{"calculation_version":"2026-10-10.1","days":30,"nights":[{"best_hours":0.5,"best_label":"marginal","best_window":"03:30\u201304:00","dark_hours":5.37,"date":"2026-07-23","moon_free_dark_hours":2.97,"moon_illumination":73,"moon_separation":178.5,"score":4,"score_astronomy":13,"score_weather":33,"transit_alt":72.5,"transit_local":"09:00","verdict":"poor","weather_source":"history","weekday":"Thu"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":5.42,"date":"2026-07-24","moon_free_dark_hours":2.37,"moon_illumination":81,"moon_separation":169.2,"score":0,"score_astronomy":17,"score_weather":0,"transit_alt":72.5,"transit_local":"08:55","verdict":"unusable","weather_source":"history","weekday":"Fri"},{"best_hours":0.33,"best_label":"good","best_window":"03:55\u201304:15","dark_hours":5.47,"date":"2026-07-25","moon_free_dark_hours":1.62,"moon_illumination":88,"moon_separation":157.4,"score":17,"score_astronomy":19,"score_weather":92,"transit_alt":72.5,"transit_local":"08:55","verdict":"poor","weather_source":"history","weekday":"Sat"},{"best_hours":0.08,"best_label":"good","best_window":"03:55\u201304:00","dark_hours":5.52,"date":"2026-07-26","moon_free_dark_hours":0.75,"moon_illumination":93,"moon_separation":145.5,"score":15,"score_astronomy":20,"score_weather":75,"transit_alt":72.5,"transit_local":"08:50","verdict":"poor","weather_source":"history","weekday":"Sun"},{"best_hours":0.5,"best_label":"good","best_window":"03:50\u201304:20","dark_hours":5.58,"date":"2026-07-27","moon_free_dark_hours":0.0,"moon_illumination":97,"moon_separation":133.6,"score":19,"score_astronomy":19,"score_weather":98,"transit_alt":72.5,"transit_local":"08:45","verdict":"poor","weather_source":"history","weekday":"Mon"},{"best_hours":1.17,"best_label":"marginal","best_window":"03:10\u201304:20","dark_hours":5.63,"date":"2026-07-28","moon_free_dark_hours":0.0,"moon_illumination":100,"moon_separation":121.6,"score":17,"score_astronomy":20,"score_weather":83,"transit_alt":72.5,"transit_local":"08:40","verdict":"poor","weather_source":"history","weekday":"Tue"},{"best_hours":0.5,"best_label":"good","best_window":"03:50\u201304:20","dark_hours":5.68,"date":"2026-07-29","moon_free_dark_hours":0.0,"moon_illumination":100,"moon_separation":109.3,"score":18,"score_astronomy":18,"score_weather":100,"transit_alt":72.5,"transit_local":"08:40","verdict":"poor","weather_source":"history","weekday":"Wed"},{"best_hours":0.42,"best_label":"good","best_window":"03:55\u201304:20","dark_hours":5.74,"date":"2026-07-30","moon_free_dark_hours":0.0,"moon_illumination":98,"moon_separation":97.0,"score":16,"score_astronomy":16,"score_weather":100,"transit_alt":72.5,"transit_local":"08:35","verdict":"poor","weather_source":"history","weekday":"Thu"},{"best_hours":1.42,"best_label":"marginal","best_window":"03:00\u201304:25","dark_hours":5.79,"date":"2026-07-31","moon_free_dark_hours":0.0,"moon_illumination":95,"moon_separation":84.4,"score":14,"score_astronomy":14,"score_weather":100,"transit_alt":72.5,"transit_local":"08:30","verdict":"poor","weather_source":"history","weekday":"Fri"},{"best_hours":1.33,"best_label":"marginal","best_window":"03:05\u201304:25","dark_hours":5.85,"date":"2026-08-01","moon_free_dark_hours":0.0,"moon_illumination":89,"moon_separation":71.6,"score":12,"score_astronomy":12,"score_weather":100,"transit_alt":72.5,"transit_local":"08:25","verdict":"poor","weather_source":"history","weekday":"Sat"},{"best_hours":1.33,"best_label":"marginal","best_window":"03:05\u201304:25","dark_hours":5.9,"date":"2026-08-02","moon_free_dark_hours":0.0,"moon_illumination":82,"moon_separation":58.7,"score":11,"score_astronomy":11,"score_weather":100,"transit_alt":72.5,"transit_local":"08:20","verdict":"poor","weather_source":"history","weekday":"Sun"},{"best_hours":1.5,"best_label":"marginal","best_window":"03:00\u201304:30","dark_hours":5.96,"date":"2026-08-03","moon_free_dark_hours":0.32,"moon_illumination":73,"moon_separation":45.5,"score":11,"score_astronomy":11,"score_weather":100,"transit_alt":72.5,"transit_local":"08:20","verdict":"poor","weather_source":"history","weekday":"Mon"},{"best_hours":1.58,"best_label":"marginal","best_window":"02:55\u201304:30","dark_hours":6.01,"date":"2026-08-04","moon_free_dark_hours":0.75,"moon_illumination":63,"moon_separation":32.0,"score":11,"score_astronomy":11,"score_weather":99,"transit_alt":72.5,"transit_local":"08:15","verdict":"poor","weather_source":"history","weekday":"Tue"},{"best_hours":1.75,"best_label":"marginal","best_window":"02:45\u201304:30","dark_hours":6.07,"date":"2026-08-05","moon_free_dark_hours":1.23,"moon_illumination":52,"moon_separation":18.3,"score":16,"score_astronomy":16,"score_weather":97,"transit_alt":72.5,"transit_local":"08:10","verdict":"poor","weather_source":"history","weekday":"Wed"},{"best_hours":1.0,"best_label":"good","best_window":"03:35\u201304:35","dark_hours":6.13,"date":"2026-08-06","moon_free_dark_hours":1.87,"moon_illumination":40,"moon_separation":4.4,"score":21,"score_astronomy":22,"score_weather":97,"transit_alt":72.5,"transit_local":"08:05","verdict":"poor","weather_source":"history","weekday":"Thu"},{"best_hours":1.42,"best_label":"good","best_window":"03:10\u201304:35","dark_hours":6.18,"date":"2026-08-07","moon_free_dark_hours":2.67,"moon_illumination":30,"moon_separation":10.0,"score":29,"score_astronomy":29,"score_weather":100,"transit_alt":72.5,"transit_local":"08:00","verdict":"poor","weather_source":"history","weekday":"Fri"},{"best_hours":2.17,"best_label":"marginal","best_window":"02:25\u201304:35","dark_hours":6.24,"date":"2026-08-08","moon_free_dark_hours":3.67,"moon_illumination":19,"moon_separation":24.5,"score":23,"score_astronomy":36,"score_weather":63,"transit_alt":72.5,"transit_local":"08:00","verdict":"poor","weather_source":"history","weekday":"Sat"},{"best_hours":1.75,"best_label":"good","best_window":"02:55\u201304:40","dark_hours":6.3,"date":"2026-08-09","moon_free_dark_hours":4.88,"moon_illumination":11,"moon_separation":39.1,"score":44,"score_astronomy":44,"score_weather":99,"transit_alt":72.5,"transit_local":"07:55","verdict":"marginal","weather_source":"history","weekday":"Sun"},{"best_hours":1.92,"best_label":"good","best_window":"02:45\u201304:40","dark_hours":6.35,"date":"2026-08-10","moon_free_dark_hours":6.22,"moon_illumination":5,"moon_separation":53.9,"score":49,"score_astronomy":49,"score_weather":100,"transit_alt":72.5,"transit_local":"07:50","verdict":"marginal","weather_source":"history","weekday":"Mon"},{"best_hours":2.0,"best_label":"good","best_window":"02:40\u201304:40","dark_hours":6.41,"date":"2026-08-11","moon_free_dark_hours":6.38,"moon_illumination":1,"moon_separation":68.6,"score":52,"score_astronomy":52,"score_weather":100,"transit_alt":72.5,"transit_local":"07:45","verdict":"marginal","weather_source":"history","weekday":"Tue"},{"best_hours":2.08,"best_label":"good","best_window":"02:40\u201304:45","dark_hours":6.47,"date":"2026-08-12","moon_free_dark_hours":6.45,"moon_illumination":0,"moon_separation":83.1,"score":55,"score_astronomy":55,"score_weather":100,"transit_alt":72.5,"transit_local":"07:40","verdict":"marginal","weather_source":"history","weekday":"Wed"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":6.53,"date":"2026-08-13","moon_free_dark_hours":6.5,"moon_illumination":2,"moon_separation":97.4,"score":0,"score_astronomy":57,"score_weather":0,"transit_alt":72.5,"transit_local":"07:40","verdict":"unusable","weather_source":"history","weekday":"Thu"},{"best_hours":0.75,"best_label":"good","best_window":"04:00\u201304:45","dark_hours":6.58,"date":"2026-08-14","moon_free_dark_hours":6.57,"moon_illumination":6,"moon_separation":111.3,"score":27,"score_astronomy":59,"score_weather":46,"transit_alt":72.5,"transit_local":"07:35","verdict":"poor","weather_source":"history","weekday":"Fri"},{"best_hours":2.33,"best_label":"good","best_window":"02:25\u201304:45","dark_hours":6.64,"date":"2026-08-15","moon_free_dark_hours":6.62,"moon_illumination":12,"moon_separation":124.9,"score":61,"score_astronomy":61,"score_weather":100,"transit_alt":72.5,"transit_local":"07:30","verdict":"marginal","weather_source":"history","weekday":"Sat"},{"best_hours":2.5,"best_label":"good","best_window":"02:20\u201304:50","dark_hours":6.7,"date":"2026-08-16","moon_free_dark_hours":6.68,"moon_illumination":20,"moon_separation":138.0,"score":65,"score_astronomy":65,"score_weather":100,"transit_alt":72.5,"transit_local":"07:25","verdict":"marginal","weather_source":"history","weekday":"Sun"},{"best_hours":2.58,"best_label":"good","best_window":"02:15\u201304:50","dark_hours":6.76,"date":"2026-08-17","moon_free_dark_hours":6.55,"moon_illumination":29,"moon_separation":150.7,"score":67,"score_astronomy":67,"score_weather":100,"transit_alt":72.5,"transit_local":"07:25","verdict":"marginal","weather_source":"history","weekday":"Mon"},{"best_hours":1.25,"best_label":"marginal","best_window":"01:45\u201303:00","dark_hours":6.81,"date":"2026-08-18","moon_free_dark_hours":6.15,"moon_illumination":39,"moon_separation":163.0,"score":23,"score_astronomy":69,"score_weather":33,"transit_alt":72.5,"transit_local":"07:20","verdict":"poor","weather_source":"history","weekday":"Tue"},{"best_hours":2.75,"best_label":"good","best_window":"02:10\u201304:55","dark_hours":6.87,"date":"2026-08-19","moon_free_dark_hours":5.68,"moon_illumination":48,"moon_separation":175.0,"score":72,"score_astronomy":72,"score_weather":100,"transit_alt":72.5,"transit_local":"07:15","verdict":"good","weather_source":"history","weekday":"Wed"},{"best_hours":2.83,"best_label":"good","best_window":"02:05\u201304:55","dark_hours":6.93,"date":"2026-08-20","moon_free_dark_hours":5.12,"moon_illumination":58,"moon_separation":172.8,"score":74,"score_astronomy":74,"score_weather":100,"transit_alt":72.5,"transit_local":"07:10","verdict":"good","weather_source":"history","weekday":"Thu"},{"best_hours":2.92,"best_label":"good","best_window":"02:00\u201304:55","dark_hours":6.99,"date":"2026-08-21","moon_free_dark_hours":4.42,"moon_illumination":67,"moon_separation":161.0,"score":77,"score_astronomy":77,"score_weather":100,"transit_alt":72.5,"transit_local":"07:05","verdict":"good","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":"2026-07-23","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"}}