{"calculation_version":"2026-10-10.1","days":30,"nights":[{"best_hours":4.25,"best_label":"marginal","best_window":"01:00\u201305:15","dark_hours":7.69,"date":"2045-09-02","moon_free_dark_hours":0.77,"moon_illumination":66,"moon_separation":7.2,"score":null,"score_astronomy":28,"score_weather":null,"transit_alt":72.6,"transit_local":"06:20","verdict":"unknown","weather_source":"none","weekday":"Sat"},{"best_hours":4.5,"best_label":"marginal","best_window":"00:45\u201305:15","dark_hours":7.74,"date":"2045-09-03","moon_free_dark_hours":1.45,"moon_illumination":55,"moon_separation":6.1,"score":null,"score_astronomy":40,"score_weather":null,"transit_alt":72.6,"transit_local":"06:15","verdict":"unknown","weather_source":"none","weekday":"Sun"},{"best_hours":3.75,"best_label":"good","best_window":"01:30\u201305:15","dark_hours":7.8,"date":"2045-09-04","moon_free_dark_hours":2.32,"moon_illumination":44,"moon_separation":19.4,"score":null,"score_astronomy":55,"score_weather":null,"transit_alt":72.6,"transit_local":"06:10","verdict":"unknown","weather_source":"none","weekday":"Mon"},{"best_hours":4.08,"best_label":"good","best_window":"01:15\u201305:20","dark_hours":7.86,"date":"2045-09-05","moon_free_dark_hours":3.38,"moon_illumination":34,"moon_separation":33.2,"score":null,"score_astronomy":74,"score_weather":null,"transit_alt":72.6,"transit_local":"06:10","verdict":"unknown","weather_source":"none","weekday":"Tue"},{"best_hours":4.33,"best_label":"good","best_window":"01:00\u201305:20","dark_hours":7.91,"date":"2045-09-06","moon_free_dark_hours":4.63,"moon_illumination":23,"moon_separation":47.4,"score":null,"score_astronomy":89,"score_weather":null,"transit_alt":72.6,"transit_local":"06:05","verdict":"unknown","weather_source":"none","weekday":"Wed"},{"best_hours":4.42,"best_label":"good","best_window":"00:55\u201305:20","dark_hours":7.96,"date":"2045-09-07","moon_free_dark_hours":5.97,"moon_illumination":14,"moon_separation":62.0,"score":null,"score_astronomy":95,"score_weather":null,"transit_alt":72.6,"transit_local":"06:00","verdict":"unknown","weather_source":"none","weekday":"Thu"},{"best_hours":4.5,"best_label":"good","best_window":"00:50\u201305:20","dark_hours":8.02,"date":"2045-09-08","moon_free_dark_hours":7.35,"moon_illumination":7,"moon_separation":76.9,"score":null,"score_astronomy":100,"score_weather":null,"transit_alt":72.6,"transit_local":"05:55","verdict":"unknown","weather_source":"none","weekday":"Fri"},{"best_hours":4.67,"best_label":"good","best_window":"00:45\u201305:25","dark_hours":8.07,"date":"2045-09-09","moon_free_dark_hours":8.05,"moon_illumination":2,"moon_separation":92.0,"score":null,"score_astronomy":100,"score_weather":null,"transit_alt":72.6,"transit_local":"05:50","verdict":"unknown","weather_source":"none","weekday":"Sat"},{"best_hours":4.75,"best_label":"good","best_window":"00:40\u201305:25","dark_hours":8.13,"date":"2045-09-10","moon_free_dark_hours":8.1,"moon_illumination":0,"moon_separation":107.1,"score":null,"score_astronomy":100,"score_weather":null,"transit_alt":72.6,"transit_local":"05:50","verdict":"unknown","weather_source":"none","weekday":"Sun"},{"best_hours":4.75,"best_label":"good","best_window":"00:40\u201305:25","dark_hours":8.18,"date":"2045-09-11","moon_free_dark_hours":8.17,"moon_illumination":1,"moon_separation":122.1,"score":null,"score_astronomy":100,"score_weather":null,"transit_alt":72.6,"transit_local":"05:45","verdict":"unknown","weather_source":"none","weekday":"Mon"},{"best_hours":4.83,"best_label":"good","best_window":"00:35\u201305:25","dark_hours":8.23,"date":"2045-09-12","moon_free_dark_hours":8.22,"moon_illumination":5,"moon_separation":136.8,"score":null,"score_astronomy":100,"score_weather":null,"transit_alt":72.6,"transit_local":"05:40","verdict":"unknown","weather_source":"none","weekday":"Tue"},{"best_hours":5.0,"best_label":"good","best_window":"00:30\u201305:30","dark_hours":8.29,"date":"2045-09-13","moon_free_dark_hours":8.27,"moon_illumination":11,"moon_separation":151.1,"score":null,"score_astronomy":100,"score_weather":null,"transit_alt":72.6,"transit_local":"05:35","verdict":"unknown","weather_source":"none","weekday":"Wed"},{"best_hours":5.08,"best_label":"good","best_window":"00:25\u201305:30","dark_hours":8.34,"date":"2045-09-14","moon_free_dark_hours":8.32,"moon_illumination":20,"moon_separation":165.0,"score":null,"score_astronomy":100,"score_weather":null,"transit_alt":72.6,"transit_local":"05:30","verdict":"unknown","weather_source":"none","weekday":"Thu"},{"best_hours":5.17,"best_label":"good","best_window":"00:20\u201305:30","dark_hours":8.39,"date":"2045-09-15","moon_free_dark_hours":7.98,"moon_illumination":29,"moon_separation":178.1,"score":null,"score_astronomy":100,"score_weather":null,"transit_alt":72.6,"transit_local":"05:30","verdict":"unknown","weather_source":"none","weekday":"Fri"},{"best_hours":5.17,"best_label":"good","best_window":"00:20\u201305:30","dark_hours":8.45,"date":"2045-09-16","moon_free_dark_hours":7.3,"moon_illumination":39,"moon_separation":168.5,"score":null,"score_astronomy":100,"score_weather":null,"transit_alt":72.6,"transit_local":"05:25","verdict":"unknown","weather_source":"none","weekday":"Sat"},{"best_hours":5.33,"best_label":"good","best_window":"00:15\u201305:35","dark_hours":8.5,"date":"2045-09-17","moon_free_dark_hours":6.48,"moon_illumination":49,"moon_separation":156.0,"score":null,"score_astronomy":100,"score_weather":null,"transit_alt":72.6,"transit_local":"05:20","verdict":"unknown","weather_source":"none","weekday":"Sun"},{"best_hours":5.42,"best_label":"good","best_window":"00:10\u201305:35","dark_hours":8.55,"date":"2045-09-18","moon_free_dark_hours":5.55,"moon_illumination":58,"moon_separation":143.7,"score":null,"score_astronomy":100,"score_weather":null,"transit_alt":72.6,"transit_local":"05:15","verdict":"unknown","weather_source":"none","weekday":"Mon"},{"best_hours":5.42,"best_label":"good","best_window":"00:10\u201305:35","dark_hours":8.6,"date":"2045-09-19","moon_free_dark_hours":4.55,"moon_illumination":68,"moon_separation":131.6,"score":null,"score_astronomy":100,"score_weather":null,"transit_alt":72.6,"transit_local":"05:15","verdict":"unknown","weather_source":"none","weekday":"Tue"},{"best_hours":5.42,"best_label":"good","best_window":"00:10\u201305:35","dark_hours":8.65,"date":"2045-09-20","moon_free_dark_hours":3.53,"moon_illumination":76,"moon_separation":119.7,"score":null,"score_astronomy":100,"score_weather":null,"transit_alt":72.6,"transit_local":"05:10","verdict":"unknown","weather_source":"none","weekday":"Wed"},{"best_hours":5.42,"best_label":"good","best_window":"00:15\u201305:40","dark_hours":8.7,"date":"2045-09-21","moon_free_dark_hours":2.48,"moon_illumination":84,"moon_separation":107.9,"score":null,"score_astronomy":100,"score_weather":null,"transit_alt":72.6,"transit_local":"05:05","verdict":"unknown","weather_source":"none","weekday":"Thu"},{"best_hours":5.33,"best_label":"good","best_window":"00:20\u201305:40","dark_hours":8.75,"date":"2045-09-22","moon_free_dark_hours":1.47,"moon_illumination":90,"moon_separation":96.0,"score":null,"score_astronomy":100,"score_weather":null,"transit_alt":72.6,"transit_local":"05:00","verdict":"unknown","weather_source":"none","weekday":"Fri"},{"best_hours":4.42,"best_label":"good","best_window":"01:15\u201305:40","dark_hours":8.81,"date":"2045-09-23","moon_free_dark_hours":0.45,"moon_illumination":95,"moon_separation":84.2,"score":null,"score_astronomy":100,"score_weather":null,"transit_alt":72.6,"transit_local":"04:55","verdict":"unknown","weather_source":"none","weekday":"Sat"},{"best_hours":3.0,"best_label":"good","best_window":"02:40\u201305:40","dark_hours":8.86,"date":"2045-09-24","moon_free_dark_hours":0.0,"moon_illumination":98,"moon_separation":72.2,"score":null,"score_astronomy":71,"score_weather":null,"transit_alt":72.6,"transit_local":"04:55","verdict":"unknown","weather_source":"none","weekday":"Sun"},{"best_hours":0.42,"best_label":"good","best_window":"05:15\u201305:40","dark_hours":8.91,"date":"2045-09-25","moon_free_dark_hours":0.0,"moon_illumination":100,"moon_separation":60.1,"score":null,"score_astronomy":51,"score_weather":null,"transit_alt":72.6,"transit_local":"04:50","verdict":"unknown","weather_source":"none","weekday":"Mon"},{"best_hours":5.83,"best_label":"marginal","best_window":"23:55\u201305:45","dark_hours":8.96,"date":"2045-09-26","moon_free_dark_hours":0.0,"moon_illumination":100,"moon_separation":47.9,"score":null,"score_astronomy":34,"score_weather":null,"transit_alt":72.6,"transit_local":"04:45","verdict":"unknown","weather_source":"none","weekday":"Tue"},{"best_hours":3.25,"best_label":"marginal","best_window":"02:30\u201305:45","dark_hours":9.0,"date":"2045-09-27","moon_free_dark_hours":0.0,"moon_illumination":97,"moon_separation":35.5,"score":null,"score_astronomy":21,"score_weather":null,"transit_alt":72.6,"transit_local":"04:40","verdict":"unknown","weather_source":"none","weekday":"Wed"},{"best_hours":1.42,"best_label":"marginal","best_window":"04:20\u201305:45","dark_hours":9.05,"date":"2045-09-28","moon_free_dark_hours":0.0,"moon_illumination":93,"moon_separation":22.9,"score":null,"score_astronomy":18,"score_weather":null,"transit_alt":72.6,"transit_local":"04:35","verdict":"unknown","weather_source":"none","weekday":"Thu"},{"best_hours":6.17,"best_label":"marginal","best_window":"23:35\u201305:45","dark_hours":9.1,"date":"2045-09-29","moon_free_dark_hours":0.0,"moon_illumination":87,"moon_separation":10.2,"score":null,"score_astronomy":21,"score_weather":null,"transit_alt":72.6,"transit_local":"04:35","verdict":"unknown","weather_source":"none","weekday":"Fri"},{"best_hours":6.58,"best_label":"marginal","best_window":"23:15\u201305:50","dark_hours":9.15,"date":"2045-09-30","moon_free_dark_hours":0.33,"moon_illumination":79,"moon_separation":3.0,"score":null,"score_astronomy":30,"score_weather":null,"transit_alt":72.6,"transit_local":"04:30","verdict":"unknown","weather_source":"none","weekday":"Sat"},{"best_hours":6.83,"best_label":"marginal","best_window":"23:00\u201305:50","dark_hours":9.2,"date":"2045-10-01","moon_free_dark_hours":1.13,"moon_illumination":70,"moon_separation":16.0,"score":null,"score_astronomy":44,"score_weather":null,"transit_alt":72.6,"transit_local":"04:25","verdict":"unknown","weather_source":"none","weekday":"Sun"}],"note":"score_astronomy for every night; score_weather/score only where a forecast (next 4 days) or ERA5 history exists \u2014 null otherwise","start":"2045-09-02","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"}}