{"calculation_version":"2026-10-10.1","days":30,"nights":[{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":11.51,"date":"2025-12-20","moon_free_dark_hours":11.5,"moon_illumination":1,"moon_separation":143.5,"score":0,"score_astronomy":89,"score_weather":0,"transit_alt":42.9,"transit_local":"00:00","verdict":"unusable","weather_source":"history","weekday":"Sat"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":11.51,"date":"2025-12-21","moon_free_dark_hours":11.48,"moon_illumination":3,"moon_separation":137.8,"score":0,"score_astronomy":89,"score_weather":0,"transit_alt":42.9,"transit_local":"23:55","verdict":"unusable","weather_source":"history","weekday":"Sun"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":11.51,"date":"2025-12-22","moon_free_dark_hours":11.2,"moon_illumination":8,"moon_separation":129.9,"score":0,"score_astronomy":89,"score_weather":0,"transit_alt":42.9,"transit_local":"23:50","verdict":"unusable","weather_source":"history","weekday":"Mon"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":11.51,"date":"2025-12-23","moon_free_dark_hours":10.08,"moon_illumination":14,"moon_separation":120.8,"score":0,"score_astronomy":89,"score_weather":0,"transit_alt":42.9,"transit_local":"23:45","verdict":"unusable","weather_source":"history","weekday":"Tue"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":11.5,"date":"2025-12-24","moon_free_dark_hours":8.95,"moon_illumination":21,"moon_separation":110.7,"score":0,"score_astronomy":89,"score_weather":0,"transit_alt":42.9,"transit_local":"23:45","verdict":"unusable","weather_source":"history","weekday":"Wed"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":11.5,"date":"2025-12-25","moon_free_dark_hours":7.82,"moon_illumination":30,"moon_separation":100.2,"score":0,"score_astronomy":89,"score_weather":0,"transit_alt":42.9,"transit_local":"23:40","verdict":"unusable","weather_source":"history","weekday":"Thu"},{"best_hours":1.0,"best_label":"marginal","best_window":"21:00\u201322:00","dark_hours":11.5,"date":"2025-12-26","moon_free_dark_hours":6.68,"moon_illumination":41,"moon_separation":89.2,"score":19,"score_astronomy":89,"score_weather":22,"transit_alt":42.9,"transit_local":"23:35","verdict":"poor","weather_source":"history","weekday":"Fri"},{"best_hours":6.17,"best_label":"good","best_window":"20:40\u201302:50","dark_hours":11.49,"date":"2025-12-27","moon_free_dark_hours":5.53,"moon_illumination":51,"moon_separation":77.9,"score":87,"score_astronomy":87,"score_weather":100,"transit_alt":42.9,"transit_local":"23:30","verdict":"good","weather_source":"history","weekday":"Sat"},{"best_hours":2.75,"best_label":"good","best_window":"00:00\u201302:45","dark_hours":11.48,"date":"2025-12-28","moon_free_dark_hours":4.32,"moon_illumination":62,"moon_separation":66.6,"score":65,"score_astronomy":82,"score_weather":79,"transit_alt":42.9,"transit_local":"23:25","verdict":"marginal","weather_source":"history","weekday":"Sun"},{"best_hours":7.33,"best_label":"marginal","best_window":"19:55\u201303:15","dark_hours":11.48,"date":"2025-12-29","moon_free_dark_hours":3.05,"moon_illumination":73,"moon_separation":55.6,"score":57,"score_astronomy":57,"score_weather":100,"transit_alt":42.9,"transit_local":"23:25","verdict":"marginal","weather_source":"history","weekday":"Mon"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":11.47,"date":"2025-12-30","moon_free_dark_hours":1.72,"moon_illumination":83,"moon_separation":45.5,"score":1,"score_astronomy":36,"score_weather":3,"transit_alt":42.9,"transit_local":"23:20","verdict":"poor","weather_source":"history","weekday":"Tue"},{"best_hours":1.0,"best_label":"marginal","best_window":"01:00\u201302:00","dark_hours":11.46,"date":"2025-12-31","moon_free_dark_hours":0.4,"moon_illumination":91,"moon_separation":37.6,"score":9,"score_astronomy":20,"score_weather":44,"transit_alt":42.9,"transit_local":"23:15","verdict":"poor","weather_source":"history","weekday":"Wed"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":11.45,"date":"2026-01-01","moon_free_dark_hours":0.0,"moon_illumination":97,"moon_separation":33.7,"score":12,"score_astronomy":12,"score_weather":100,"transit_alt":42.9,"transit_local":"23:10","verdict":"poor","weather_source":"history","weekday":"Thu"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":11.44,"date":"2026-01-02","moon_free_dark_hours":0.0,"moon_illumination":100,"moon_separation":35.5,"score":9,"score_astronomy":12,"score_weather":76,"transit_alt":42.9,"transit_local":"23:10","verdict":"poor","weather_source":"history","weekday":"Fri"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":11.43,"date":"2026-01-03","moon_free_dark_hours":0.0,"moon_illumination":100,"moon_separation":42.0,"score":0,"score_astronomy":19,"score_weather":0,"transit_alt":42.9,"transit_local":"23:05","verdict":"unusable","weather_source":"history","weekday":"Sat"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":11.42,"date":"2026-01-04","moon_free_dark_hours":0.0,"moon_illumination":97,"moon_separation":51.4,"score":0,"score_astronomy":33,"score_weather":0,"transit_alt":42.9,"transit_local":"23:00","verdict":"unusable","weather_source":"history","weekday":"Sun"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":11.4,"date":"2026-01-05","moon_free_dark_hours":0.88,"moon_illumination":92,"moon_separation":62.0,"score":4,"score_astronomy":52,"score_weather":7,"transit_alt":42.9,"transit_local":"22:55","verdict":"poor","weather_source":"history","weekday":"Mon"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":11.39,"date":"2026-01-06","moon_free_dark_hours":2.1,"moon_illumination":84,"moon_separation":73.0,"score":0,"score_astronomy":84,"score_weather":0,"transit_alt":42.9,"transit_local":"22:50","verdict":"unusable","weather_source":"history","weekday":"Tue"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":11.37,"date":"2026-01-07","moon_free_dark_hours":3.23,"moon_illumination":76,"moon_separation":83.9,"score":0,"score_astronomy":88,"score_weather":0,"transit_alt":42.9,"transit_local":"22:50","verdict":"unusable","weather_source":"history","weekday":"Wed"},{"best_hours":2.67,"best_label":"good","best_window":"23:00\u201301:40","dark_hours":11.36,"date":"2026-01-08","moon_free_dark_hours":4.32,"moon_illumination":67,"moon_separation":94.6,"score":54,"score_astronomy":89,"score_weather":60,"transit_alt":42.9,"transit_local":"22:45","verdict":"marginal","weather_source":"history","weekday":"Thu"},{"best_hours":2.0,"best_label":"good","best_window":"21:00\u201323:00","dark_hours":11.34,"date":"2026-01-09","moon_free_dark_hours":5.4,"moon_illumination":57,"moon_separation":104.9,"score":38,"score_astronomy":89,"score_weather":43,"transit_alt":42.9,"transit_local":"22:40","verdict":"poor","weather_source":"history","weekday":"Fri"},{"best_hours":1.0,"best_label":"good","best_window":"21:00\u201322:00","dark_hours":11.32,"date":"2026-01-10","moon_free_dark_hours":6.43,"moon_illumination":47,"moon_separation":114.8,"score":36,"score_astronomy":89,"score_weather":40,"transit_alt":42.9,"transit_local":"22:35","verdict":"poor","weather_source":"history","weekday":"Sat"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":11.31,"date":"2026-01-11","moon_free_dark_hours":7.48,"moon_illumination":38,"moon_separation":124.0,"score":0,"score_astronomy":89,"score_weather":0,"transit_alt":42.9,"transit_local":"22:30","verdict":"unusable","weather_source":"history","weekday":"Sun"},{"best_hours":6.5,"best_label":"good","best_window":"19:15\u201301:45","dark_hours":11.29,"date":"2026-01-12","moon_free_dark_hours":8.53,"moon_illumination":29,"moon_separation":132.3,"score":88,"score_astronomy":89,"score_weather":99,"transit_alt":42.9,"transit_local":"22:30","verdict":"good","weather_source":"history","weekday":"Mon"},{"best_hours":1.0,"best_label":"marginal","best_window":"23:00\u201300:00","dark_hours":11.27,"date":"2026-01-13","moon_free_dark_hours":9.57,"moon_illumination":21,"moon_separation":139.4,"score":12,"score_astronomy":89,"score_weather":14,"transit_alt":42.9,"transit_local":"22:25","verdict":"poor","weather_source":"history","weekday":"Tue"},{"best_hours":6.5,"best_label":"good","best_window":"19:10\u201301:40","dark_hours":11.25,"date":"2026-01-14","moon_free_dark_hours":10.57,"moon_illumination":14,"moon_separation":144.4,"score":89,"score_astronomy":89,"score_weather":100,"transit_alt":42.9,"transit_local":"22:20","verdict":"good","weather_source":"history","weekday":"Wed"},{"best_hours":4.0,"best_label":"good","best_window":"19:00\u201323:00","dark_hours":11.23,"date":"2026-01-15","moon_free_dark_hours":11.22,"moon_illumination":8,"moon_separation":146.3,"score":77,"score_astronomy":89,"score_weather":87,"transit_alt":42.9,"transit_local":"22:15","verdict":"good","weather_source":"history","weekday":"Thu"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":11.2,"date":"2026-01-16","moon_free_dark_hours":11.18,"moon_illumination":4,"moon_separation":144.6,"score":0,"score_astronomy":89,"score_weather":0,"transit_alt":42.9,"transit_local":"22:15","verdict":"unusable","weather_source":"history","weekday":"Fri"},{"best_hours":3.0,"best_label":"good","best_window":"21:00\u201300:00","dark_hours":11.18,"date":"2026-01-17","moon_free_dark_hours":11.17,"moon_illumination":1,"moon_separation":139.6,"score":67,"score_astronomy":89,"score_weather":76,"transit_alt":42.9,"transit_local":"22:10","verdict":"marginal","weather_source":"history","weekday":"Sat"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":11.16,"date":"2026-01-18","moon_free_dark_hours":11.15,"moon_illumination":0,"moon_separation":132.1,"score":0,"score_astronomy":89,"score_weather":0,"transit_alt":42.9,"transit_local":"22:05","verdict":"unusable","weather_source":"history","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":"2025-12-20","target":{"common_name":"Great Orion Nebula","dec":-5.3876,"name":"M 42","ra":83.8201,"simbad_url":"https://simbad.cds.unistra.fr/simbad/sim-id?Ident=M42","source":"sesame","type":"HII","type_text":"HII region \u2014 a star-forming nebula"}}