{"assessment":{"best_window":{"end":"2027-09-11T02:25Z","end_local":"05:25","hours":5.25,"label":"good","mean_quality":0.86,"start":"2027-09-10T21:10Z","start_local":"00:10"},"cost":{"altitude":0.0,"clouds":0.0,"darkness":2.59,"moon":2.1},"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":"Astronomically worth it \u2014 weather unknown","hourly":[{"alt":null,"cloud":null,"high":null,"iso":"2027-09-10T17:00Z","label":"unusable","low":null,"mid":null,"moon_alt":20,"precip":null,"q":0.0,"rh":null,"sky":"civil twilight","temp":null,"time":"20:00","wind":null},{"alt":null,"cloud":null,"high":null,"iso":"2027-09-10T18:00Z","label":"poor","low":null,"mid":null,"moon_alt":23,"precip":null,"q":0.28,"rh":null,"sky":"astronomical twilight","temp":null,"time":"21:00","wind":null},{"alt":null,"cloud":null,"high":null,"iso":"2027-09-10T19:00Z","label":"marginal","low":null,"mid":null,"moon_alt":24,"precip":null,"q":0.56,"rh":null,"sky":"night","temp":null,"time":"22:00","wind":null},{"alt":null,"cloud":null,"high":null,"iso":"2027-09-10T20:00Z","label":"marginal","low":null,"mid":null,"moon_alt":21,"precip":null,"q":0.57,"rh":null,"sky":"night","temp":null,"time":"23:00","wind":null},{"alt":null,"cloud":null,"high":null,"iso":"2027-09-10T21:00Z","label":"marginal","low":null,"mid":null,"moon_alt":16,"precip":null,"q":0.6,"rh":null,"sky":"night","temp":null,"time":"00:00","wind":null},{"alt":null,"cloud":null,"high":null,"iso":"2027-09-10T22:00Z","label":"good","low":null,"mid":null,"moon_alt":10,"precip":null,"q":0.63,"rh":null,"sky":"night","temp":null,"time":"01:00","wind":null},{"alt":null,"cloud":null,"high":null,"iso":"2027-09-10T23:00Z","label":"good","low":null,"mid":null,"moon_alt":1,"precip":null,"q":0.68,"rh":null,"sky":"night","temp":null,"time":"02:00","wind":null},{"alt":null,"cloud":null,"high":null,"iso":"2027-09-11T00:00Z","label":"good","low":null,"mid":null,"moon_alt":-8,"precip":null,"q":1.0,"rh":null,"sky":"night","temp":null,"time":"03:00","wind":null},{"alt":null,"cloud":null,"high":null,"iso":"2027-09-11T01:00Z","label":"good","low":null,"mid":null,"moon_alt":-18,"precip":null,"q":1.0,"rh":null,"sky":"night","temp":null,"time":"04:00","wind":null},{"alt":null,"cloud":null,"high":null,"iso":"2027-09-11T02:00Z","label":"good","low":null,"mid":null,"moon_alt":-29,"precip":null,"q":1.0,"rh":null,"sky":"night","temp":null,"time":"05:00","wind":null},{"alt":null,"cloud":null,"high":null,"iso":"2027-09-11T03:00Z","label":"poor","low":null,"mid":null,"moon_alt":-39,"precip":null,"q":0.15,"rh":null,"sky":"nautical twilight","temp":null,"time":"06:00","wind":null}],"peak_quality":1.0,"peak_sky":1.0,"quality_hours":6.73,"reasons":["daylight and twilight cost 2.6 quality-hours","moonlight cost 2.1 quality-hours"],"reference_hours":4.0,"score":null,"score_astronomy":100,"score_weather":null,"sky_hours":6.73,"verdict":"unknown","verdict_astronomy":"good","weather_known":false,"windows":[{"end":"2027-09-10T17:10Z","end_local":"20:10","hours":0.58,"label":"unusable","mean_quality":0.0,"start":"2027-09-10T16:35Z","start_local":"19:35"},{"end":"2027-09-10T18:20Z","end_local":"21:20","hours":1.17,"label":"poor","mean_quality":0.18,"start":"2027-09-10T17:10Z","start_local":"20:10"},{"end":"2027-09-10T21:10Z","end_local":"00:10","hours":2.83,"label":"marginal","mean_quality":0.57,"start":"2027-09-10T18:20Z","start_local":"21:20"},{"end":"2027-09-11T02:25Z","end_local":"05:25","hours":5.25,"label":"good","mean_quality":0.86,"start":"2027-09-10T21:10Z","start_local":"00:10"},{"end":"2027-09-11T03:00Z","end_local":"06:00","hours":0.58,"label":"marginal","mean_quality":0.5,"start":"2027-09-11T02:25Z","start_local":"05:25"},{"end":"2027-09-11T03:30Z","end_local":"06:30","hours":0.5,"label":"poor","mean_quality":0.15,"start":"2027-09-11T03:00Z","start_local":"06:00"},{"end":"2027-09-11T04:00Z","end_local":"07:00","hours":0.5,"label":"unusable","mean_quality":0.0,"start":"2027-09-11T03:30Z","start_local":"06:30"}]},"calculation_version":"2026-10-10.1","forecast":[],"forecast_source":"none","forecast_updated_at":null,"limits":{"good_alt":30.0,"usable_alt":20.0},"night":{"dark_from":"2027-09-10T18:15:28Z","dark_hours":8.09,"dark_to":"2027-09-11T02:21:01Z","moon":{"illumination":0.786,"phase":"waxing gibbous","waxing":true},"moon_free_dark_hours":3.22,"moonrise":"2027-09-10T14:06:50Z","moonset":"2027-09-10T23:07:49Z","sunrise":"2027-09-11T03:56:44Z","sunset":"2027-09-10T16:39:50Z","twilight":{"astronomical":{"end":"2027-09-10T18:15:28Z","start":"2027-09-11T02:21:01Z"},"civil":{"end":"2027-09-10T17:07:53Z","start":"2027-09-11T03:28:40Z"},"nautical":{"end":"2027-09-10T17:41:06Z","start":"2027-09-11T02:55:24Z"}},"window_end":"2027-09-11T09:00:00Z","window_start":"2027-09-10T09:00:00Z"},"night_date":"2027-09-10","site":{"elev_m":1750,"lat":41.693,"lon":24.739,"name":"NAO Rozhen"},"warnings":["No cloud data for this night (beyond the 4-day forecast, or not yet in the archive) \u2014 the score is geometry only."]}
