{"calculation_version":"2026-10-10.1","days":30,"nights":[{"best_hours":8.75,"best_label":"good","best_window":"21:00\u201305:45","dark_hours":8.92,"date":"2031-09-26","moon_free_dark_hours":2.57,"moon_illumination":81,"moon_separation":75.5,"score":null,"score_astronomy":100,"score_weather":null,"transit_alt":89.6,"transit_local":"01:45","verdict":"unknown","weather_source":"none","weekday":"Fri"},{"best_hours":5.83,"best_label":"good","best_window":"23:55\u201305:45","dark_hours":8.97,"date":"2031-09-27","moon_free_dark_hours":1.38,"moon_illumination":89,"moon_separation":63.5,"score":null,"score_astronomy":100,"score_weather":null,"transit_alt":89.7,"transit_local":"01:40","verdict":"unknown","weather_source":"none","weekday":"Sat"},{"best_hours":1.92,"best_label":"good","best_window":"03:50\u201305:45","dark_hours":9.02,"date":"2031-09-28","moon_free_dark_hours":0.22,"moon_illumination":95,"moon_separation":52.1,"score":null,"score_astronomy":91,"score_weather":null,"transit_alt":89.7,"transit_local":"01:35","verdict":"unknown","weather_source":"none","weekday":"Sun"},{"best_hours":9.08,"best_label":"marginal","best_window":"20:40\u201305:45","dark_hours":9.07,"date":"2031-09-29","moon_free_dark_hours":0.0,"moon_illumination":99,"moon_separation":42.1,"score":null,"score_astronomy":52,"score_weather":null,"transit_alt":89.6,"transit_local":"01:30","verdict":"unknown","weather_source":"none","weekday":"Mon"},{"best_hours":9.08,"best_label":"marginal","best_window":"20:40\u201305:45","dark_hours":9.12,"date":"2031-09-30","moon_free_dark_hours":0.0,"moon_illumination":100,"moon_separation":34.7,"score":null,"score_astronomy":37,"score_weather":null,"transit_alt":89.5,"transit_local":"01:30","verdict":"unknown","weather_source":"none","weekday":"Tue"},{"best_hours":3.92,"best_label":"marginal","best_window":"20:40\u201300:35","dark_hours":9.17,"date":"2031-10-01","moon_free_dark_hours":0.0,"moon_illumination":98,"moon_separation":31.4,"score":null,"score_astronomy":36,"score_weather":null,"transit_alt":89.7,"transit_local":"01:25","verdict":"unknown","weather_source":"none","weekday":"Wed"},{"best_hours":9.25,"best_label":"marginal","best_window":"20:35\u201305:50","dark_hours":9.22,"date":"2031-10-02","moon_free_dark_hours":0.0,"moon_illumination":95,"moon_separation":33.2,"score":null,"score_astronomy":47,"score_weather":null,"transit_alt":89.7,"transit_local":"01:20","verdict":"unknown","weather_source":"none","weekday":"Thu"},{"best_hours":9.83,"best_label":"marginal","best_window":"20:00\u201305:50","dark_hours":9.27,"date":"2031-10-03","moon_free_dark_hours":0.0,"moon_illumination":89,"moon_separation":39.1,"score":null,"score_astronomy":58,"score_weather":null,"transit_alt":89.7,"transit_local":"01:15","verdict":"unknown","weather_source":"none","weekday":"Fri"},{"best_hours":3.25,"best_label":"good","best_window":"20:35\u201323:50","dark_hours":9.31,"date":"2031-10-04","moon_free_dark_hours":0.72,"moon_illumination":82,"moon_separation":47.3,"score":null,"score_astronomy":90,"score_weather":null,"transit_alt":89.6,"transit_local":"01:10","verdict":"unknown","weather_source":"none","weekday":"Sat"},{"best_hours":6.42,"best_label":"good","best_window":"20:30\u201302:55","dark_hours":9.36,"date":"2031-10-05","moon_free_dark_hours":1.52,"moon_illumination":73,"moon_separation":56.6,"score":null,"score_astronomy":97,"score_weather":null,"transit_alt":89.5,"transit_local":"01:10","verdict":"unknown","weather_source":"none","weekday":"Sun"},{"best_hours":8.75,"best_label":"good","best_window":"20:30\u201305:15","dark_hours":9.41,"date":"2031-10-06","moon_free_dark_hours":2.37,"moon_illumination":64,"moon_separation":66.4,"score":null,"score_astronomy":100,"score_weather":null,"transit_alt":89.7,"transit_local":"01:05","verdict":"unknown","weather_source":"none","weekday":"Mon"},{"best_hours":9.42,"best_label":"good","best_window":"20:30\u201305:55","dark_hours":9.45,"date":"2031-10-07","moon_free_dark_hours":3.28,"moon_illumination":55,"moon_separation":76.3,"score":null,"score_astronomy":100,"score_weather":null,"transit_alt":89.7,"transit_local":"01:00","verdict":"unknown","weather_source":"none","weekday":"Tue"},{"best_hours":9.5,"best_label":"good","best_window":"20:25\u201305:55","dark_hours":9.5,"date":"2031-10-08","moon_free_dark_hours":4.23,"moon_illumination":46,"moon_separation":86.4,"score":null,"score_astronomy":100,"score_weather":null,"transit_alt":89.7,"transit_local":"00:55","verdict":"unknown","weather_source":"none","weekday":"Wed"},{"best_hours":9.5,"best_label":"good","best_window":"20:25\u201305:55","dark_hours":9.54,"date":"2031-10-09","moon_free_dark_hours":5.18,"moon_illumination":36,"moon_separation":96.5,"score":null,"score_astronomy":100,"score_weather":null,"transit_alt":89.5,"transit_local":"00:50","verdict":"unknown","weather_source":"none","weekday":"Thu"},{"best_hours":9.58,"best_label":"good","best_window":"20:25\u201306:00","dark_hours":9.59,"date":"2031-10-10","moon_free_dark_hours":6.18,"moon_illumination":27,"moon_separation":106.6,"score":null,"score_astronomy":100,"score_weather":null,"transit_alt":89.6,"transit_local":"00:50","verdict":"unknown","weather_source":"none","weekday":"Fri"},{"best_hours":9.67,"best_label":"good","best_window":"20:20\u201306:00","dark_hours":9.64,"date":"2031-10-11","moon_free_dark_hours":7.18,"moon_illumination":19,"moon_separation":116.6,"score":null,"score_astronomy":100,"score_weather":null,"transit_alt":89.7,"transit_local":"00:45","verdict":"unknown","weather_source":"none","weekday":"Sat"},{"best_hours":9.67,"best_label":"good","best_window":"20:20\u201306:00","dark_hours":9.68,"date":"2031-10-12","moon_free_dark_hours":8.2,"moon_illumination":12,"moon_separation":126.3,"score":null,"score_astronomy":100,"score_weather":null,"transit_alt":89.7,"transit_local":"00:40","verdict":"unknown","weather_source":"none","weekday":"Sun"},{"best_hours":9.67,"best_label":"good","best_window":"20:20\u201306:00","dark_hours":9.72,"date":"2031-10-13","moon_free_dark_hours":9.25,"moon_illumination":6,"moon_separation":135.3,"score":null,"score_astronomy":100,"score_weather":null,"transit_alt":89.6,"transit_local":"00:35","verdict":"unknown","weather_source":"none","weekday":"Mon"},{"best_hours":9.83,"best_label":"good","best_window":"20:15\u201306:05","dark_hours":9.77,"date":"2031-10-14","moon_free_dark_hours":9.75,"moon_illumination":2,"moon_separation":143.0,"score":null,"score_astronomy":100,"score_weather":null,"transit_alt":89.5,"transit_local":"00:35","verdict":"unknown","weather_source":"none","weekday":"Tue"},{"best_hours":9.83,"best_label":"good","best_window":"20:15\u201306:05","dark_hours":9.81,"date":"2031-10-15","moon_free_dark_hours":9.8,"moon_illumination":0,"moon_separation":147.8,"score":null,"score_astronomy":100,"score_weather":null,"transit_alt":89.6,"transit_local":"00:30","verdict":"unknown","weather_source":"none","weekday":"Wed"},{"best_hours":9.83,"best_label":"good","best_window":"20:15\u201306:05","dark_hours":9.86,"date":"2031-10-16","moon_free_dark_hours":9.83,"moon_illumination":0,"moon_separation":148.2,"score":null,"score_astronomy":100,"score_weather":null,"transit_alt":89.7,"transit_local":"00:25","verdict":"unknown","weather_source":"none","weekday":"Thu"},{"best_hours":9.92,"best_label":"good","best_window":"20:10\u201306:05","dark_hours":9.9,"date":"2031-10-17","moon_free_dark_hours":9.88,"moon_illumination":3,"moon_separation":143.8,"score":null,"score_astronomy":100,"score_weather":null,"transit_alt":89.7,"transit_local":"00:20","verdict":"unknown","weather_source":"none","weekday":"Fri"},{"best_hours":9.92,"best_label":"good","best_window":"20:10\u201306:05","dark_hours":9.94,"date":"2031-10-18","moon_free_dark_hours":9.92,"moon_illumination":8,"moon_separation":135.7,"score":null,"score_astronomy":100,"score_weather":null,"transit_alt":89.6,"transit_local":"00:15","verdict":"unknown","weather_source":"none","weekday":"Sat"},{"best_hours":10.0,"best_label":"good","best_window":"20:10\u201306:10","dark_hours":9.98,"date":"2031-10-19","moon_free_dark_hours":9.45,"moon_illumination":15,"moon_separation":125.6,"score":null,"score_astronomy":100,"score_weather":null,"transit_alt":89.5,"transit_local":"00:15","verdict":"unknown","weather_source":"none","weekday":"Sun"},{"best_hours":10.0,"best_label":"good","best_window":"20:10\u201306:10","dark_hours":10.02,"date":"2031-10-20","moon_free_dark_hours":8.52,"moon_illumination":24,"moon_separation":114.4,"score":null,"score_astronomy":100,"score_weather":null,"transit_alt":89.7,"transit_local":"00:10","verdict":"unknown","weather_source":"none","weekday":"Mon"},{"best_hours":10.08,"best_label":"good","best_window":"20:05\u201306:10","dark_hours":10.07,"date":"2031-10-21","moon_free_dark_hours":7.48,"moon_illumination":34,"moon_separation":102.6,"score":null,"score_astronomy":100,"score_weather":null,"transit_alt":89.7,"transit_local":"00:05","verdict":"unknown","weather_source":"none","weekday":"Tue"},{"best_hours":10.08,"best_label":"good","best_window":"20:05\u201306:10","dark_hours":10.11,"date":"2031-10-22","moon_free_dark_hours":6.37,"moon_illumination":46,"moon_separation":90.5,"score":null,"score_astronomy":100,"score_weather":null,"transit_alt":89.7,"transit_local":"00:00","verdict":"unknown","weather_source":"none","weekday":"Wed"},{"best_hours":10.0,"best_label":"good","best_window":"20:05\u201306:05","dark_hours":10.15,"date":"2031-10-23","moon_free_dark_hours":5.23,"moon_illumination":57,"moon_separation":78.5,"score":null,"score_astronomy":100,"score_weather":null,"transit_alt":89.5,"transit_local":"23:55","verdict":"unknown","weather_source":"none","weekday":"Thu"},{"best_hours":10.0,"best_label":"good","best_window":"20:00\u201306:00","dark_hours":10.19,"date":"2031-10-24","moon_free_dark_hours":4.08,"moon_illumination":68,"moon_separation":66.6,"score":null,"score_astronomy":100,"score_weather":null,"transit_alt":89.6,"transit_local":"23:55","verdict":"unknown","weather_source":"none","weekday":"Fri"},{"best_hours":7.67,"best_label":"good","best_window":"22:20\u201305:00","dark_hours":10.23,"date":"2031-10-25","moon_free_dark_hours":2.95,"moon_illumination":78,"moon_separation":55.4,"score":null,"score_astronomy":94,"score_weather":null,"transit_alt":89.7,"transit_local":"23:50","verdict":"unknown","weather_source":"none","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":"2031-09-26","target":{"common_name":"Andromeda Galaxy","dec":41.26875,"morphology":"SA(s)b","name":"M 31","ra":10.68470833,"simbad_url":"https://simbad.cds.unistra.fr/simbad/sim-id?Ident=M31","source":"sesame","type":"AGN","type_text":"galaxy with an active nucleus","vmag":3.44}}