{"calculation_version":"2026-10-10.1","days":30,"nights":[{"best_hours":6.42,"best_label":"marginal","best_window":"22:15\u201304:40","dark_hours":6.43,"date":"2025-08-11","moon_free_dark_hours":0.0,"moon_illumination":92,"moon_separation":46.5,"score":39,"score_astronomy":39,"score_weather":100,"transit_alt":89.5,"transit_local":"04:40","verdict":"poor","weather_source":"history","weekday":"Mon"},{"best_hours":6.5,"best_label":"marginal","best_window":"22:15\u201304:45","dark_hours":6.48,"date":"2025-08-12","moon_free_dark_hours":0.0,"moon_illumination":84,"moon_separation":37.2,"score":40,"score_astronomy":40,"score_weather":100,"transit_alt":89.6,"transit_local":"04:40","verdict":"marginal","weather_source":"history","weekday":"Tue"},{"best_hours":6.58,"best_label":"marginal","best_window":"22:10\u201304:45","dark_hours":6.54,"date":"2025-08-13","moon_free_dark_hours":0.3,"moon_illumination":75,"moon_separation":31.2,"score":51,"score_astronomy":51,"score_weather":100,"transit_alt":89.7,"transit_local":"04:35","verdict":"marginal","weather_source":"history","weekday":"Wed"},{"best_hours":0.33,"best_label":"good","best_window":"22:35\u201322:55","dark_hours":6.6,"date":"2025-08-14","moon_free_dark_hours":0.77,"moon_illumination":65,"moon_separation":30.3,"score":63,"score_astronomy":76,"score_weather":82,"transit_alt":89.7,"transit_local":"04:30","verdict":"marginal","weather_source":"history","weekday":"Thu"},{"best_hours":6.42,"best_label":"good","best_window":"22:25\u201304:50","dark_hours":6.66,"date":"2025-08-15","moon_free_dark_hours":1.32,"moon_illumination":53,"moon_separation":35.2,"score":83,"score_astronomy":83,"score_weather":100,"transit_alt":89.6,"transit_local":"04:25","verdict":"good","weather_source":"history","weekday":"Fri"},{"best_hours":6.5,"best_label":"good","best_window":"22:20\u201304:50","dark_hours":6.71,"date":"2025-08-16","moon_free_dark_hours":1.97,"moon_illumination":42,"moon_separation":43.8,"score":87,"score_astronomy":88,"score_weather":99,"transit_alt":89.5,"transit_local":"04:20","verdict":"good","weather_source":"history","weekday":"Sat"},{"best_hours":6.42,"best_label":"good","best_window":"22:25\u201304:50","dark_hours":6.77,"date":"2025-08-17","moon_free_dark_hours":2.82,"moon_illumination":31,"moon_separation":54.2,"score":90,"score_astronomy":94,"score_weather":96,"transit_alt":89.6,"transit_local":"04:20","verdict":"good","weather_source":"history","weekday":"Sun"},{"best_hours":1.0,"best_label":"good","best_window":"01:00\u201302:00","dark_hours":6.83,"date":"2025-08-18","moon_free_dark_hours":3.85,"moon_illumination":21,"moon_separation":65.6,"score":41,"score_astronomy":100,"score_weather":41,"transit_alt":89.7,"transit_local":"04:15","verdict":"marginal","weather_source":"history","weekday":"Mon"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":6.89,"date":"2025-08-19","moon_free_dark_hours":5.03,"moon_illumination":13,"moon_separation":77.4,"score":0,"score_astronomy":100,"score_weather":0,"transit_alt":89.7,"transit_local":"04:10","verdict":"unusable","weather_source":"history","weekday":"Tue"},{"best_hours":6.83,"best_label":"good","best_window":"22:05\u201304:55","dark_hours":6.94,"date":"2025-08-20","moon_free_dark_hours":6.28,"moon_illumination":6,"moon_separation":89.2,"score":100,"score_astronomy":100,"score_weather":100,"transit_alt":89.6,"transit_local":"04:05","verdict":"good","weather_source":"history","weekday":"Wed"},{"best_hours":6.92,"best_label":"good","best_window":"22:00\u201304:55","dark_hours":7.0,"date":"2025-08-21","moon_free_dark_hours":6.98,"moon_illumination":2,"moon_separation":100.9,"score":100,"score_astronomy":100,"score_weather":100,"transit_alt":89.5,"transit_local":"04:05","verdict":"good","weather_source":"history","weekday":"Thu"},{"best_hours":6.58,"best_label":"good","best_window":"22:25\u201305:00","dark_hours":7.06,"date":"2025-08-22","moon_free_dark_hours":7.03,"moon_illumination":0,"moon_separation":112.2,"score":97,"score_astronomy":100,"score_weather":97,"transit_alt":89.6,"transit_local":"04:00","verdict":"good","weather_source":"history","weekday":"Fri"},{"best_hours":5.0,"best_label":"good","best_window":"00:00\u201305:00","dark_hours":7.12,"date":"2025-08-23","moon_free_dark_hours":7.1,"moon_illumination":0,"moon_separation":122.9,"score":86,"score_astronomy":100,"score_weather":86,"transit_alt":89.7,"transit_local":"03:55","verdict":"good","weather_source":"history","weekday":"Sat"},{"best_hours":7.0,"best_label":"good","best_window":"22:00\u201305:00","dark_hours":7.17,"date":"2025-08-24","moon_free_dark_hours":7.15,"moon_illumination":3,"moon_separation":132.7,"score":94,"score_astronomy":100,"score_weather":94,"transit_alt":89.7,"transit_local":"03:50","verdict":"good","weather_source":"history","weekday":"Sun"},{"best_hours":6.08,"best_label":"good","best_window":"23:00\u201305:05","dark_hours":7.23,"date":"2025-08-25","moon_free_dark_hours":7.22,"moon_illumination":7,"moon_separation":141.2,"score":83,"score_astronomy":100,"score_weather":83,"transit_alt":89.5,"transit_local":"03:45","verdict":"good","weather_source":"history","weekday":"Mon"},{"best_hours":4.08,"best_label":"good","best_window":"01:00\u201305:05","dark_hours":7.29,"date":"2025-08-26","moon_free_dark_hours":7.27,"moon_illumination":13,"moon_separation":147.3,"score":57,"score_astronomy":100,"score_weather":57,"transit_alt":89.6,"transit_local":"03:45","verdict":"marginal","weather_source":"history","weekday":"Tue"},{"best_hours":7.33,"best_label":"good","best_window":"21:45\u201305:05","dark_hours":7.34,"date":"2025-08-27","moon_free_dark_hours":7.32,"moon_illumination":20,"moon_separation":150.0,"score":100,"score_astronomy":100,"score_weather":100,"transit_alt":89.7,"transit_local":"03:40","verdict":"good","weather_source":"history","weekday":"Wed"},{"best_hours":7.33,"best_label":"good","best_window":"21:45\u201305:05","dark_hours":7.4,"date":"2025-08-28","moon_free_dark_hours":7.1,"moon_illumination":28,"moon_separation":148.6,"score":100,"score_astronomy":100,"score_weather":100,"transit_alt":89.7,"transit_local":"03:35","verdict":"good","weather_source":"history","weekday":"Thu"},{"best_hours":7.5,"best_label":"good","best_window":"21:40\u201305:10","dark_hours":7.46,"date":"2025-08-29","moon_free_dark_hours":6.7,"moon_illumination":37,"moon_separation":143.5,"score":100,"score_astronomy":100,"score_weather":100,"transit_alt":89.6,"transit_local":"03:30","verdict":"good","weather_source":"history","weekday":"Fri"},{"best_hours":5.0,"best_label":"good","best_window":"23:00\u201304:00","dark_hours":7.51,"date":"2025-08-30","moon_free_dark_hours":6.2,"moon_illumination":47,"moon_separation":136.0,"score":61,"score_astronomy":100,"score_weather":61,"transit_alt":89.5,"transit_local":"03:25","verdict":"marginal","weather_source":"history","weekday":"Sat"},{"best_hours":7.58,"best_label":"good","best_window":"21:35\u201305:10","dark_hours":7.57,"date":"2025-08-31","moon_free_dark_hours":5.57,"moon_illumination":56,"moon_separation":127.2,"score":100,"score_astronomy":100,"score_weather":100,"transit_alt":89.6,"transit_local":"03:25","verdict":"good","weather_source":"history","weekday":"Sun"},{"best_hours":7.17,"best_label":"good","best_window":"22:00\u201305:10","dark_hours":7.62,"date":"2025-09-01","moon_free_dark_hours":4.78,"moon_illumination":66,"moon_separation":117.4,"score":97,"score_astronomy":100,"score_weather":97,"transit_alt":89.7,"transit_local":"03:20","verdict":"good","weather_source":"history","weekday":"Mon"},{"best_hours":7.67,"best_label":"good","best_window":"21:35\u201305:15","dark_hours":7.68,"date":"2025-09-02","moon_free_dark_hours":3.85,"moon_illumination":75,"moon_separation":107.0,"score":100,"score_astronomy":100,"score_weather":100,"transit_alt":89.7,"transit_local":"03:15","verdict":"good","weather_source":"history","weekday":"Tue"},{"best_hours":1.0,"best_label":"good","best_window":"02:00\u201303:00","dark_hours":7.74,"date":"2025-09-03","moon_free_dark_hours":2.75,"moon_illumination":83,"moon_separation":96.1,"score":38,"score_astronomy":100,"score_weather":38,"transit_alt":89.6,"transit_local":"03:10","verdict":"poor","weather_source":"history","weekday":"Wed"},{"best_hours":1.25,"best_label":"good","best_window":"04:00\u201305:15","dark_hours":7.79,"date":"2025-09-04","moon_free_dark_hours":1.57,"moon_illumination":90,"moon_separation":84.8,"score":40,"score_astronomy":100,"score_weather":40,"transit_alt":89.5,"transit_local":"03:10","verdict":"marginal","weather_source":"history","weekday":"Thu"},{"best_hours":0.08,"best_label":"good","best_window":"04:55\u201305:00","dark_hours":7.85,"date":"2025-09-05","moon_free_dark_hours":0.37,"moon_illumination":96,"moon_separation":73.2,"score":14,"score_astronomy":100,"score_weather":14,"transit_alt":89.6,"transit_local":"03:05","verdict":"poor","weather_source":"history","weekday":"Fri"},{"best_hours":0.33,"best_label":"good","best_window":"05:00\u201305:20","dark_hours":7.9,"date":"2025-09-06","moon_free_dark_hours":0.0,"moon_illumination":99,"moon_separation":61.6,"score":59,"score_astronomy":67,"score_weather":88,"transit_alt":89.7,"transit_local":"03:00","verdict":"marginal","weather_source":"history","weekday":"Sat"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":7.96,"date":"2025-09-07","moon_free_dark_hours":0.0,"moon_illumination":100,"moon_separation":50.3,"score":0,"score_astronomy":55,"score_weather":0,"transit_alt":89.7,"transit_local":"02:55","verdict":"unusable","weather_source":"history","weekday":"Sun"},{"best_hours":4.33,"best_label":"marginal","best_window":"01:00\u201305:20","dark_hours":8.01,"date":"2025-09-08","moon_free_dark_hours":0.0,"moon_illumination":98,"moon_separation":40.1,"score":22,"score_astronomy":40,"score_weather":55,"transit_alt":89.5,"transit_local":"02:50","verdict":"poor","weather_source":"history","weekday":"Mon"},{"best_hours":8.08,"best_label":"marginal","best_window":"21:20\u201305:25","dark_hours":8.06,"date":"2025-09-09","moon_free_dark_hours":0.0,"moon_illumination":94,"moon_separation":32.6,"score":38,"score_astronomy":39,"score_weather":98,"transit_alt":89.5,"transit_local":"02:50","verdict":"poor","weather_source":"history","weekday":"Tue"}],"note":"score_astronomy for every night; score_weather/score only where a forecast (next 4 days) or ERA5 history exists \u2014 null otherwise","start":"2025-08-11","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}}