{"calculation_version":"2026-10-10.1","days":30,"nights":[{"best_hours":1.08,"best_label":"good","best_window":"04:25\u201305:30","dark_hours":8.38,"date":"2025-09-15","moon_free_dark_hours":3.77,"moon_illumination":34,"moon_separation":38.4,"score":23,"score_astronomy":23,"score_weather":100,"transit_alt":42.9,"transit_local":"07:15","verdict":"poor","weather_source":"history","weekday":"Mon"},{"best_hours":1.33,"best_label":"good","best_window":"04:10\u201305:30","dark_hours":8.44,"date":"2025-09-16","moon_free_dark_hours":5.0,"moon_illumination":24,"moon_separation":45.7,"score":29,"score_astronomy":29,"score_weather":100,"transit_alt":42.9,"transit_local":"07:10","verdict":"poor","weather_source":"history","weekday":"Tue"},{"best_hours":1.5,"best_label":"good","best_window":"04:05\u201305:35","dark_hours":8.49,"date":"2025-09-17","moon_free_dark_hours":6.23,"moon_illumination":15,"moon_separation":54.8,"score":32,"score_astronomy":35,"score_weather":92,"transit_alt":42.9,"transit_local":"07:10","verdict":"poor","weather_source":"history","weekday":"Wed"},{"best_hours":1.75,"best_label":"good","best_window":"03:50\u201305:35","dark_hours":8.54,"date":"2025-09-18","moon_free_dark_hours":7.43,"moon_illumination":8,"moon_separation":64.8,"score":39,"score_astronomy":39,"score_weather":100,"transit_alt":42.9,"transit_local":"07:05","verdict":"poor","weather_source":"history","weekday":"Thu"},{"best_hours":1.75,"best_label":"good","best_window":"03:50\u201305:35","dark_hours":8.59,"date":"2025-09-19","moon_free_dark_hours":8.57,"moon_illumination":4,"moon_separation":75.1,"score":42,"score_astronomy":43,"score_weather":97,"transit_alt":42.9,"transit_local":"07:00","verdict":"marginal","weather_source":"history","weekday":"Fri"},{"best_hours":1.83,"best_label":"good","best_window":"03:45\u201305:35","dark_hours":8.64,"date":"2025-09-20","moon_free_dark_hours":8.62,"moon_illumination":1,"moon_separation":85.5,"score":45,"score_astronomy":45,"score_weather":99,"transit_alt":42.9,"transit_local":"06:55","verdict":"marginal","weather_source":"history","weekday":"Sat"},{"best_hours":2.0,"best_label":"good","best_window":"03:40\u201305:40","dark_hours":8.7,"date":"2025-09-21","moon_free_dark_hours":8.68,"moon_illumination":0,"moon_separation":95.9,"score":47,"score_astronomy":47,"score_weather":100,"transit_alt":42.9,"transit_local":"06:55","verdict":"marginal","weather_source":"history","weekday":"Sun"},{"best_hours":2.08,"best_label":"good","best_window":"03:35\u201305:40","dark_hours":8.75,"date":"2025-09-22","moon_free_dark_hours":8.73,"moon_illumination":1,"moon_separation":106.0,"score":48,"score_astronomy":48,"score_weather":100,"transit_alt":42.9,"transit_local":"06:50","verdict":"marginal","weather_source":"history","weekday":"Mon"},{"best_hours":2.17,"best_label":"good","best_window":"03:30\u201305:40","dark_hours":8.8,"date":"2025-09-23","moon_free_dark_hours":8.78,"moon_illumination":4,"moon_separation":115.7,"score":50,"score_astronomy":50,"score_weather":100,"transit_alt":42.9,"transit_local":"06:45","verdict":"marginal","weather_source":"history","weekday":"Tue"},{"best_hours":0.5,"best_label":"good","best_window":"03:30\u201304:00","dark_hours":8.85,"date":"2025-09-24","moon_free_dark_hours":8.83,"moon_illumination":9,"moon_separation":124.8,"score":35,"score_astronomy":52,"score_weather":68,"transit_alt":42.9,"transit_local":"06:40","verdict":"poor","weather_source":"history","weekday":"Wed"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":8.9,"date":"2025-09-25","moon_free_dark_hours":8.88,"moon_illumination":15,"moon_separation":133.0,"score":0,"score_astronomy":53,"score_weather":0,"transit_alt":42.9,"transit_local":"06:35","verdict":"unusable","weather_source":"history","weekday":"Thu"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":8.95,"date":"2025-09-26","moon_free_dark_hours":8.77,"moon_illumination":22,"moon_separation":139.9,"score":3,"score_astronomy":55,"score_weather":6,"transit_alt":42.9,"transit_local":"06:35","verdict":"poor","weather_source":"history","weekday":"Fri"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":9.0,"date":"2025-09-27","moon_free_dark_hours":8.18,"moon_illumination":31,"moon_separation":144.5,"score":0,"score_astronomy":57,"score_weather":0,"transit_alt":42.9,"transit_local":"06:30","verdict":"unusable","weather_source":"history","weekday":"Sat"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":9.05,"date":"2025-09-28","moon_free_dark_hours":7.48,"moon_illumination":40,"moon_separation":146.1,"score":0,"score_astronomy":59,"score_weather":0,"transit_alt":42.9,"transit_local":"06:25","verdict":"unusable","weather_source":"history","weekday":"Sun"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":9.09,"date":"2025-09-29","moon_free_dark_hours":6.62,"moon_illumination":49,"moon_separation":144.0,"score":7,"score_astronomy":60,"score_weather":12,"transit_alt":42.9,"transit_local":"06:20","verdict":"poor","weather_source":"history","weekday":"Mon"},{"best_hours":2.75,"best_label":"good","best_window":"03:05\u201305:50","dark_hours":9.14,"date":"2025-09-30","moon_free_dark_hours":5.6,"moon_illumination":59,"moon_separation":138.7,"score":61,"score_astronomy":63,"score_weather":96,"transit_alt":42.9,"transit_local":"06:15","verdict":"marginal","weather_source":"history","weekday":"Tue"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":9.19,"date":"2025-10-01","moon_free_dark_hours":4.48,"moon_illumination":69,"moon_separation":130.9,"score":0,"score_astronomy":64,"score_weather":0,"transit_alt":42.9,"transit_local":"06:15","verdict":"unusable","weather_source":"history","weekday":"Wed"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":9.24,"date":"2025-10-02","moon_free_dark_hours":3.3,"moon_illumination":78,"moon_separation":121.6,"score":0,"score_astronomy":66,"score_weather":0,"transit_alt":42.9,"transit_local":"06:10","verdict":"unusable","weather_source":"history","weekday":"Thu"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":9.29,"date":"2025-10-03","moon_free_dark_hours":2.1,"moon_illumination":86,"moon_separation":111.0,"score":0,"score_astronomy":65,"score_weather":0,"transit_alt":42.9,"transit_local":"06:05","verdict":"unusable","weather_source":"history","weekday":"Fri"},{"best_hours":2.67,"best_label":"good","best_window":"03:10\u201305:50","dark_hours":9.33,"date":"2025-10-04","moon_free_dark_hours":0.87,"moon_illumination":93,"moon_separation":99.7,"score":61,"score_astronomy":61,"score_weather":100,"transit_alt":42.9,"transit_local":"06:00","verdict":"marginal","weather_source":"history","weekday":"Sat"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":9.38,"date":"2025-10-05","moon_free_dark_hours":0.0,"moon_illumination":98,"moon_separation":87.7,"score":1,"score_astronomy":43,"score_weather":3,"transit_alt":42.9,"transit_local":"05:55","verdict":"poor","weather_source":"history","weekday":"Sun"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":9.43,"date":"2025-10-06","moon_free_dark_hours":0.0,"moon_illumination":100,"moon_separation":75.6,"score":0,"score_astronomy":32,"score_weather":0,"transit_alt":42.9,"transit_local":"05:55","verdict":"unusable","weather_source":"history","weekday":"Mon"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":9.47,"date":"2025-10-07","moon_free_dark_hours":0.0,"moon_illumination":99,"moon_separation":63.6,"score":0,"score_astronomy":22,"score_weather":0,"transit_alt":42.9,"transit_local":"05:50","verdict":"unusable","weather_source":"history","weekday":"Tue"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":9.52,"date":"2025-10-08","moon_free_dark_hours":0.0,"moon_illumination":95,"moon_separation":52.3,"score":0,"score_astronomy":16,"score_weather":0,"transit_alt":42.9,"transit_local":"05:45","verdict":"unusable","weather_source":"history","weekday":"Wed"},{"best_hours":1.0,"best_label":"marginal","best_window":"05:00\u201306:00","dark_hours":9.57,"date":"2025-10-09","moon_free_dark_hours":0.0,"moon_illumination":89,"moon_separation":42.6,"score":12,"score_astronomy":13,"score_weather":94,"transit_alt":42.9,"transit_local":"05:40","verdict":"poor","weather_source":"history","weekday":"Thu"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":9.61,"date":"2025-10-10","moon_free_dark_hours":0.38,"moon_illumination":80,"moon_separation":35.9,"score":1,"score_astronomy":13,"score_weather":10,"transit_alt":42.9,"transit_local":"05:40","verdict":"poor","weather_source":"history","weekday":"Fri"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":9.66,"date":"2025-10-11","moon_free_dark_hours":1.32,"moon_illumination":70,"moon_separation":33.9,"score":1,"score_astronomy":18,"score_weather":4,"transit_alt":42.9,"transit_local":"05:35","verdict":"poor","weather_source":"history","weekday":"Sat"},{"best_hours":2.0,"best_label":"marginal","best_window":"02:00\u201304:00","dark_hours":9.7,"date":"2025-10-12","moon_free_dark_hours":2.43,"moon_illumination":59,"moon_separation":37.0,"score":15,"score_astronomy":28,"score_weather":52,"transit_alt":42.9,"transit_local":"05:30","verdict":"poor","weather_source":"history","weekday":"Sun"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":9.74,"date":"2025-10-13","moon_free_dark_hours":3.63,"moon_illumination":48,"moon_separation":43.7,"score":0,"score_astronomy":42,"score_weather":1,"transit_alt":42.9,"transit_local":"05:25","verdict":"unusable","weather_source":"history","weekday":"Mon"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":9.79,"date":"2025-10-14","moon_free_dark_hours":4.87,"moon_illumination":38,"moon_separation":52.5,"score":0,"score_astronomy":56,"score_weather":0,"transit_alt":42.9,"transit_local":"05:20","verdict":"unusable","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":"2025-09-15","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"}}
