{"assessment":{"best_window":{"end":"2026-01-08T23:25Z","end_local":"01:25","hours":2.42,"label":"good","mean_quality":0.66,"start":"2026-01-08T21:00Z","start_local":"23:00"},"cost":{"altitude":0.0,"clouds":3.43,"darkness":2.66,"moon":2.95},"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":"Possible, with compromises","hourly":[{"alt":null,"cloud":100,"high":0,"iso":"2026-01-08T16:00Z","label":"unusable","low":100,"mid":0,"moon_alt":-46,"precip":0.0,"q":0.0,"rh":94,"sky":"nautical twilight","temp":-7.5,"time":"18:00","wind":9.4},{"alt":null,"cloud":100,"high":0,"iso":"2026-01-08T17:00Z","label":"unusable","low":100,"mid":0,"moon_alt":-40,"precip":0.0,"q":0.0,"rh":92,"sky":"night","temp":-8.0,"time":"19:00","wind":9.4},{"alt":null,"cloud":54,"high":0,"iso":"2026-01-08T18:00Z","label":"marginal","low":54,"mid":2,"moon_alt":-32,"precip":0.0,"q":0.4,"rh":88,"sky":"night","temp":-8.3,"time":"20:00","wind":11.2},{"alt":null,"cloud":59,"high":0,"iso":"2026-01-08T19:00Z","label":"marginal","low":59,"mid":2,"moon_alt":-22,"precip":0.0,"q":0.34,"rh":87,"sky":"night","temp":-8.9,"time":"21:00","wind":14.3},{"alt":null,"cloud":45,"high":0,"iso":"2026-01-08T20:00Z","label":"marginal","low":45,"mid":1,"moon_alt":-12,"precip":0.0,"q":0.5,"rh":83,"sky":"night","temp":-9.1,"time":"22:00","wind":16.9},{"alt":null,"cloud":7,"high":0,"iso":"2026-01-08T21:00Z","label":"good","low":7,"mid":0,"moon_alt":-1,"precip":0.0,"q":0.92,"rh":67,"sky":"night","temp":-9.6,"time":"23:00","wind":18.6},{"alt":null,"cloud":3,"high":0,"iso":"2026-01-08T22:00Z","label":"good","low":3,"mid":0,"moon_alt":9,"precip":0.0,"q":0.67,"rh":45,"sky":"night","temp":-9.5,"time":"00:00","wind":21.7},{"alt":null,"cloud":4,"high":0,"iso":"2026-01-08T23:00Z","label":"good","low":4,"mid":0,"moon_alt":20,"precip":0.0,"q":0.61,"rh":45,"sky":"night","temp":-9.8,"time":"01:00","wind":17.8},{"alt":null,"cloud":0,"high":0,"iso":"2026-01-09T00:00Z","label":"good","low":0,"mid":0,"moon_alt":29,"precip":0.0,"q":0.6,"rh":49,"sky":"night","temp":-10.0,"time":"02:00","wind":18.6},{"alt":null,"cloud":0,"high":0,"iso":"2026-01-09T01:00Z","label":"marginal","low":0,"mid":0,"moon_alt":37,"precip":0.0,"q":0.57,"rh":38,"sky":"night","temp":-10.2,"time":"03:00","wind":18.7},{"alt":null,"cloud":0,"high":0,"iso":"2026-01-09T02:00Z","label":"marginal","low":0,"mid":0,"moon_alt":43,"precip":0.0,"q":0.55,"rh":36,"sky":"night","temp":-10.0,"time":"04:00","wind":20.2},{"alt":null,"cloud":0,"high":0,"iso":"2026-01-09T03:00Z","label":"marginal","low":0,"mid":0,"moon_alt":45,"precip":0.0,"q":0.54,"rh":42,"sky":"night","temp":-9.9,"time":"05:00","wind":21.4},{"alt":null,"cloud":5,"high":0,"iso":"2026-01-09T04:00Z","label":"marginal","low":5,"mid":0,"moon_alt":44,"precip":0.0,"q":0.52,"rh":51,"sky":"night","temp":-9.8,"time":"06:00","wind":20.3},{"alt":null,"cloud":1,"high":0,"iso":"2026-01-09T05:00Z","label":"poor","low":1,"mid":0,"moon_alt":39,"precip":0.0,"q":0.08,"rh":51,"sky":"nautical twilight","temp":-9.6,"time":"07:00","wind":15.8}],"peak_quality":0.92,"peak_sky":1.0,"quality_hours":5.72,"reasons":["cloud cover cost 3.4 quality-hours","moonlight cost 2.9 quality-hours","daylight and twilight cost 2.7 quality-hours"],"reference_hours":4.0,"score":63,"score_astronomy":100,"score_weather":63,"sky_hours":9.14,"verdict":"marginal","verdict_astronomy":"good","weather_known":true,"windows":[{"end":"2026-01-08T18:00Z","end_local":"20:00","hours":2.92,"label":"unusable","mean_quality":0.0,"start":"2026-01-08T15:05Z","start_local":"17:05"},{"end":"2026-01-08T21:00Z","end_local":"23:00","hours":3.0,"label":"marginal","mean_quality":0.41,"start":"2026-01-08T18:00Z","start_local":"20:00"},{"end":"2026-01-08T23:25Z","end_local":"01:25","hours":2.42,"label":"good","mean_quality":0.66,"start":"2026-01-08T21:00Z","start_local":"23:00"},{"end":"2026-01-09T00:00Z","end_local":"02:00","hours":0.58,"label":"marginal","mean_quality":0.59,"start":"2026-01-08T23:25Z","start_local":"01:25"},{"end":"2026-01-09T00:10Z","end_local":"02:10","hours":0.17,"label":"good","mean_quality":0.6,"start":"2026-01-09T00:00Z","start_local":"02:00"},{"end":"2026-01-09T04:10Z","end_local":"06:10","hours":4.0,"label":"marginal","mean_quality":0.56,"start":"2026-01-09T00:10Z","start_local":"02:10"},{"end":"2026-01-09T05:20Z","end_local":"07:20","hours":1.17,"label":"poor","mean_quality":0.17,"start":"2026-01-09T04:10Z","start_local":"06:10"},{"end":"2026-01-09T05:50Z","end_local":"07:50","hours":0.5,"label":"unusable","mean_quality":0.0,"start":"2026-01-09T05:20Z","start_local":"07:20"}]},"calculation_version":"2026-10-10.1","forecast":[{"cloud":99,"dark":false,"high":0,"local":"17:00","low":99,"mid":0,"precip":0.0,"rh":91,"temp":-6.4,"time":"2026-01-08T15:00Z","wind":9.4},{"cloud":100,"dark":false,"high":0,"local":"18:00","low":100,"mid":0,"precip":0.0,"rh":94,"temp":-7.5,"time":"2026-01-08T16:00Z","wind":9.4},{"cloud":100,"dark":true,"high":0,"local":"19:00","low":100,"mid":0,"precip":0.0,"rh":92,"temp":-8.0,"time":"2026-01-08T17:00Z","wind":9.4},{"cloud":54,"dark":true,"high":0,"local":"20:00","low":54,"mid":2,"precip":0.0,"rh":88,"temp":-8.3,"time":"2026-01-08T18:00Z","wind":11.2},{"cloud":59,"dark":true,"high":0,"local":"21:00","low":59,"mid":2,"precip":0.0,"rh":87,"temp":-8.9,"time":"2026-01-08T19:00Z","wind":14.3},{"cloud":45,"dark":true,"high":0,"local":"22:00","low":45,"mid":1,"precip":0.0,"rh":83,"temp":-9.1,"time":"2026-01-08T20:00Z","wind":16.9},{"cloud":7,"dark":true,"high":0,"local":"23:00","low":7,"mid":0,"precip":0.0,"rh":67,"temp":-9.6,"time":"2026-01-08T21:00Z","wind":18.6},{"cloud":3,"dark":true,"high":0,"local":"00:00","low":3,"mid":0,"precip":0.0,"rh":45,"temp":-9.5,"time":"2026-01-08T22:00Z","wind":21.7},{"cloud":4,"dark":true,"high":0,"local":"01:00","low":4,"mid":0,"precip":0.0,"rh":45,"temp":-9.8,"time":"2026-01-08T23:00Z","wind":17.8},{"cloud":0,"dark":true,"high":0,"local":"02:00","low":0,"mid":0,"precip":0.0,"rh":49,"temp":-10.0,"time":"2026-01-09T00:00Z","wind":18.6},{"cloud":0,"dark":true,"high":0,"local":"03:00","low":0,"mid":0,"precip":0.0,"rh":38,"temp":-10.2,"time":"2026-01-09T01:00Z","wind":18.7},{"cloud":0,"dark":true,"high":0,"local":"04:00","low":0,"mid":0,"precip":0.0,"rh":36,"temp":-10.0,"time":"2026-01-09T02:00Z","wind":20.2},{"cloud":0,"dark":true,"high":0,"local":"05:00","low":0,"mid":0,"precip":0.0,"rh":42,"temp":-9.9,"time":"2026-01-09T03:00Z","wind":21.4},{"cloud":5,"dark":true,"high":0,"local":"06:00","low":5,"mid":0,"precip":0.0,"rh":51,"temp":-9.8,"time":"2026-01-09T04:00Z","wind":20.3},{"cloud":1,"dark":false,"high":0,"local":"07:00","low":1,"mid":0,"precip":0.0,"rh":51,"temp":-9.6,"time":"2026-01-09T05:00Z","wind":15.8},{"cloud":0,"dark":false,"high":0,"local":"08:00","low":0,"mid":0,"precip":0.0,"rh":53,"temp":-8.7,"time":"2026-01-09T06:00Z","wind":19.1}],"forecast_source":"history","forecast_updated_at":"2026-10-17T10:38:11Z","limits":{"good_alt":30.0,"usable_alt":20.0},"night":{"dark_from":"2026-01-08T16:47:04Z","dark_hours":11.36,"dark_to":"2026-01-09T04:08:33Z","moon":{"illumination":0.667,"phase":"waning gibbous","waxing":false},"moon_free_dark_hours":4.32,"moonrise":"2026-01-08T21:07:53Z","moonset":"2026-01-09T08:59:46Z","sunrise":"2026-01-09T05:47:43Z","sunset":"2026-01-08T15:07:46Z","twilight":{"astronomical":{"end":"2026-01-08T16:47:04Z","start":"2026-01-09T04:08:33Z"},"civil":{"end":"2026-01-08T15:38:52Z","start":"2026-01-09T05:16:40Z"},"nautical":{"end":"2026-01-08T16:13:31Z","start":"2026-01-09T04:42:04Z"}},"window_end":"2026-01-09T10:00:00Z","window_start":"2026-01-08T10:00:00Z"},"night_date":"2026-01-08","site":{"elev_m":1750,"lat":41.693,"lon":24.739,"name":"NAO Rozhen"},"warnings":[]}