{"calculation_version":"2026-10-10.1","days":30,"nights":[{"best_hours":0.83,"best_label":"good","best_window":"04:10\u201305:00","dark_hours":9.06,"date":"2025-03-13","moon_free_dark_hours":0.0,"moon_illumination":100,"moon_separation":123.5,"score":20,"score_astronomy":25,"score_weather":82,"transit_alt":71.1,"transit_local":"08:55","verdict":"poor","weather_source":"history","weekday":"Thu"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":9.01,"date":"2025-03-14","moon_free_dark_hours":0.0,"moon_illumination":100,"moon_separation":116.8,"score":0,"score_astronomy":25,"score_weather":0,"transit_alt":71.1,"transit_local":"08:50","verdict":"unusable","weather_source":"history","weekday":"Fri"},{"best_hours":0.92,"best_label":"good","best_window":"04:05\u201305:00","dark_hours":8.96,"date":"2025-03-15","moon_free_dark_hours":0.0,"moon_illumination":98,"moon_separation":109.3,"score":20,"score_astronomy":23,"score_weather":89,"transit_alt":71.1,"transit_local":"08:45","verdict":"poor","weather_source":"history","weekday":"Sat"},{"best_hours":0.92,"best_label":"good","best_window":"04:05\u201305:00","dark_hours":8.91,"date":"2025-03-16","moon_free_dark_hours":0.87,"moon_illumination":94,"moon_separation":101.4,"score":22,"score_astronomy":22,"score_weather":99,"transit_alt":71.1,"transit_local":"08:40","verdict":"poor","weather_source":"history","weekday":"Sun"},{"best_hours":1.75,"best_label":"marginal","best_window":"03:10\u201304:55","dark_hours":8.86,"date":"2025-03-17","moon_free_dark_hours":1.88,"moon_illumination":88,"moon_separation":93.3,"score":18,"score_astronomy":21,"score_weather":84,"transit_alt":71.1,"transit_local":"08:40","verdict":"poor","weather_source":"history","weekday":"Mon"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":8.81,"date":"2025-03-18","moon_free_dark_hours":2.93,"moon_illumination":82,"moon_separation":85.1,"score":0,"score_astronomy":21,"score_weather":0,"transit_alt":71.1,"transit_local":"08:35","verdict":"unusable","weather_source":"history","weekday":"Tue"},{"best_hours":1.0,"best_label":"good","best_window":"03:55\u201304:55","dark_hours":8.76,"date":"2025-03-19","moon_free_dark_hours":4.0,"moon_illumination":74,"moon_separation":77.0,"score":21,"score_astronomy":21,"score_weather":100,"transit_alt":71.1,"transit_local":"08:30","verdict":"poor","weather_source":"history","weekday":"Wed"},{"best_hours":1.0,"best_label":"good","best_window":"03:50\u201304:50","dark_hours":8.71,"date":"2025-03-20","moon_free_dark_hours":5.03,"moon_illumination":65,"moon_separation":69.1,"score":22,"score_astronomy":22,"score_weather":100,"transit_alt":71.1,"transit_local":"08:25","verdict":"poor","weather_source":"history","weekday":"Thu"},{"best_hours":0.83,"best_label":"marginal","best_window":"04:00\u201304:50","dark_hours":8.66,"date":"2025-03-21","moon_free_dark_hours":6.0,"moon_illumination":55,"moon_separation":61.7,"score":12,"score_astronomy":24,"score_weather":49,"transit_alt":71.1,"transit_local":"08:25","verdict":"poor","weather_source":"history","weekday":"Fri"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":8.61,"date":"2025-03-22","moon_free_dark_hours":6.85,"moon_illumination":45,"moon_separation":55.1,"score":0,"score_astronomy":27,"score_weather":0,"transit_alt":71.1,"transit_local":"08:20","verdict":"unusable","weather_source":"history","weekday":"Sat"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":8.55,"date":"2025-03-23","moon_free_dark_hours":7.58,"moon_illumination":35,"moon_separation":49.8,"score":0,"score_astronomy":33,"score_weather":0,"transit_alt":71.1,"transit_local":"08:15","verdict":"unusable","weather_source":"history","weekday":"Sun"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":8.5,"date":"2025-03-24","moon_free_dark_hours":8.17,"moon_illumination":26,"moon_separation":46.6,"score":0,"score_astronomy":38,"score_weather":0,"transit_alt":71.1,"transit_local":"08:10","verdict":"unusable","weather_source":"history","weekday":"Mon"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":8.45,"date":"2025-03-25","moon_free_dark_hours":8.42,"moon_illumination":17,"moon_separation":46.3,"score":0,"score_astronomy":40,"score_weather":0,"transit_alt":71.1,"transit_local":"08:05","verdict":"unusable","weather_source":"history","weekday":"Tue"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":8.39,"date":"2025-03-26","moon_free_dark_hours":8.38,"moon_illumination":9,"moon_separation":49.1,"score":0,"score_astronomy":41,"score_weather":0,"transit_alt":71.1,"transit_local":"08:05","verdict":"unusable","weather_source":"history","weekday":"Wed"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":8.34,"date":"2025-03-27","moon_free_dark_hours":8.33,"moon_illumination":3,"moon_separation":54.8,"score":2,"score_astronomy":43,"score_weather":4,"transit_alt":71.1,"transit_local":"08:00","verdict":"poor","weather_source":"history","weekday":"Thu"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":8.29,"date":"2025-03-28","moon_free_dark_hours":8.27,"moon_illumination":0,"moon_separation":62.8,"score":0,"score_astronomy":43,"score_weather":0,"transit_alt":71.1,"transit_local":"07:55","verdict":"unusable","weather_source":"history","weekday":"Fri"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":8.23,"date":"2025-03-29","moon_free_dark_hours":8.22,"moon_illumination":0,"moon_separation":72.3,"score":0,"score_astronomy":44,"score_weather":0,"transit_alt":71.1,"transit_local":"08:50","verdict":"unusable","weather_source":"history","weekday":"Sat"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":8.18,"date":"2025-03-30","moon_free_dark_hours":8.17,"moon_illumination":3,"moon_separation":82.5,"score":0,"score_astronomy":45,"score_weather":0,"transit_alt":71.1,"transit_local":"08:45","verdict":"unusable","weather_source":"history","weekday":"Sun"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":8.12,"date":"2025-03-31","moon_free_dark_hours":6.85,"moon_illumination":9,"moon_separation":93.0,"score":0,"score_astronomy":46,"score_weather":0,"transit_alt":71.1,"transit_local":"08:45","verdict":"unusable","weather_source":"history","weekday":"Mon"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":8.07,"date":"2025-04-01","moon_free_dark_hours":5.47,"moon_illumination":17,"moon_separation":103.1,"score":0,"score_astronomy":47,"score_weather":0,"transit_alt":71.1,"transit_local":"08:40","verdict":"unusable","weather_source":"history","weekday":"Tue"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":8.01,"date":"2025-04-02","moon_free_dark_hours":4.15,"moon_illumination":27,"moon_separation":112.5,"score":0,"score_astronomy":47,"score_weather":0,"transit_alt":71.1,"transit_local":"08:35","verdict":"unusable","weather_source":"history","weekday":"Wed"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":7.96,"date":"2025-04-03","moon_free_dark_hours":3.0,"moon_illumination":37,"moon_separation":120.8,"score":0,"score_astronomy":48,"score_weather":0,"transit_alt":71.1,"transit_local":"08:30","verdict":"unusable","weather_source":"history","weekday":"Thu"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":7.9,"date":"2025-04-04","moon_free_dark_hours":2.05,"moon_illumination":48,"moon_separation":127.4,"score":0,"score_astronomy":50,"score_weather":0,"transit_alt":71.1,"transit_local":"08:30","verdict":"unusable","weather_source":"history","weekday":"Fri"},{"best_hours":1.33,"best_label":"good","best_window":"04:00\u201305:20","dark_hours":7.85,"date":"2025-04-05","moon_free_dark_hours":1.32,"moon_illumination":59,"moon_separation":131.9,"score":38,"score_astronomy":49,"score_weather":78,"transit_alt":71.1,"transit_local":"08:25","verdict":"poor","weather_source":"history","weekday":"Sat"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":7.79,"date":"2025-04-06","moon_free_dark_hours":0.73,"moon_illumination":69,"moon_separation":133.9,"score":0,"score_astronomy":50,"score_weather":0,"transit_alt":71.1,"transit_local":"08:20","verdict":"unusable","weather_source":"history","weekday":"Sun"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":7.74,"date":"2025-04-07","moon_free_dark_hours":0.27,"moon_illumination":78,"moon_separation":133.2,"score":1,"score_astronomy":49,"score_weather":2,"transit_alt":71.1,"transit_local":"08:15","verdict":"poor","weather_source":"history","weekday":"Mon"},{"best_hours":1.17,"best_label":"good","best_window":"04:05\u201305:15","dark_hours":7.68,"date":"2025-04-08","moon_free_dark_hours":0.0,"moon_illumination":85,"moon_separation":130.0,"score":39,"score_astronomy":45,"score_weather":87,"transit_alt":71.1,"transit_local":"08:10","verdict":"poor","weather_source":"history","weekday":"Tue"},{"best_hours":1.67,"best_label":"good","best_window":"03:35\u201305:15","dark_hours":7.62,"date":"2025-04-09","moon_free_dark_hours":0.0,"moon_illumination":92,"moon_separation":125.0,"score":43,"score_astronomy":46,"score_weather":93,"transit_alt":71.1,"transit_local":"08:10","verdict":"marginal","weather_source":"history","weekday":"Wed"},{"best_hours":0.17,"best_label":"good","best_window":"05:00\u201305:10","dark_hours":7.57,"date":"2025-04-10","moon_free_dark_hours":0.0,"moon_illumination":96,"moon_separation":118.6,"score":17,"score_astronomy":44,"score_weather":38,"transit_alt":71.1,"transit_local":"08:05","verdict":"poor","weather_source":"history","weekday":"Thu"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":7.51,"date":"2025-04-11","moon_free_dark_hours":0.0,"moon_illumination":99,"moon_separation":111.4,"score":1,"score_astronomy":41,"score_weather":3,"transit_alt":71.1,"transit_local":"08:00","verdict":"poor","weather_source":"history","weekday":"Fri"}],"note":"score_astronomy for every night; score_weather/score only where a forecast (next 4 days) or ERA5 history exists \u2014 null otherwise","start":"2025-03-13","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}}