{"assessment":{"best_window":{"end":"2027-02-19T03:40Z","end_local":"05:40","hours":5.08,"label":"marginal","mean_quality":0.43,"start":"2027-02-18T22:35Z","start_local":"00:35"},"cost":{"altitude":0.0,"clouds":0.0,"darkness":2.52,"moon":6.77},"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":"2027-02-18T16:00Z","label":"unusable","low":null,"mid":null,"moon_alt":31,"precip":null,"q":0.0,"rh":null,"sky":"civil twilight","temp":null,"time":"18:00","wind":null},{"alt":null,"cloud":null,"high":null,"iso":"2027-02-18T17:00Z","label":"poor","low":null,"mid":null,"moon_alt":41,"precip":null,"q":0.19,"rh":null,"sky":"astronomical twilight","temp":null,"time":"19:00","wind":null},{"alt":null,"cloud":null,"high":null,"iso":"2027-02-18T18:00Z","label":"marginal","low":null,"mid":null,"moon_alt":52,"precip":null,"q":0.33,"rh":null,"sky":"night","temp":null,"time":"20:00","wind":null},{"alt":null,"cloud":null,"high":null,"iso":"2027-02-18T19:00Z","label":"poor","low":null,"mid":null,"moon_alt":61,"precip":null,"q":0.29,"rh":null,"sky":"night","temp":null,"time":"21:00","wind":null},{"alt":null,"cloud":null,"high":null,"iso":"2027-02-18T20:00Z","label":"poor","low":null,"mid":null,"moon_alt":68,"precip":null,"q":0.27,"rh":null,"sky":"night","temp":null,"time":"22:00","wind":null},{"alt":null,"cloud":null,"high":null,"iso":"2027-02-18T21:00Z","label":"poor","low":null,"mid":null,"moon_alt":69,"precip":null,"q":0.27,"rh":null,"sky":"night","temp":null,"time":"23:00","wind":null},{"alt":null,"cloud":null,"high":null,"iso":"2027-02-18T22:00Z","label":"poor","low":null,"mid":null,"moon_alt":64,"precip":null,"q":0.29,"rh":null,"sky":"night","temp":null,"time":"00:00","wind":null},{"alt":null,"cloud":null,"high":null,"iso":"2027-02-18T23:00Z","label":"marginal","low":null,"mid":null,"moon_alt":55,"precip":null,"q":0.32,"rh":null,"sky":"night","temp":null,"time":"01:00","wind":null},{"alt":null,"cloud":null,"high":null,"iso":"2027-02-19T00:00Z","label":"marginal","low":null,"mid":null,"moon_alt":44,"precip":null,"q":0.36,"rh":null,"sky":"night","temp":null,"time":"02:00","wind":null},{"alt":null,"cloud":null,"high":null,"iso":"2027-02-19T01:00Z","label":"marginal","low":null,"mid":null,"moon_alt":33,"precip":null,"q":0.42,"rh":null,"sky":"night","temp":null,"time":"03:00","wind":null},{"alt":null,"cloud":null,"high":null,"iso":"2027-02-19T02:00Z","label":"marginal","low":null,"mid":null,"moon_alt":22,"precip":null,"q":0.48,"rh":null,"sky":"night","temp":null,"time":"04:00","wind":null},{"alt":null,"cloud":null,"high":null,"iso":"2027-02-19T03:00Z","label":"marginal","low":null,"mid":null,"moon_alt":12,"precip":null,"q":0.55,"rh":null,"sky":"night","temp":null,"time":"05:00","wind":null},{"alt":null,"cloud":null,"high":null,"iso":"2027-02-19T04:00Z","label":"marginal","low":null,"mid":null,"moon_alt":1,"precip":null,"q":0.31,"rh":null,"sky":"astronomical twilight","temp":null,"time":"06:00","wind":null},{"alt":null,"cloud":null,"high":null,"iso":"2027-02-19T05:00Z","label":"unusable","low":null,"mid":null,"moon_alt":-8,"precip":null,"q":0.0,"rh":null,"sky":"civil twilight","temp":null,"time":"07:00","wind":null}],"peak_quality":0.59,"peak_sky":0.59,"quality_hours":4.04,"reasons":["moonlight cost 6.8 quality-hours","daylight and twilight cost 2.5 quality-hours"],"reference_hours":4.0,"score":null,"score_astronomy":59,"score_weather":null,"sky_hours":4.04,"verdict":"unknown","verdict_astronomy":"marginal","weather_known":false,"windows":[{"end":"2027-02-18T16:30Z","end_local":"18:30","hours":0.58,"label":"unusable","mean_quality":0.0,"start":"2027-02-18T15:55Z","start_local":"17:55"},{"end":"2027-02-18T17:35Z","end_local":"19:35","hours":1.08,"label":"poor","mean_quality":0.12,"start":"2027-02-18T16:30Z","start_local":"18:30"},{"end":"2027-02-18T18:50Z","end_local":"20:50","hours":1.25,"label":"marginal","mean_quality":0.32,"start":"2027-02-18T17:35Z","start_local":"19:35"},{"end":"2027-02-18T22:35Z","end_local":"00:35","hours":3.75,"label":"poor","mean_quality":0.28,"start":"2027-02-18T18:50Z","start_local":"20:50"},{"end":"2027-02-19T03:40Z","end_local":"05:40","hours":5.08,"label":"marginal","mean_quality":0.43,"start":"2027-02-18T22:35Z","start_local":"00:35"},{"end":"2027-02-19T03:50Z","end_local":"05:50","hours":0.17,"label":"poor","mean_quality":0.3,"start":"2027-02-19T03:40Z","start_local":"05:40"},{"end":"2027-02-19T04:15Z","end_local":"06:15","hours":0.42,"label":"marginal","mean_quality":0.34,"start":"2027-02-19T03:50Z","start_local":"05:50"},{"end":"2027-02-19T04:45Z","end_local":"06:45","hours":0.5,"label":"poor","mean_quality":0.15,"start":"2027-02-19T04:15Z","start_local":"06:15"},{"end":"2027-02-19T05:15Z","end_local":"07:15","hours":0.5,"label":"unusable","mean_quality":0.0,"start":"2027-02-19T04:45Z","start_local":"06:45"}]},"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":"2027-02-18T17:30:38Z","dark_hours":10.13,"dark_to":"2027-02-19T03:38:41Z","moon":{"illumination":0.941,"phase":"waxing gibbous","waxing":true},"moon_free_dark_hours":0.0,"moonrise":"2027-02-18T12:58:59Z","moonset":"2027-02-19T04:08:00Z","sunrise":"2027-02-19T05:11:30Z","sunset":"2027-02-18T15:57:36Z","twilight":{"astronomical":{"end":"2027-02-18T17:30:38Z","start":"2027-02-19T03:38:41Z"},"civil":{"end":"2027-02-18T16:25:58Z","start":"2027-02-19T04:43:12Z"},"nautical":{"end":"2027-02-18T16:58:26Z","start":"2027-02-19T04:10:49Z"}},"window_end":"2027-02-19T10:00:00Z","window_start":"2027-02-18T10:00:00Z"},"night_date":"2027-02-18","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."]}