{"assessment":{"best_window":null,"cost":{"altitude":0.0,"clouds":3.59,"darkness":2.83,"moon":3.58},"formula":"astronomy = 100 * min(1, sky_hours / reference_hours) * peak_sky; overall = astronomy * score_weather / 100 (null when the weather is unknown)","hard_limit":"Overcast (\u226580 % cloud) for 8.7 of 8.8 dark hours \u2014 the sky is closed whatever the geometry says.","headline":"Not tonight","hourly":[{"alt":null,"cloud":80,"high":0,"iso":"2026-05-02T18:00Z","label":"unusable","low":20,"mid":76,"moon_alt":-6,"precip":0.0,"q":0.0,"rh":95,"sky":"nautical twilight","temp":-5.7,"time":"21:00","wind":4.9},{"alt":null,"cloud":98,"high":0,"iso":"2026-05-02T19:00Z","label":"unusable","low":45,"mid":95,"moon_alt":3,"precip":0.4,"q":0.0,"rh":92,"sky":"astronomical twilight","temp":-5.1,"time":"22:00","wind":5.9},{"alt":null,"cloud":100,"high":0,"iso":"2026-05-02T20:00Z","label":"unusable","low":100,"mid":87,"moon_alt":11,"precip":0.7,"q":0.0,"rh":93,"sky":"night","temp":-5.0,"time":"23:00","wind":4.7},{"alt":null,"cloud":100,"high":0,"iso":"2026-05-02T21:00Z","label":"unusable","low":100,"mid":95,"moon_alt":18,"precip":0.5,"q":0.0,"rh":96,"sky":"night","temp":-4.9,"time":"00:00","wind":6.0},{"alt":null,"cloud":100,"high":0,"iso":"2026-05-02T22:00Z","label":"unusable","low":100,"mid":63,"moon_alt":22,"precip":0.1,"q":0.0,"rh":98,"sky":"night","temp":-4.5,"time":"01:00","wind":7.2},{"alt":null,"cloud":99,"high":0,"iso":"2026-05-02T23:00Z","label":"unusable","low":98,"mid":64,"moon_alt":23,"precip":0.0,"q":0.0,"rh":97,"sky":"night","temp":-4.3,"time":"02:00","wind":7.4},{"alt":null,"cloud":100,"high":0,"iso":"2026-05-03T00:00Z","label":"unusable","low":100,"mid":17,"moon_alt":22,"precip":0.0,"q":0.0,"rh":96,"sky":"night","temp":-6.0,"time":"03:00","wind":8.1},{"alt":null,"cloud":100,"high":0,"iso":"2026-05-03T01:00Z","label":"unusable","low":100,"mid":20,"moon_alt":18,"precip":0.0,"q":0.0,"rh":96,"sky":"night","temp":-5.1,"time":"04:00","wind":9.4},{"alt":null,"cloud":99,"high":0,"iso":"2026-05-03T02:00Z","label":"unusable","low":98,"mid":73,"moon_alt":13,"precip":0.1,"q":0.0,"rh":97,"sky":"astronomical twilight","temp":-5.1,"time":"05:00","wind":10.0},{"alt":null,"cloud":100,"high":0,"iso":"2026-05-03T03:00Z","label":"unusable","low":100,"mid":98,"moon_alt":5,"precip":0.4,"q":0.0,"rh":96,"sky":"civil twilight","temp":-5.9,"time":"06:00","wind":7.2}],"peak_quality":0.08,"peak_sky":0.57,"quality_hours":0.01,"reasons":["cloud cover cost 3.6 quality-hours","moonlight cost 3.6 quality-hours","daylight and twilight cost 2.8 quality-hours"],"reference_hours":4.0,"score":0,"score_astronomy":52,"score_weather":0,"sky_hours":3.6,"verdict":"unusable","verdict_astronomy":"marginal","weather_known":true,"windows":[{"end":"2026-05-02T17:55Z","end_local":"20:55","hours":0.58,"label":"unusable","mean_quality":0.0,"start":"2026-05-02T17:20Z","start_local":"20:20"},{"end":"2026-05-02T18:00Z","end_local":"21:00","hours":0.08,"label":"poor","mean_quality":0.08,"start":"2026-05-02T17:55Z","start_local":"20:55"},{"end":"2026-05-03T03:20Z","end_local":"06:20","hours":9.33,"label":"unusable","mean_quality":0.0,"start":"2026-05-02T18:00Z","start_local":"21:00"}]},"calculation_version":"2026-10-10.1","forecast":[{"cloud":42,"dark":false,"high":0,"local":"20:00","low":18,"mid":30,"precip":0.0,"rh":91,"temp":-3.5,"time":"2026-05-02T17:00Z","wind":6.1},{"cloud":80,"dark":false,"high":0,"local":"21:00","low":20,"mid":76,"precip":0.0,"rh":95,"temp":-5.7,"time":"2026-05-02T18:00Z","wind":4.9},{"cloud":98,"dark":false,"high":0,"local":"22:00","low":45,"mid":95,"precip":0.4,"rh":92,"temp":-5.1,"time":"2026-05-02T19:00Z","wind":5.9},{"cloud":100,"dark":true,"high":0,"local":"23:00","low":100,"mid":87,"precip":0.7,"rh":93,"temp":-5.0,"time":"2026-05-02T20:00Z","wind":4.7},{"cloud":100,"dark":true,"high":0,"local":"00:00","low":100,"mid":95,"precip":0.5,"rh":96,"temp":-4.9,"time":"2026-05-02T21:00Z","wind":6.0},{"cloud":100,"dark":true,"high":0,"local":"01:00","low":100,"mid":63,"precip":0.1,"rh":98,"temp":-4.5,"time":"2026-05-02T22:00Z","wind":7.2},{"cloud":99,"dark":true,"high":0,"local":"02:00","low":98,"mid":64,"precip":0.0,"rh":97,"temp":-4.3,"time":"2026-05-02T23:00Z","wind":7.4},{"cloud":100,"dark":true,"high":0,"local":"03:00","low":100,"mid":17,"precip":0.0,"rh":96,"temp":-6.0,"time":"2026-05-03T00:00Z","wind":8.1},{"cloud":100,"dark":true,"high":0,"local":"04:00","low":100,"mid":20,"precip":0.0,"rh":96,"temp":-5.1,"time":"2026-05-03T01:00Z","wind":9.4},{"cloud":99,"dark":false,"high":0,"local":"05:00","low":98,"mid":73,"precip":0.1,"rh":97,"temp":-5.1,"time":"2026-05-03T02:00Z","wind":10.0},{"cloud":100,"dark":false,"high":0,"local":"06:00","low":100,"mid":98,"precip":0.4,"rh":96,"temp":-5.9,"time":"2026-05-03T03:00Z","wind":7.2},{"cloud":100,"dark":false,"high":0,"local":"07:00","low":100,"mid":29,"precip":0.5,"rh":94,"temp":-5.3,"time":"2026-05-03T04:00Z","wind":8.9}],"forecast_source":"history","forecast_updated_at":"2026-10-14T07:01:23Z","limits":{"good_alt":30.0,"usable_alt":20.0},"night":{"dark_from":"2026-05-02T19:08:37Z","dark_hours":6.31,"dark_to":"2026-05-03T01:26:55Z","moon":{"illumination":0.985,"phase":"full moon","waxing":false},"moon_free_dark_hours":0.0,"moonrise":"2026-05-02T18:37:52Z","moonset":"2026-05-03T03:33:20Z","sunrise":"2026-05-03T03:15:20Z","sunset":"2026-05-02T17:20:09Z","twilight":{"astronomical":{"end":"2026-05-02T19:08:37Z","start":"2026-05-03T01:26:55Z"},"civil":{"end":"2026-05-02T17:50:34Z","start":"2026-05-03T02:44:56Z"},"nautical":{"end":"2026-05-02T18:27:53Z","start":"2026-05-03T02:07:38Z"}},"window_end":"2026-05-03T09:00:00Z","window_start":"2026-05-02T09:00:00Z"},"night_date":"2026-05-02","site":{"elev_m":1750,"lat":41.693,"lon":24.739,"name":"NAO Rozhen"},"warnings":[]}
