_hours":10.76,"dark_to":"2026-02-02T03:57:10Z","moon":{"illumination":1.0,"phase":"full moon","waxing":false},"moon_free_dark_hours":0.0,"moonrise":"2026-02-01T15:10:33Z","moonset":"2026-02-02T05:52:17Z","sunrise":"2026-02-02T05:32:17Z","sunset":"2026-02-01T15:36:21Z","twilight":{"astronomical":{"end":"2026-02-01T17:11:43Z","start":"2026-02-02T03:57:10Z"},"civil":{"end":"2026-02-01T16:05:48Z","start":"2026-02-02T05:02:55Z"},"nautical":{"end":"2026-02-01T16:39:05Z","start":"2026-02-02T04:29:44Z"}},"window_end":"2026-02-02T10:00:00Z","window_start":"2026-02-01T10:00:00Z"},"night_date":"2026-02-01","site":{"elev_m":1750,"lat":41.693,"lon":24.739,"name":"NAO Rozhen"},"warnings":[]}
