{"calculation_version":"2026-10-10.1","days":30,"nights":[{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":7.11,"date":"2025-04-18","moon_free_dark_hours":4.13,"moon_illumination":71,"moon_separation":145.7,"score":0,"score_astronomy":0,"score_weather":93,"transit_alt":72.5,"transit_local":"15:20","verdict":"unusable","weather_source":"history","weekday":"Fri"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":7.05,"date":"2025-04-19","moon_free_dark_hours":4.88,"moon_illumination":62,"moon_separation":133.2,"score":0,"score_astronomy":0,"score_weather":60,"transit_alt":72.5,"transit_local":"15:20","verdict":"unusable","weather_source":"history","weekday":"Sat"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":6.99,"date":"2025-04-20","moon_free_dark_hours":5.5,"moon_illumination":52,"moon_separation":120.5,"score":0,"score_astronomy":0,"score_weather":26,"transit_alt":72.5,"transit_local":"15:15","verdict":"unusable","weather_source":"history","weekday":"Sun"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":6.93,"date":"2025-04-21","moon_free_dark_hours":6.0,"moon_illumination":41,"moon_separation":107.4,"score":0,"score_astronomy":0,"score_weather":0,"transit_alt":72.5,"transit_local":"15:10","verdict":"unusable","weather_source":"history","weekday":"Mon"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":6.87,"date":"2025-04-22","moon_free_dark_hours":6.43,"moon_illumination":30,"moon_separation":93.9,"score":0,"score_astronomy":0,"score_weather":0,"transit_alt":72.5,"transit_local":"15:05","verdict":"unusable","weather_source":"history","weekday":"Tue"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":6.81,"date":"2025-04-23","moon_free_dark_hours":6.8,"moon_illumination":21,"moon_separation":79.9,"score":0,"score_astronomy":0,"score_weather":0,"transit_alt":72.5,"transit_local":"15:00","verdict":"unusable","weather_source":"history","weekday":"Wed"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":6.76,"date":"2025-04-24","moon_free_dark_hours":6.73,"moon_illumination":12,"moon_separation":65.4,"score":0,"score_astronomy":0,"score_weather":0,"transit_alt":72.5,"transit_local":"15:00","verdict":"unusable","weather_source":"history","weekday":"Thu"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":6.7,"date":"2025-04-25","moon_free_dark_hours":6.68,"moon_illumination":5,"moon_separation":50.6,"score":0,"score_astronomy":0,"score_weather":0,"transit_alt":72.5,"transit_local":"14:55","verdict":"unusable","weather_source":"history","weekday":"Fri"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":6.64,"date":"2025-04-26","moon_free_dark_hours":6.62,"moon_illumination":1,"moon_separation":35.4,"score":0,"score_astronomy":0,"score_weather":0,"transit_alt":72.5,"transit_local":"14:50","verdict":"unusable","weather_source":"history","weekday":"Sat"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":6.58,"date":"2025-04-27","moon_free_dark_hours":6.57,"moon_illumination":0,"moon_separation":20.2,"score":0,"score_astronomy":0,"score_weather":0,"transit_alt":72.5,"transit_local":"14:45","verdict":"unusable","weather_source":"history","weekday":"Sun"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":6.52,"date":"2025-04-28","moon_free_dark_hours":6.5,"moon_illumination":2,"moon_separation":5.0,"score":0,"score_astronomy":0,"score_weather":0,"transit_alt":72.5,"transit_local":"14:40","verdict":"unusable","weather_source":"history","weekday":"Mon"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":6.47,"date":"2025-04-29","moon_free_dark_hours":5.68,"moon_illumination":7,"moon_separation":10.1,"score":0,"score_astronomy":0,"score_weather":0,"transit_alt":72.5,"transit_local":"14:40","verdict":"unusable","weather_source":"history","weekday":"Tue"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":6.41,"date":"2025-04-30","moon_free_dark_hours":4.42,"moon_illumination":14,"moon_separation":24.7,"score":0,"score_astronomy":0,"score_weather":0,"transit_alt":72.5,"transit_local":"14:35","verdict":"unusable","weather_source":"history","weekday":"Wed"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":6.35,"date":"2025-05-01","moon_free_dark_hours":3.35,"moon_illumination":23,"moon_separation":38.9,"score":0,"score_astronomy":0,"score_weather":0,"transit_alt":72.5,"transit_local":"14:30","verdict":"unusable","weather_source":"history","weekday":"Thu"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":6.29,"date":"2025-05-02","moon_free_dark_hours":2.5,"moon_illumination":33,"moon_separation":52.7,"score":0,"score_astronomy":0,"score_weather":0,"transit_alt":72.5,"transit_local":"14:25","verdict":"unusable","weather_source":"history","weekday":"Fri"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":6.23,"date":"2025-05-03","moon_free_dark_hours":1.85,"moon_illumination":43,"moon_separation":66.0,"score":0,"score_astronomy":0,"score_weather":0,"transit_alt":72.5,"transit_local":"14:20","verdict":"unusable","weather_source":"history","weekday":"Sat"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":6.18,"date":"2025-05-04","moon_free_dark_hours":1.33,"moon_illumination":54,"moon_separation":78.9,"score":0,"score_astronomy":0,"score_weather":0,"transit_alt":72.5,"transit_local":"14:20","verdict":"unusable","weather_source":"history","weekday":"Sun"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":6.12,"date":"2025-05-05","moon_free_dark_hours":0.92,"moon_illumination":64,"moon_separation":91.4,"score":0,"score_astronomy":0,"score_weather":0,"transit_alt":72.5,"transit_local":"14:15","verdict":"unusable","weather_source":"history","weekday":"Mon"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":6.06,"date":"2025-05-06","moon_free_dark_hours":0.55,"moon_illumination":73,"moon_separation":103.7,"score":0,"score_astronomy":0,"score_weather":0,"transit_alt":72.5,"transit_local":"14:10","verdict":"unusable","weather_source":"history","weekday":"Tue"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":6.0,"date":"2025-05-07","moon_free_dark_hours":0.22,"moon_illumination":81,"moon_separation":115.8,"score":0,"score_astronomy":0,"score_weather":0,"transit_alt":72.5,"transit_local":"14:05","verdict":"unusable","weather_source":"history","weekday":"Wed"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":5.95,"date":"2025-05-08","moon_free_dark_hours":0.0,"moon_illumination":88,"moon_separation":127.7,"score":0,"score_astronomy":0,"score_weather":0,"transit_alt":72.5,"transit_local":"14:05","verdict":"unusable","weather_source":"history","weekday":"Thu"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":5.89,"date":"2025-05-09","moon_free_dark_hours":0.0,"moon_illumination":93,"moon_separation":139.6,"score":0,"score_astronomy":0,"score_weather":0,"transit_alt":72.5,"transit_local":"14:00","verdict":"unusable","weather_source":"history","weekday":"Fri"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":5.84,"date":"2025-05-10","moon_free_dark_hours":0.0,"moon_illumination":97,"moon_separation":151.4,"score":0,"score_astronomy":0,"score_weather":0,"transit_alt":72.5,"transit_local":"13:55","verdict":"unusable","weather_source":"history","weekday":"Sat"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":5.78,"date":"2025-05-11","moon_free_dark_hours":0.0,"moon_illumination":99,"moon_separation":163.2,"score":0,"score_astronomy":0,"score_weather":0,"transit_alt":72.5,"transit_local":"13:50","verdict":"unusable","weather_source":"history","weekday":"Sun"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":5.73,"date":"2025-05-12","moon_free_dark_hours":0.0,"moon_illumination":100,"moon_separation":175.1,"score":0,"score_astronomy":0,"score_weather":0,"transit_alt":72.5,"transit_local":"13:45","verdict":"unusable","weather_source":"history","weekday":"Mon"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":5.67,"date":"2025-05-13","moon_free_dark_hours":0.0,"moon_illumination":98,"moon_separation":172.9,"score":0,"score_astronomy":0,"score_weather":0,"transit_alt":72.5,"transit_local":"13:45","verdict":"unusable","weather_source":"history","weekday":"Tue"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":5.62,"date":"2025-05-14","moon_free_dark_hours":0.42,"moon_illumination":95,"moon_separation":160.9,"score":0,"score_astronomy":0,"score_weather":0,"transit_alt":72.5,"transit_local":"13:40","verdict":"unusable","weather_source":"history","weekday":"Wed"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":5.56,"date":"2025-05-15","moon_free_dark_hours":1.32,"moon_illumination":90,"moon_separation":148.7,"score":0,"score_astronomy":0,"score_weather":0,"transit_alt":72.5,"transit_local":"13:35","verdict":"unusable","weather_source":"history","weekday":"Thu"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":5.51,"date":"2025-05-16","moon_free_dark_hours":2.12,"moon_illumination":84,"moon_separation":136.3,"score":0,"score_astronomy":0,"score_weather":0,"transit_alt":72.5,"transit_local":"13:30","verdict":"unusable","weather_source":"history","weekday":"Fri"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":5.46,"date":"2025-05-17","moon_free_dark_hours":2.77,"moon_illumination":76,"moon_separation":123.8,"score":0,"score_astronomy":0,"score_weather":0,"transit_alt":72.5,"transit_local":"13:25","verdict":"unusable","weather_source":"history","weekday":"Sat"}],"note":"score_astronomy for every night; score_weather/score only where a forecast (next 4 days) or ERA5 history exists \u2014 null otherwise","start":"2025-04-18","target":{"common_name":"Seven Sisters","dec":24.11388889,"name":"Cl Melotte 22","ra":56.60083333,"simbad_url":"https://simbad.cds.unistra.fr/simbad/sim-id?Ident=M45","source":"sesame","type":"OpC","type_text":"open cluster"}}