{"assessment":{"best_window":{"end":"2026-04-28T00:00Z","end_local":"03:00","hours":4.92,"label":"marginal","mean_quality":0.39,"start":"2026-04-27T19:05Z","start_local":"22:05"},"cost":{"altitude":0.0,"clouds":1.04,"darkness":2.81,"moon":3.63},"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":23,"high":0,"iso":"2026-04-27T18:00Z","label":"poor","low":23,"mid":0,"moon_alt":45,"precip":0.0,"q":0.05,"rh":87,"sky":"nautical twilight","temp":3.0,"time":"21:00","wind":2.8},{"alt":null,"cloud":10,"high":0,"iso":"2026-04-27T19:00Z","label":"poor","low":9,"mid":0,"moon_alt":49,"precip":0.0,"q":0.18,"rh":88,"sky":"astronomical twilight","temp":2.1,"time":"22:00","wind":1.7},{"alt":null,"cloud":1,"high":0,"iso":"2026-04-27T20:00Z","label":"marginal","low":0,"mid":0,"moon_alt":49,"precip":0.0,"q":0.39,"rh":89,"sky":"night","temp":1.1,"time":"23:00","wind":2.4},{"alt":null,"cloud":13,"high":12,"iso":"2026-04-27T21:00Z","label":"marginal","low":2,"mid":0,"moon_alt":44,"precip":0.0,"q":0.35,"rh":91,"sky":"night","temp":0.3,"time":"00:00","wind":3.1},{"alt":null,"cloud":9,"high":7,"iso":"2026-04-27T22:00Z","label":"marginal","low":2,"mid":0,"moon_alt":37,"precip":0.0,"q":0.4,"rh":92,"sky":"night","temp":0.3,"time":"01:00","wind":3.6},{"alt":null,"cloud":16,"high":16,"iso":"2026-04-27T23:00Z","label":"marginal","low":1,"mid":0,"moon_alt":28,"precip":0.0,"q":0.41,"rh":94,"sky":"night","temp":0.5,"time":"02:00","wind":4.9},{"alt":null,"cloud":42,"high":17,"iso":"2026-04-28T00:00Z","label":"poor","low":30,"mid":0,"moon_alt":17,"precip":0.0,"q":0.29,"rh":98,"sky":"night","temp":-0.6,"time":"03:00","wind":5.8},{"alt":null,"cloud":43,"high":0,"iso":"2026-04-28T01:00Z","label":"marginal","low":43,"mid":0,"moon_alt":6,"precip":0.0,"q":0.32,"rh":99,"sky":"night","temp":-0.5,"time":"04:00","wind":4.9},{"alt":null,"cloud":62,"high":0,"iso":"2026-04-28T02:00Z","label":"poor","low":62,"mid":0,"moon_alt":-5,"precip":0.0,"q":0.16,"rh":100,"sky":"astronomical twilight","temp":-0.1,"time":"05:00","wind":5.2},{"alt":null,"cloud":98,"high":0,"iso":"2026-04-28T03:00Z","label":"unusable","low":98,"mid":0,"moon_alt":-16,"precip":0.0,"q":0.0,"rh":100,"sky":"civil twilight","temp":-0.5,"time":"06:00","wind":5.1}],"peak_quality":0.52,"peak_sky":1.0,"quality_hours":2.77,"reasons":["moonlight cost 3.6 quality-hours","daylight and twilight cost 2.8 quality-hours","cloud cover cost 1.0 quality-hours"],"reference_hours":4.0,"score":69,"score_astronomy":95,"score_weather":73,"sky_hours":3.81,"verdict":"marginal","verdict_astronomy":"good","weather_known":true,"windows":[{"end":"2026-04-27T18:00Z","end_local":"21:00","hours":0.83,"label":"unusable","mean_quality":0.0,"start":"2026-04-27T17:10Z","start_local":"20:10"},{"end":"2026-04-27T19:05Z","end_local":"22:05","hours":1.08,"label":"poor","mean_quality":0.11,"start":"2026-04-27T18:00Z","start_local":"21:00"},{"end":"2026-04-28T00:00Z","end_local":"03:00","hours":4.92,"label":"marginal","mean_quality":0.39,"start":"2026-04-27T19:05Z","start_local":"22:05"},{"end":"2026-04-28T00:15Z","end_local":"03:15","hours":0.25,"label":"poor","mean_quality":0.3,"start":"2026-04-28T00:00Z","start_local":"03:00"},{"end":"2026-04-28T01:40Z","end_local":"04:40","hours":1.42,"label":"marginal","mean_quality":0.33,"start":"2026-04-28T00:15Z","start_local":"03:15"},{"end":"2026-04-28T02:55Z","end_local":"05:55","hours":1.25,"label":"poor","mean_quality":0.13,"start":"2026-04-28T01:40Z","start_local":"04:40"},{"end":"2026-04-28T03:25Z","end_local":"06:25","hours":0.5,"label":"unusable","mean_quality":0.0,"start":"2026-04-28T02:55Z","start_local":"05:55"}]},"calculation_version":"2026-10-10.1","forecast":[{"cloud":91,"dark":false,"high":0,"local":"20:00","low":91,"mid":0,"precip":0.0,"rh":81,"temp":4.6,"time":"2026-04-27T17:00Z","wind":5.5},{"cloud":23,"dark":false,"high":0,"local":"21:00","low":23,"mid":0,"precip":0.0,"rh":87,"temp":3.0,"time":"2026-04-27T18:00Z","wind":2.8},{"cloud":10,"dark":false,"high":0,"local":"22:00","low":9,"mid":0,"precip":0.0,"rh":88,"temp":2.1,"time":"2026-04-27T19:00Z","wind":1.7},{"cloud":1,"dark":true,"high":0,"local":"23:00","low":0,"mid":0,"precip":0.0,"rh":89,"temp":1.1,"time":"2026-04-27T20:00Z","wind":2.4},{"cloud":13,"dark":true,"high":12,"local":"00:00","low":2,"mid":0,"precip":0.0,"rh":91,"temp":0.3,"time":"2026-04-27T21:00Z","wind":3.1},{"cloud":9,"dark":true,"high":7,"local":"01:00","low":2,"mid":0,"precip":0.0,"rh":92,"temp":0.3,"time":"2026-04-27T22:00Z","wind":3.6},{"cloud":16,"dark":true,"high":16,"local":"02:00","low":1,"mid":0,"precip":0.0,"rh":94,"temp":0.5,"time":"2026-04-27T23:00Z","wind":4.9},{"cloud":42,"dark":true,"high":17,"local":"03:00","low":30,"mid":0,"precip":0.0,"rh":98,"temp":-0.6,"time":"2026-04-28T00:00Z","wind":5.8},{"cloud":43,"dark":true,"high":0,"local":"04:00","low":43,"mid":0,"precip":0.0,"rh":99,"temp":-0.5,"time":"2026-04-28T01:00Z","wind":4.9},{"cloud":62,"dark":false,"high":0,"local":"05:00","low":62,"mid":0,"precip":0.0,"rh":100,"temp":-0.1,"time":"2026-04-28T02:00Z","wind":5.2},{"cloud":98,"dark":false,"high":0,"local":"06:00","low":98,"mid":0,"precip":0.0,"rh":100,"temp":-0.5,"time":"2026-04-28T03:00Z","wind":5.1},{"cloud":98,"dark":false,"high":0,"local":"07:00","low":98,"mid":0,"precip":0.0,"rh":98,"temp":-0.4,"time":"2026-04-28T04:00Z","wind":5.5}],"forecast_source":"history","forecast_updated_at":"2026-10-14T07:01:23Z","limits":{"good_alt":30.0,"usable_alt":20.0},"night":{"dark_from":"2026-04-27T19:00:31Z","dark_hours":6.6,"dark_to":"2026-04-28T01:36:15Z","moon":{"illumination":0.863,"phase":"waxing gibbous","waxing":true},"moon_free_dark_hours":0.02,"moonrise":"2026-04-27T13:12:59Z","moonset":"2026-04-28T01:34:17Z","sunrise":"2026-04-28T03:22:01Z","sunset":"2026-04-27T17:14:43Z","twilight":{"astronomical":{"end":"2026-04-27T19:00:31Z","start":"2026-04-28T01:36:15Z"},"civil":{"end":"2026-04-27T17:44:39Z","start":"2026-04-28T02:52:06Z"},"nautical":{"end":"2026-04-27T18:21:07Z","start":"2026-04-28T02:15:38Z"}},"window_end":"2026-04-28T09:00:00Z","window_start":"2026-04-27T09:00:00Z"},"night_date":"2026-04-27","site":{"elev_m":1750,"lat":41.693,"lon":24.739,"name":"NAO Rozhen"},"warnings":[]}
