{"assessment":{"best_window":{"end":"2026-12-31T04:10Z","end_local":"06:10","hours":11.5,"label":"good","mean_quality":0.88,"start":"2026-12-30T16:40Z","start_local":"18:40"},"cost":{"altitude":0.0,"clouds":0.0,"darkness":2.7,"moon":1.53},"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":"2026-12-30T15:00Z","label":"unusable","low":null,"mid":null,"moon_alt":-52,"precip":null,"q":0.0,"rh":null,"sky":"civil twilight","temp":null,"time":"17:00","wind":null},{"alt":null,"cloud":null,"high":null,"iso":"2026-12-30T16:00Z","label":"poor","low":null,"mid":null,"moon_alt":-55,"precip":null,"q":0.15,"rh":null,"sky":"nautical twilight","temp":null,"time":"18:00","wind":null},{"alt":null,"cloud":null,"high":null,"iso":"2026-12-30T17:00Z","label":"good","low":null,"mid":null,"moon_alt":-54,"precip":null,"q":1.0,"rh":null,"sky":"night","temp":null,"time":"19:00","wind":null},{"alt":null,"cloud":null,"high":null,"iso":"2026-12-30T18:00Z","label":"good","low":null,"mid":null,"moon_alt":-48,"precip":null,"q":1.0,"rh":null,"sky":"night","temp":null,"time":"20:00","wind":null},{"alt":null,"cloud":null,"high":null,"iso":"2026-12-30T19:00Z","label":"good","low":null,"mid":null,"moon_alt":-40,"precip":null,"q":1.0,"rh":null,"sky":"night","temp":null,"time":"21:00","wind":null},{"alt":null,"cloud":null,"high":null,"iso":"2026-12-30T20:00Z","label":"good","low":null,"mid":null,"moon_alt":-30,"precip":null,"q":1.0,"rh":null,"sky":"night","temp":null,"time":"22:00","wind":null},{"alt":null,"cloud":null,"high":null,"iso":"2026-12-30T21:00Z","label":"good","low":null,"mid":null,"moon_alt":-20,"precip":null,"q":1.0,"rh":null,"sky":"night","temp":null,"time":"23:00","wind":null},{"alt":null,"cloud":null,"high":null,"iso":"2026-12-30T22:00Z","label":"good","low":null,"mid":null,"moon_alt":-9,"precip":null,"q":1.0,"rh":null,"sky":"night","temp":null,"time":"00:00","wind":null},{"alt":null,"cloud":null,"high":null,"iso":"2026-12-30T23:00Z","label":"good","low":null,"mid":null,"moon_alt":1,"precip":null,"q":0.8,"rh":null,"sky":"night","temp":null,"time":"01:00","wind":null},{"alt":null,"cloud":null,"high":null,"iso":"2026-12-31T00:00Z","label":"good","low":null,"mid":null,"moon_alt":11,"precip":null,"q":0.77,"rh":null,"sky":"night","temp":null,"time":"02:00","wind":null},{"alt":null,"cloud":null,"high":null,"iso":"2026-12-31T01:00Z","label":"good","low":null,"mid":null,"moon_alt":21,"precip":null,"q":0.74,"rh":null,"sky":"night","temp":null,"time":"03:00","wind":null},{"alt":null,"cloud":null,"high":null,"iso":"2026-12-31T02:00Z","label":"good","low":null,"mid":null,"moon_alt":29,"precip":null,"q":0.71,"rh":null,"sky":"night","temp":null,"time":"04:00","wind":null},{"alt":null,"cloud":null,"high":null,"iso":"2026-12-31T03:00Z","label":"good","low":null,"mid":null,"moon_alt":35,"precip":null,"q":0.7,"rh":null,"sky":"night","temp":null,"time":"05:00","wind":null},{"alt":null,"cloud":null,"high":null,"iso":"2026-12-31T04:00Z","label":"good","low":null,"mid":null,"moon_alt":38,"precip":null,"q":0.69,"rh":null,"sky":"night","temp":null,"time":"06:00","wind":null},{"alt":null,"cloud":null,"high":null,"iso":"2026-12-31T05:00Z","label":"poor","low":null,"mid":null,"moon_alt":38,"precip":null,"q":0.1,"rh":null,"sky":"nautical twilight","temp":null,"time":"07:00","wind":null}],"peak_quality":1.0,"peak_sky":1.0,"quality_hours":10.69,"reasons":["daylight and twilight cost 2.7 quality-hours","moonlight cost 1.5 quality-hours"],"reference_hours":4.0,"score":null,"score_astronomy":100,"score_weather":null,"sky_hours":10.69,"verdict":"unknown","verdict_astronomy":"good","weather_known":false,"windows":[{"end":"2026-12-30T15:35Z","end_local":"17:35","hours":0.67,"label":"unusable","mean_quality":0.0,"start":"2026-12-30T14:55Z","start_local":"16:55"},{"end":"2026-12-30T16:10Z","end_local":"18:10","hours":0.58,"label":"poor","mean_quality":0.15,"start":"2026-12-30T15:35Z","start_local":"17:35"},{"end":"2026-12-30T16:40Z","end_local":"18:40","hours":0.5,"label":"marginal","mean_quality":0.5,"start":"2026-12-30T16:10Z","start_local":"18:10"},{"end":"2026-12-31T04:10Z","end_local":"06:10","hours":11.5,"label":"good","mean_quality":0.88,"start":"2026-12-30T16:40Z","start_local":"18:40"},{"end":"2026-12-31T04:45Z","end_local":"06:45","hours":0.58,"label":"marginal","mean_quality":0.34,"start":"2026-12-31T04:10Z","start_local":"06:10"},{"end":"2026-12-31T05:20Z","end_local":"07:20","hours":0.58,"label":"poor","mean_quality":0.1,"start":"2026-12-31T04:45Z","start_local":"06:45"},{"end":"2026-12-31T05:50Z","end_local":"07:50","hours":0.5,"label":"unusable","mean_quality":0.0,"start":"2026-12-31T05:20Z","start_local":"07:20"}]},"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":"2026-12-30T16:39:35Z","dark_hours":11.47,"dark_to":"2026-12-31T04:07:49Z","moon":{"illumination":0.485,"phase":"last quarter","waxing":false},"moon_free_dark_hours":6.22,"moonrise":"2026-12-30T22:53:21Z","moonset":"2026-12-31T09:53:32Z","sunrise":"2026-12-31T05:47:59Z","sunset":"2026-12-30T14:59:20Z","twilight":{"astronomical":{"end":"2026-12-30T16:39:35Z","start":"2026-12-31T04:07:49Z"},"civil":{"end":"2026-12-30T15:30:49Z","start":"2026-12-31T05:16:32Z"},"nautical":{"end":"2026-12-30T16:05:47Z","start":"2026-12-31T04:41:35Z"}},"window_end":"2026-12-31T10:00:00Z","window_start":"2026-12-30T10:00:00Z"},"night_date":"2026-12-30","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."]}