{"calculation_version":"2026-10-10.1","days":30,"nights":[{"best_hours":0.33,"best_label":"good","best_window":"05:00\u201305:20","dark_hours":7.75,"date":"2026-04-07","moon_free_dark_hours":4.28,"moon_illumination":71,"moon_separation":62.7,"score":21,"score_astronomy":29,"score_weather":73,"transit_alt":71.1,"transit_local":"08:15","verdict":"poor","weather_source":"history","weekday":"Tue"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":7.69,"date":"2026-04-08","moon_free_dark_hours":5.08,"moon_illumination":62,"moon_separation":55.9,"score":0,"score_astronomy":30,"score_weather":1,"transit_alt":71.1,"transit_local":"08:15","verdict":"unusable","weather_source":"history","weekday":"Wed"},{"best_hours":0.17,"best_label":"marginal","best_window":"02:50\u201303:00","dark_hours":7.64,"date":"2026-04-09","moon_free_dark_hours":5.75,"moon_illumination":53,"moon_separation":50.2,"score":2,"score_astronomy":35,"score_weather":5,"transit_alt":71.1,"transit_local":"08:10","verdict":"poor","weather_source":"history","weekday":"Thu"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":7.58,"date":"2026-04-10","moon_free_dark_hours":6.32,"moon_illumination":43,"moon_separation":46.3,"score":0,"score_astronomy":44,"score_weather":0,"transit_alt":71.1,"transit_local":"08:05","verdict":"unusable","weather_source":"history","weekday":"Fri"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":7.52,"date":"2026-04-11","moon_free_dark_hours":6.75,"moon_illumination":33,"moon_separation":44.6,"score":1,"score_astronomy":49,"score_weather":2,"transit_alt":71.1,"transit_local":"08:00","verdict":"poor","weather_source":"history","weekday":"Sat"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":7.47,"date":"2026-04-12","moon_free_dark_hours":7.15,"moon_illumination":24,"moon_separation":45.6,"score":0,"score_astronomy":54,"score_weather":0,"transit_alt":71.1,"transit_local":"07:55","verdict":"unusable","weather_source":"history","weekday":"Sun"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":7.41,"date":"2026-04-13","moon_free_dark_hours":7.4,"moon_illumination":16,"moon_separation":49.5,"score":0,"score_astronomy":56,"score_weather":0,"transit_alt":71.1,"transit_local":"07:55","verdict":"unusable","weather_source":"history","weekday":"Mon"},{"best_hours":0.17,"best_label":"good","best_window":"02:50\u201303:00","dark_hours":7.35,"date":"2026-04-14","moon_free_dark_hours":7.33,"moon_illumination":9,"moon_separation":55.7,"score":8,"score_astronomy":58,"score_weather":14,"transit_alt":71.1,"transit_local":"07:50","verdict":"poor","weather_source":"history","weekday":"Tue"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":7.29,"date":"2026-04-15","moon_free_dark_hours":7.28,"moon_illumination":3,"moon_separation":63.9,"score":0,"score_astronomy":59,"score_weather":0,"transit_alt":71.1,"transit_local":"07:45","verdict":"unusable","weather_source":"history","weekday":"Wed"},{"best_hours":1.58,"best_label":"marginal","best_window":"04:00\u201305:35","dark_hours":7.24,"date":"2026-04-16","moon_free_dark_hours":7.22,"moon_illumination":0,"moon_separation":73.3,"score":20,"score_astronomy":59,"score_weather":34,"transit_alt":71.1,"transit_local":"07:40","verdict":"poor","weather_source":"history","weekday":"Thu"},{"best_hours":2.33,"best_label":"good","best_window":"02:40\u201305:00","dark_hours":7.18,"date":"2026-04-17","moon_free_dark_hours":7.17,"moon_illumination":0,"moon_separation":83.6,"score":58,"score_astronomy":61,"score_weather":96,"transit_alt":71.1,"transit_local":"07:40","verdict":"marginal","weather_source":"history","weekday":"Fri"},{"best_hours":2.25,"best_label":"good","best_window":"02:40\u201304:55","dark_hours":7.12,"date":"2026-04-18","moon_free_dark_hours":7.1,"moon_illumination":3,"moon_separation":94.2,"score":60,"score_astronomy":62,"score_weather":96,"transit_alt":71.1,"transit_local":"07:35","verdict":"marginal","weather_source":"history","weekday":"Sat"},{"best_hours":2.42,"best_label":"good","best_window":"02:30\u201304:55","dark_hours":7.06,"date":"2026-04-19","moon_free_dark_hours":5.85,"moon_illumination":9,"moon_separation":104.6,"score":56,"score_astronomy":63,"score_weather":89,"transit_alt":71.1,"transit_local":"07:30","verdict":"marginal","weather_source":"history","weekday":"Sun"},{"best_hours":2.42,"best_label":"good","best_window":"02:25\u201304:50","dark_hours":7.0,"date":"2026-04-20","moon_free_dark_hours":4.55,"moon_illumination":16,"moon_separation":114.5,"score":58,"score_astronomy":63,"score_weather":92,"transit_alt":71.1,"transit_local":"07:25","verdict":"marginal","weather_source":"history","weekday":"Mon"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":6.95,"date":"2026-04-21","moon_free_dark_hours":3.42,"moon_illumination":26,"moon_separation":123.2,"score":0,"score_astronomy":65,"score_weather":0,"transit_alt":71.1,"transit_local":"07:20","verdict":"unusable","weather_source":"history","weekday":"Tue"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":6.89,"date":"2026-04-22","moon_free_dark_hours":2.52,"moon_illumination":37,"moon_separation":130.0,"score":0,"score_astronomy":66,"score_weather":0,"transit_alt":71.1,"transit_local":"07:20","verdict":"unusable","weather_source":"history","weekday":"Wed"},{"best_hours":1.67,"best_label":"good","best_window":"02:20\u201304:00","dark_hours":6.83,"date":"2026-04-23","moon_free_dark_hours":1.8,"moon_illumination":48,"moon_separation":134.3,"score":38,"score_astronomy":66,"score_weather":57,"transit_alt":71.1,"transit_local":"07:15","verdict":"poor","weather_source":"history","weekday":"Thu"},{"best_hours":1.33,"best_label":"good","best_window":"03:25\u201304:45","dark_hours":6.77,"date":"2026-04-24","moon_free_dark_hours":1.23,"moon_illumination":59,"moon_separation":135.5,"score":60,"score_astronomy":67,"score_weather":90,"transit_alt":71.1,"transit_local":"07:10","verdict":"marginal","weather_source":"history","weekday":"Fri"},{"best_hours":2.42,"best_label":"good","best_window":"02:20\u201304:45","dark_hours":6.71,"date":"2026-04-25","moon_free_dark_hours":0.8,"moon_illumination":69,"moon_separation":133.5,"score":64,"score_astronomy":66,"score_weather":98,"transit_alt":71.1,"transit_local":"07:05","verdict":"marginal","weather_source":"history","weekday":"Sat"},{"best_hours":2.5,"best_label":"good","best_window":"02:10\u201304:40","dark_hours":6.65,"date":"2026-04-26","moon_free_dark_hours":0.38,"moon_illumination":78,"moon_separation":128.9,"score":65,"score_astronomy":65,"score_weather":100,"transit_alt":71.1,"transit_local":"07:00","verdict":"marginal","weather_source":"history","weekday":"Sun"},{"best_hours":0.5,"best_label":"good","best_window":"02:30\u201303:00","dark_hours":6.6,"date":"2026-04-27","moon_free_dark_hours":0.02,"moon_illumination":86,"moon_separation":122.4,"score":41,"score_astronomy":66,"score_weather":61,"transit_alt":71.1,"transit_local":"07:00","verdict":"marginal","weather_source":"history","weekday":"Mon"},{"best_hours":0.58,"best_label":"good","best_window":"04:00\u201304:35","dark_hours":6.54,"date":"2026-04-28","moon_free_dark_hours":0.0,"moon_illumination":92,"moon_separation":114.8,"score":35,"score_astronomy":57,"score_weather":62,"transit_alt":71.1,"transit_local":"06:55","verdict":"poor","weather_source":"history","weekday":"Tue"},{"best_hours":0.17,"best_label":"marginal","best_window":"01:50\u201302:00","dark_hours":6.48,"date":"2026-04-29","moon_free_dark_hours":0.0,"moon_illumination":97,"moon_separation":106.6,"score":9,"score_astronomy":53,"score_weather":17,"transit_alt":71.1,"transit_local":"06:50","verdict":"poor","weather_source":"history","weekday":"Wed"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":6.42,"date":"2026-04-30","moon_free_dark_hours":0.0,"moon_illumination":99,"moon_separation":98.0,"score":0,"score_astronomy":48,"score_weather":0,"transit_alt":71.1,"transit_local":"06:45","verdict":"unusable","weather_source":"history","weekday":"Thu"},{"best_hours":1.17,"best_label":"good","best_window":"02:50\u201304:00","dark_hours":6.36,"date":"2026-05-01","moon_free_dark_hours":0.0,"moon_illumination":100,"moon_separation":89.4,"score":33,"score_astronomy":42,"score_weather":78,"transit_alt":71.1,"transit_local":"06:45","verdict":"poor","weather_source":"history","weekday":"Fri"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":6.31,"date":"2026-05-02","moon_free_dark_hours":0.0,"moon_illumination":98,"moon_separation":80.8,"score":0,"score_astronomy":39,"score_weather":0,"transit_alt":71.1,"transit_local":"06:40","verdict":"unusable","weather_source":"history","weekday":"Sat"},{"best_hours":1.08,"best_label":"good","best_window":"03:25\u201304:30","dark_hours":6.25,"date":"2026-05-03","moon_free_dark_hours":0.5,"moon_illumination":95,"moon_separation":72.5,"score":36,"score_astronomy":37,"score_weather":96,"transit_alt":71.1,"transit_local":"06:35","verdict":"poor","weather_source":"history","weekday":"Sun"},{"best_hours":1.42,"best_label":"marginal","best_window":"03:00\u201304:25","dark_hours":6.19,"date":"2026-05-04","moon_free_dark_hours":1.45,"moon_illumination":91,"moon_separation":64.7,"score":14,"score_astronomy":35,"score_weather":41,"transit_alt":71.1,"transit_local":"06:30","verdict":"poor","weather_source":"history","weekday":"Mon"},{"best_hours":1.33,"best_label":"good","best_window":"03:05\u201304:25","dark_hours":6.13,"date":"2026-05-05","moon_free_dark_hours":2.28,"moon_illumination":84,"moon_separation":57.6,"score":36,"score_astronomy":36,"score_weather":100,"transit_alt":71.1,"transit_local":"06:25","verdict":"poor","weather_source":"history","weekday":"Tue"},{"best_hours":1.67,"best_label":"good","best_window":"02:20\u201304:00","dark_hours":6.08,"date":"2026-05-06","moon_free_dark_hours":3.0,"moon_illumination":77,"moon_separation":51.6,"score":37,"score_astronomy":38,"score_weather":98,"transit_alt":71.1,"transit_local":"06:25","verdict":"poor","weather_source":"history","weekday":"Wed"}],"note":"score_astronomy for every night; score_weather/score only where a forecast (next 4 days) or ERA5 history exists \u2014 null otherwise","start":"2026-04-07","target":{"dec":22.71085365,"name":"HD 189733","ra":300.18213726,"simbad_url":"https://simbad.cds.unistra.fr/simbad/sim-id?Ident=HD%20189733","source":"sesame","spectral_type":"K2V","type":"BY*","type_text":"BY Draconis variable \u2014 a spotted, rotating star","vmag":7.648}}