{"calculation_version":"2026-10-10.1","days":30,"nights":[{"best_hours":4.67,"best_label":"good","best_window":"00:45\u201305:25","dark_hours":8.08,"date":"2040-09-09","moon_free_dark_hours":8.07,"moon_illumination":11,"moon_separation":145.9,"score":null,"score_astronomy":100,"score_weather":null,"transit_alt":72.5,"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":8.14,"date":"2040-09-10","moon_free_dark_hours":7.85,"moon_illumination":18,"moon_separation":158.8,"score":null,"score_astronomy":100,"score_weather":null,"transit_alt":72.5,"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":8.19,"date":"2040-09-11","moon_free_dark_hours":7.42,"moon_illumination":27,"moon_separation":171.5,"score":null,"score_astronomy":100,"score_weather":null,"transit_alt":72.5,"transit_local":"05:45","verdict":"unknown","weather_source":"none","weekday":"Tue"},{"best_hours":4.83,"best_label":"good","best_window":"00:35\u201305:25","dark_hours":8.25,"date":"2040-09-12","moon_free_dark_hours":6.88,"moon_illumination":37,"moon_separation":173.0,"score":null,"score_astronomy":100,"score_weather":null,"transit_alt":72.5,"transit_local":"05:40","verdict":"unknown","weather_source":"none","weekday":"Wed"},{"best_hours":5.0,"best_label":"good","best_window":"00:30\u201305:30","dark_hours":8.3,"date":"2040-09-13","moon_free_dark_hours":6.2,"moon_illumination":48,"moon_separation":160.0,"score":null,"score_astronomy":100,"score_weather":null,"transit_alt":72.5,"transit_local":"05:35","verdict":"unknown","weather_source":"none","weekday":"Thu"},{"best_hours":5.08,"best_label":"good","best_window":"00:25\u201305:30","dark_hours":8.35,"date":"2040-09-14","moon_free_dark_hours":5.37,"moon_illumination":60,"moon_separation":146.1,"score":null,"score_astronomy":100,"score_weather":null,"transit_alt":72.5,"transit_local":"05:30","verdict":"unknown","weather_source":"none","weekday":"Fri"},{"best_hours":5.08,"best_label":"good","best_window":"00:25\u201305:30","dark_hours":8.4,"date":"2040-09-15","moon_free_dark_hours":4.33,"moon_illumination":70,"moon_separation":131.9,"score":null,"score_astronomy":100,"score_weather":null,"transit_alt":72.5,"transit_local":"05:25","verdict":"unknown","weather_source":"none","weekday":"Sat"},{"best_hours":5.08,"best_label":"good","best_window":"00:25\u201305:30","dark_hours":8.46,"date":"2040-09-16","moon_free_dark_hours":3.12,"moon_illumination":80,"moon_separation":117.5,"score":null,"score_astronomy":100,"score_weather":null,"transit_alt":72.5,"transit_local":"05:25","verdict":"unknown","weather_source":"none","weekday":"Sun"},{"best_hours":5.08,"best_label":"good","best_window":"00:30\u201305:35","dark_hours":8.51,"date":"2040-09-17","moon_free_dark_hours":1.83,"moon_illumination":89,"moon_separation":102.9,"score":null,"score_astronomy":100,"score_weather":null,"transit_alt":72.5,"transit_local":"05:20","verdict":"unknown","weather_source":"none","weekday":"Mon"},{"best_hours":4.58,"best_label":"good","best_window":"01:00\u201305:35","dark_hours":8.56,"date":"2040-09-18","moon_free_dark_hours":0.53,"moon_illumination":95,"moon_separation":88.3,"score":null,"score_astronomy":100,"score_weather":null,"transit_alt":72.5,"transit_local":"05:15","verdict":"unknown","weather_source":"none","weekday":"Tue"},{"best_hours":3.0,"best_label":"good","best_window":"02:35\u201305:35","dark_hours":8.61,"date":"2040-09-19","moon_free_dark_hours":0.0,"moon_illumination":99,"moon_separation":73.7,"score":null,"score_astronomy":67,"score_weather":null,"transit_alt":72.5,"transit_local":"05:10","verdict":"unknown","weather_source":"none","weekday":"Wed"},{"best_hours":6.17,"best_label":"marginal","best_window":"00:00\u201306:10","dark_hours":8.66,"date":"2040-09-20","moon_free_dark_hours":0.0,"moon_illumination":100,"moon_separation":59.2,"score":null,"score_astronomy":46,"score_weather":null,"transit_alt":72.5,"transit_local":"05:10","verdict":"unknown","weather_source":"none","weekday":"Thu"},{"best_hours":5.5,"best_label":"marginal","best_window":"00:10\u201305:40","dark_hours":8.71,"date":"2040-09-21","moon_free_dark_hours":0.0,"moon_illumination":98,"moon_separation":45.1,"score":null,"score_astronomy":30,"score_weather":null,"transit_alt":72.5,"transit_local":"05:05","verdict":"unknown","weather_source":"none","weekday":"Fri"},{"best_hours":5.42,"best_label":"marginal","best_window":"00:15\u201305:40","dark_hours":8.77,"date":"2040-09-22","moon_free_dark_hours":0.0,"moon_illumination":94,"moon_separation":31.3,"score":null,"score_astronomy":19,"score_weather":null,"transit_alt":72.5,"transit_local":"05:00","verdict":"unknown","weather_source":"none","weekday":"Sat"},{"best_hours":5.75,"best_label":"marginal","best_window":"23:55\u201305:40","dark_hours":8.82,"date":"2040-09-23","moon_free_dark_hours":0.13,"moon_illumination":88,"moon_separation":18.1,"score":null,"score_astronomy":20,"score_weather":null,"transit_alt":72.5,"transit_local":"04:55","verdict":"unknown","weather_source":"none","weekday":"Sun"},{"best_hours":6.0,"best_label":"marginal","best_window":"23:40\u201305:40","dark_hours":8.87,"date":"2040-09-24","moon_free_dark_hours":0.65,"moon_illumination":80,"moon_separation":6.0,"score":null,"score_astronomy":27,"score_weather":null,"transit_alt":72.5,"transit_local":"04:50","verdict":"unknown","weather_source":"none","weekday":"Mon"},{"best_hours":6.33,"best_label":"marginal","best_window":"23:25\u201305:45","dark_hours":8.92,"date":"2040-09-25","moon_free_dark_hours":1.2,"moon_illumination":71,"moon_separation":8.9,"score":null,"score_astronomy":38,"score_weather":null,"transit_alt":72.5,"transit_local":"04:50","verdict":"unknown","weather_source":"none","weekday":"Tue"},{"best_hours":6.58,"best_label":"marginal","best_window":"23:10\u201305:45","dark_hours":8.97,"date":"2040-09-26","moon_free_dark_hours":1.87,"moon_illumination":62,"moon_separation":20.7,"score":null,"score_astronomy":54,"score_weather":null,"transit_alt":72.5,"transit_local":"04:45","verdict":"unknown","weather_source":"none","weekday":"Wed"},{"best_hours":5.75,"best_label":"good","best_window":"00:00\u201305:45","dark_hours":9.01,"date":"2040-09-27","moon_free_dark_hours":2.63,"moon_illumination":53,"moon_separation":32.6,"score":null,"score_astronomy":68,"score_weather":null,"transit_alt":72.5,"transit_local":"04:40","verdict":"unknown","weather_source":"none","weekday":"Thu"},{"best_hours":6.25,"best_label":"good","best_window":"23:30\u201305:45","dark_hours":9.06,"date":"2040-09-28","moon_free_dark_hours":3.52,"moon_illumination":43,"moon_separation":44.5,"score":null,"score_astronomy":82,"score_weather":null,"transit_alt":72.5,"transit_local":"04:35","verdict":"unknown","weather_source":"none","weekday":"Fri"},{"best_hours":6.33,"best_label":"good","best_window":"23:25\u201305:45","dark_hours":9.11,"date":"2040-09-29","moon_free_dark_hours":4.48,"moon_illumination":34,"moon_separation":56.3,"score":null,"score_astronomy":89,"score_weather":null,"transit_alt":72.5,"transit_local":"04:30","verdict":"unknown","weather_source":"none","weekday":"Sat"},{"best_hours":6.5,"best_label":"good","best_window":"23:20\u201305:50","dark_hours":9.16,"date":"2040-09-30","moon_free_dark_hours":5.5,"moon_illumination":25,"moon_separation":68.1,"score":null,"score_astronomy":97,"score_weather":null,"transit_alt":72.5,"transit_local":"04:30","verdict":"unknown","weather_source":"none","weekday":"Sun"},{"best_hours":6.5,"best_label":"good","best_window":"23:20\u201305:50","dark_hours":9.21,"date":"2040-10-01","moon_free_dark_hours":6.57,"moon_illumination":18,"moon_separation":80.0,"score":null,"score_astronomy":100,"score_weather":null,"transit_alt":72.5,"transit_local":"04:25","verdict":"unknown","weather_source":"none","weekday":"Mon"},{"best_hours":6.58,"best_label":"good","best_window":"23:15\u201305:50","dark_hours":9.26,"date":"2040-10-02","moon_free_dark_hours":7.65,"moon_illumination":11,"moon_separation":92.0,"score":null,"score_astronomy":100,"score_weather":null,"transit_alt":72.5,"transit_local":"04:20","verdict":"unknown","weather_source":"none","weekday":"Tue"},{"best_hours":6.67,"best_label":"good","best_window":"23:10\u201305:50","dark_hours":9.3,"date":"2040-10-03","moon_free_dark_hours":8.75,"moon_illumination":6,"moon_separation":104.2,"score":null,"score_astronomy":100,"score_weather":null,"transit_alt":72.5,"transit_local":"04:15","verdict":"unknown","weather_source":"none","weekday":"Wed"},{"best_hours":6.83,"best_label":"good","best_window":"23:05\u201305:55","dark_hours":9.35,"date":"2040-10-04","moon_free_dark_hours":9.33,"moon_illumination":2,"moon_separation":116.7,"score":null,"score_astronomy":100,"score_weather":null,"transit_alt":72.5,"transit_local":"04:15","verdict":"unknown","weather_source":"none","weekday":"Thu"},{"best_hours":6.83,"best_label":"good","best_window":"23:05\u201305:55","dark_hours":9.4,"date":"2040-10-05","moon_free_dark_hours":9.38,"moon_illumination":0,"moon_separation":129.4,"score":null,"score_astronomy":100,"score_weather":null,"transit_alt":72.5,"transit_local":"04:10","verdict":"unknown","weather_source":"none","weekday":"Fri"},{"best_hours":6.92,"best_label":"good","best_window":"23:00\u201305:55","dark_hours":9.44,"date":"2040-10-06","moon_free_dark_hours":9.43,"moon_illumination":1,"moon_separation":142.3,"score":null,"score_astronomy":100,"score_weather":null,"transit_alt":72.5,"transit_local":"04:05","verdict":"unknown","weather_source":"none","weekday":"Sat"},{"best_hours":7.0,"best_label":"good","best_window":"22:55\u201305:55","dark_hours":9.49,"date":"2040-10-07","moon_free_dark_hours":9.47,"moon_illumination":3,"moon_separation":155.4,"score":null,"score_astronomy":100,"score_weather":null,"transit_alt":72.5,"transit_local":"04:00","verdict":"unknown","weather_source":"none","weekday":"Sun"},{"best_hours":7.08,"best_label":"good","best_window":"22:50\u201305:55","dark_hours":9.54,"date":"2040-10-08","moon_free_dark_hours":9.52,"moon_illumination":8,"moon_separation":168.5,"score":null,"score_astronomy":100,"score_weather":null,"transit_alt":72.5,"transit_local":"03:55","verdict":"unknown","weather_source":"none","weekday":"Mon"}],"note":"score_astronomy for every night; score_weather/score only where a forecast (next 4 days) or ERA5 history exists \u2014 null otherwise","start":"2040-09-09","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"}}