{"assessment":{"best_window":{"end":"2027-12-13T04:00Z","end_local":"06:00","hours":3.42,"label":"marginal","mean_quality":0.4,"start":"2027-12-13T00:35Z","start_local":"02:35"},"cost":{"altitude":0.0,"clouds":0.0,"darkness":2.66,"moon":8.27},"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":"2027-12-12T15:00Z","label":"unusable","low":null,"mid":null,"moon_alt":14,"precip":null,"q":0.0,"rh":null,"sky":"civil twilight","temp":null,"time":"17:00","wind":null},{"alt":null,"cloud":null,"high":null,"iso":"2027-12-12T16:00Z","label":"poor","low":null,"mid":null,"moon_alt":24,"precip":null,"q":0.22,"rh":null,"sky":"astronomical twilight","temp":null,"time":"18:00","wind":null},{"alt":null,"cloud":null,"high":null,"iso":"2027-12-12T17:00Z","label":"marginal","low":null,"mid":null,"moon_alt":35,"precip":null,"q":0.38,"rh":null,"sky":"night","temp":null,"time":"19:00","wind":null},{"alt":null,"cloud":null,"high":null,"iso":"2027-12-12T18:00Z","label":"marginal","low":null,"mid":null,"moon_alt":46,"precip":null,"q":0.32,"rh":null,"sky":"night","temp":null,"time":"20:00","wind":null},{"alt":null,"cloud":null,"high":null,"iso":"2027-12-12T19:00Z","label":"poor","low":null,"mid":null,"moon_alt":56,"precip":null,"q":0.27,"rh":null,"sky":"night","temp":null,"time":"21:00","wind":null},{"alt":null,"cloud":null,"high":null,"iso":"2027-12-12T20:00Z","label":"poor","low":null,"mid":null,"moon_alt":66,"precip":null,"q":0.24,"rh":null,"sky":"night","temp":null,"time":"22:00","wind":null},{"alt":null,"cloud":null,"high":null,"iso":"2027-12-12T21:00Z","label":"poor","low":null,"mid":null,"moon_alt":73,"precip":null,"q":0.22,"rh":null,"sky":"night","temp":null,"time":"23:00","wind":null},{"alt":null,"cloud":null,"high":null,"iso":"2027-12-12T22:00Z","label":"poor","low":null,"mid":null,"moon_alt":73,"precip":null,"q":0.22,"rh":null,"sky":"night","temp":null,"time":"00:00","wind":null},{"alt":null,"cloud":null,"high":null,"iso":"2027-12-12T23:00Z","label":"poor","low":null,"mid":null,"moon_alt":66,"precip":null,"q":0.24,"rh":null,"sky":"night","temp":null,"time":"01:00","wind":null},{"alt":null,"cloud":null,"high":null,"iso":"2027-12-13T00:00Z","label":"poor","low":null,"mid":null,"moon_alt":56,"precip":null,"q":0.28,"rh":null,"sky":"night","temp":null,"time":"02:00","wind":null},{"alt":null,"cloud":null,"high":null,"iso":"2027-12-13T01:00Z","label":"marginal","low":null,"mid":null,"moon_alt":45,"precip":null,"q":0.32,"rh":null,"sky":"night","temp":null,"time":"03:00","wind":null},{"alt":null,"cloud":null,"high":null,"iso":"2027-12-13T02:00Z","label":"marginal","low":null,"mid":null,"moon_alt":34,"precip":null,"q":0.38,"rh":null,"sky":"night","temp":null,"time":"04:00","wind":null},{"alt":null,"cloud":null,"high":null,"iso":"2027-12-13T03:00Z","label":"marginal","low":null,"mid":null,"moon_alt":24,"precip":null,"q":0.44,"rh":null,"sky":"night","temp":null,"time":"05:00","wind":null},{"alt":null,"cloud":null,"high":null,"iso":"2027-12-13T04:00Z","label":"poor","low":null,"mid":null,"moon_alt":13,"precip":null,"q":0.26,"rh":null,"sky":"astronomical twilight","temp":null,"time":"06:00","wind":null},{"alt":null,"cloud":null,"high":null,"iso":"2027-12-13T05:00Z","label":"poor","low":null,"mid":null,"moon_alt":4,"precip":null,"q":0.09,"rh":null,"sky":"nautical twilight","temp":null,"time":"07:00","wind":null}],"peak_quality":0.51,"peak_sky":0.51,"quality_hours":3.91,"reasons":["moonlight cost 8.3 quality-hours","daylight and twilight cost 2.7 quality-hours"],"reference_hours":4.0,"score":null,"score_astronomy":49,"score_weather":null,"sky_hours":3.91,"verdict":"unknown","verdict_astronomy":"marginal","weather_known":false,"windows":[{"end":"2027-12-12T15:25Z","end_local":"17:25","hours":0.58,"label":"unusable","mean_quality":0.0,"start":"2027-12-12T14:50Z","start_local":"16:50"},{"end":"2027-12-12T16:35Z","end_local":"18:35","hours":1.17,"label":"poor","mean_quality":0.14,"start":"2027-12-12T15:25Z","start_local":"17:25"},{"end":"2027-12-12T18:25Z","end_local":"20:25","hours":1.83,"label":"marginal","mean_quality":0.35,"start":"2027-12-12T16:35Z","start_local":"18:35"},{"end":"2027-12-13T00:35Z","end_local":"02:35","hours":6.17,"label":"poor","mean_quality":0.25,"start":"2027-12-12T18:25Z","start_local":"20:25"},{"end":"2027-12-13T04:00Z","end_local":"06:00","hours":3.42,"label":"marginal","mean_quality":0.4,"start":"2027-12-13T00:35Z","start_local":"02:35"},{"end":"2027-12-13T05:10Z","end_local":"07:10","hours":1.17,"label":"poor","mean_quality":0.17,"start":"2027-12-13T04:00Z","start_local":"06:00"},{"end":"2027-12-13T05:40Z","end_local":"07:40","hours":0.5,"label":"unusable","mean_quality":0.0,"start":"2027-12-13T05:10Z","start_local":"07:10"}]},"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":"2027-12-12T16:30:48Z","dark_hours":11.47,"dark_to":"2027-12-13T03:58:59Z","moon":{"illumination":0.991,"phase":"full moon","waxing":true},"moon_free_dark_hours":0.0,"moonrise":"2027-12-12T13:34:40Z","moonset":"2027-12-13T05:25:08Z","sunrise":"2027-12-13T05:39:12Z","sunset":"2027-12-12T14:50:39Z","twilight":{"astronomical":{"end":"2027-12-12T16:30:48Z","start":"2027-12-13T03:58:59Z"},"civil":{"end":"2027-12-12T15:22:05Z","start":"2027-12-13T05:07:44Z"},"nautical":{"end":"2027-12-12T15:57:02Z","start":"2027-12-13T04:32:46Z"}},"window_end":"2027-12-13T10:00:00Z","window_start":"2027-12-12T10:00:00Z"},"night_date":"2027-12-12","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."]}
