{"assessment":{"best_window":{"end":"2027-05-13T01:10Z","end_local":"04:10","hours":5.75,"label":"good","mean_quality":0.83,"start":"2027-05-12T19:25Z","start_local":"22:25"},"cost":{"altitude":0.0,"clouds":0.0,"darkness":2.93,"moon":1.11},"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":"2027-05-12T18:00Z","label":"unusable","low":null,"mid":null,"moon_alt":55,"precip":null,"q":0.0,"rh":null,"sky":"civil twilight","temp":null,"time":"21:00","wind":null},{"alt":null,"cloud":null,"high":null,"iso":"2027-05-12T19:00Z","label":"marginal","low":null,"mid":null,"moon_alt":46,"precip":null,"q":0.34,"rh":null,"sky":"astronomical twilight","temp":null,"time":"22:00","wind":null},{"alt":null,"cloud":null,"high":null,"iso":"2027-05-12T20:00Z","label":"good","low":null,"mid":null,"moon_alt":35,"precip":null,"q":0.7,"rh":null,"sky":"night","temp":null,"time":"23:00","wind":null},{"alt":null,"cloud":null,"high":null,"iso":"2027-05-12T21:00Z","label":"good","low":null,"mid":null,"moon_alt":24,"precip":null,"q":0.74,"rh":null,"sky":"night","temp":null,"time":"00:00","wind":null},{"alt":null,"cloud":null,"high":null,"iso":"2027-05-12T22:00Z","label":"good","low":null,"mid":null,"moon_alt":13,"precip":null,"q":0.77,"rh":null,"sky":"night","temp":null,"time":"01:00","wind":null},{"alt":null,"cloud":null,"high":null,"iso":"2027-05-12T23:00Z","label":"good","low":null,"mid":null,"moon_alt":2,"precip":null,"q":0.8,"rh":null,"sky":"night","temp":null,"time":"02:00","wind":null},{"alt":null,"cloud":null,"high":null,"iso":"2027-05-13T00:00Z","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":"2027-05-13T01:00Z","label":"good","low":null,"mid":null,"moon_alt":-17,"precip":null,"q":1.0,"rh":null,"sky":"night","temp":null,"time":"04:00","wind":null},{"alt":null,"cloud":null,"high":null,"iso":"2027-05-13T02:00Z","label":"poor","low":null,"mid":null,"moon_alt":-25,"precip":null,"q":0.15,"rh":null,"sky":"nautical twilight","temp":null,"time":"05:00","wind":null},{"alt":null,"cloud":null,"high":null,"iso":"2027-05-13T03:00Z","label":"unusable","low":null,"mid":null,"moon_alt":-31,"precip":null,"q":0.0,"rh":null,"sky":"civil twilight","temp":null,"time":"06:00","wind":null}],"peak_quality":1.0,"peak_sky":1.0,"quality_hours":5.55,"reasons":["daylight and twilight cost 2.9 quality-hours","moonlight cost 1.1 quality-hours"],"reference_hours":4.0,"score":null,"score_astronomy":100,"score_weather":null,"sky_hours":5.55,"verdict":"unknown","verdict_astronomy":"good","weather_known":false,"windows":[{"end":"2027-05-12T18:05Z","end_local":"21:05","hours":0.58,"label":"unusable","mean_quality":0.0,"start":"2027-05-12T17:30Z","start_local":"20:30"},{"end":"2027-05-12T18:45Z","end_local":"21:45","hours":0.67,"label":"poor","mean_quality":0.1,"start":"2027-05-12T18:05Z","start_local":"21:05"},{"end":"2027-05-12T19:25Z","end_local":"22:25","hours":0.67,"label":"marginal","mean_quality":0.34,"start":"2027-05-12T18:45Z","start_local":"21:45"},{"end":"2027-05-13T01:10Z","end_local":"04:10","hours":5.75,"label":"good","mean_quality":0.83,"start":"2027-05-12T19:25Z","start_local":"22:25"},{"end":"2027-05-13T01:55Z","end_local":"04:55","hours":0.75,"label":"marginal","mean_quality":0.5,"start":"2027-05-13T01:10Z","start_local":"04:10"},{"end":"2027-05-13T02:35Z","end_local":"05:35","hours":0.67,"label":"poor","mean_quality":0.15,"start":"2027-05-13T01:55Z","start_local":"04:55"},{"end":"2027-05-13T03:05Z","end_local":"06:05","hours":0.5,"label":"unusable","mean_quality":0.0,"start":"2027-05-13T02:35Z","start_local":"05:35"}]},"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":"2027-05-12T19:24:39Z","dark_hours":5.75,"dark_to":"2027-05-13T01:09:48Z","moon":{"illumination":0.469,"phase":"waxing crescent","waxing":true},"moon_free_dark_hours":1.93,"moonrise":null,"moonset":"2027-05-12T23:12:46Z","sunrise":"2027-05-13T03:03:55Z","sunset":"2027-05-12T17:30:30Z","twilight":{"astronomical":{"end":"2027-05-12T19:24:39Z","start":"2027-05-13T01:09:48Z"},"civil":{"end":"2027-05-12T18:01:57Z","start":"2027-05-13T02:32:28Z"},"nautical":{"end":"2027-05-12T18:41:01Z","start":"2027-05-13T01:53:25Z"}},"window_end":"2027-05-13T09:00:00Z","window_start":"2027-05-12T09:00:00Z"},"night_date":"2027-05-12","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."]}