{"assessment":{"best_window":{"end":"2027-08-20T01:55Z","end_local":"04:55","hours":6.92,"label":"marginal","mean_quality":0.4,"start":"2027-08-19T19:00Z","start_local":"22:00"},"cost":{"altitude":0.0,"clouds":0.0,"darkness":2.66,"moon":4.52},"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 possible, with compromises \u2014 weather unknown","hourly":[{"alt":null,"cloud":null,"high":null,"iso":"2027-08-19T18:00Z","label":"poor","low":null,"mid":null,"moon_alt":-1,"precip":null,"q":0.15,"rh":null,"sky":"nautical twilight","temp":null,"time":"21:00","wind":null},{"alt":null,"cloud":null,"high":null,"iso":"2027-08-19T19:00Z","label":"marginal","low":null,"mid":null,"moon_alt":11,"precip":null,"q":0.56,"rh":null,"sky":"night","temp":null,"time":"22:00","wind":null},{"alt":null,"cloud":null,"high":null,"iso":"2027-08-19T20:00Z","label":"marginal","low":null,"mid":null,"moon_alt":21,"precip":null,"q":0.49,"rh":null,"sky":"night","temp":null,"time":"23:00","wind":null},{"alt":null,"cloud":null,"high":null,"iso":"2027-08-19T21:00Z","label":"marginal","low":null,"mid":null,"moon_alt":31,"precip":null,"q":0.43,"rh":null,"sky":"night","temp":null,"time":"00:00","wind":null},{"alt":null,"cloud":null,"high":null,"iso":"2027-08-19T22:00Z","label":"marginal","low":null,"mid":null,"moon_alt":40,"precip":null,"q":0.38,"rh":null,"sky":"night","temp":null,"time":"01:00","wind":null},{"alt":null,"cloud":null,"high":null,"iso":"2027-08-19T23:00Z","label":"marginal","low":null,"mid":null,"moon_alt":47,"precip":null,"q":0.35,"rh":null,"sky":"night","temp":null,"time":"02:00","wind":null},{"alt":null,"cloud":null,"high":null,"iso":"2027-08-20T00:00Z","label":"marginal","low":null,"mid":null,"moon_alt":50,"precip":null,"q":0.34,"rh":null,"sky":"night","temp":null,"time":"03:00","wind":null},{"alt":null,"cloud":null,"high":null,"iso":"2027-08-20T01:00Z","label":"marginal","low":null,"mid":null,"moon_alt":48,"precip":null,"q":0.34,"rh":null,"sky":"night","temp":null,"time":"04:00","wind":null},{"alt":null,"cloud":null,"high":null,"iso":"2027-08-20T02:00Z","label":"poor","low":null,"mid":null,"moon_alt":43,"precip":null,"q":0.18,"rh":null,"sky":"astronomical twilight","temp":null,"time":"05:00","wind":null},{"alt":null,"cloud":null,"high":null,"iso":"2027-08-20T03:00Z","label":"poor","low":null,"mid":null,"moon_alt":35,"precip":null,"q":0.06,"rh":null,"sky":"nautical twilight","temp":null,"time":"06:00","wind":null}],"peak_quality":0.56,"peak_sky":0.56,"quality_hours":3.15,"reasons":["moonlight cost 4.5 quality-hours","daylight and twilight cost 2.7 quality-hours"],"reference_hours":4.0,"score":null,"score_astronomy":44,"score_weather":null,"sky_hours":3.15,"verdict":"unknown","verdict_astronomy":"marginal","weather_known":false,"windows":[{"end":"2027-08-19T17:50Z","end_local":"20:50","hours":0.58,"label":"unusable","mean_quality":0.0,"start":"2027-08-19T17:15Z","start_local":"20:15"},{"end":"2027-08-19T19:00Z","end_local":"22:00","hours":1.17,"label":"poor","mean_quality":0.2,"start":"2027-08-19T17:50Z","start_local":"20:50"},{"end":"2027-08-20T01:55Z","end_local":"04:55","hours":6.92,"label":"marginal","mean_quality":0.4,"start":"2027-08-19T19:00Z","start_local":"22:00"},{"end":"2027-08-20T03:05Z","end_local":"06:05","hours":1.17,"label":"poor","mean_quality":0.12,"start":"2027-08-20T01:55Z","start_local":"04:55"},{"end":"2027-08-20T03:35Z","end_local":"06:35","hours":0.5,"label":"unusable","mean_quality":0.0,"start":"2027-08-20T03:05Z","start_local":"06:05"}]},"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":"2027-08-19T18:59:09Z","dark_hours":6.86,"dark_to":"2027-08-20T01:50:38Z","moon":{"illumination":0.937,"phase":"waning gibbous","waxing":false},"moon_free_dark_hours":0.0,"moonrise":"2027-08-19T18:03:23Z","moonset":"2027-08-20T06:27:04Z","sunrise":"2027-08-20T03:34:14Z","sunset":"2027-08-19T17:15:36Z","twilight":{"astronomical":{"end":"2027-08-19T18:59:09Z","start":"2027-08-20T01:50:38Z"},"civil":{"end":"2027-08-19T17:45:06Z","start":"2027-08-20T03:04:42Z"},"nautical":{"end":"2027-08-19T18:20:52Z","start":"2027-08-20T02:28:56Z"}},"window_end":"2027-08-20T09:00:00Z","window_start":"2027-08-19T09:00:00Z"},"night_date":"2027-08-19","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."]}
