{"calculation_version":"2026-10-10.1","days":30,"nights":[{"best_hours":0.33,"best_label":"marginal","best_window":"04:50\u201305:10","dark_hours":7.5,"date":"2026-08-30","moon_free_dark_hours":0.0,"moon_illumination":92,"moon_separation":76.1,"score":3,"score_astronomy":3,"score_weather":100,"transit_alt":42.9,"transit_local":"08:20","verdict":"poor","weather_source":"history","weekday":"Sun"},{"best_hours":0.33,"best_label":"marginal","best_window":"04:50\u201305:10","dark_hours":7.56,"date":"2026-08-31","moon_free_dark_hours":0.0,"moon_illumination":85,"moon_separation":65.1,"score":3,"score_astronomy":3,"score_weather":100,"transit_alt":42.9,"transit_local":"08:15","verdict":"poor","weather_source":"history","weekday":"Mon"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":7.61,"date":"2026-09-01","moon_free_dark_hours":0.18,"moon_illumination":76,"moon_separation":54.6,"score":3,"score_astronomy":4,"score_weather":75,"transit_alt":42.9,"transit_local":"08:10","verdict":"poor","weather_source":"history","weekday":"Tue"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":7.67,"date":"2026-09-02","moon_free_dark_hours":0.77,"moon_illumination":66,"moon_separation":45.1,"score":0,"score_astronomy":4,"score_weather":0,"transit_alt":42.9,"transit_local":"08:10","verdict":"unusable","weather_source":"history","weekday":"Wed"},{"best_hours":0.42,"best_label":"marginal","best_window":"04:50\u201305:15","dark_hours":7.72,"date":"2026-09-03","moon_free_dark_hours":1.5,"moon_illumination":55,"moon_separation":37.6,"score":5,"score_astronomy":6,"score_weather":76,"transit_alt":42.9,"transit_local":"08:05","verdict":"poor","weather_source":"history","weekday":"Thu"},{"best_hours":0.92,"best_label":"marginal","best_window":"04:20\u201305:15","dark_hours":7.78,"date":"2026-09-04","moon_free_dark_hours":2.42,"moon_illumination":43,"moon_separation":33.7,"score":8,"score_astronomy":8,"score_weather":100,"transit_alt":42.9,"transit_local":"08:00","verdict":"poor","weather_source":"history","weekday":"Fri"},{"best_hours":0.08,"best_label":"good","best_window":"05:10\u201305:15","dark_hours":7.83,"date":"2026-09-05","moon_free_dark_hours":3.52,"moon_illumination":32,"moon_separation":34.9,"score":12,"score_astronomy":12,"score_weather":100,"transit_alt":42.9,"transit_local":"07:55","verdict":"poor","weather_source":"history","weekday":"Sat"},{"best_hours":0.5,"best_label":"good","best_window":"04:50\u201305:20","dark_hours":7.89,"date":"2026-09-06","moon_free_dark_hours":4.78,"moon_illumination":22,"moon_separation":40.7,"score":17,"score_astronomy":17,"score_weather":100,"transit_alt":42.9,"transit_local":"07:50","verdict":"poor","weather_source":"history","weekday":"Sun"},{"best_hours":0.67,"best_label":"good","best_window":"04:40\u201305:20","dark_hours":7.94,"date":"2026-09-07","moon_free_dark_hours":6.1,"moon_illumination":13,"moon_separation":49.5,"score":20,"score_astronomy":20,"score_weather":100,"transit_alt":42.9,"transit_local":"07:50","verdict":"poor","weather_source":"history","weekday":"Mon"},{"best_hours":0.83,"best_label":"good","best_window":"04:30\u201305:20","dark_hours":8.0,"date":"2026-09-08","moon_free_dark_hours":7.42,"moon_illumination":6,"moon_separation":60.0,"score":23,"score_astronomy":23,"score_weather":100,"transit_alt":42.9,"transit_local":"07:45","verdict":"poor","weather_source":"history","weekday":"Tue"},{"best_hours":0.5,"best_label":"good","best_window":"04:30\u201305:00","dark_hours":8.05,"date":"2026-09-09","moon_free_dark_hours":8.05,"moon_illumination":2,"moon_separation":71.3,"score":16,"score_astronomy":26,"score_weather":61,"transit_alt":42.9,"transit_local":"07:40","verdict":"poor","weather_source":"history","weekday":"Wed"},{"best_hours":1.0,"best_label":"good","best_window":"04:25\u201305:25","dark_hours":8.11,"date":"2026-09-10","moon_free_dark_hours":8.1,"moon_illumination":0,"moon_separation":82.7,"score":28,"score_astronomy":28,"score_weather":100,"transit_alt":42.9,"transit_local":"07:35","verdict":"poor","weather_source":"history","weekday":"Thu"},{"best_hours":1.08,"best_label":"good","best_window":"04:20\u201305:25","dark_hours":8.16,"date":"2026-09-11","moon_free_dark_hours":8.13,"moon_illumination":1,"moon_separation":94.1,"score":29,"score_astronomy":29,"score_weather":100,"transit_alt":42.9,"transit_local":"07:35","verdict":"poor","weather_source":"history","weekday":"Fri"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":8.21,"date":"2026-09-12","moon_free_dark_hours":8.18,"moon_illumination":4,"moon_separation":105.2,"score":0,"score_astronomy":30,"score_weather":0,"transit_alt":42.9,"transit_local":"07:30","verdict":"unusable","weather_source":"history","weekday":"Sat"},{"best_hours":1.17,"best_label":"good","best_window":"04:20\u201305:30","dark_hours":8.27,"date":"2026-09-13","moon_free_dark_hours":8.25,"moon_illumination":9,"moon_separation":115.7,"score":32,"score_astronomy":33,"score_weather":96,"transit_alt":42.9,"transit_local":"07:25","verdict":"poor","weather_source":"history","weekday":"Sun"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":8.32,"date":"2026-09-14","moon_free_dark_hours":8.3,"moon_illumination":15,"moon_separation":125.4,"score":0,"score_astronomy":35,"score_weather":0,"transit_alt":42.9,"transit_local":"07:20","verdict":"unusable","weather_source":"history","weekday":"Mon"},{"best_hours":1.42,"best_label":"good","best_window":"04:05\u201305:30","dark_hours":8.37,"date":"2026-09-15","moon_free_dark_hours":8.32,"moon_illumination":23,"moon_separation":134.0,"score":36,"score_astronomy":36,"score_weather":99,"transit_alt":42.9,"transit_local":"07:15","verdict":"poor","weather_source":"history","weekday":"Tue"},{"best_hours":1.5,"best_label":"good","best_window":"04:00\u201305:30","dark_hours":8.42,"date":"2026-09-16","moon_free_dark_hours":7.77,"moon_illumination":32,"moon_separation":140.9,"score":37,"score_astronomy":37,"score_weather":100,"transit_alt":42.9,"transit_local":"07:15","verdict":"poor","weather_source":"history","weekday":"Wed"},{"best_hours":1.58,"best_label":"good","best_window":"03:55\u201305:30","dark_hours":8.48,"date":"2026-09-17","moon_free_dark_hours":7.12,"moon_illumination":41,"moon_separation":145.4,"score":39,"score_astronomy":39,"score_weather":100,"transit_alt":42.9,"transit_local":"07:10","verdict":"poor","weather_source":"history","weekday":"Thu"},{"best_hours":1.67,"best_label":"good","best_window":"03:55\u201305:35","dark_hours":8.53,"date":"2026-09-18","moon_free_dark_hours":6.35,"moon_illumination":51,"moon_separation":146.5,"score":37,"score_astronomy":41,"score_weather":90,"transit_alt":42.9,"transit_local":"07:05","verdict":"poor","weather_source":"history","weekday":"Fri"},{"best_hours":1.5,"best_label":"good","best_window":"04:05\u201305:35","dark_hours":8.58,"date":"2026-09-19","moon_free_dark_hours":5.45,"moon_illumination":60,"moon_separation":144.0,"score":31,"score_astronomy":43,"score_weather":72,"transit_alt":42.9,"transit_local":"07:00","verdict":"poor","weather_source":"history","weekday":"Sat"},{"best_hours":1.83,"best_label":"good","best_window":"03:45\u201305:35","dark_hours":8.63,"date":"2026-09-20","moon_free_dark_hours":4.43,"moon_illumination":69,"moon_separation":138.5,"score":44,"score_astronomy":44,"score_weather":100,"transit_alt":42.9,"transit_local":"06:55","verdict":"marginal","weather_source":"history","weekday":"Sun"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":8.68,"date":"2026-09-21","moon_free_dark_hours":3.37,"moon_illumination":78,"moon_separation":131.0,"score":0,"score_astronomy":45,"score_weather":0,"transit_alt":42.9,"transit_local":"06:55","verdict":"unusable","weather_source":"history","weekday":"Mon"},{"best_hours":1.67,"best_label":"good","best_window":"04:00\u201305:40","dark_hours":8.73,"date":"2026-09-22","moon_free_dark_hours":2.28,"moon_illumination":85,"moon_separation":122.1,"score":38,"score_astronomy":48,"score_weather":80,"transit_alt":42.9,"transit_local":"06:50","verdict":"poor","weather_source":"history","weekday":"Tue"},{"best_hours":1.92,"best_label":"good","best_window":"03:45\u201305:40","dark_hours":8.78,"date":"2026-09-23","moon_free_dark_hours":1.2,"moon_illumination":92,"moon_separation":112.3,"score":47,"score_astronomy":48,"score_weather":99,"transit_alt":42.9,"transit_local":"06:45","verdict":"marginal","weather_source":"history","weekday":"Wed"},{"best_hours":0.17,"best_label":"good","best_window":"03:50\u201304:00","dark_hours":8.84,"date":"2026-09-24","moon_free_dark_hours":0.1,"moon_illumination":96,"moon_separation":101.8,"score":20,"score_astronomy":44,"score_weather":45,"transit_alt":42.9,"transit_local":"06:40","verdict":"poor","weather_source":"history","weekday":"Thu"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":8.89,"date":"2026-09-25","moon_free_dark_hours":0.0,"moon_illumination":99,"moon_separation":90.8,"score":0,"score_astronomy":31,"score_weather":0,"transit_alt":42.9,"transit_local":"06:40","verdict":"unusable","weather_source":"history","weekday":"Fri"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":8.94,"date":"2026-09-26","moon_free_dark_hours":0.0,"moon_illumination":100,"moon_separation":79.6,"score":0,"score_astronomy":25,"score_weather":0,"transit_alt":42.9,"transit_local":"06:35","verdict":"unusable","weather_source":"history","weekday":"Sat"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":8.98,"date":"2026-09-27","moon_free_dark_hours":0.0,"moon_illumination":98,"moon_separation":68.3,"score":9,"score_astronomy":19,"score_weather":50,"transit_alt":42.9,"transit_local":"06:30","verdict":"poor","weather_source":"history","weekday":"Sun"},{"best_hours":0.0,"best_label":null,"best_window":null,"dark_hours":9.03,"date":"2026-09-28","moon_free_dark_hours":0.0,"moon_illumination":94,"moon_separation":57.4,"score":0,"score_astronomy":14,"score_weather":0,"transit_alt":42.9,"transit_local":"06:25","verdict":"unusable","weather_source":"history","weekday":"Mon"}],"note":"score_astronomy for every night; score_weather/score only where a forecast (next 4 days) or ERA5 history exists \u2014 null otherwise","start":"2026-08-30","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"}}